Cheilostome bryozoan diversity from the southwest Atlantic region: is Antarctica really isolated?

Blanca Figuerola

During the Cenozoic, the break-up of Gondwana was accompanied by a gradual separation of its components and the subsequent establishment of the Antarctic Circumpolar Current, leading to a relative thermal and biogeographic isolation of the Antarctic fauna. However, the zoogeographical affinities of several taxa from South America and Antarctica have been subject to debate, bringing into question the extent of Antarctic isolation. Here we present new data on bryozoan species and their spatial distribution in the Argentine Patagonian (AP) region, as well as an analysis of the bryozoological similarities between deep ranges from Argentina and neighbouring regions. A total of 108 species of cheilostome bryozoans (378 samples), belonging to 59 genera was found. Five new genera and 36 new species were found in the AP region, while 71 species were reported for the first time from Argentina. The bathymetric ranges of 94 species (87 %) were expanded and a high proportion of the identified species (44.4 %) also had an Antarctic distribution. The bryozoological affinities found in the current study between the nearest geographical neighbours are in agreement with the hypothesis of the sequential separation of Gondwana during the Cenozoic. Moreover, a high number of shared species, mainly from the slope, were found in this study between the AP region and Antarctica, thus supporting the idea that the Southern Ocean may have been less isolated over geological time than once thought.

Journal of Sea Research 85 (2014) 1–17 Contents lists available at ScienceDirect Journal of Sea Research journal homepage: www.elsevier.com/locate/seares Cheilostome bryozoan diversity from the southwest Atlantic region: Is Antarctica really isolated? Blanca Figuerola a,⁎, Dennis P. Gordon b, Virginia Polonio c, Javier Cristobo c, Conxita Avila a a b c Animal Biology Department (Invertebrates) and Biodiversity Research Institute (IrBIO), Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028 Barcelona, Catalunya Spain National Institute of Water and Atmospheric Research, Private Bag 14901, Kilbirnie, Wellington 6021, New Zealand Oceanographic Centre of Gijón, Spanish Institute of Oceanography (IEO), Av. Príncipe de Asturias, 70 bis, 33212, Gijón, Asturias, Spain a r t i c l e i n f o Article history: Received 14 May 2013 Received in revised form 1 September 2013 Accepted 12 September 2013 Available online 20 September 2013 Keywords: Antarctic Polar Front Falkland/Malvinas Current Spatial Patterns Species Richness Zoogeography Marine Invertebrates a b s t r a c t During the Cenozoic, the break-up of Gondwana was accompanied by a gradual separation of its components and the subsequent establishment of the Antarctic Circumpolar Current, leading to a relative thermal and biogeographic isolation of the Antarctic fauna. However, the zoogeographical afﬁnities of several taxa from South America and Antarctica have been subject to debate, bringing into question the extent of Antarctic isolation. Here we present new data on bryozoan species and their spatial distribution in the Argentine Patagonian (AP) region, as well as an analysis of the bryozoological similarities between deep ranges from Argentina and neighboring regions. A total of 108 species of cheilostome bryozoans (378 samples), belonging to 59 genera was found. Five new genera and 36 new species were found in the AP region, while 71 species were reported for the ﬁrst time from Argentina. The bathymetric ranges of 94 species (87%) were expanded and a high proportion of the identiﬁed species (44.4%) also had an Antarctic distribution. The bryozoological afﬁnities found in the current study between the nearest geographical neighbors are in agreement with the hypothesis of the sequential separation of Gondwana during the Cenozoic. Moreover, a high number of shared species, mainly from the slope, were found in this study between the AP region and Antarctica, thus supporting the idea that the Southern Ocean may have been less isolated over geological time than once thought. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The Patagonian continental shelf and slope, one of the most productive Large Marine Ecosystems (LMEs) of the Southern Hemisphere, extends for about 5649 km along the Atlantic coast of South America (Acha et al., 2004; Miloslavich et al., 2011). There, two major winddriven currents coexist: the cold nutrient-rich Falkland/Malvinas and the warm Brazil currents. The Malvinas Current is a branch of the ACC (Antarctic Circumpolar Current), ﬂowing northward along the continental shelf of Argentina to about latitude 30° to 40° S, where it is deﬂected eastward after meeting the warm southward-ﬂowing Brazil Current (Legeckis and Gordon, 1982). At the conﬂuence of these currents, there is high biological production on the continental shelf and slope, promoting elevated biomass of benthic invertebrates (Acha et al., 2004). Thus, this region is inhabited by particular species with a wide range of distributions and adaptations to ﬂuctuating conditions resulting from the inﬂuence of these subtropical and subantarctic waters (Miloslavich et al., 2011). In recent years, several exotic species have been recorded in the Patagonian region, making it increasingly difﬁcult to establish the original ⁎ Corresponding author. Tel.: +34934020161. E-mail address: bﬁguerola@gmail.com (B. Figuerola). 1385-1101/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.seares.2013.09.003 composition of coastal communities, considering that the biodiversity of the southwestern Atlantic is poorly known (Orensanz et al., 2002). Since the mid-1700s, the number of new species from South America has increased exponentially and particularly high numbers have been found in Argentina, although marine-invertebrate diversity has not been well studied and even less so in the deep-sea. In particular, the best-known benthic invertebrates in this region are molluscs, echinoderms and cnidarians (Miloslavich et al., 2011). In contrast, considering the high bryozoan diversity found with little sampling effort in different areas of the coast, shelf and slope, bryozoan species richness, mainly in northern shelf areas, is still largely underestimated (López Gappa, 2000; Moyano, 1999). Thus, more studies are needed for this region, mainly at slope and abyssal depths, to evaluate the connectivity of bryozoan populations between the Southern Ocean and South America (Arntz et al., 2005; Barnes and De Grave, 2001; Figuerola et al., 2012; Hastings, 1943; Moyano, 1982, 1999). In fact, the assessment of biodiversity and biogeography is of particular importance in the conservation and sustainable management of species, especially in Antarctica (Brandt et al., 2004). From this perspective, studies of comparative diversity in the deep sea between Antarctica and the last separated fragments of Gondwana are key to understanding the evolution of regional communities and their relationships with the fauna outside the Polar Front (Clarke, 2008; Clarke et al., 2005a). Therefore, the abundance and 2 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 richness of bryozoans, mainly cheilostomes, on temperate and polar continental shelves of the Southern Hemisphere, linked to their strong fossil record, makes them an ideal taxon for the reconstruction of the paleozoogeographical history of the fragmentation of Gondwana (Barnes and Grifﬁths, 2008). During the Cenozoic, the break-up of Gondwana, the ancient supercontinent comprising most of the landmasses in today's southern hemisphere, was produced as a sequential separation of their fragments. Before the Antarctic–South American separation, Australia drifted apart from Antarctica. The last shelf links between them were lost, leading to the creation of a seaway, the Hoces Sea (Drake Passage), the subsequent establishment of the clockwise ACC about 25 Ma ago, and a gradual cooling (Lawver and Gahagan, 2003; Upchurch, 2008). Therefore, the last separated fragments of Gondwana included in particular South America, as well as continental shelves and islands of the Subantarctic Region, located in the Southern Ocean, between the PT and the Subtropical Convergence (between 35° and 45°S), which served as stepping-stones for the dispersion of shallow fauna. In particular, the Subantarctic Region comprises southern Chile, Patagonia, and New Zealand. All of these historical events led to relative thermal and biogeographic isolation of the Antarctic fauna, and thus, to high Antarctic endemism (Arntz et al., 1997; Lawver and Gahagan, 2003; Scher and Martin, 2006). In fact, the ACC is the unique global link connecting all major oceans (Atlantic, Paciﬁc, and Indian), being the largest oceanic current system on Earth and promoting the dispersal of marine organisms such as larvae or adults from west to east around Antarctica (Olbers et al., 2004; Orsi et al., 1995). In contrast, the Antarctic Polar Front (PT), one of several strong fronts within the ACC, is considered a strong hydrographic barrier to free north–south dispersal of shallow benthic fauna. Therefore, the close zoogeographical links between South America and west Antarctica (particularly the Antarctic Peninsula and the Scotia Arc), and less with New Zealand and Australia, may be explained by their associations during the Cenozoic and by faunal exchange through ACC circulation (Brandt et al., 2007a; Clarke, 2003; Clarke et al., 2005; Crame, 1999; Downey et al., 2012; Moyano, 1999, 2005; Zinsmeister, 1982). However, the zoogeographical afﬁnities between South America and Antarctica of diverse taxonomic groups such as bryozoans have been subject to debate in the literature, bringing into question the extent of Antarctic isolation (e.g. Arntz et al., 2005; Barnes and De Grave, 2001; Figuerola et al., 2012; Grifﬁths et al., 2009; Moyano, 1982, 1999). In this sense, all the main deep-sea regions are directly connected