European Journal of Taxonomy 519: 1–25
https://doi.org/10.5852/ejt.2019.519
ISSN 2118-9773
www.europeanjournaloftaxonomy.eu
2019 · Oliveira L.M. et al.
This work is licensed under a Creative Commons Attribution License (CC BY 4.0).
Research article
urn:lsid:zoobank.org:pub:D9E64DD6-D675-4E25-B9B8-A44C14CE0B22
Polysyncraton (Ascidiacea, Didemnidae): a re-examination of some
specimens and descriptions of three new species
Livia M. OLIVEIRA 1,*, Bert W. HOEKSEMA 2 & Rosana M. ROCHA 3
1,3
Laboratório de Sistemática e Ecologia de Invertebrados Marinhos, Departamento de Zoologia,
Universidade Federal do Paraná, CP 19020, 81531-980 Curitiba, Brazil.
2
Department of Taxonomy and Systematics, Naturalis Biodiversity Center, P.O. Box 9517,
2300 RA Leiden, the Netherlands.
*
Corresponding author: liviaoliveira@ufpr.br
2
Email: bert.hoeksema@naturalis.nl
3
Email: rmrocha@ufpr.br
1
urn:lsid:zoobank.org:author:2058206A-50D4-4956-8888-358701793D7F
urn:lsid:zoobank.org:author:548DBAFD-040B-4773-A043-6FCC466160A1
3
urn:lsid:zoobank.org:author:E170DE7A-DB70-4E5B-8488-45FA680812DA
2
Abstract. Polysyncraton Nott, 1892 is the second largest genus of didemnid ascidians; it has a wide
distribution ranging from temperate to tropical waters. Seventy-one specimens of Polysyncraton from
eight museum collections and recently collected samples were analyzed. This resulted in the description
of three new species (P. cabofriense Oliveira & Rocha sp. nov. from Brazil, P. globosum Oliveira &
Rocha sp. nov. from Australia and P. snelliusi Oliveira & Rocha sp. nov. from Suriname) and emended
descriptions of three further species (P. amethysteum (Van Name, 1902), P. magnilarvum (Millar, 1962)
and P. purou C. Monniot & F. Monniot, 1987).
Keywords. Ascidian, biodiversity, COI, taxonomy, Tunicata.
Oliveira L.M., Hoeksema B.W. & Rocha R.M. 2019. Polysyncraton (Ascidiacea, Didemnidae): a re-examination
of some specimens and descriptions of three new species. European Journal of Taxonomy 519: 1–25.
https://doi.org/10.5852/ejt.2019.519
Introduction
Polysyncraton Nott, 1892 was originally established to accommodate two species, P. paradoxum Nott,
1892 and P. fuscum Nott, 1892. These species have four rows of stigmata, an atrial languet, many testis
follicles and a spiral-shaped sperm duct. Sluiter (1909) was doubtful about the inclusion of undescribed
species within Polysyncraton, due to the combination of characteristics observed, and suggested
that the presence of the atrial languet should be excluded as a diagnostic feature of Polysyncraton
in order to accommodate his new species. Hartmeyer (1912) also emphasized the large variation of
characters among species within Polysyncraton, such as the presence or absence of an atrial languet,
and characteristics shared with Didemnum Savigny, 1816, such as the number of testis follicles, and
suggested that Polysyncraton should be re-examined.
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European Journal of Taxonomy 519: 1–25 (2019)
Currently, the genus is characterized by species with a large thorax, a large atrial languet, lateral thoracic
organs usually located at the anterior region, more than three testis follicles (exceptionally three or
less), five or less coils of the sperm duct and larvae that are usually large, gemmiparous and with more
than six pairs of ectodermal ampullae (Monniot et al. 1991; Kott 2001). Although many morphological
characteristics of Polysyncraton are similar to those of Didemnum, the unique combinations of
characteristics shown by both genera allows their taxonomic separation. Moreover, a recent molecular
study also suggested this separation, although the support of those clades was not strong (Oliveira et al.
2017).
The large number of species within Polysyncraton results in many species being differentiated by
subtle morphological differences, which have not been described well in older literature. In an effort to
complement the description of these species, many specimens (including types) from several localities
around the world were re-examined and two new species were described, one from the Atlantic Ocean
and one from Australia. Here we also describe a new species from recent collections in Brazil and
another probably undescribed species that requires samples with larvae for a complete description.
Material and methods
A total of 71 samples representing 13 species of Polysyncraton was studied, some of them used for
comparison (P. adelon Monniot F. & Monniot C., 2001, P. horridum Monniot F. & Monniot C., 2008,
P. lacazei (Giard, 1872), P. louminae Monniot F., 1984 and P. trivolutum (Millar, 1960)). Those species
are not included here because we did not find any further characters complementary to their original
description.
Colonies in Polysyncraton can be slimy, soft or brittle in a gradient of spicule absence to high spicule
density. In relation to surface texture, colonies can be smooth, reticulated or papillated in various
arrangements (Monniot 1991; Kott 2001). There are usually many cloacas with a smooth or lobed rim.
We used those characters in combination with zooid and larval characters to separate species. To obtain
the spicules a piece of the colony (25 mm2) was incinerated under an ethanol lamp flame and put it in
bleach for 5–10 min. to remove the remaining tissue. For colonies with a low density of spicules, a
piece of the colony was boiled in bleach until the tissue had been completely digested. After rinsing in
water two or three times, the spicules were then stored in an microtube containing 70% ethanol. A drop
of spicules from the storage vial was poured on a small piece of copper tape fixed to a SEM stub and
covered in Quick Carbon Coater SC-701C for analysis under a JEOL JSM-6480-LV scanning electron
microscope at Naturalis Biodiversity Center, Leiden. Part of the samples were covered in gold and
analyzed under a JEOL JSM-6360-LV at the Universidade Federal do Paraná.
For all colonies with a high density of spicules, hydrochloric acid (HCl) was used to decalcify a small
piece of the colony for easier dissection and study of zooids and larvae. Transverse sections of various
thickness were cut from those pieces using a razor blade. The zooids and larvae were removed with
microsurgery instruments under a Zeiss Discovery V8 MS-163 stereo microscope. They were stained
with Harris hematoxylin and observed under a light microscope. The zooids and larvae were measured
and photographed with a differential interference contrast (DIC) microscope (Zeiss Axio Scope) coupled
to a camera (A1 AxioCam Mrc). Zooids and larval characters used to describe the species are illustrated
in Fig. 1.
The large colony variation in the density of spicules and colouration in P. amethysteum (Van Name, 1902)
pointed to the necessity of a molecular approach to better understand the limits of this variation. Total
mitochondrial DNA was extracted from one piece of the colony (1 cm²) using Invitrogen® DNeasy &
Tissue Kit by Life Technologies following the standard protocol. PCR amplification reactions followed
the Platinum taq DNA Polymerase protocol with slight modifications. The PCR protocol consisted of
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
an initial denaturation step of 98 °C for 30 s, denaturation step of 98 °C for 5s followed by 60 cycles
with an annealing temperature step of 45 °C for 5 s, extension step of 72 °C for 15 s, and a final
extension step of 72 °C for 5 min. We used the tunicate-specific primers (Tun_for 5’-TCGACTAATCAT
AAAGATATTAG-3’ and Tun_rev2 3’-AACTTGTATTTAAATTACGATC-5’) designed by Stefaniak
et al. (2009). The sequences are available from BOLD (Table 1).
