Figure 10 - uploaded by Robin Overstreet
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Texadina sphinctostoma. A-C. Shelled-veliger showing architecture of protoconch (SEM). C. Note recent differential growth of lip. Scales: A, B = 10 µm; C = 50 µm.
Source publication
Heleobops sp. of Hershler and Thompson appears to be the only previously published record for the gastropod family Hydrobiidae Troschel in tidal waters of the St. Andrew Bay System, Florida. Six species occurred in bayous, marshes, and brackish ponds associated with the System during studies conducted between 1984 and 1999: Texadina barretti (Morri...
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We describe the lightning whelk (Busycon sinistrum) and show how its shells were used
among coastal peoples along the Gulf of Mexico and lower Atlantic coast. During the Middle and Late
Archaic periods, lightning whelk shells were transported hundreds of km from the coasts to the
Midsouth where they were made into a variety of artifacts that were i...
We describe an additional species in the oegopsid squid family Onychoteuthidae from the Gulf of Mexico. Although similar to Onykia rancureli Okutani (=Callimachus rancureli sensu Bolstad), the species described here differs by having fewer hooks and carpal suckers on the tentacle clubs and a wider head. In considering the generic relationships of t...
We describe the lightning whelk (Busycon sinistrum) and show how its shells were used among coastal peoples along the Gulf of Mexico and lower Atlantic coast. During the Middle and Late Archaic periods, lightning whelk shells were transported hundreds of km from the coasts to the Midsouth where they were made into a variety of artifacts that were i...
Citations
... The non-native red-rimmed melania snail (Melanoides tuberculata) was the dominant food item for Mayan Cichlid in the latter study. The serrate crownsnail and other estuarine hydrobiids have been collected from a variety of anthropogenic features such as ditches, canals, drainage pipes, culverts, and water-control structures (Heard et al. 2002), while the red-rimmed melania snail commonly occurs in canals and becomes concentrated where water discharges into estuaries (Roessler et al. 1977, Wingard et al. 2008. The consumption of these gastropods may reflect the generalist feeding strategy of Mayan Cichlid and likely enhances their ability to become established in Florida's stormwater conveyance structures. ...
Foraging habits of the non-native Mayan Cichlid (Mayaheros urophthalmus) were investigated in the tidal tributaries to the Estero Bay and Wiggins Pass estuaries in southwest Florida (USA) during 2011-2013. Dietary analysis was conducted by identifying contents in the digestive tracts of 747 fish and volumetrically measuring the food items. Detritus was the predominant food item by frequency (97–100%), volume (34–48%), and alimentary importance index (47–64%). Bivalves, gastropods, decapod and cirriped crustaceans, coleopterans, serpulid polychaetes, and fish scales frequently (>50%) occurred in samples but volume and importance differed among tributaries. Results indicate that the Mayan Cichlid in southwest Florida tidal tributaries is an opportunistic predator of hard-shelled invertebrates. Although there was considerable overlap in dietary composition, percent volume of food items was significantly different among tributaries during dry seasons. In each tributary, detritus was consumed in greater percentage during the dry season and benthic invertebrates were consumed in greater percentages during the wet season. Consumption of detritus, algae, and plant material may be incidental to predation on benthic invertebrates but more information is needed on digestion and assimilation of food items. Variability in diet among the tributaries in the current study and among other studies was presumably a function of habitat characteristics and the corresponding availability of prey types.
... Presently, the only known first intermediate hosts for species of Homalometron are snails belonging in the Hydrobiidae, whereas, metacercariae are found in a broader range of invertebrate second intermediate hosts including snails (Hydrobiidae and Viviparidae), veneroid bivalves (Sphaeriidae, Unionidae, and Veneridae), oligochaetes (Naididae), and captive polychaetes (Table III). Most hydrobiid species are highly specific to certain ranges of salinity and are incapable of tolerating extended variation from an optimal range (see Heard et al., 2002), suggesting that the range of a particular hydrobiid species that serves as first intermediate host for a species of Homalometron is a vital factor influencing species range, radiation, and evolution in the genus. More extensive molecular analyses using marine species of Homalometron and investigations of marine hydrobiid snails for larval stages of apocreadiids should help to provide a more powerful assessment of evolutionary patterns in the genus. ...