below 3000 m, and as a result the PT appears to be less of a barrier to the natural north–south migration (Brandt et al., 2007a; Clarke et al., 2005). Moreover, the Scotia Arc archipelago proposed by some authors as the only physical link between these two regions, being a potential bryozoan exchange pathway, apart from deep abyssal plains (e.g. Barnes, 2005; Moyano, 1999, 2005). Other potential dispersal pathways are the Malvinas Current, a branch of the ACC ﬂowing northwards below 800–1000 m (Hastings, 1943; Legeckis and Gordon, 1982), and eddies of the ACC (Clarke et al., 2005), suggesting the existence of a potential permeability of the PF (e.g. Thatje and Fuentes, 2003; Thatje et al., 2005a). On the other hand, human dispersal mechanisms have increased faunal exchange and the introduction of new species to Antarctica, by marine debris, ballast water or biofouling of ships' hulls (Barnes, 2002; Lewis et al., 2003; Thatje et al., 2005a). In this study, we present new data on species richness and the spatial patterns of bryozoans from the southwestern Atlantic (Argentine Patagonian (AP) region). We also investigate whether our data agree with the biogeographic regions proposed previously by others, and whether Antarctic isolation exists for cheilostome bryozoans. To accomplish this, we analyse bryozoans, one of the best-studied Antarctic taxa, comparing our data with the nearest geographic neighbors from South American, South African, Australian, New Zealand, Subantarctic and Antarctic regions, given the historic links between these regions during the Cenozoic. 2. Material and methods Samples from Patagonia were collected during ﬁve cruises (Patagonia 0108, 0209, 0210, 1108 and 1208) of the “ATLANTIS” project carried out by the Instituto Español de Oceanografía, on board the R/V Miguel Oliver. A total of 51 stations were surveyed (2008–2010). Depths of collections ranged from 140 to 1897.67 m, and sampling was done by using rock dredges. Sampling sites were georeferenced by GPS and depth was registered at each station (Fig. 1; Table 1). 2.1. Species identiﬁcation and literature data Once on board, the colonies of bryozoans were preserved in 70% ethanol for taxonomic identiﬁcation using the existing literature: d'Orbigny (1842), Busk (1884), Waters (1904), Hastings (1943), López Gappa (1982), Gordon (1984, 1986, 1989), López Gappa and Lichtschein (1990), Hayward (1995), López de la Cuadra and García-Gómez (2000), Branch and Hayward (2005), Hayward and Winston (2011) and Ramalho et al. (2011). Some literature data regarding bathymetric ranges and biogeographic distribution of the studied species were obtained from Busk (1884), Hastings (1943), López Gappa (1982, 2000), López Gappa and Lichtschein (1990), Branch and Hayward (2005), Hayward and Winston (2011) and Ramalho et al. (2011), as well as from the SCAR's Marine Biodiversity Information database (SCARMarBIN; http://www.scarmarbin.be/) and the Global Biodiversity Information Facility database (GBIF; www.gbif.org); (Table 2; Appendix B). 2.2. Statistics Relative abundance (N), relative species richness (S, number of species present) and three diversity indices (Margalef, Shannon-Wiener and Simpson's) were calculated for each slope region and latitude sampled in the AP region, in order to provide new information about community composition of cheilostome bryozoans (Table 3). The Margalef (DMG) index is based on the number of species (species richness), while the others are indices of proportional abundances of species. The Shannon-Wiener (H′) index is strongly inﬂuenced by the occurrence of rare species and Simpson's (1 − Lambda′) index by the importance of the most dominant species. An expected species accumulation curve was also computed, and Chao1 and Jacknife1 methods were used to estimate the theoretical number of expected species in this region. With the purpose of knowing if a relationship exists between the number of bryozoan species and the depth or latitude from the AP region, non-parametric correlations were calculated (Kendall's tau; Sokal and Rohlf, 1981). In order to better represent the spatial patterns of bryozoan communities from the entire Argentine region along depth ranges and compared to other neighboring regions, our new data from Patagonia were analysed together with previous data on depth ranges and biogeographic regions from Argentina (Fig. 2). Presence/absence data were used to perform similarity matrices using the Bray–Curtis similarity index. Bray–Curtis index was chosen, as one of the most widely employed indices, being equivalent to the Sörensen index for presence– absence matrices (Clarke et al., 2006; Legendre and Legendre, 2012). The resulting similarity matrices were analyzed by cluster analysis (single-linkage clustering method) and multi-dimensional scaling (MDS). The cluster was then plotted to evaluate the similarities in species composition between the different regions. The MDS analysis was used to evaluate the similarities between ranges of depth for the species because it assumes no shape between variables (Legendre and Legendre, 2012). In order to categorize the continuous variable depth and to represent it in the MDS analysis, it was divided into 100 m interval categories (e.g. 100 m category includes depths of 0–100 m). The ﬁrst two dimensions were plotted and the distance between dots B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 3 Fig. 1. Map of the sampling stations from AP shelf and slope. denotes their similarity measured by the stress value. A stress value of less than 0.1 indicates that the plot accurately represents similarities, while a stress value greater than 0.3 indicates that the points are close to being randomly placed (Clarke, 1993). Bathymetric ranges and biogeographic regions for each species found in the current study and species from Argentina are detailed in Table 1 and Appendix B, respectively. In order to verify that the deﬁned groups were statistically supported, we performed an analysis of similarity (ANOSIM), Global R statistic, which does not require normal distributional data. The ANOSIM randomization test compares within- and between-group similarity of elements measured by the Bray–Curtis index and calculates a global R statitistic. The resulting R-value ranges between 0 and 1, with high values indicating a large degree of discrimination among groups (Clarke and Green, 1988). To identify the taxa that better explain the differences between the various depth zones, SIMPER analyses were carried out using Bray–Curtis similarity matrices (Appendix A). Low contributions were set at 60%. All statistic analyses were performed using Vegan software (R version 2.15.2). 3. Results A total of 108 species of cheilostome bryozoans (378 samples), belonging to 34 families and 59 genera, were found at depths between 138.33 and 1897.67 m within an area of the southwestern Atlantic between 42° and 47° S, and between 57° and 60° W (Tables 1 and 2; Fig. 1). The list of identiﬁed samples includes 5 new genera and 36 new species which will be described in further studies. Also, we found a new, second species of the genus Membranicellaria and a new, fourth species of the genus Malakosaria, as well as the second record in this region for seven other species. Furthermore, a total of 71 out of 108 species (65.7%) were reported for the ﬁrst time for Argentina. Therefore, an expansion of their known geographical distribution is reported here as well (Table 2). Remarkably, a high percentage of the identiﬁed species (48 of 108, 44.4%) had been reported to have an Antarctic distribution previously, while only two species found here were reported to be endemic to Argentina (Table 2). The most common family was Smittinidae with 57 samples (15%), followed by Phidoloporidae (42 samples, 11.1%), Aspidostomatidae 4 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 Table 1 Depth and coordinates of the sampling stations. Ref. Station Date Latitude (S) Longitude (W) Depth (m) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 PAT0210DR04 PAT0210DR06 PAT0210DR05 PAT0210DR07 PAT0210DR09 PAT0210DR08 PAT0210DR11 PAT0209DR15 PAT0209DR14 PAT0209DR13 PAT0209DR16 PAT0209DR12 PAT0209DR01 PAT0209DR11 PAT0209DR10 PAT0209DR08 PAT0209DR05 PAT0209DR06 PAT0209DR02 PAT0209DR07 PAT0209DR04 PAT0209DR03 PAT1108DR11 PAT1108DR01 PAT1108DR02 PAT0209DR09 PAT1108DR09 PAT1108DR10 PAT1108DR10R PAT1208DR05 PAT1208DR07 PAT1208DR03 PAT1208DR04 PAT1208DR09 PAT1208DR16 PAT1208DR14 PAT1208DR11 PAT0108DR14 PAT1208DR06 PAT1208DR17 PAT1208DR15 PAT1208DR01 PAT1208DR12 PAT1208DR13 PAT1108DR08 PAT1108DR03 PAT1108DR07 PAT1108DR04 PAT1208DR10 PAT1208DR02 PAT1108DR05 20/02/10 23/02/10 21/02/10 25/02/10 27/02/10 26/02/10 28/02/10 20/02/09 19/02/09 19/02/09 20/02/09 18/02/09 07/02/09 17/02/09 16/02/09 14/02/09 11/02/09 12/02/09 08/02/09 13/02/09 10/02/09 09/02/09 26/11/08 16/11/08 17/11/08 15/02/09 24/11/08 25/11/08 25/11/08 06/12/08 08/12/08 04/12/08 5/12/200 10/12/08 15/12/08 13/12/08 11/12/08 25/01/08 07/12/08 16/12/08 14/12/08 03/12/08 12/12/08 13/12/08 13/11/08 18/11/08 21/11/08 19/11/08 11/12/08 02/12/08 06/12/08 41° 35′ 34.8″ 42° 0′ 43.92″ 42° 0′ 5.76″ 42° 16′ 51.96″ 42° 4′ 8.76″ 42° 6′ 55.08″ 42° 7′ 15.6″ 43° 17′ 5.78″ 43° 19′ 45.76″ 43° 20′ 46.93″ 43° 3′ 58.75″ 43° 40′ 33.52″ 43° 55′ 0.86″ 43° 58′ 52.70″ 44° 10′ 3.55″ 44° 19′ 8.65″ 44° 39′ 19.74″ 44° 42′ 2.81″ 44° 43′ 54.78″ 44° 44′ 35.55″ 44° 45′ 4.05″ 44° 46′ 7.74″ 44° 52′ 19.38″ 44° 53′ 23.23″ 44° 54′ 30.42″ 44° 8′ 23.63″ 45° 11′ 25.59″ 45° 35′ 53.84″ 45° 36′ 20.99″ 45° 39′ 17.40″ 45° 40′ 56.46″ 45° 49′ 34.20″ 45° 49′ 37.08″ 45° 51′ 20.10″ 45° 51′ 40.079″ 45° 57′ 51.00″ 45° 58′ 29.94″ 45° 8′ 5.72″ 46° 1′ 37.51″ 46° 13′ 2.10″ 46° 14′ 24.95″ 46° 15′ 33.36″ 46° 23′ 54.90″ 46° 24′ 46.14″ 46° 33′ 38.33″ 46° 38′ 22.62″ 46° 38′ 40.53″ 46° 57′ 43.19″ 46° 6′ 54.60″ 46° 8′ 43.32″ 47° 16′ 26.17″ 57° 34′ 54.12″ 57° 34′ 7.32″ 57° 33′ 16.92″ 58° 11′ 11.04″ 57° 26′ 29.76″ 57° 29′ 55.68″ 57° 27′ 58.68″ 59° 0′ 3.25″ 58° 56′ 24.15″ 58° 54′ 37.43″ 58° 44′ 37.50″ 59° 6′ 5.87″ 59° 