The phylogenetic reconstruction is based on the Maximum Likelihood (ML) and Bayesian Inference
(BI). The ML tree was generated using the RAxML-HPC2 on XSEDE (8.2.10) (Stamatakis 2014),
under the GTRCAT model (Stamatakis 2006) and 1000 nonparametric bootstrap replications. BI was
conducted using MrBayes on XSEDE (3.2.6) (Ronquist et al. 2012) with a model partitioned by codon
position in the protein-coding gene. The BI analysis was performed with 10 million generations for
each run, sampling trees every 1000 generations, using Markov Chain Monte Carlo (MCMC). The first
25% of generations were discarded as burn-in (2.5 million generations) before the calculation of the
consensus tree. Both ML and BI analyses were run through CIPRES Science Gateway ver. 3.3. (Miller
Fig. 1. Morphology of Polysyncraton. a. Zooid characters. b. Larval characters.
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European Journal of Taxonomy 519: 1–25 (2019)
Table 1. Accession numbers of the specimens, sequences IDs and the localities where the samples were collected.
Locality
Source
Polysyncraton amethysteum
P. amethysteum
BOLD
accession
number
UPDID089-17
UPDID090-17
Paraíba, PB, Brazil
Santa Catarina, SC, Brazil
this study
this study
P. amethysteum
UPDID091-17
Espírito Santo, ES, Brazil
this study
P. amethysteum
UPDID092-17
Espírito Santo, ES, Brazil
this study
P. amethysteum
UPDID093-17
Paraíba, PB, Brazil
this study
P. amethysteum
UPDID094-17
Paraná, PR, Brazil
this study
Species
Genbank
accession
number
P. amethysteum
UPDID159-18
Polysyncraton sp.
KU221186.1
Polysyncraton sp.
KU221187.1
Polysyncraton lacazei
AY600986.1
Bocas del Toro, Panama
this study
Espírito Santo, ES, Brazil
Oliveira et al. (2017)
Ceará, CE, Brazil
Oliveira et al. (2017)
Mediterranean Sea, Spain Turon & López-Legentil (2004)
Polysyncraton poro
KU221217.1
Moorea, French Polynesia
Oliveira et al. (2017)
Polysyncraton poro
KU221222.1
Moorea, French Polynesia
Oliveira et al. (2017)
Rio de Janeiro, RJ, Brazil
this study
Polysyncraton sp.
Cystodytes dellechiajei
UPDID096-17
AY523076.1
Mediterranean Sea, Spain Turon & López-Legentil (2004)
et al. 2010). The figure of the recovered phylogenetic tree (Fig. 5) was made using FigTree 1.4.2
(Rambaut 2014).
Institutional abbreviations
AMNH = American Museum of Natural History, New York, USA
DZUP = Ascidiacea Collection of the Departamento de Zoologia, Universidade Federal do Paraná,
Curitiba, Brazil
LIPY
= Tunicata Collection of Laboratório de Invertebrados Marinhos Paulo Young, Universidade
Federal da Paraíba, João Pessoa, Brazil
MNHN = Muséum national d’Histoire naturelle, Paris, France
NHM = Natural History Museum, London
UF
= Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
USNM = National Museum of Natural History, Smithsonian Institution, Washington DC, USA
ZMA
= Zoölogisch Museum of Amsterdam, now part of Naturalis Biodiversity Center, Leiden,
the Netherlands
Results
Class Ascidiacea Blainville, 1824
Order Aplousobranchia Lahille, 1886
Family Didemnidae Giard, 1872
Genus Polysyncraton Nott, 1892
Polysyncraton amethysteum (Van Name, 1902)
Figs 2–5
Polysyncraton amethysteum Van Name 1902: 366, pl. 54, figs 62, 64–67.
Polysyncraton amethysteum – Rodrigues 1962: 195. — Millar 1977: 200, fig. 21. — Rocha et al. 2005:
467. — Lotufo & Silva 2006: 228. — F. Monniot 2016: 207, fig. 4D.
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
Didemnum (Polysyncraton) amethysteum – Van Name 1921: 333, figs 27–29; 1945: 95, fig. 41, pl. 18,
fig. 3. — Moure et al. 1954: 236. — Millar 1958: 499.
Material examined
Paratype
BERMUDA • 1 colony; NHM 1914.5.18.103.
Other material
BRAZIL – Paraíba • 4 colonies; Barra de Camaratuba; 06°36′12″ S, 34°57′51″ W; 0–0.3 m depth;
13 Mar. 2013; L.M. Oliveira leg.; intertidal zone; DZUP POSC-23 to DZUP POSC-25, LIPY UFPB
TUN-395, slides DZUP DID5.30 to DID5.31 • 1 colony; same collecting data as for preceding but
6 May 2008; Projeto Biota Paraíba leg.; intertidal zone; LIPY UFPB TUN-230 • 4 colonies; Baia da
Traição, 06°41′15″ S, 34°55′50″ W; 0–0.3 m depth; 12 Mar 2013; L.M. Oliveira leg.; intertidal zone;
DZUP POSC-13 to POSC-14, slides DZUP DID5.13 to DID5.14 • 3 colonies; Quebramar Cabedelo;
06°57′42″ S, 34°50′34″ W; 0–0.5 m depth; 25 Mar. 2013; L.M. Oliveira leg.; intertidal zone; DZUP
POSC-29 to POSC-31 • 1 colony; Pomar das Esponjas; 07°08′04″ S, 34°46′20″ W; 1–5 m depth; 12
Jan. 2009; Projeto Biota Paraíba leg.; snorkeling; LIPY UFPB TUN-176 • 2 colonies; Ponta do Cabo
Branco; 07o08′50″ S, 34o47′51″ W; 0–0.3 m depth; 28 Mar. 2013; L.M. Oliveira and R.M. Rocha leg.;
intertidal zone; DZUP POSC-15 to POSC-16, slides DZUP DID5.15 to DID5.16 • 4 colonies; Praia
de Carapibus; 7°16′19″ S, 34°48′07″ W; 0–0.3 m depth; 26 Mar. 2013; L.M. Oliveira and R.M. Rocha
leg.; intertidal zone; DZUP POSC-26 to DZUP POSC-28, LIPY UFPB TUN-396 • 5 colonies; Praia de
Coqueirinho; 07°16′19″ S, 34°48′07″ W; 0–0.3 m depth; 27 Mar. 2013; L.M. Oliveira and R.M. Rocha
leg.; intertidal zone; DZUP POSC-18 to POSC-22 • 3 colonies; same collecting data as for preceding but
3 Jun. 2008; Projeto Biota Paraíba leg.; intertidal zone; LIPY UFPB TUN-153, LIPY UFPB TUN-156. –
Pernambuco • 1 colony; Goiana, Pontas de Pedras; 07°37′17″ S, 34°48′15″ W; 13 Dec. 2013, J. Nogueira
leg.; intertidal zone; DZUP POSC-045. – Espírito Santo • 2 colonies; Carapebus; 20°13″46.02″ S,
40°12′12.67″ W; 0–0.3 m depth; 24 Jan 2012; G.A. Gamba leg.; intertidal zone; DZUP POSC-055, slide
DZUP DID5.06 • 3 colonies; Aracruz, Santa Cruz; 20°01′53.12″ S, 40°09′29.22″ W; 0–0.3 m depth; 25
Jan. 2012; G.A. Gamba leg.; intertidal zone; DZUP POSC-056 to POSC-057, DZUP POSC-059, slides
DZUP DID5.07 to DID5.08, DZUP DID5.10.