Two species of digeneans belonging in Homalometron are described from Nearctic freshwater fundulid fishes: Homalometron robisoni n. sp. is described from the Blackstripe Topminnow, Fundulus notatus, from Oklahoma and Homalometron frocioneae n. sp. is described from the Banded Killifish, Fundulus diaphanus, from New York. Homalometron robisoni n. sp. differs from all congeners by having vitelline follicles that extend into the forebody, a feature that necessitates altering the generic diagnosis for the genus. Homalometron frocioneae n. sp. may be distinguished from North and Middle American congeners by the position of the intestinal bifurcation (relatively more posterior in the forebody than in other species), and tegumental spine coverage on the body (spines are absent from the posterior body extremity and on most of the dorsal surface). Comparison of ribosomal DNA (ITS 1 and 2 regions, 5.8S gene, and partial fragment of 28S gene) from the 2 new species and some congeners from the Western Hemisphere provided evidence for the validity of the 2 new species and affirmed an close relationship between H. robisoni n. sp. and Homalometron pallidum. Comparison of ribosomal DNA from newly collected Homalometron spp. and larval stages of an apocreadiid from brackish water hydrobiid snails (cercariae in rediae in Littoridinops palustris and metacercariae in L. palustris and Amnicola limosa) from a tidal river in Mississippi revealed that larval stages represented Homalometron cupuloris. A phylogeny based on Baysian Inference analysis using partial 28S rDNA gene fragments from 14 species of Homalometron (all from the Western Hemisphere), 1 megaperine, and rooted by a second megaperine was conducted and produced a strongly supported phylogram that estimates the interrelationships among species. The estimated phylogeny suggests that ecological factors such as salinity and food web interactions between species of Homalometron, intermediate hosts and fishes drive coevolutionary forces influencing speciation within Homalometron.
... Salinity is one of the most important abiotic factors regulating fresh water snail populations (Perera 1996; Vázquez and Gutiérrez 2007), and euryhalinic species are expected to have an advantage over those that do not show this ability. Also, L. monroensis is viviparous which gives it an advantage in establishing new populations (e.g., Heard et al. 2002; Köhler et al. 2004). As discussed above, the distribution of this species seems to be constrained to the western part of Cuba. ...
Littoridinops monroensis Frauenfeld, 1863 was found in recent surveys in the Guanahacabibes Peninsula, Cuba. The species seems to be well established in this area with populations occurring in diverse habitats. L. monroensis has never been recorded from other monitored localities in the country and constitutes a new species record for Cuba. Its appearance in this survey may be because of a recent introduction. Migratory birds might have played an important role in the introduction since this region is a protected area and access is very restricted. Ecological data and the distribution of this species in Cuba is presented.
Populations of hydrobiid snails and their larval trematode parasites in salt marsh along the Skidaway River were studied to determine their distribution. Additionally, the prevalence of larval trematodes infecting the snails was examined to investigate definitive host distribution patterns on the Skidaway River and to identify sites for future studies on second intermediate host susceptibility to trematode infection. To do so, surface sediment and vegetation were collected at low tide from 0.5-m2 quadrats along 20 vertical transects beginning in high marsh at the forest edge and salt meadow, passing through high, medium, and low Spartina alterniflora zones, and ending in the low marsh at creekbed level. Samples were filtered through sieves to concentrate snails, which were then counted and identified. Two species of hydrobiid snails, Spurwinkia salsa (4201 specimens) and Onobops jacksoni (136 specimens) were collected. Hydrobiid snails were found in sediments and on plant stems throughout the S. alterniflora zones, and snail density was greatest in the higher Spartina zones. Sediments from the 3 Spartina zones differed with respect to percent sand, but not percent silt or clay. Salinity and chlorophyll-a levels did not differ between the 3 Spartina zones, and there was no relationship between hydrobiid abundance and the abundance of other snail species. The mean prevalence of trematode infection in S. salsa and O. jacksoni snails was 5.5% and 7.5%, respectively. Snails were infected most commonly with either an oculate monostome, possibly the heterophyid Phagicola diminuta, or 2 types of xiphidiocercariae, one of which likely includes the microphallid Microphallus turgidus. No infected snails were found in over half of the collection sites, and the distribution of infected snails was patchy and unpredictable.