18′ 3.75″ 59° 17′ 25.8″ 59° 10′ 58.66″ 59° 22′ 22.08″ 59° 45′ 21.27″ 59° 13′ 54.36″ 59° 36′ 28.43″ 59° 19′ 17.45″ 59° 16′ 0.49″ 59° 26′ 15.60″ 59° 38′ 7.50″ 60° 1′ 41.63″ 59° 55′ 10.73″ 59° 23′ 0.20″ 59° 47′ 42.16″ 59° 47′ 23.25″ 59° 46′ 24.24″ 59° 39′ 52.14″ 59° 55′ 39″ 59° 47′ 54.26″ 59° 47′ 59.28″ 59° 41′ 19.62″ 59° 57′ 4.5″ 59° 47′ 53.28″ 59° 37′ 9.72″ 59° 31′ 47.60″ 59° 56′ 23.81″ 60° 18′ 31.80″ 60° 35′ 7.24″ 60° 42′ 50.82″ 60° 53′ 8.7″ 60° 53′ 49.14″ 60° 48′ 54.11″ 59° 30′ 23.22″ 60° 51′ 57.58″ 59° 21′ 49.08″ 59° 34′ 15.63″ 60° 16′ 43.56″ 59° 10′ 49.90″ 436 485 586 1096 1048 1090 1148 1244 1553 1472 1529 1635 1393 1500 1581 1478 991 1898 1248 1620 1577 1513 1248 650 659 1629 941 1051 1232 1263 839 925 973 1038 761 854 1088 1180 748 157 146 825 138 140 145 1061 148 1242 959 846 1399 (41, 10.8%), Cellariidae (31, 8.2%), Celleporidae (24, 6.3%), Microporellidae (22, 5.8%), Buffonellodidae (19, 5%), Flustridae and Lekythoporidae (16, 4.2%) and Foveolariidae (15, 3.9%). The new species belong to the genera Adeonella, Amastigia, Arachnopusia, Aspericreta, Buffonellodes, Caberea, Cellarinella, Cornucopina, Ellisina, Escharella, Euthyroides, Fenestrulina, Figularia, Himantozoum, Ipsibuffonella, Lageneschara, Malakosaria, Melicerita, Membranicellaria, Microporella, Orthoporidra, Osthimosia, Reteporella, Smittina, Smittinella, Smitoidea and Spigaleos. Smittina and Aspidostoma, with 47 and 41 samples respectively, were the dominant genera. The most abundant species was Aspidostoma giganteum, which represented 10.8% of the total specimens collected, and Smittina rogickae (6.8%). 3.1. Species richness and diversity indices The highest values of species richness and of the three diversity indices were found around latitude 44° S (Table 3; % S = 57; DMG = 11.617, H′ = 3.699 and 1 − Lambda′ = 0.963) with Aspidostoma giganteum, Smittina anecdota and S. rogickae as dominant species. In contrast, the values were low at latitudes 41° and 47° S. In reference to depth, the middle slope had the highest values of species richness and diversity (Table 3; % S = 77.78; DMG = 14.94, H′ = 3.89 and 1 − Lambda′ = 0.964), with A. giganteum as the dominant species. The expected species accumulation curve has still to reach the asymptote (Fig. 6). Species richness estimates (Chao1 and Jack1) indicated that the theoretical number of expected species would be between 162 and 155, respectively. 3.2. Bathymetric distribution The new data from this study were analysed jointly with data from the literature and existing databases, revealing new bathymetric ranges in 94 species (87% of the species found in our study). Columnella magna, Cornucopina pectogemma and Cellaria clavata were the only species found in deeper waters (5340, 3501 and 3442 m, respectively) and showed the widest bathymetric ranges. The majority of species (72.2%) were present at depths between 0 and 1600 m. Of a total of 108 species analysed from the literature and our new data, no species were restricted to the continental shelf (128–200 m as deﬁned by Portela et al., 2012; Fig. 3). The correlations between species number and depth (tau = 0.7914, p = 0.4287; Fig. 4) and latitude (tau = −0.7997, p = 0.4239; Fig. 5) from the AP region were not signiﬁcant. Low MDS stress values (0.03) indicate good representation in the 2-dimensional ordination (Clarke, 1993). Five depth zones were discriminated by the MDS analysis in the bathymetric distribution of the species from Argentina (Fig. 7): (1) a zone between 0 and 200 m with the presence of 125 species, (2) a zone between 200 and 1600 m characterized by the presence of 85 species, (3) a zone between 1600 and 1900 m with the presence of 14 species; (4) a zone between 1900 and 3900 m with the presence of 11 species and (5) a zone between 3900 and 4500 m, with the presence of 6 species. A signiﬁcant difference in species composition between groups was found (ANOSIM Global R = 0.9306, p = 0.001). A high number of species (71, 54, 52 and 53, respectively) accounted for about 60% of the dissimilarity between group 1 and groups 2, 3, 4 and 5 (Appendix A). Twenty-six species contribute the most to these differences between groups 2 and 3, and between 2 and 4, and 27 species to the differences between 2 and 5. Aspidostoma giganteum, Austroﬂustra gerlachi, Smittoidea malleata and Talivittacella problematica contributed most in explaining the differences between groups 3 and 4. In the case of group 3 versus group 5, the differences were mainly explained by Cellaria clavata, Formosocellaria magniﬁca, Smittoidea malleata and Columnella gracilis. The highest contribution in the differences between groups 4 and 5 was due to Cellaria clavata, Formosocellaria magniﬁca, Columnella gracilis and C. magna armata (to know which groups these particular species are associated with, see Appendix A and B) (Table 4). 3.3. Biogeographic distribution Cluster analyses suggested ﬁve principal groups of similar faunal composition between regions (Figs. 2 and 8). The ﬁrst group (1) was represented by the Antarctic and AP regions (this study), with 46 species in common, and subantarctic South Georgia and the Sandwich Islands with 18 shared species. Other South American regions (Argentina, Chile and Falkland Islands), all clustered together (2), and were notably close to the ﬁrst group, sharing 39 species between them. The temperate Australian and New Zealand regions were more dispersed, both forming the same cluster (3), with 17 species in common. Finally, South Africa (4) and the isolated Heard and McDonald Islands (Kerguelen Plateau) (5) were strong outliers, characterized by a lower number of species. The ANOSIM tests showed that these groupings were statistically strong (ANOSIM Global R = 0.992, p = 0.001). B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 5 Table 2 Bathymetric ranges and biogeographic distributions of the species studied using data from the present study, the literature, and the GBIF and SCAR databases (see also www.bryozoa.net and invertebrates.si.edu/antiz). *New bathymetric range described in this study, **First record for Argentina. Localities: AN = Antarctica; AR = Argentina; AT = Atlantic; AU = Australia; B = Brazil; BI = Bouvet Island; CH = Chile; CI = Cook Islands; FI = Falkland Islands (Malvinas); FR = France; G = Greece; H = Hungary; HI/MI = Heard Island and McDonald Islands; M = Morocco; N = Norway; NA = North Atlantic; NZ = New Zealand; SAF = South Africa; SAM = South America; SAT = South Atlantic; SE = Seychelles; SG/SS = South Georgia and the South Sandwich Islands; SH = Saint Helena; SI = South Indian Ocean; SO = Somalia; U = Uruguay. Species Bathymetric range (m) Biogeographic distribution References Adelascopora secunda Hayward and Thorpe, 1988 Adeonella sp. Aimulosia australis Jullien, 1888 Amastigia benemunita (Busk, 1884) Amastigia crassimarginata (Busk, 1884) Amastigia gaussi (Kluge, 1914) Amastigia sp. 1 Amastigia sp. 2 Amphiblestrum familiaris Hayward and Thorpe, 1989 Apiophragma hyalina (Waters, 1904) Arachnopusia sp. Aspericreta favulosa Hayward and Thorpe, 1989 Aspericreta sp. Aspidostoma coronatum (Thornely, 1924) Aspidostoma giganteum (Busk, 1854) Austroﬂustra australis López Gappa, 1982 Austroﬂustra gerlachi López Gappa, 1982 Buffonellodes rimosa Jullien, 1888 Buffonellodes sp. Cabarea darwinii var. guntheri Hastings, 1943 45–1635.33* (previously 903) 485* 18–1500* (previously 250) 50–586.33* (previously 341) 368–990.67* (previously 463) 5–1586 157.67* 145*–146* 40–2032 100–1538 1478.33*–1635.33* 286–1247.67* (previously 1208) 1629* 104–1581.33* (previously 975) 186–1893 140*–1241.67* (previously 272–535) 272–1897.67* (previously 535) 0–846.03* (previously 121) 1241.67*–1620* 336–1096* (previously 463) AN, AR, CH, SG/SS AR** AN, AR, CI, CH, SAT, SG/SS AR, CH, F, SH AR AN, AR**, FI, SG/SS AR** AR** AN, AR** AN, AR** AR** AN, AR** AR** AN, AR**, SG/SS AN, AR, CH, FI, SAT AR, FI, SAT AR, FI, SAT AN, AR**, AT, FI, G, H, H, NZ AR** AR Caberea darwinii Busk, 1884 5–1513* (previously 697) Caberea sp. Camptoplites bicornis var. quadriavicularis Hastings, 1943 Cellaria clavata (Busk, 1884) 761.33* 336–1399* (previously 341) 0–3442 Cellaria malvinensis (Busk, 1852) 0–846.03* (previously 548) Cellarinella dubia Waters, 1904 Cellarinella sp. Chaperiopsis patulosa (Waters, 1904) Chaperiopsis sp. Chartella notialis Hayward and Winston, 1994 Chronocerastes sp. Columnella magna (Busk, 1884) Cornucopina pectogemma (Goldstein, 1882) 0–516 140*–854* 15–838.67* (previously 500) 1472.33*–1635.33* 272–1148.33* (previously 511) 1061.5* 1635.33* 1478.33* 1247.67* 15–1629.00* (previously 1162) 18–1528.67* (previously 579) 93–1620* (previously 522) 132–1528.67* (previously 1150) 990.67* 1148.33*–1635.33* 384–987 145–1629* (previously 297) 177–761.33* (previously 177) 384–990.67* (previously 494) 40–511 1399* 212–1472.33* (previously 231) AN, AR, AU, B, CH, FI, HI/MI, N, NZ, SAF, SG/SS, SH AR** AR, SAT AN, AR, FR, CH, FI, HI/MI, SAT, SG/SS, SI AN, AR, CH, FI, M, NZ, SAF, SAT, SG/SS, SI AN, AR, AU, CH, FI AR** AN, AR, FI AR** AN, AR AR** AN, AR, NZ, SAF, SE, SG/SS, SO AN, AR**, NA, NZ, SAF, SAT, SG/SS, SH, SI AR** AR** AR** AR** AN, AR**, SG/SS AN, AR** AN, AR** AN, AR, FI, SG/SS AR** AR** AR, AU, CH, NZ AR, FI AN, AR**, HI/MI, SG/SS AN, AR** AN, AR, FI, SAT AR** AR**, SAT, SG/SS GBIF and SCAR databases This study López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases This study This study GBIF and SCAR databases GBIF and SCAR databases This study GBIF and SCAR databases This study GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases This study López Gappa (2000); Hastings (1943); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases This study This study This study This study GBIF and SCAR databases GBIF and SCAR databases GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases This study This study López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases GBIF and SCAR databases Hayward and Winston (2011) López Gappa (2000); GBIF and SCAR databases This study GBIF and SCAR databases 