GHANA: 7 colonies; Elmira Gold Coast; 11 Oct. 1938; F.R. Irvine and V.G. Foote leg.; NHM
1959.5.27.23, NHM 1959.5.27.24 • 1 colony; Elmira Gold Coast; 28 Dec. 1932, E.D. Plumptre leg.;
NHM 1937.1.5.1.
PUERTO RICO • 1 colony; 10 Jul 1915; AMNH 797 • 1 colony; 30 Jun 1915; AMNH 798.
UNITED STATES – Florida • several colonies; Atlantic side, Biscayne Bay, banks near Soldiers Keys;
3 Mar. 1916; W.G Van Name leg.; AMNH 314 • 2 colonies; Gulf of Mexico, St. Teresa, seagrass beds;
29°53′41.3″ N, 84°33′23.4″ W; 2 m depth; 7 Nov 2011; sand; UF 1127 • 1 colony; Gulf of Mexico, north
of St. Petersburg; 29°01′40.8″ N, 83°35′19.3″ W; 18–20 m depth; 12 Mar 2011; G. Paulay, M. Bemis
and N. Evans leg.; UF 1037 • 5 colonies; Gulf of Mexico, Hudson; 28°21′05.4″ N, 82°55′04.8″ W; 6 m
depth; 2 May 2011; G. Paulay leg.; UF 1749, slide DZUP DID5.09 • 1 colony; Gulf of Mexico, Dry
Tortugas, n° 23; 10 Jun. 1931; Tandy-Colman leg.; NHM 1931.12.25.2 • 1 colony; Gulf of Mexico, off
Florida; 26°16′49″ N, 82°44′01″ W; 30.4 m depth; 19 Jul. 1981; USNM 17364.
Emended description
The specimen in NHM 1914.5.18.103 (Bermuda) has not been dissected because of the small size of
the colony. It has a gelatinous and transparent tunic, without spicules, through which zooids could be
seen on the colony surface without a pattern of organization. The specimen from the Atlantic coast of
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European Journal of Taxonomy 519: 1–25 (2019)
Florida (AMNH 314) has a brownish colour, is also small (3 cm in diameter and 1 mm thick), with
several cloacal apertures and a spicule layer on the colony surface. The zooids are brownish and the
atrial languet is bifurcated. The lateral thoracic organ is circular and protruding at the level of the 2nd
row of stigmata. The abdomen has a glandular tissue. The testis has three follicles surrounded by four
coils of the sperm duct. Other specimens from the Gulf of Mexico (USNM 17364; Fig. 2; UF 1037,
UF 1127 and UF 1749) have an atrial languet with a flat tip rather than bifurcated and testis with four
follicles surrounded by five coils of the sperm duct. The glandular tissue in the abdomen has not been
observed. Larvae were found in sample UF 1749 only. They look like those found in the specimens from
São Paulo, Brazil. The specimens from Puerto Rico (AMNH 797 and AMNH 798) are similar in spicule
density and zooid morphology to the samples from the Gulf of Mexico.
The colonies from Ghana (NHM 1959.5.27.23-24) are less than 3 cm in diameter. In contrast with the
information given about this sample by Millar (1953), the larval trunk is 0.8 mm long. The colonies are
pinkish-purple, gelatinous, the colony surface is smooth, shiny and marked with a spicule accumulation
around the oral siphons. The zooids are 0.8–1.0 mm long. The oral siphon has six short triangular lobes.
The atrial aperture is small. The atrial languet is bifurcated, sometimes with a flat tip. The lateral thoracic
Fig. 2. Polysyncraton amethysteum (Van Name, 1902), Florida (USNM 17364). a. Thorax with
bifurcated atrial languet (small arrow) and thoracic organ (big arrow). b. Stained abdomen, sperm duct
with five coils (arrow). c. Detail of the testis with four follicles and sperm duct with four coils (arrow).
Scale bars: 0.1 mm.
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
Fig. 3. Polysyncraton amethysteum (Van Name, 1902), Paraíba, Brazil. a–b. Colonies in situ.
c–d. Colony surface detail (arrow indicates one cloacal aperture) (DZUP POSC-14 and DZUP POSC13, respectively). e. Cross section of the colony, with thin layer of spicules (arrow) (DZUP POSC-14).
f. Spicules. Scale bars: e = 1 mm; f = 10 µm.
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European Journal of Taxonomy 519: 1–25 (2019)
Fig. 4. Polysyncraton amethysteum (Van Name, 1902), Brazil (DZUP DID-034, POSC-016; LIPY UFPB
TUN-293). Structures stained with hemalum. a. Thorax, atrial languet (arrow). b. Abdomen showing the
position of the testis (arrow). c–f. Larvae in Brazilian specimens from São Paulo (c) and Paraíba (d–f),
different stages in the same colony (e–f). Scale bars: 0.1 mm.
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
organs are circular, not protruding and located in the anterior region of the thorax at the level of the 2nd
row of stigmata, close to the atrial aperture. The pharynx has six stigmata per half row. The abdomen
is positioned horizontally in relation to the thorax. The secondary gut loop overlays the stomach. The
testis is divided in five follicles surrounded by three coils of the sperm duct. The larvae are present on the
colony surface. They are elliptical, gemmiparous, uncoloured, trunk measuring 0.8–1.0 mm. A tail with
a diameter of 35 µm winds about halfway around the trunk. Three adhesive papillae are close together.
The sucker of the central adhesive papilla is 100 µm in diameter. There are six elongated ectodermal
ampullae on each side. The sensorial vesicle lays in the posterior region of the larval trunk. The ocellus
is 40 µm long. The distance between ocellus and anterior region of the tail is 200 µm. Larva with two
embryos: oozoid dorsal and blastozooid ventral.