145*–297 (previously 272) 1513*–1629* 73–854* (previously 73) 124–1513* (previously 128) 973.33* 1051.33*–1247.67* 74–1247.67* (previously 621) 145*–1577* 1263*–1577* 59–825.17* (previously 697) 5–1577* (previously 1162) 119–825.17* (previously 124) 49*–903* 990.67*–1581.33* AR, FI, U AR** AN, AR, FI, SAM AN, AR** AR** AR** AN, AR, FI, SAT AR** AR** AN, AR, FI, SAF, SAT, SI AN, AR, CH, FI, SAF, AN, SG/SS AN, AR** AR, AT, CH, FI, NZ, SG/SS AR** López Gappa (2000); GBIF and SCAR databases This study López Gappa (2000); GBIF and SCAR databases Hayward and Winston (2011) This study This study López Gappa (2000); GBIF and SCAR databases This study This study López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases Hayward and Winston (2011) López Gappa (2000); GBIF and SCAR databases This study Cornucopina sp. Ellisina sp. Escharella sp. Euthyroides sp. Exochella hymanae (Rogick, 1956) Fenestrulina antarctica Hayward and Thorpe, 1990 Fenestrulina crystallina Hayward and Winston, 2011 Fenestrulina fritilla Hayward and Ryland, 1990 Fenestrulina sp. Figularia sp. Foveolaria elliptica Busk, 1884 Foveolaria terriﬁca (Hincks, 1881) Galeopsis bullatus Hayward, 1993 Gigantopora spathula Hayward and Winston, 2011 Himantozoum obtusum Hastings, 1943 Himantozoum sp. Hippomonavella ramosae López de la Cuadra and García-Gómez, 2000 Ichthyaria oculata Busk, 1884 Ipsibuffonella sp. Jolietina latimarginata (Busk, 1884) Lageneschara peristomata Hayward and Winston, 2011 Lageneschara sp. Malakosaria sp. Melicerita blancoae López Gappa, 1981 Melicerita sp. Membranicellaria sp. Menipea ﬂagellifera Busk, 1884 Micropora brevissima Waters, 1904 Microporella crustula Hayward and Winston, 2011 Microporella hyadesi (Jullien, 1888) Microporella sp. 748*–−5340 (previously 890) 80–3501 This study López Gappa (2000); GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases This study López Gappa (2000); GBIF and SCAR databases This study GBIF and SCAR databases This study López Gappa (2000); GBIF and SCAR databases GBIF and SCAR databases (continued on next page) 6 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 Table 2 (continued) Species Bathymetric range (m) Biogeographic distribution References Notoplites antarcticus Waters, 1904 Ogivalia elegans (d'Orbigny, 1842) Ogivalia sagittirostra Hayward and Winston, 1994 Orthoporidra brachyrhyncha Moyano, 1985 Orthoporidra compacta (Waters, 1904) Orthoporidra stenorhyncha Moyano, 1985 Osthimosia sp. Osthimosia bicornis (Busk, 1881) 104–990.67* (previously 634) 73–1244.33* (previously 866) 384–973.33* (previously 494) 104–1635.33* (previously 975) 5–2010 120–1289 138.33* 0–2000 GBIF and SCAR databases López Gappa (2000); GBIF and SCAR databases GBIF and SCAR databases GBIF and SCAR databases GBIF and SCAR databases GBIF and SCAR databases This study López Gappa (2000); GBIF and SCAR databases Osthimosia clavata Waters, 1904 Osthimosia malingae Hayward, 1992 Osthimosia notialis Hayward, 1992 Paracellaria elephantina Hayward and Thorpe, 1989 Paracellaria elizabethae Branch and Hayward, 2005 Parasmittina dubitata Hayward, 1980 Reteporella antennata Ramalho et al., 2011 Reteporella gigantea (Busk, 1884) Reteporella longichila Hayward, 1993 Reteporella magellensis (Busk, 1884) Reteporella sp. 1 Reteporella sp. 2 Reteporella sp. 3 Reteporella sp. 4 Reteporella sp. 5 Reteporella sp. 6 Reteporella sulcula Hayward and Winston, 2011 Reteporella tortuosa Hayward and Winston, 2011 Smittina anecdota Hayward and Thorpe, 1990 Smittina rogickae Hayward and Taylor, 1984 Smittina sp. 1 Smittina sp. 2 Smittinella sp. Canu and Bassler, in Bassler, 1934 Smittoidea malleata Hayward and Thorpe, 1989 Smittoidea sp. 1 Smittoidea sp. 2 Spigaleos sp. 1 Spigaleos sp. 2 Talivittaticella frigida (Waters, 1904) 15–1629* (previously 1414) 61–761.33* (previously 247) 18–846.03* (previously 622) 485–1478.33* (previously 610) 360–1478.33* (previously 376) 6–1248* (previously 144) 341–485* (previously 341) 360–1513* (previously 914.4) 7–748* (previously 634) 91–1393.33* (previously 1097) 973.33*–1528.67* 990.67*–1577* 1247.67*–1629* 854*–973.33* 854* 973.33*–1393.33* 384–940.67* (previously 494) 384–1472.33* (previously 494) 170–1635.33* (previously 1489) 0–1635.33* (previously 1497) 1513* 1393.33*–1629* 761.33* 73–1897.67* (previously 1150) 1513*–1635.33* 138.33* 748*–1620* 1244.33* 145–1577* (previously 600) AN, AR** AR, CH, FI, SAT AN, AR, CH, FI, SG/SS AN, AR AN, AR**, NZ, SG/SS AN, AR** AR** AN, AR, BI, CH, FI, HI/MI, NZ, SAF, SG/SS AN, AR AN, AR**, SAT AN, AR, SAT, SG/SS AN, AR**, SAT AR**, SAF AR, CH, FI, SAT AR**, B SAF AN, AR** AR, FI, SAT AR** AR** AR** AR** AR** AR** AN, AR** AN, AR** AN, AR**, HI/MI AN, AR** AR** AR** AR** AN, AR** AR** AR** AR** AR** AN, AR, SAF Turritigera cribrata Hayward, 1993 New genus 1 New genus 2 New genus 3 New genus 4 New genus 5 73–1581.33* (previously 628) 1399*–1629* 1472.33* 1096*–1553* 1577* 1635.33* AN, AR**, AU, SG/SS AR** AR** AR** AR** AR** 4. Discussion Cheilostome bryozoans from the AP continental shelf and slope exhibit a high range of eurybathy with new bathymetric ranges in 94 species (87% of the studied species). Remarkably, 43 bryozoan species have been recorded here deeper than 1000 m, the most eurybathic species being Columnella magna, with a depth range of 748–5340 m. Thus, an expansion in the known geographic distribution of most species has been reported here. In agreement with this, few bryozoan species have been reported deeper than the shelf break and most samples come from less than 500 m (López Gappa, 2000). Considering that 44.4% of the bryozoan species found here were also previously reported in Antarctica, the bathymetric ranges determined by our study are in agreement with other studies establishing wide depth ranges for most Antarctic cheilostome bryozoans (Barnes and Kuklinski, 2010; Figuerola et al., 2012). Moreover, recent studies reported a lower proportion of Antarctic cheilostome bryozoan species to be endemic, supporting the idea that the Southern Ocean may have been less isolated over geological time than once thought (56%, Barnes and Grifﬁths, 2008; 55%, Figuerola et al., 2012). The low endemicity and wide eurybathy of bryozan species found in this study also demonstrate their capacity to live in regions with a wide range of conditions (e.g. temperature and salinity), as Barnes and Grifﬁths (2008) suggested. High diversity was found in the AP region, with 28% of the analysed samples (378) belonging to different species, including several new GBIF and SCAR databases GBIF and SCAR databases GBIF and SCAR databases GBIF and SCAR databases Branch and Hayward (2005) López Gappa (2000); GBIF and SCAR databases Ramalho et al. (2011) Branch and Hayward (2005); Busk (1884) GBIF and SCAR databases Hayward and Winston (2011) This study This study This study This study This study This study Hayward and Winston (2011) Hayward and Winston (2011) GBIF and SCAR databases GBIF and SCAR databases This study This study This study GBIF and SCAR databases This study This study This study This study Branch and Hayward (2005); López Gappa (2000) GBIF and SCAR databases This study This study This study This study This study genera and new species of the genus Membranicellaria. The highest values of percentage relative species richness (% S = 57) and of the three diversity indices (DMG = 11.617, H′ = 3.699 and 1 − Lambda′ = 0.963) were found at about 44° latitude. These values are in good agreement with the large biological production found on the continental shelf and slope at latitudes 30° to 46° S, which clearly allows for the establishment of diverse benthic invertebrate assemblages. This high diversity is probably related to the existence of the conﬂuence of two major wind-driven currents, the subantarctic nutrient-rich Falkland/ Malvinas and the subtropical Brazil currents (Acha et al., 2004; López Gappa and Lichtschein, 1990; Miloslavich et al., 2011). Furthermore, the richest stations from Patagonia occurred on the middle slope (% S = 77.78; DMG = 14.94, H′ = 3.89 and 1 − Lambda′ = 0.964), coinciding with the zone of the Falkland/Malvinas Current (below 800–1000 m), where there is upwelling of nutrient-rich waters and associated plankton blooms (Muñoz et al., 2012). Similarly to our results, a high density of cold-water corals with associated fauna was found on the AP continental slope (Muñoz et al., 2012). Cold-water coral ecosystems, with their complex three-dimensional habitat structures, are among the richest biodiversity hotspots in the deep sea, providing food and a multitude of microniches, shelter and nursery areas for a number of associated species, including bryozoans (Van den Hove and Moreau, 2007). However, the interpretation of these results must be treated with some caution because of the scarce sampling effort in the middle slope. B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 7 Table 3 Species distribution and latitude. Number of sampling stations, dominant species found in the sample, total number of individuals found (no. ind), percentage of relative species richness (% S), Margalef index (DMg), Shannon–Wiener diversity index, H′ (base loge) and Simpson's Index (1 − Lambda′) for each latitude zone. Latitude (S) no. stations Dominant species 41° 1 42° 43° 44° 45° 46° 47° 6 7 12 12 12 1 A. coronatum, C. notialis, F. terriﬁca, M. blancoae, O. brachyrhyncha A. secunda, A. giganteum, C. clavata A. giganteum, S. anecdota, S. rogickae A. giganteum, S. anecdota, S. rogickae A. giganteum, Spigaleos sp. A. vulgaris, C. clavata A. giganteum Remarkably, 65.7% of the species analysed were here reported for the ﬁrst time in Argentina, demonstrating that this region has been poorly explored so far (Hastings, 1943; López Gappa, 2000; López Gappa and Lichtschein, 1990). Indeed, the expected species-accumulation curve showed no sign of approaching an asymptote. One hundred and eight species have been found to date, but the species richness statistics (Chao1 and Jack1) predict that between 162 and 155 species will be found