The morphological characteristics of the zooids of the Brazilian specimens are very similar to those
observed by Van Name (1902), although the variation in colony colour and spicule density is much
larger in Brazil. The colour varies from purple to brick. The colonies are 3 to10 cm in diameter and 1 to
3 mm thick (Fig. 3). The atrial languet can be bifurcated or with a flat tip. The pharynx has seven to nine
stigmata per half row. The lateral thoracic organ is circular and protruding at the level of the 2nd row of
stigmata. The testis has three to five follicles (even in zooids of the same colony), surrounded by three to
five coils of the sperm duct. The larva is gemmiparous, with a trunk that is 0.8 to1.0 mm long. A tail 85
to 90 µm wide winds about three-quarters of the way around the trunk. The peduncles of the adhesive
papillae are long, while the sucker of the central adhesive papilla is 63 to 80 µm in diameter. There are
six or eight pairs of ectodermal ampullae, but four pairs in different stages of duplication were seen in
immature larvae (Fig. 4c–f). The sensorial vesicle is in the mid or posterior dorsal region of the larval
trunk. The ocellus is 56 to 60 µm long. The distance between the ocellus and the anterior region of the
tail is 185 to 238 µm. The pharynx of the oozooid has 8, 7, 6, 6 stigmata on each half row.
Remarks
Lotufo (2002) claimed that Brazilian specimensof this species differ from the ones described by Van
Name (1902) in the different arrangement of spicules and in the single cloaca per colony. However,
Fig. 5. Maximum likelihood tree of species of Polysyncraton based on analysis of 16 sequences of
mitochondrial COI. Numbers on or below branches represent the support value of the bootstrap for
Maximum likelihood (> 70%) and posterior Bayesian probabilities (> 0.97). Abbreviations of Brazilian
states are explained in Table 1.
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European Journal of Taxonomy 519: 1–25 (2019)
the colonies studied by us showed a huge variation in colour, spicule density and cloaca number as
also observed by Pérès (1949) and Millar (1953) in African specimens. Lotufo (2002) also mentioned
having studied a sample from the type series deposited in the American Museum of Natural History,
with very large larvae (1.5 mm trunk length), but we were not able to find and examine this sample in
the museum collection. The only sample close to the type locality with available larvae was one from
Florida (UF1749), with larvae whose trunk varies from 0.8 mm to 1.2 mm within the same colony. F.
Monniot (2016) compared specimens from French Guiana with those from Bermuda and concluded that
they belonged to the same species.
Molecular analyses (ML and IB) also suggest the existence of only one valid species. Samples from
Panama to south Brazil grouped in one clade, corresponding to P. amethysteum with a significant
bootstrap value (95%) and posterior probability support (IB = 1) (Fig. 5). Although this clade seems to
be split in two branches, one of them does not have enough bootstrap support. The intraspecific genetic
divergence (p-distance) among haplotypes ranged from 0.7 to 9.8%, while the interspecific divergence
with P. lacazei was ~22%, and with P. poro was ~27%. Based on genetic evidence and the lack of clear
morphological separation in the samples examined, we consider that they all belong to P. amethysteum,
a species with a large phenotypic variation.
The haplotype UPDID096-17 from Rio de Janeiro, in contrast, is a different species with 12.4 to 14.9 %
distance from P. amethysteum, and will be commented on later (Polysyncraton sp.).
Distribution
Type locality: Bermuda (Van Name 1902). Other localities: United States – Florida (Van Name 1945),
Puerto Rico, Cuba, Belize (Goodbody 2000; Van Name 1945), Guadeloupe, Martinique (Gravier 1955),
Panama (this study), Colombia (Van Name 1945), French Guiana (F. Monniot 2016), Brazil – Ceará to
Santa Catarina (Millar 1977; Lotufo 2002; Rocha et al. 2012), Cape Verde, Senegal, Ghana (Pérès 1948;
Millar 1953; C. Monniot & F. Monniot 1967).
Polysyncraton cabofriense Oliveira & Rocha sp. nov.
urn:lsid:zoobank.org:act:356E2138-BAED-47B4-8E06-8182B064EB7B
Fig. 6
Etymology
The name refers to the region where the species was found.
Material examined
Holotype
BRAZIL • 1 colony; Rio de Janeiro, Cabo Frio, Pargos Island, Enseada do Pinguim; 22°51′10″ S,
41°54′22″ W; ~10 m depth; 7 May 2014; L.F. Skinner leg.; scuba; DZUP POSC-50, slide DZUP DID5.02.
Paratypes
BRAZIL • 2 colonies; same collecting data as for holotype; DZUP POSC-46, DZUP POSC-49, slide
DZUP DID5.05 • 2 colonies; Comprida Island, Ponta Leste; 22°51′41″ S, 41°56′12″ W; ~8 m depth;
6 May 2014; L.F. Skinner leg.; DZUP POSC-47, DZUP POSC-48, slides DZUP DID5.03, DZUP
DID5.04.
Description
Living colonies are yellowish, with a diameter of 3 to 15 cm and a thickness of 2 to 3 mm. When preserved
in formalin, colonies usually lose their colour and become cream coloured, sometimes white. They have
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
Fig. 6. Polysyncraton cabofriense Oliveira & Rocha sp. nov. (DZUP POSC-50). a. Colony in situ.
b. Colony surface (arrows indicating common cloacal apertures with lobes). c. Spicules. d. Thorax
stained (big arrow indicating the lateral thoracic organ and small arrow the atrial languet). e. Abdomen
(arrow indicating the sperm duct coil). f. Larva. Scale bars: d–f = 0.1 mm. Photo (a) courtesy of L.S.
Skinner.
11
European Journal of Taxonomy 519: 1–25 (2019)
an irregular shape, molding themselves to the substrate. The colony surface has several common cloacal
apertures, each one with short lobes (Fig. 6a–b). The tunic is firm, brittle and smooth. Green algae were
observed on the surface of some colonies. Spicules are distributed in the whole tunic, with relatively high
concentrations on each side of the thorax at the level of the lateral thoracic organ. There are two kinds
of spicules: stellate, 32 to 40 µm in diameter, with 6 or 7 blunt-tipped conical rays in transverse optical
section; others are smaller (25 to 28 µm in diameter), with round and short rays (Fig. 6c).
Zooids are 0.8 to 1.0 mm long. The oral siphon has six small triangular lobes. The atrial aperture is wide,
exposing most of the pharynx. The atrial languet is pointed and thin (Fig. 6d) or wide and rounded. In
some specimens it was absent, probably lost during dissection. The lateral thoracic organs are circular,
not protruding and localised between the first and second rows of stigmata on the border of the atrial
aperture. The pharynx has seven stigmata in the first two half rows and six stigmata on the posterior two
half rows. The muscular process is lacking. The testis is divided in three oval follicles surrounded by
three coils of the sperm duct. The oocyte is single, measuring 0.6 mm.
The larvae are elliptical, gemmiparous, the trunk measuring 0.9 to 1.0 mm. A tail with a diameter of
95 µm winds about ¾ of a turn around the trunk. The three adhesive papillae show a short and wide
peduncle. The sucker of the central adhesive papilla is 124 µm in diameter. There are 10 pairs of rounded
ectodermal ampullae. The ocellus is 45 µm long and 346 µm distant from the anterior region of the tail.
Remarks
Only two species of Polysyncraton have been reported from Brazil, P. amethysteum with a distribution
along the whole coastline and P. maurizelae Paiva et al., 2015 from Rocas Atoll (Paiva et al. 2015).
Polysyncraton cabofriense sp. nov. differs from P. amethysteum by its colour, higher density of spicules,
lobed cloaca and larvae with more pairs of ectodermal ampullae. Polysyncraton maurizeliae has orange
colonies with smooth common cloacal apertures, zooids longer and with 12 stigmata in the 1st row, and
the lateral thoracic organ in the 3rd row. Among other species from the Atlantic, P. louminae F. Monniot,
1984 has a colony of similar shape and spicules, but the colony is grey, zooids have longer oral siphons
and two testis follicles surrounded by 3 to 5 coils of the sperm duct, and the larvae are not gemmiparous
and have more pairs of ectodermal ampullae (F. Monniot 1984).
Distribution
Type locality: Brazil (Rio de Janeiro).
Polysyncraton globosum Oliveira & Rocha sp. nov.
urn:lsid:zoobank.org:act:1BF4A55D-4A94-4598-8BC0-4A26E33EF5DD
Fig. 7
Didemnum (Polysyncraton) magnetae – Millar 1963: 702 (misidentification, not Hastings, 1931).
Etymology
The name refers to the shape of the colony.
Material examined
Holotype
AUSTRALIA • 1 colony; Bowerbank leg.; NHM 1866.3.21.21, slides NHM 1866.3.21.21, DZUP DID
5.12.
Paratype
AUSTRALIA • 1 colony; Bowerbank leg.; NHM 1866.3.21.20, slide NHM 1866.3.21.20.
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
Fig. 7. Polysyncraton globosum Oliveira & Rocha sp. nov., Australia (NHM 1866.3.21.21). a. Preserved
colony. b. Spicules. c. Thorax (big arrow indicates the lateral thoracic organ and small arrows the muscle
fibers present on each side of the thorax). d. Abdomen. e–f. Larva stained with hemalum (the arrows in
f indicate the membrane of the tail). Scale bars: b = 10 µm; c–d = 0.1 mm; e–f = 0.2 mm.
13
European Journal of Taxonomy 519: 1–25 (2019)
Description
The species is characterised by its globular colonies, 3.5 cm at maximum length (Fig. 7a). The tunic is
gelatinous and the colony surface is smooth. The spicules are distributed in low density, mainly on the
colony surface. Just one cloacal aperture with a smooth edge was observed in each colony. The globular
spicules are 20 to 30 µm in diameter and have numerous thin rays (16 to 18 rays in optical transverse
section) (Fig. 7b).
The thorax has 12 conspicuous muscle bundles on each side (Fig. 7c). The oral siphon has six triangular
lobes. The atrial languet is bifurcated but was lost in some thoraces when the zooids were dissected.
The lateral thoracic organ is circular, not protruding, located at the level of the 1st row of stigmata, in the
middle of the thorax (Fig. 7c). The second gut loop does not overlay the stomach. The testis is divided
in six follicles surrounded by two or three coils of the sperm duct (Fig. 7d), although the description
by Millar (1963) mentioned up to eight follicles. Larvae are elliptical, the trunk 1.0 to 1.3 mm long
(Fig. 7e). The tail winds about ¾ of the way around the trunk. At the left side of the larva, it is possible to
see a wide membrane projecting from the sides of the tail (Fig. 7f). The three adhesive papillae with long
and thin peduncles are close together and there are eight pairs of rectangular ectodermal ampullae. The
Fig. 8. Polysyncraton magnetae Hastings, 1931, type specimen (NHM 1930.12.17.46). a. Preserved
colony. b. Cross section of the colony showing cavities found in the median region (arrows). c. Spicules.
d. Cross section of a decalcified colony. Scale bars: a = 1 cm; c = 10 µm.
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
sensory vesicle is in the central region of the larval trunk, with the ocellus and estatocyte close together.
The larva is not gemmiparous.
Remarks
These Australian specimens, which were deposited at the Natural History Museum in London,
have previously been identified as P. magnetae Hastings, 1931 by Millar (1963). The sample NHM
1930.12.17.46 from the Great Barrier Reef, Stat. XXIII, R/V “Magneta”, collected on 12 Mar. 1929 is
part of the type series of P. magnetae and was re-examined (Fig. 8). Although also looking globular,
the colony is not as solid as in P. globosum sp. nov. and has a high density of spicules in the tunic,
with cylindrical rays of a larger diameter and in a smaller number than in P. globulosum (Fig. 8). The
atrial languet in P. magnetae is almost imperceptible, short and pointed, and could be missed during
dissection, although Hastings (1931) described it as large. Unfortunately, the larva of P. magnetae is
not known for comparison with congeneric species. Kott (2001) also realised that Millar’s identification
was wrong and suggested that the NHM material belonged to P. meandratum F. Monniot, 1993. We do
not agree with this suggestion because P. meandratum has thin and sheet-like colonies, an atrial languet
larger than those observed in P. globosum sp. nov., less male follicles and a larva less than half the size
of that of P. globosum sp. nov. (F. Monniot 1993).
Distribution
Type locality: Australia (Millar 1963).
Polysyncraton magnilarvum (Millar, 1962)
Fig. 9
Didemnum (Polysyncraton) magnilarvum Millar, 1962: 165, fig. 25.
Material examined
MADAGASCAR • 3 slides; South Madagascar, further collecting data unknown; MNHN A2-2466,
MNHN A2-2767, MNHN A2-2470.
Emended description
The specimen from Magadascar has a long and trifurcated atrial languet (Fig. 9a), while Millar’s material
from Mozambique has a short atrial languet (Millar 1962). The lateral thoracic organs are circular and
not protruding, localised in the anterior half of the thorax at the level of the 1st row of stigmata, close to
the endostyle (Fig. 9b). The muscular process is longer than the abdomen, up to 1.4 mm in length and
inserted in the middle of the esophageal peduncle. The abdomen is positioned perpendicularly to the
thorax. The secondary gut loop does not overlay the stomach (Fig. 9a). The stoloniferous vessels are
small and rounded, and a glandular tissue in the shape of a crescent lays inside the gut loop on the right
side. The testis is slightly below the gut loop, divided in 10 to 12 follicles and surrounded by three to five
coils of the sperm duct (Fig. 9c–d). The larvae are elliptical, gemmiparous and the trunk is 1.4 mm long.
A tail with a diameter of 104 µm winds halfway around the trunk. The three adhesive papillae are close
to each other, with short peduncles. The sucker of the central adhesive papilla is 133 µm in diameter
and the peduncle is 401 µm long. There are 12 to 15 elongated ectodermal ampullae on each side of
the larva body, 113 to 333 µm long, depending on the developmental stage of the larva (Fig. 9e). The
sensorial vesicle (including ocellus and statocyte) is located in the mid-dorsal region of the larval trunk.
The ocellus is 57 µm long and 436 µm distant from the anterior region of the tail.