in this region as more samples are collected. To the best of our knowledge, the existence of horizontal and vertical variability in bryozoan communities found in the current study provides new information on the structure of these communities in Argentina. MDS analysis shows that bryozoans are distributed in zones or depth bands. The AP continental shelf generally goes down to 100 m depth (128–200 m; Portela et al., 2012), while the upper slope descends to depths from 128–200 m to 250–750 m and the mid-continental slope from 250–750 to about 1600 m (Muñoz et al., 2012). The bryozoan No. ind %S H′ 1 − Lambda′ 5 5 2.485 1.609 0.8 28 72 124 71 71 7 20 36 57 38 37 6 5.701 8.183 11.617 8.679 8.445 2.569 2.88 3.353 3.699 3.39 3.379 1.747 0.936 0.956 0.963 0.955 0.957 0.816 DMG distribution found in the current study ﬁts quite well with these proposed limits: the species composition of the continental shelf (0–200 m) differs from that of the middle continental slope (200–1600 m), the lower slope (1600–4000 m) and deep water (4000–4500 m). Moreover, MDS discriminates two regions in the lower slope (1600–3900 m and 3900–4000 m). These differences in species composition could be explained by the presence of a variable habitat of the slope characterized by both depositional and erosive elements (e.g. terraces, moats and channels), which progressively connect the continental shelf with the abyssal plain between 43° and 49° S (Hernández-Molina et al., 2010; Muñoz et al., 2012). SIMPER analyses showed that the differences in species' composition between the continental shelf, upper, middle and lower slope regions were explained by a large number of bryozoan species, suggesting that the structure of the bryozoan communities was diverse and complex. In contrast, few species contribute most to explaining the differences in communities Fig. 2. General map of neighboring regions of Antarctica. 8 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 Fig. 3. New bathymetric ranges of the bryozoan species found in the present study, including our own data, the literature and the GBIF and SCAR databases. between slope and deep waters. This fact may be related to the general bathymetric trend of a decrease in species numbers with increasing depth towards the abyssal basins, which can be related to the decreasing availability of food (e.g. Linse et al., 2007). However, the bryozoan species richness value is still largely underestimated in the deeper waters of this region, as discussed above. Cluster analyses of regional bryozoan species composition support the hypothesis of the sequential separation of Gondwana during the Cenozoic. The Antarctic and AP regions in the current study were clustered together, with 46 species in common, suggesting closer faunal afﬁnities. The regions of Argentina, Chile and the Falkland Islands, with strong geographical links, were notably clustered closer to the ﬁrst group, while subantarctic South Georgia and the Sandwich Islands occupied an intermediate position between Antarctica and South America. Our results are in agreement with previous studies reporting the occurrence of several shared marine species between Antarctica and South America was reported in other studies (e.g. Arntz et al., 2005; Barnes and De Grave, 2001; Barnes and Grifﬁths, 2008; Figuerola et al., 2012; Moyano, 1982, 1999; Ramos-Esplá et al., 2005). Interestingly, some authors suggested a strong similarity between these two regions for molluscs, ascidians and bryozoans (Grifﬁths et al., 2009; Linse, 2002; Primo and Vázquez, 2007). Thus, these similar compositions could be related to the fact that these were the last fragments drifting apart during the break-up of Gondwana (Clarke, 2003; Clarke et al., 2005; Lawver and Gahagan, 2003; Upchurch, 2008). On the other hand, dispersal mechanisms play an essential role in the distributional patterns (Downey et al., 2012). In fact, marine organisms can freely migrate in and out of the Polar Front via the deep abyssal plains (above approximately 3000 m), where the Southern Ocean is connected to the other oceans. A strong deep-sea faunal exchange exists, but it requires some degree of eurybathy in potentially colonizing species (Brandt et al., 2007a). In this sense, most bryozoan species in the current study came from depths over 900 m and are eurybathic. Thus, the dispersal pathway could partly explain the high percentage of Antarctic Fig. 4. Number of bryozoan species from the AP region for each depth range. The correlation between species number and depth (tau = 0.7914, p = 0.4287) from the AP region was not signiﬁcant. Fig. 5. Number of bryozoan species from the AP region at different latitudes. The correlation between species number and latitude (tau = −0.7997, p = 0.4239) from the AP region was not signiﬁcant. B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 9 Table 4 Species distribution and depth. Number of sampled stations, dominant species found in the sample, total number of individuals found (No. ind), Margalef index (DMg), Shannon–Wiener diversity index, H′ (base loge) and Simpson's Index (1 − Lambda′) at different depth ranges. Depth range Continental shelf (0–200) Upper slope (200–800) Middle slope (800–1600) Lower slope (1600–1900) Fig. 6. Expected species accumulation curve (black solid line) with 95% conﬁdence interval (gray area) based on data from 51 stations for bryozoans from the AP region. bryozoan species found in the AP region. Supporting this, some authors have suggested that migrations of the Antarctic fauna to South America via the deep ocean occur during glacial maxima, in relation to extinction avoidance, when the continental ice sheets extend to the edge of the continental shelf in many Antarctic areas (e.g. Brandt et al., 2007a; Clarke, 2008; Thatje et al., 2005b). This fact could help to understand some bryozoogeographical links found in this study between neighboring regions. However, we have to keep in mind that nearly all bryozoans possess low larval-dispersal potential (most cheilostomes release lecithotrophic larvae of short pelagic duration), unlike other taxa, and only highly dispersive taxa usually show strong links to other oceans (Barnes and Grifﬁths, 2008; Brandt et al., 2007b). In any case, currents can distribute lecithotrophic larvae at considerable distances (Brandt et al., 2007a). On the other hand, bryozoans can use diverse potential dispersal mechanisms, such as fouling on a variety of different ﬂoating substrata including macroalgae (Watts et al., 1998). In fact, bryozoans are commonly effective colonizers of surfaces and are frequently Fig. 7. Multidimensional scaling ordination (MDS) of the different species in relation to depth using data from the present study, the literature and the GBIF and SCAR databases. Points numbered 100–4500 correspond to different depth ranges (stress = 0.03). Group 1: 0–200 m; group 2: 200–1600 m; group 3: 1600–1900 m; group 4: 1900–4000 m and group 5: 4000–4500 m. No. stations Dominant species No. ind %S DMG H′ 1− Lambda′ 6 C. clavata 39 21.3 6.01 2.968 0.939 7 C. clavata, M. blancoae A. giganteum 44 27.78 7.66 3.229 0.95 259 77.78 14.936 3.895 0.964 36 22.22 6.418 3.015 0.941 34 4 A. giganteum, S. rogickae reported as rafters (Key et al., 2012; Thiel and Gutow, 2005). Moreover, the epibiosis of bryozoan colonies on motile marine animals such as crabs, isopods and pycnogonids can improve gamete dispersal and increase their geographic ranges. In particular, a considerable percentage of Antarctic pycnogonids (26% of 115 pycnogonids belonging to 9 species) were reported to be fouled by Antarctic cheilostome bryozoans (Key et al., 2012). Additionally, ten cheilostome bryozoans were found on the abundant giant Antarctic marine isopod Glyptonotus antarcticus, and one of the reported species was Smittina rogickae (Key and Barnes, 1999), frequently found in our study. Furthermore, bryozoans may colonize distant locations via island archipelagos, like those in the Scotia arc, that act as stepping stones. On the other hand, subantarctic South Georgia and the Sandwich Islands (part of the Scotia Arc archipelagos) are the tips of a subsurface mountain chain linking the Andes and the Antarctic Peninsula, and therefore, they are geographically in an intermediate position. Our results are in accordance with this too. Other studies on different taxa also demonstrated that South Georgia and the Sandwich Islands are transitional regions, thus supporting the role of the Scotia Arc archipelagos as physical links between Antarctica and South America (Arntz et al., 2005; Barnes, 2005; Primo and Vázquez, 2007), with, in some cases, a gradient of similarity between Patagonia, the Scotia Arc and the Antarctic Peninsula (e.g. Ramos-Esplá et al., 2005). In agreement with this, the Scotia Arc showed a shelf fauna predominantly Magellanic on the northern branch, whereas on the southern branch it was predominantly Antarctic (e.g. Arntz and Brey, 2003). Brandt et al. (2007a) suggested that wider dispersal is produced by the distribution of water masses in the world oceans. The high percentage of bryozoan species from the AP region with an Antarctic distribution found in the current study may suggest that the PT appears to be less of a barrier for this group, as other authors have also debated (e.g. Brandt et al., 2007a; Clarke et al., 2005). Recent studies also suggest the existence of a potential permeability of the PF, facilitating the explanation of some zoogeographical links and demonstrating that the barriers to biological invasion are primarily physiological rather than geographical (e.g. Thatje and Fuentes, 2003; Thatje et al., 2005a). The presence of some common bryozoan species between these regions may also be in part explained by the potential passive northwards transport of larvae (or perhaps even adults) via the Falkland/Malvinas Current to considerable distances (Brandt et al., 2007a; Hastings, 1943; Legeckis and Gordon, 1982). Thus, the inﬂuence of subantarctic water in low latitudes leads