15
European Journal of Taxonomy 519: 1–25 (2019)
Remarks
This species was first reported from Mozambique by Millar in 1961, but the original description was
published later by him in 1962 (Millar 1962) with the following diagnostic characters: short atrial
languet, testis with eight to ten follicles surrounded by 2½ coils of the sperm duct and larva with 15
pairs of ectodermal ampullae. The sample from Madagascar has a larger atrial languet and a larger
number of testis follicles and coils of the sperm duct, but the larval characters are the same. Kott (1975)
synonymised it with P. aspiculatum Tokioka, 1949, but later, C. Monniot et al. (2001) confirmed that
Fig. 9. Polysyncraton magnilarvum (Millar, 1962), stained with hemalum. a. Zooid (arrow pointing at
atrial languet). b. Ventral view of the anterior region of the thorax (arrow indicating the lateral thoracic
organ). c. Testis follicles (arrow indicating one lobe). d. Abdomen (arrow indicates the sperm duct)
(MNHN A2-2466). e. Larva (MNHN A2-2467). Scale bars: a = 0.2 mm; c–e = 0.1 mm.
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OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
both species were valid and differentiated P. aspiculatum by its globular spicules, the larvae with a trunk
length of 1 mm of trunk length and eight pairs of ectodermal ampullae.
Distribution
Type locality: Mozambique (Millar 1962). South Madagascar (this study).
Polysyncraton purou C. Monniot & F. Monniot, 1987
Fig. 10
Polysyncraton purou C. Monniot & F. Monniot, 1987: 49, fig. 16d–h, pl. 3i.
Polysyncraton purou – F. Monniot 1993: 11. — Kott 2001: 126, figs 60, 162C, pl. 6F; 2002: 33, fig. 12A–
D; 2005: 2436, fig. 19D.
Material examined
TANZANIA • 3 slides; MNHN A2-843, MNHN A2-846, MNHN A2-847.
Remarks
This species was described from French Polynesia by C. Monniot & F. Monniot (1987). All the
characteristics of the specimens from Tanzania correspond to those in the original description (Fig. 10),
thus enlarging the known distribution of this species.
Monniot & Monniot (2001) described P. vestiens from Palau as a different species from P. purou based
on the smaller spicules, a wider atrial aperture and the absence of the muscular process in P. vestiens.
However, in the specimens from Tanzania there is a variation in the size of the spicules and they are
smaller (43 to 55 µm) than in specimens from Tahiti. The muscular process in P. purou is very small and
not visible in some zooids (Fig. 10a–b). Since the size of the atrial aperture is also a variable character
that depends on the contraction of the zooid, there is doubt as to whether P. vestiens is a valid species.
Distribution
Type locality: French Polynesia (C. Monniot & F. Monniot 1987). Australia (Kott 2001), New Caledonia
(F. Monniot 1993) and Tanzania (this study).
Polysyncraton snelliusi Oliveira & Rocha sp. nov.
urn:lsid:zoobank.org:act:650A74FA-077A-46B4-B1EF-9BF5CC2B44E6
Fig. 11
Etymology
The name refers to the campaign vessel that collected the material.
Material examined
Holotype
SURINAME • 1 colony; Guiana Shelf, stat. 97; 07°16.8′ N, 56°47.6′ W; 64 m depth; 13 Apr. 1966;
HNLMS Snellius leg.; Onderzoek Continentaal Plat Suriname (OCPS); RMNH.UROCH.1109.
Description
The colony is yellowish in preserved material, measuring 8 cm in diameter and 2 mm thick. It has an
irregular shape, molding itself on top of a sponge. The colony surface has several common cloacal
apertures with six to eight short lobes each (Fig. 11b). The cloacal cavity is wide and positioned at the
17
European Journal of Taxonomy 519: 1–25 (2019)
Fig. 10. Polysyncraton purou C. Monniot & F. Monniot, 1987, with structures stained with hemalum
(MNHN A2-843). a. Zooid with bifurcated atrial languet (arrow). b. Thorax with button-like atrial
languet (big arrow) and muscular process (small arrow). c. Abdomen with gonads (large arrow indicates
oocyte). d. Immature larva. e. Mature larva. Scale bar: 0.1 mm.
18
OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
thoracic level. The tunic is firm, brittle and with many papillae associated with one of the lobes of the
oral siphons. The zooids form circular systems around the cloaca and also linear systems along the
cloacal channels, which are marked by a depression on the colony surface. They have a brown colour,
leaving white circular or irregular patches on the colony surface (Fig. 11c). Two types of stellate spicules
are distributed in the tunic. The larger ones (40 to 60 µm in diameter) have six rays in transverse optical
section, but many other shorter rays among the main ones. Also, the rays are either blunt or more
pointed. The smaller spicules (23 to 50 µm in diameter, a few to 60 µm), have seven to eight conical rays
with round tips in transverse optical section, without intermediate rays (Fig. 11d).
The zooids are 1.0 mm long. The oral siphon is short (0.2 mm), with six long triangular lobes. The
atrial aperture is wide, exposing almost all the pharynx, without an atrial languet. The pharynx stigmata
formula is 12, 12, 11, 9. The lateral thoracic organs are circular, not protruding and localised at the
level of the 2nd row of stigmata. The muscular process is lacking. The esophageal peduncle is short and
straight. The testis is divided in four follicles surrounded by three coils of the sperm duct. The secondary
gut loop does not overlay the stomach (Fig. 11e).
The larvae are elliptical, not gemmiparous, with the trunk 0.8 to 0.9 mm long. A tail with a diameter of
116 µm winds halfway around the trunk. The sucker of the central adhesive papilla is 95 µm in diameter
and the peduncle is 235 µm long. There are 12 to 14 elongated, thin ectodermal ampullae on each side
of the larva, 105 to 120 µm long (Fig. 11f). The sensorial vesicle (including ocellus and statocyte) is
slightly posterior to the mid-dorsal region of the larval trunk. The ocellus is 54 µm long and 361 µm
distant from the anterior region of the tail.
Remarks
Eight species of Polysyncraton have been reported from the Atlantic Ocean (Rocha et al. 2012; Paiva
et al. 2015) and none of them look like the one described herein. Polysyncraton snelliusi sp. nov. can
be distinguished from P. cabofriense sp. nov. by the absence of papillae on the colony surface and the
presence of gemmiparous larvae in the latter. Among other species with papillae on the colony surface,
P. echinatum Kott, 2001 has a gelatinous tunic, stellate spicules without secondary rays and smaller
larvae (trunk 0.6 mm long), with four subdividing ectodermal ampullae on each side; P. meandratum
F. Monniot, 1993 has globular spicules with flat-tipped rays, a bifurcated atrial languet and larvae with
eight pairs of ectodermal ampullae; P. pseudorugosum F. Monniot, 1993 has stellate spicules with sharp
pointed rays and deeper common cloacal canals, seven testis follicles and smaller larvae with eight pairs
of ectodermal ampullae.
Distribution
Type locality: Suriname (Guyana Shelf).
Polysyncraton sp.
Fig. 12
Material examined
BRAZIL • 1 colony; Rio de Janeiro, Cabo Frio, Pargos Island, Enseada do Pinguim; 22°51′10″ S,
41°54′22″ W; ~10 m depth; 7 May 2014; L.F. Skinner leg.; DZUP POSC-033, slide DZUP DID5.29.