to conditions favorable to the establishment of cold-water organisms in these regions. Other dispersal pathways, like eddies of ACC, may increase the bryozoan connexion found between these regions, transporting bryozoan colonies attached to driftwood and other marine debris (Clarke et al., 2005). On the other hand, the increase of human dispersal mechanisms (e.g. ballast water and marine debris of anthropogenic origin such as ﬂoating plastic) in and out of Antarctica has favored faunal exchange and the introduction of alien species, by-passing oceanographic barriers (Aronson et al., 2007; 10 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 Fig. 8. Dendrogram of the hierarchical clustering (single linkage) of the bryozoan fauna using Bray–Curtis distance. Additional data have been obtained from the literature and from GBIF and SCAR databases. Barnes, 2002; Thatje et al., 2005a). Fouling allows very rapid dispersion over scales from kilometers to global level. Interestingly, many bryozoans are important components of biofouling, able to travel on vessel hulls and human/marine debris (Watts et al., 1998). Accordingly, most of the exotic bryozoans found on the Argentine coast were components of the fouling community restricted to commercial harbors, such as that of Mar del Plata (Orensanz et al., 2002). However, part of the difﬁculty for potential colonizers is the drop in temperature across the PF. In any case, climate change will probably allow the establishing of new taxa in Antarctica, overcoming the current marine barriers. Our study also showed that the Australasian region (New Zealand and Australia) tends to cluster separately, supporting the idea that this region was separated long before the Antarctic–South American separation. Finally, the regions of South Africa and the Antarctic Heard and McDonald Islands represent the most separated groups. In agreement with the low values of similarity of South Africa with other regions, the ﬁrst break across Gondwana was probably initiated in the midJurassic, when East Gondwana, comprising Antarctica, Madagascar, India and Australia, began to separate from Africa (Upchurch, 2008). In support, “hotspots” of cheilostome regional endemisms have been found in South Africa (Barnes and Grifﬁths, 2008; Grifﬁths et al., 2009). On the other hand, the remote Heard and McDonald Islands (53° S) situated in the south Indian Ocean, within the PF between South Africa and Australia, present low afﬁnity to the other regions, as showed by the cluster analysis. The eastwards ﬂow of the ACC, carrying bryozoan species attached to drifting natural (e.g. macrophytes) or artiﬁcial substrata, could explain the long-distance dispersal of some bryozoan species (Barnes, 2002). Barnes (2002) reported Bryozoa as one of the most abundant taxa on marine debris. Also, Watts et al. (1998) argued that rafting was a key element in the biogeography of cheilostome bryozoans. In agreement with this, Moyano (1999) also found a mixture of Magellanic and Antarctic bryozoan species in other remote subantarctic regions of the Indian Ocean inﬂuenced by the ACC (Prince Edward, Crozet and Kerguelen). In fact, Heard Island and other subantarctic islands clustered together in a previous bryozoan diversity study (Barnes and Grifﬁths, 2008). Moreover, Grifﬁths et al. (2009) reported that the majority of species found at Heard Island were also recorded at Kerguelen Island, suggesting that this similarity is related to the fact that, in the past, both islands (which share the Kerguelen Plateau) were on the same side of the PF. Considering that the greatest outliers in the analyses were these Antarctic islands, and that they have not been adequately sampled bryozoologically, their dissimilarity could perhaps be related to undersampling and to the large distances between Antarctica and other regions of the southern hemisphere, as well as to their isolation and the long period of separation of the land masses. 5. Summary and conclusions A high diversity of bryozoans was found in the AP region, probably related to the existence of the conﬂuence of two major wind-driven currents, the subantarctic nutrient-rich Falkland/Malvinas and the subtropical Brazil currents. Moreover, new genera and species were discovered and 65.7% of the species were reported for the ﬁrst time in Argentina, conﬁrming that this region has been poorly explored so far. Thus, more studies on the biodiversity and biogeography are needed in this region, in order to know the taxonomic composition, the biogeographic and bathymetric ranges of their species and, consequently, to detect future changes caused by anthropogenic perturbations. In addition, the diversity patterns found in this study are partly inﬂuenced by the different sampling effort in the region and the number of stations without bryozoans may be overestimated. In fact, future explorations, mainly of slope and deep-water bryozoan faunas of South American and Antarctic margins and basins, could show a higher number of shared species than reported here. There was evidence of bryozoological afﬁnities in the current study between Argentina and the nearest geographical neighbors, mainly Antarctica, supporting the hypothesis of sequential separation of Gondwana during the Cenozoic. Moreover, other potential pathways may explain the high similarity found in the bryozoan communities, mainly from slope depths in the AP region, thus overcoming the oceanic barrier of the PF. Therefore, the high number AP species shared with Antarctica in our study, linked to the lower proportion of endemic Antarctic cheilostome bryozoans reported in recent studies (closer to 50%), support the idea that the Southern Ocean may have been less isolated over geological time than once thought. Acknowledgments The authors wish to thank Dr. López Gappa (Museo Argentino de Ciencias Naturales) for his help with the bibliography, Dr. Maceda for statistic advice and E. Szöcs for comments on the Vegan package. We are also very grateful for the helpful suggestions of the anonymous reviewers. We wish to thank the crew of the R.V. Miguel Oliver (owned by the Spanish Secretariat of the Sea [SGM]) and SGM for ship B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 time and technical support and the members of the Spanish Oceanography Institute (IEO) who participated in the cruises. The research stage of the ﬁrst author during her PhD at the National Institute 11 of Water and Atmospheric Research in New Zealand was funded by the Spanish Government (projects ACTIQUIM I and II; CGL2007-65453/ANT, CTM2010-17415/ANT). Appendix A. Results of the SIMPER analysis showing the species that contribute most to the dissimilarity between depth zones of the MDS. Contrib. %: percentage contribution of the species to the total dissimilarity; Cum. %: cumulative contribution to the total dissimilarity 1 vs 2 Species Contrib. % Cum. % Adeonella patagonica Amastigia nuda Amphiblestrum novella Andreella uncifera Arachnopusia globosa Austroﬂustra gerlachi Beania costata Beania inermis Beania maxilla Beania inermis unicornis Calloporina patagonica Cellaria scoresbyi Cellaria variabilis Cellarinella dubia Chaperiopsis propinqua Ellisina antarctica Exochella longirostris Fenestrulina dupla Foveolaria terriﬁca Lacerna hosteensis Menipea patagonica Scruparia ambigua Smittina jacobensis Smittina jullieni Smittina lebruni Smittina leptodentata Smittina monacha Talivittaticella frigida Villicharixa strigosa Adelascopora secunda Beania magellanica Buffonellodes glabra Celleporina bicostata Ellisina incrustans Reteporella gigantea Arachnopusia monoceros Cellaria ornata Notoplites elongatus Osthimosia eatonensis Smittoidea sigillata Tricellaria aculeata Reteporella tortuosa Camptoplites bicornis quadravicularis Austroﬂustra australis Amastigia benemunita Aspidostoma giganteum Himantozoum obtusum Smittina anecdota Chartella notialis Carbasea ovoidea Osthimosia clavata Caberea darwinii guntheri Turritigera stellata Aspidostoma coronatum Fenestrulina antarctica Fenestrulina crystallina Chaperiopsis erecta Amastigia crassimarginata Buffonellodes rimosa Camptoplites reticulatus Cellaria malvinensis Chaperiopsis patulosa Menipea ﬂagellifera Paracellaria elephantina Arachnopusia admiranda Bracebridgua subsulcata 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.79 7.42 7.42 7.42 7.42 7.42 7.42 6.916 6.916 6.916 6.916 6.916 6.916 6.27 6.16 6.03 5.85 5.85 5.85 5.85 5.43 5.3 5.3 4.83 4.83 4.76 4.76 4.76 4.32 4.23 4.23 4.23 4.23 4.23 4.23 4.1 4.09 4.09 1.09 2.06 3.08 4.11 5.14 6.17 7.2 8.23 9.26 10.29 11.31 12.34 13.37 14.4 15.43 16.46 17.49 18.51 19.54 20.57 21.6 22.63 23.66 24.69 25.71 26.74 27.77 28.8 29.83 30.79 31.75 32.72 33.68 34.64 35.6 36.5 37.4 38.29 39.19 40.09 40.99 41.8 42.6 43.39 44.14 44.9 45.66 46.41 47.12 47.81 48.5 49.12 49.75 50.36 50.98 51.6 52.16 52.71 53.26 53.81 54.36 54.9 55.45 55.98 56.51 57.05 Species 1 vs 5 2 vs 3 Adeonella patagonica Amastigia benemunita Amastigia nuda Amphiblestrum novella Andreella uncifera Arachnopusia globosa Arachnopusia monoceros Beania costata Beania inermis Beania magellanica Beania maxilla Beania inermis unicornis Buffonellodes glabra Buffonellodes rimosa Caberea darwinii Calloporina patagonica Camptoplites reticulatus Carbasea ovoidea Cellaria clavata Cellaria malvinensis Cellaria ornata Cellaria scoresbyi Cellaria variabilis Cellarinella dubia Celleporina bicostata Chaperiopsis patulosa Chaperiopsis propinqua Ellisina antarctica Ellisina incrustans Exochella longirostris Fenestrulina dupla Formosocellaria magniﬁca Himantozoum obtusum Lacerna hosteensis Melicerita blancoae Menipea ﬂagellifera Menipea patagonica Micropora brevissima Notoplites elongatus Ogivalia elegans Osthimosia bicornis Osthimosia eatonensis Parasmittina dubitata Scruparia ambigua Smittina jacobensis Smittina jullieni Smittina lebruni Smittina leptodentata Smittina monacha Smittina smittiana Smittoidea sigillata Tricellaria aculeata Villicharixa strigosa Caberea darwinii Fenestrulina fritilla Lageneschara peristomata