Remarks
The colony is orange in situ, measuring 3 cm in diameter and 1 to 2 mm thick. The tunic is firm and
gelatinous. The cloacal aperture has five lobes. The spicules are distributed in the colony surface only
and are more concentrated around the oral siphon of each zooid. They are burr-like, with a large number
19
European Journal of Taxonomy 519: 1–25 (2019)
Fig. 11. Polysyncraton snelliusi Oliveira & Rocha sp. nov. a. Preserved colony. b. Colony surface (arrow
indicates the common cloacal aperture with lobes). c. Papillae on the colony surface. d. Spicules (large
type). e. Abdomen with gonads, large arrow indicates the follicle (one follicle hidden) and the small
arrow the sperm duct. f. Larva. Scale bars: e–f = 0.2 mm.
20
OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
of rays, 15 to 25 µm in diameter. The zooids are orange. The oral siphon is short, with six triangular
lobes. The atrial aperture is wide, exposing almost all the pharynx, with 9, 9, 8, 8–7 stigmata per half
row. The atrial languet is large and bifurcated. The lateral thoracic organ is circular, not protruding,
located at the level of the 1st row of stigmata. The muscular process is shorter than the abdomen, inserted
in the middle of the esophageal peduncle. The testis is divided in four follicles surrounded by four coils
of the sperm duct. Larvae were not found.
In the phylogenetic reconstruction (Fig. 5), this species (UPDID096-17) is separate from P. amethysteum,
from which it differs by the colour of the colony, lobed cloaca and the position of the lateral thoracic
organ. Lotufo (2002) reported orange specimens from Rio de Janeiro and Espírito Santo, but we were
able to examine the sample from Angra dos Reis and concluded that Lotufo’s sample (ColBio Tun 1245)
actually belongs to the genus Leptoclinides Bjerkan, 1905.
Fig. 12. Polysyncraton sp. a. Preserved colony. b. Thorax. c. Abdomen. Scale bars: a = 1 cm; b–c =
0.1 mm.
21
European Journal of Taxonomy 519: 1–25 (2019)
This species differs from P. cabofriense sp. nov., by the colour of the colony, the abundance, shape and
position of the spicules, and in having more follicles and coils of the sperm duct. Given the single colony
found and lack of larvae we prefer not to name it, although characters suggest that it is an undescribed
species.
Distribution
Brazil: Rio de Janeiro (this study).
Discussion
Didemnidae is one of the largest families in Ascidiacea and its interspecific differentiation is usually
achieved by the combination of characters, among which larval characters are usually very important. For
Polysyncraton, the spicule density, distribution, shape and size, the size of the lateral organ, the number
of testicular follicles and coils of the sperm duct, the size of the larva, the gemmiparous condition and
the number of ectodermal ampullae are known as the most important characters to differentiate species
(Kott 1962; F. Monniot 1984). We have also observed specific differences in the colour and shape of the
colony (sheet-like or globose) and the cloaca rim (smooth or lobed).
Unfortunately, formalin fixation is routine in protocols of ascidian preservation (C. Monniot & F. Monniot
1972), even though samples are maintained in ethanol for long term preservation in museum collections.
Thus, genetic studies are only possible with samples specifically collected for this purpose and we were
only able to use genetic evidence to delimit species from samples recently collected along the Brazilian
coast. This genetic study was useful to demonstrate that P. amethysteum has a large distribution range
along the West Atlantic and the Gulf of Mexico, with a lot of variation in colour, spicule density, number
of testicular follicles and sperm duct coils, and larva size.
Most of the diversification in Polysyncraton is found in the Indo-Pacific, with Australia being the beststudied country (Kott 2001). Genetic studies with the goal to understand the evolution of this genus will
have to focus on the biodiversity in this region. Even though the Pacific is the most species-rich region,
we were able to identify a new species (Polysyncraton globosum sp. nov.) from Australia, which has
almost 45% of all Polysyncraton species currently known.
Considering that only three species of Polysyncraton were previously known from the tropical West
Atlantic (P. amethysteum, P. louminae and P. maurizelae), the two new species from this region here
described, and another possibly undescribed species, represent a significant contribution. It is important to
also emphasize that sampling efforts in the West Atlantic and Gulf of Mexico are still not comprehensive
and other species are expected to be discovered.
Acknowledgments
We would like to thank Françoise Monniot and Tito Lotufo for allowing us to borrow samples, Luis
Felipe Skinner for his help during the field work and Miranda Lowe, Linda Cole and Estefanía Rodriguez
for receiving LMO at the NHM, USNM and AMNH. Naturalis Biodiversity Center offered logistical
support. CNPq (141490/2014-4, 201086/2015-SWE, 445783/2014-1) financed part of this project, and
the National Science Foundation (DEB-1456674) financed LMO’s visit to the American collections.
References
Goodbody I. 2000. Diversity and distribution of ascidians (Tunicata) in the Pelican Cays, Belize. Atoll
Research Bulletin 480: 303–333. Available from https://repository.si.edu/handle/10088/5860 [accessed
20 Mar. 2019].
22
OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
Gravier R. 1955. Ascidies récoltées par le « Président Théodore Tissier » (Campagne de Printemps
1951). Revue des Travaux de l’Institut des Pêches maritimes 19: 611–631.
Hartmeyer R. 1912. Die Ascidien der Deutschen Tiefsee-Expedition. Deutsche Tiefsee-Expedition 16:
225–392.
Hastings A.B. 1931. Tunicata. Great Barrier Reef Expedition 1928–29. Scientific Reports 4: 69–110.
Available from https://biodiversitylibrary.org/page/49516617 [accessed 20 Jul. 2018].
Kott P. 1962. The ascidians of Australia. 3. Aplousobranchiata Lahille: Didemnidae Giard. Australian
Journal of Marine and Freshwater Research 13 (3): 265–334.
Kott P. 1975. The Ascidians of South Australia. III. Northern Sector of the Great Australian Bight and
additional records. Transactions of the Royal Society of South Australia 99 (1): 1–20.
Available from https://biodiversitylibrary.org/page/41070575 [accessed 20 Jul. 2018].
Kott P. 2001. The Australian Ascidiacea. Part 4, Aplousobranchia (3), Didemnidae. Memoirs of the
Queensland Museum 47 (1): 1–410.
Available from https://biodiversitylibrary.org/page/40460926 [accessed 20 Jul. 2018].
Kott P. 2002. Ascidiacea (Tunicata) from Darwin, Northern Territory, Australia. The Beagle: Records of
the Museums and Art Galleries of the Northern Territory 18: 19–55.
Kott P. 2005. Ascidians from the Solomon Islands. The Beagle: Records of the Museums and Art
Galleries of the Northern Territory 21: 53–66.
Lotufo T.M.C. 2002. Ascidiacea (Chordata: Tunicata) do litoral tropical brasileiro. PhD Thesis.
Instituto de Biociências da Universidade de São Paulo, Brazil.
Lotufo T.M.C. & Silva A.M.B. 2006. Ascidiacea do litoral Cearense. In: Matthews-Cascon H. & Lotufo
T.M.C. (eds) Biota marinha da Costa Oeste do Ceará: 221–247. Série Biodiversidade 24, Ministério do
Meio Ambiente, Fortaleza, Brazil.