Micropora brevissima Talivittacella frigida Reteporella gigantea Osthimosia bicornis Reteporella magellensis Smittoidea malleata Reteporella tortuosa Camptoplites bicornis quadravicularis Foveolaria terriﬁca Orthoporidra brachyrhyncha Contrib. % 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 1.07 2.25 2.25 2.25 2.25 2.25 2.14 2.01 1.82 1.82 1.78 1.7 1.6 1.6 Cum. % 1.07 2.15 3.44 4.29 5.37 6.44 7.52 8.59 9.66 10.74 11.81 12.88 13.96 15.032 16.1 17.18 18.25 19.33 20.4 21.47 22.56 23.62 24.7 25.77 26.84 27.92 28.99 30.06 31.14 32.21 33.28 34.36 35.43 36.5 37.58 38.65 39.73 40.7 41.87 42.95 44.02 45.1 46.17 47.24 48.32 49.39 50.46 51.54 52.61 53.68 54.76 55.83 56.9 2.98 5.95 8.93 11.90 14.98 14.88 17.7 22.78 25.15 27.5 29.74 31.86 33.97 (continued on next page) 12 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 Appendix (continued) A (continued) 1 vs 3 1 vs 4 Species Contrib. % Cum. % Species Contrib. % Cum. % Carbasea elegans Catadysis immersum Chiastosella watersi Chondriovelum angustilobatum Fenestrulina incusa Adeonella patagonica Amastigia benemunita Amastigia nuda Amphiblestrum novella Andreella uncifera Arachnopusia globosa Arachnopusia monoceros Aspidostoma giganteum Austroﬂustra gerlachi Beania costata Beania inermis Beania magellanica Beania maxilla Beania inermis unicornis Buffonellodes glabra Buffonellodes rimosa Caberea darwinii Calloporina patagonica Camptoplites reticulatus Carbasea ovoidea Cellaria malvinensis Cellaria ornata Cellaria scoresbyi Cellaria variabilis Cellarinella dubia Celleporina bicostata Chaperiopsis patulosa Chaperiopsis propinqua Ellisina antarctica Ellisina incrustans Exochella longirostris Fenestrulina dupla Himantozoum obtusum Lacerna hosteensis Melicerita blancoae Menipea ﬂagellifera Menipea patagonica Micropora brevissima Notoplites elongatus Ogivalia elegans Osthimosia bicornis Osthimosia eatonensis Parasmittina dubitata Scruparia ambigua Smittina jacobensis Smittina jullieni Smittina lebruni Smittina leptodentata Smittina monacha Smittina smittiana Smittoidea malleata Smittoidea sigillata Tricellaria aculeata Villicharixa strigosa Adeonella patagonica Amastigia benemunita Amastigia nuda Amphiblestrum novella Andreella uncifera Arachnopusia globosa Arachnopusia monoceros Beania costata Beania inermis Beania magellanica Beania maxilla Beania inermis unicornis Buffonellodes glabra Buffonellodes rimosa Caberea darwinii Calloporina patagonica Camptoplites reticulatus Carbasea ovoidea 4.09 4.09 4.09 4.09 4.09 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.05 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 57.58 58.11 58.64 59.17 59.7 1.08 2.15 3.23 4.3 5.38 6.45 7.53 8.6 9.68 10.75 11.83 12.9 13.98 15.05 16.13 17.2 18.29 19.35 20.43 21.51 22.58 23.66 24.73 25.81 26.88 27.96 29.03 30.11 31.18 32.26 33.33 34.41 35.49 36.56 37.64 38.71 39.79 40.86 41.94 43.01 44.09 45.16 46.24 47.31 48.39 49.46 50.54 51.61 52.69 53.76 54.84 55.91 56.99 58.07 1.12 2.24 3.35 4.47 5.59 6.71 7.83 8.95 10.06 11.18 12.3 13.42 14.54 15.66 16.77 17.89 19.01 20.13 Smittina rogickae Austroﬂustra australis Melicerita blancoae Ogivalia elegans Orthoporidra compacta Parasmittina dubitata Adelascopora secunda Aspidostoma coronatum Fenestrulina antarctica Chartella notialis Smittina anecdota Osthimosia clavata Fenestrulina crystallina Austroﬂustra gerlachi Caberea darwinii Fenestrulina fritilla Foveolaria terriﬁca Lageneschara peristomata Micropora brevissima Orthoporidra brachyrhyncha Smittina rogickae Talivittacella frigida Adelascopora secunda Reteporella gigantea Osthimosia bicornis Reteporella magellensis Reteporella tortuosa Aspidostoma giganteum Smittina anecdota Camptoplites bicornis quadravicularis Osthimosia clavata Austroﬂustra australis Melicerita blancoae Ogivalia elegans Orthoporidra compacta Parasmittina dubitata Aspidostoma coronatum Fenestrulina antarctica Fenestrulina crystallina Austroﬂustra gerlachi Caberea darwinii Cellaria clavata Fenestrulina fritilla Formosocellaria magniﬁca Foveolaria terriﬁca Lageneschara peristomata Micropora brevissima Orthoporidra brachyrhyncha Smittina rogickae Talivittacella frigida Adelascopora secunda Reteporella gigantea Osthimosia bicornis Columnella gracilis Columnella magna armata Cookinella ﬂustroides Domosclerus corrugatus Reteporella magellensis Reteporella tortuosa Aspidostoma giganteum Smittina anecdota Camptoplites bicornis quadravicularis Osthimosia clavata Austroﬂustra australis Melicerita blancoae Ogivalia elegans Aspidostoma giganteum Austroﬂustra gerlachi Smittoidea malleata Talivittacella problematica Cellaria clavata Formosocellaria magniﬁca Smittoidea malleata Columnella gracilis Cellaria clavata Formosocellaria magniﬁca Columnella gracilis 1.6 1.6 1.6 1.6 1.6 1.6 1.56 1.47 1.47 1.41 1.4 1.34 1.29 2.52 2.52 2.52 2.52 2.52 2.52 2.52 2.52 2.52 2.4 2.4 2.24 2.01 1.98 1.97 1.97 1.89 1.82 1.76 1.76 1.76 1.76 1.76 1.66 1.66 1.66 2.39 2.39 2.39 2.39 2.39 2.39 2.39 2.39 2.39 2.39 2.39 2.26 2.26 2.12 1.95 1.95 1.95 1.95 1.92 1.88 1.86 1.86 1.79 1.71 1.68 1.68 1.68 10.17 10.17 10.17 5.9 8.37 8.37 8.37 6.44 9.99 9.54 9.14 36.09 38.19 40.3 42.41 44.52 46.63 48.68 50.62 52.56 54.42 56.27 58.04 59.74 2.71 5.43 8.14 10.85 13.56 16.28 18.99 21.7 24.42 26.99 29.57 31.98 34.14 36.28 38.4 40.53 42.56 44.52 46.41 48.32 50.2 52.1 53.99 55.79 57.58 59.37 2.46 4.91 7.37 9.83 12.29 14.74 17.2 19.66 22.11 24.57 27.02 29.36 31.69 33.88 35.89 37.9 39.9 41.92 43.89 45.82 47.74 49.66 51.5 53.26 54.99 56.72 58.45 16.05 32.09 4814 57.46 30.18 40.23 50.29 58.03 14.4 28.16 41.34 2 vs 4 2 vs 5 3 vs 4 3 vs 5 4 vs 5 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 13 Appendix (continued) A (continued) Species Contrib. % Cum. % Species Cellaria malvinensis Cellaria ornata Cellaria scoresbyi Cellaria variabilis Cellarinella dubia Celleporina bicostata Chaperiopsis patulosa Chaperiopsis propinqua Ellisina antarctica Ellisina incrustans Exochella longirostris Fenestrulina dupla Himantozoum obtusum Lacerna hosteensis Melicerita blancoae Menipea ﬂagellifera Menipea patagonica Micropora brevissima Notoplites elongatus Ogivalia elegans Osthimosia bicornis Osthimosia eatonensis Parasmittina dubitata Scruparia ambigua Smittina jacobensis Smittina jullieni Smittina lebruni Smittina leptodentata Smittina monacha Smittina smittiana Smittoidea sigillata Tricellaria aculeata Villicharixa strigosa Talivittaticella problematica 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 0.66 21.25 22.37 23.48 24.6 25.72 26.84 27.96 29.08 30.19 31.31 32.43 33.55 34.67 35.79 36.91 38.02 39.14 40.26 41.38 42.5 43.62 44.73 45.85 46.97 48.1 49.21 50.33 52.45 52.56 53.68 54.8 55.92 57.04 57.71 Columnella magna armata Contrib. % 9.14 Cum. % 54.52 Appendix B. Bathymetric ranges and biogeographic distributions of the species studied. Pulled data from the present study, the literature and the GBIF and SCAR databases. Localities: AN = Antarctica; AR = Argentina; AU = Australia; CH = Chile; FI = Falkland Islands (Malvinas); HI/MI = Heard Island and McDonald Islands; NZ = New Zealand; SAF = South Africa; SG/SS = South Georgia and the South Sandwich Islands. –: unknown Species Bathymetric range (m) Geographic distr. Adelascopora secunda Hayward and Thorpe, 1988 Adeonella patagonica Hayward, 1988 Aetea anguina (Linnaeus, 1758) Aetea australis Jullien, 1888 Aetea curta Jullien, 1888 Aetea ligulata Busk, 1852 Aetea sica (Couch, 1844) Aimulosia australis Jullien, 1888 Amastigia benemunita (Busk, 1884) Amastigia crassimarginata (Busk, 1884) Amastigia gaussi (Kluge, 1914) Amastigia nuda Busk, 1852 Amastigia vibraculifera Hastings, 1943 Amphiblestrum familiaris Hayward and Thorpe, 1989 Amphiblestrum novella Hayward and Thorpe, 1989 Apiophragma hyalina (Waters, 1904) Andreella patagonica López Gappa, 1981 Andreella uncifera (Busk, 1884) Arachnopusia admiranda Moyano, 1982 Arachnopusia globosa Hayward and Thorpe, 1988 Arachnopusia monoceros (Busk, 1854) Arachnopusia valligera Hayward and Thorpe, 1988 Aspericreta favulosa Hayward and Thorpe, 1989 Aspidostoma coronatum (Thornely, 1924) Aspidostoma giganteum (Busk, 1854) Austroﬂustra australis López-Gappa, 1982 Austroﬂustra gerlachi López Gappa, 1982 Austrothoa yagana Moyano and Gordon, 1980 Beania costata (Busk, 1876) Beania fragilis Ridley, 1881 Beania inermis (Busk, 1852) 400–1700 0–100 0–200 0–100 0–101 0–102 0–103 140–1500 0–600 300–1000 200–500 0–00 0–00 1100–1200 0–00 1400–1500 0–00 0–200 100–200 0–200 0–400 0–100 1200–1300 900–1600 700–1900 200–1300 200–1900 – 0–170 0–100 0–200 AN, AR, CH, SG/SS AN, CH AN, AR, AU, CH, FI, NZ, SAF AR, AU, NZ AR, AU AR, FI, NZ AR AN, AR, CH, SG/SS AR, CH AR AN, AR**, FI, SG/SS AR, FI, NZ AR, FI AN, AR** AR, FI AN, AR** AR AN, AR, CH, FI AR AR, FI AN, AR, AU, CH, FI, SAF, SG/SS AR, NZ AN, AR** AN, AR**, SG/SS AN, AR, CH, FI AR, FI AR, FI AR, CH AN, AR, AU, FI, SAF AR, CH AN, AR, AU, CH, FI, NZ (continued on next page) 14 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 Appendix (continued) B (continued) Species Bathymetric range (m) Geographic distr. Beania magellanica (Busk, 1852) Beania maxilla (Jullien, 1888) Beania unicornis Hastings, 1943 Bracebridgia subsulcata (Smitt, 1873) Buffonellodes glabra Hayward, 1991 Buffonellodes rimosa Jullien, 1888 Bugula ﬂabellata Thompson in Gray, 1848 Bugula hyadesi Jullien, 1888 Bugula multiserialis (d'Orbigny, 1847) Bugula neritina (Linnaeus, 1758) Bugula simplex Hincks, 1886 Bugula stolonifera Ryland, 1960 Caberea darwinii Busk, 1884 Caberea darwinii guntheri Hastings, 1943 Callopora deseadensis López Gappa, 1981 Calloporina patagonica Hayward and Ryland, 1990 Camptoplites asymmetricus Hastings, 1943 Camptoplites atlanticus Hastings, 1943 Camptoplites bicornis (Busk, 1884) Camptoplites bicornis var. quadriavicularis Hastings, 1943 Camptoplites reticulatus (Busk, 1881) Carbasea elegans Busk, 1852 Carbasea ovoidea Busk, 1852 Catadysis immersum (Busk, 1884) Cellaria clavata (Busk, 1884) Cellaria dubia (Busk, 1884) Cellaria malvinensis (Busk, 1852) Cellaria ornata (d'Orbigny, 1847) Cellaria scoresbyi Hastings, 1946 Cellaria variabilis (Busk, 1884) Cellarinella dubia Waters, 1904 Celleporella alia Hayward, 1993 Celleporella bougainvillei (d'Orbigny, 1847) Celleporella chiloensis Moyano, 1982 Celleporella discreta (Busk, 1884) Celleporella hyalina Linnaeus, 1767 Celleporella patagonica Busk, 1852 Celleporella tehuelcha López Gappa, 1985 Celleporina bicostata Hayward, 1980 Chaperia acanthina (Lamouroux, 1825) Chaperiopsis erecta (Busk, 1884) Chaperiopsis galeata (Busk, 1854) Chaperiopsis indefensa Hayward and Thorpe, 1988 Chaperiopsis orbiculata Hayward and Thorpe, 1988 Chaperiopsis patulosa (Waters, 1904) Chaperiopsis propinqua Hayward and Thorpe, 1988 Chartella notialis Hayward and Winston, 1994 Chiastosella watersi Stach, 1937 Chondriovelum angustilobatum Moyano, 1974 Chorizopora brongniartii (Audouin, 1826) Codonellina galeata (Busk, 1854) Columnella cribraria Busk, 1884 Columnella gracilis (Busk, 1884) Columnella magna (Busk, 1884) Columnella magna var. armata (Busk, 1884) Conopeum reticulum (Linnaeus, 1767) Cookinella ﬂustroides d'Hondt, 1981 Cornucopina ovalis versa Hastings, 1943 Cornucopina pectogemma (Goldstein, 1882) Crepidacantha crinispina Levinsen, 1909 Cryptostomaria cylindrica (Harmer, 1926) Cryptosula pallasiana (Moll, 1803) Discoporella depressa (Conrad, 1841) Domosclerus corrugatus (Busk, 1884) Electra longispina (Calvet, 1904) Electra monostachys (Busk, 1854) Ellisina antarctica Hastings, 1945 Ellisina incrustans (Waters, 1898) Euginoma biseriata d'Hondt, 1981 Euginoma cavalieri Lagaaij, 1963 Exochella discors Hayward, 1991 Exochella hymanae (Rogick, 1956) Exochella longirostris Jullien, 1888 Fenestrulina antarctica Hayward and Thorpe, 1990 Fenestrulina crystallina Hayward and Ryland, 1990 Fenestrulina dupla Hayward and Ryland, 1990 Fenestrulina fritilla Hayward and Ryland, 1990 0–300 0–200 0–200 0–200 0–300 0–900 0–100 0–100 – 0–100 – 0–100 0–100 0–400 0–100 0–200 300–500 100–300 0–100 200–1400 1000–4500 100–200 0–700 100–200 0–3500 1000–1100 0–900 0–400 0–200 0–200 0–200 100–700 0–100 – – 0–100 0–101 0–102 0–100 – 300–1100 0–100 0–100 100–500 0–900 0–200 200–1200 100–200 100–200 0–100 0–100 3400–3500 4400–4500 700–1100 4400–4500 – 4300–4500 200–500 100–1000 – 3800–3900 0–100 0–100 4300–4500 0–100 0–100 0–200 0–300 2700–2800 2000–2100 0–100 1500–1700 0–200 900–1600 900–1700 0–200 100–1600 AR, AU, CH, FI, NZ, SAF AR, CH, FI AR AR AR, CH, FI AN, AR**, FI, NZ AR, AU, NZ AR AR AN, AR, AU, NZ AR AR, AU, CH, FI, NZ AN, AR, AU, CH, FI, HI/MI, NZ, SAF, SG/SS AR AR, CH AR AR, NZ AR, FI AN, AR, NZ AR AR, NZ AR, AN AN, AR, CH, HI/MI, SG/SS AR, FI AN, AR, CH, FI, HI/MI, SG/SS AN, AR AN, AR, CH, FI, NZ, SAF, SG/SS AR AR, CH, FI, NZ, SAF AR, CH, FI AN, AR, AU, CH, FI AN, AR AN, AR, SG/SS AR, CH AR, CH AN, AR, AU, CH, NZ, SAF, SG/SS AR AR AR, FI AR, NZ AR, SG/SS AN, AR, CH, FI, SG/SS, HI/MI AR AN, AR, SG/SS AN, AR, FI AR, CH, FI AN, AR AR, NZ AR, CH AR, NZ AR AR AR AN, AR, NZ, SAF, SG/SS AR AR AR AR, FI AN, AR**, NZ, SAF, SG/SS AR, AU, NZ AR AR, AU, NZ AR AR, NZ, SAF AR AR AN, AR, CH, NZ AN, AR, CH, FI AR AR AR AN, AR**, SG/SS AN, AR, CH, FI AN, AR** AN, AR** AR AN, AR**, FI, SG/SS B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 15 Appendix B (continued) (continued) Species Bathymetric range (m) Geographic distr. Fenestrulina incusa Hayward and Ryland, 1990 Fenestrulina majuscula Hayward, 1980 Fenestrulina malusii Audouin, 1826 Flustrapora magellanica Moyano, 1970 Formosocellaria magniﬁca (Busk, 1884) Foveolaria elliptica Busk, 1884 Foveolaria cyclops (Busk, 1854) Foveolaria terriﬁca (Hincks, 1881) Galeopsis bullatus Hayward, 1993 Galeopsis patagonicus Hayward, 1993 Galeopsis pentagonus (d'Orbigny, 1847) Gigantopora spathula Hayward and Winston, 2011 Gregarinidra variabilis (Moyano, 1974) Hemismittoidea hexaspinosa (Uttley and Bullivant, 1972) Himantozoum margaritiferum (Busk, 1884) Himantozoum obtusum Hastings, 1943 Hippadenella falklandensis Hayward, 1991 Hippadenella margaritifera (Quoy and Gaimard, 1824) Hippadenella rouzaudi (Calvet, 1904) Hippomonavella ramosae López de la Cuadra and García Gómez, 2000 Hippoporina aulacomyae López Gappa, 1981 Hippothoa divaricata Lamouroux, 1821 Hippothoa ﬂagellum Manzoni, 1870 Ichthyaria oculata Busk, 1884 Ichthyaria profunda d'Hondt, 1981 Inversiula nutrix Jullien, 1888 Inversiula patagonica Hayward and Ryland, 1991 Jolietina latimarginata (Busk, 1884) Lacerna eatoni (Busk, 1876) Lacerna hosteensis Jullien, 1888 Lageneschara peristomata Hayward and Winston, 2011 Melicerita atlantica Busk, 1884 Melicerita blancoae López Gappa, 1981 Melicerita temaukeli Moyano, 1997 Membranicellaria dubia (Busk, 1884) Membranipora membranacea (Linnaeus, 1767) Menipea ﬂagellifera Busk, 1884 Menipea patagonica Busk, 1852 Micropora brevissima Waters, 1904 Microporella crustula Hayward and Winston, 2011 Micropora notialis Hayward and Ryland, 1993 Microporella diademata (Lamouroux, 1825) Microporella hyadesi (Jullien, 1888) Neoﬂustra dimorphica López Gappa, 1982 Notoplites antarcticus (Waters, 1904) Notoplites crateriformis (Busk, 1884) Notoplites elongatus (Busk, 1884) Odontoporella adpressa (Busk, 1854) Ogivalia elegans (d'Orbigny, 1847) Ogivalia sagittirostra Hayward and Winston, 1994 Orthoporidra brachyrhyncha Moyano, 1985 Orthoporidra compacta (Waters, 1904) Orthoporidra petiolata (Waters, 1905) Orthoporidra stenorhyncha Moyano, 1985 Orthoporidroides erectus (Waters, 1888) Osthimosia bicornis (Busk, 1881) Osthimosia clavata Waters, 1904 Osthimosia eatonensis (Busk, 1881) Osthimosia malingae Hayward, 1992 Osthimosia magna Moyano, 1974 Osthimosia notialis Hayward, 1992 Osthimosia rudis (Busk, 1881) Paracellaria cellarioides Hayward and Thorpe, 1989 Paracellaria elephantina Hayward and Thorpe, 1989 Paracellaria elizabethae Branch and Hayward, 2005 Paraﬁgularia magellanica (Calvet, 1904) Parasmittina dubitata Hayward, 1980 Phonicosia jousseaumei Jullien, 1888 Platychelyna planulata Hayward, 1980 Plesiothoa australis Moyano and Gordon, 1980 Porella hyadesi Jullien, 1888 Reteporella spatulifera (Waters, 1905) Reteporella antennata Ramalho et al., 2011 Reteporella gigantea (Busk, 1884) Reteporella longichila Hayward, 1993 Reteporella magellensis (Busk, 1884) 100–200 0–100 0–100 100–200 3400–4500 300–900 – 200–1700 700–800 100–200 100–200 300–1000 100–200 – – 0–600 0–100 – 0–100 1400–1500 – – – 100–300 2700–2800 100–200 100–200 700–900 0–100 0–200 100–1600 – 0–1300 – – – 0–900 0–200 0–1600 100–900 0–100 0–200 0–200 – 900–1000 3400–3500 0–400 0–100 0–1300 300–1000 100–1700 100–1300 – 100–200 200–300 0–1500 700–1700 0–300 100–800 0–100 800–900 1000–1100 200–500 800–1500 1400–1500 – 0–1300 – 200–300 – – 100–200 400–500 300–1600 700–800 100–1400 AR AR, CH, FI AN, AR, AU, CH, SG/SS, NZ AN, AR AR AR, AU, CH, NZ AR, NZ AR, FI AN, AR**, HI/MI, SG/SS AR, FI AR, FI, NZ AN, AR** AR, FI AR, NZ AR AN, AR, FI AR, FI AR AR, CH, FI AR**, SG/SS AR AR, CH AN, AR, AU, FI, NZ, SG/SS AR, FI AR AN, AR, SG/SS AR AN, AR, FI AN, AR, CH AN, AR, CH, FI, SG/SS AN, AR** AR AN, AR, FI AR, CH AR AU, AR, CH, NZ, SAF AN, AR, FI, SAF AR, CH, FI AN, AR, CH, FI, SAF, SG/SS AN, AR** AR, AN, CH, NZ, SG/SS AR, AU, NZ AR, CH, FI, NZ, SG/SS AR AN, AR** AR AR, AN, FI, SAF AR, FI AR, CH, FI AN, AR, CH, FI, SG/SS AN, AR AN, NZ, SG/SS AR, AN AN, AR** AR, CH AN, AR, CH, FI, HI/MI, NZ, SAF, SG/SS AN, AR AN, AR, CH, FI, SG/SS, NZ AN, AR** AR, FI AN, AR, SG/SS AR AR, FI, SG/SS AN, AR** AR**, SAF AR, CH AR, CH, FI AR, AU, NZ AR, FI AR, NZ AN, AR AR AR** SAF AN, AR** AR, FI (continued on next page) 16 B. Figuerola et al. / Journal of Sea Research 85 (2014) 1–17 Appendix (continued) B (continued) Species Bathymetric range (m) Geographic distr. Reteporella sulcula Hayward and Winston, 2011 Reteporella tortuosa Hayward and Winston, 2011 Reteporellina moyanoi d'Hondt, 1981 Romancheina labiosa (Busk, 1854) Sclerodomus denticulatus Busk, 1884 Scruparia ambigua (d'Orbigny, 1847) Scrupocellaria puelcha (d'Orbigny, 1847) Securiﬂustra bifoliata d'Hondt, 1981 Smittina anecdota Hayward and Thorpe, 1990 Smittina insulata Hayward and Thorpe, 1990 Smittina jacobensis (Busk, 1884) Smittina jullieni Moyano, 1983 Smittina lebruni (Waters, 1905) Smittina leptodentata Hayward and Thorpe, 1990 Smittina marionensis (Busk, 1854) Smittina monacha Jullien, 1888 Smittina plioﬁstulata Hayward and Thorpe, 1990 Smittina portiuscula Hayward and Thorpe, 1990 Smittina rogickae Hayward and Taylor, 1984 Smittina smittiana (Busk, 1884) Smittina stigmatophora (Busk, 1884) Smittina uruguayensis d'Hondt, 1981 Smittoidea cribrooecia Hayward and Thorpe, 1990 Smittoidea malleata Hayward and Thorpe, 1989 Smittoidea pachydermata Hayward and Thorpe, 1990 Smittoidea rhynchota Hayward and Thorpe, 1990 Smittoidea sigillata (Jullien, 1888) Sphaerulobryozoon pedunculatum d'Hondt, 1981 Stephanollona longispinata (Busk, 1884) Stomhypselosaria watersi Hayward and Thorpe, 1989 Talivittaticella frigida (Waters, 1904) Talivittaticella problematica (d'Hondt, 1981) Tricellaria aculeata (d'Orbigny, 1847) Turbicellepora patagonica Hayward, 1992 Turritigera cribrata Hayward, 1993 Turritigera stellata Busk, 1884 Umbonula alvareziana (d'Orbigny, 1847) 400–1000 400–1500 – 0–100 – 0–200 100–200 200–600 600–1700 100–200 0–200 0–200 0–200 0–200 – 0–200 200–400 0–100 100–1700 0–1100 0–100 1600–1700 100–200 1500–1900 100–200 100–200 0–400 2000–2500 – 100–700 200–1600 2700–3900 0–400 0–100 1400–1600 200–1100 – AN, AR** AN, AR** AR AR, CH AR AR, CH, NZ AR AR, FI AN, AR**, HI/MI AR, FI AR, SAF AR, CH, FI AR, CH AR, CH, FI AN, AR AR, CH, FI AR, FI AR AN, AR** A, AR, CH, FI AR AR AR, FI AN, AR** AR, CH, FI AN, AR, FI, SG/SS AN, AR, CH, FI AR AR, NZ AN, AR, FI, SG/SS AN, AR, SAF AR, NZ AR, CH, FI, NZ AR AN, AR**, AU, SG/SS AN, AR AR References Acha, E.M., Mianzan, H.W., Guerrero, R.A., Favero, M., Bava, J., 2004. 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Cheilostome bryozoan diversity from the southwest Atlantic region: is Antarctica really isolated?

Cheilostome bryozoan diversity from the southwest Atlantic region: is Antarctica really isolated?

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