Millar R.H. 1953. On a collection of ascidians from the Gold Coast. Proceedings of the Zoological
Society of London 123 (2): 277–325. https://doi.org/10.1111/j.1096-3642.1953.tb00176.x
Millar R.H. 1958. Some ascidians from Brazil. Annals and Magazine of Natural History 1: 497–514.
https://doi.org/10.1080/00222935808650975
Millar R.H. 1962. Further descriptions of South African ascidians. Annals of the South African Museum
46 (7): 113–196.
Millar R.H. 1963. Australian ascidians in the British Museum (Natural History). Proceedings of the
Zoological Society of London 141 (4): 689–746. https://doi.org/10.1111/j.1469-7998.1963.tb01623.x
Millar R.H. 1977. Ascidians (Tunicata: Ascidiacea) from the northern and north-eastern Brazilian shelf.
Journal of Natural History 11: 169–223. https://doi.org/10.1080/00222937700770131
Miller M.A., Pfeiffer W. & Schwartz T. 2010. Creating the CIPRES Science Gateway for Inference of
Large Phylogenetic Trees. Gateway Computing Environments Workshop, New Orleans.
https://doi.org/10.1109/GCE.2010.5676129
Monniot C. & Monniot F. 1967. Tuniciers benthiques. Annales de l’Institut océanographique 2: 1–18.
Monniot C. & Monniot F. 1972. Clé mondiale des genres d’ascidies. Archives de Zoologie expérimentale
et générale 113: 311–367.
Monniot C. & Monniot F. 1987. Les ascidies de Polynésie française. Mémoires du Muséum national
d’Histoire naturelle, Zoologie 136: 1–155.
23
European Journal of Taxonomy 519: 1–25 (2019)
Monniot C., Monniot F. & Laboute P. 1991. Coral Reef Ascidians of New Caledonia. Editions de
l’ORSTOM 30, Muséum national d’Histoire naturelle, Paris.
Monniot C., Monniot F., Griffiths C.L. & Schleyer M. 2001. South African ascidians. Annals of the
South African Museum 108 (1): 1–141.
Available from https://biodiversitylibrary.org/page/40905473 [accessed 20 Jul. 2018].
Monniot F. 1984. Ascidies littorales de Guadeloupe VIII. Questions de systématique évolutive posées
par les Didemnidae. Bulletin du Muséum national d’Histoire naturelle, 4ième série 6ª (4): 885–905.
Monniot F. 1993. Ascidies de Nouvelle-Calédonie XIII. Le genre Polysyncraton. Bulletin du Muséum
national d’Histoire naturelle, 4ième série 15ª (1–4): 3–17.
Monniot F. 2016. Ascidians (Tunicata) of the French Guiana Expedition. Zootaxa 4114 (3): 201–245.
https://doi.org/10.11646/zootaxa.4114.3.1
Monniot F. & Monniot C. 2001. Ascidians from the tropical western Pacific. Zoosystema 23 (2): 201–
383.
Moure J.S., Björnberg T.K.S & Loureiro T.S. 1954. Protochordata ocorrentes na entrada da Baía de
Paranaguá. Dusenia 5: 233–242.
Oliveira F.A.S., Michonneau F. & Lotufo T.M.C. 2017. Molecular phylogeny of Didemnidae (Ascidiacea:
Tunicata). Zoological Journal of the Linnean Society 20: 1–10.
https://doi.org/10.1093/zoolinnean/zlw002
Paiva S.V., Oliveira-Filho R.R. & Lotufo T.M.C. 2015. Ascidians from Rocas Atoll, northeast Brazil.
Frontiers in Marine Science 2: 1–20. https://doi.org/10.3389/fmars.2015.00039
Pérès J.M. 1948. Note sur deux espèces d’ascidies du Gulf de Marseille. Bulletin du Musée d’Histoire
naturelle de Marseille 8 (2–3): 54–61.
Pérès J.M. 1949.Contribution à l’étude des ascidies de la côte occidentale d’Afrique. Bulletin de l’Institut
français d’Afrique noire 11 (1–2): 159–207.
Rambaut A. 2014. Figtree: Tree Figure Drawing Tool Version 1.4.2. Institute of Evolutionary Biology,
University of Edinburg. Available from http://tree.bio.ed.ac.uk/software/figtree/ [accessed 20 Jul. 2018].
Rocha R.M., Moreno T.R. & Metri R. 2005. Ascídias (Tunicata, Ascidiacea) da Reserva Biológica
Marinha do Arvoredo, Santa Catarina, Brasil. Revista Brasileira de Zoologia 22: 461–476.
Rocha R.M., Zanata T.B. & Moreno T.R. 2012. Keys for the identification of families and genera of
Atlantic shallow water ascidians. Biota Neotropica 12: 269–303.
https://doi.org/10.1590/S1676-06032012000100022
Rodrigues S.A. 1962. Algumas ascidias do litoral sul do Brasil. Boletim da Faculdade de Filosofia,
Ciências e Letras, Universidade de São Paulo 24: 193–216.
Ronquist F., Teslenko M., Van Der Mark P., Ayres D.L., Darling A., Höhna S., Larget B.,
Liu L., Suchard M.A. & Huelsenbeck J.P. 2012. MrBayes 3.2: Efficient bayesian phylogenetic
inference and model choice across a large model space. Systematic Biology 61 (3): 539–542.
https://doi.org/10.1093/sysbio/sys029
Sluiter C.P. 1909. Die Tunicaten der Siboga Expedition. Pt II. Die merosomen Ascidien. SibogaExpeditie 56B: 1–112.
Stamatakis A. 2006. Phylogenetic models of rate heterogeneity: a high performance computing
perspective. Proceedings of the 20th IEEE/ACM International Parallel and Distributed Processing
Symposium (IPDPS 2006). Rhodos, Greece.
24
OLIVEIRA L.M. et al., Re-examination of specimens and three new species of Polysyncraton
Stamatakis A. 2014. RAxML version 8: A tool for phylogenetic analysis and post-analysis of large
phylogenies. Bioinformatics 30: 1312–1313. https://doi.org/10.1093/bioinformatics/btu033
Stefaniak L., Lambert G., Gittenberger A., Zhang H., Lin S. & Whitlatch R.B. 2009. Genetic
conspecificity of the worldwide populations of Didemnum vexillum Kott, 2002. Aquatic Invasions 4:
29–44. https://doi.org/10.3391/ai.2009.4.1.3
Van Name W.G. 1902. The Ascidians of the Bermuda Islands. Transactions of the Connecticut Academy
of Arts and Sciences 11: 325–412. Available from https://www.biodiversitylibrary.org/page/13464308
[accessed 20 Jul. 2018].
Van Name W.G. 1921. Ascidians of the West Indian region and south eastern United States. Bulletin of
the American Museum of Natural History 44: 283–494.
Van Name W.G. 1945. The North and South American ascidians. Bulletin of the American Museum of
Natural History 84: 1–476.
Manuscript received: 26 July 2018
Manuscript accepted: 18 January 2019
Published on: 23 April 2019
Topic editor: Rudy Jocqué
Desk editor: Kristiaan Hoedemakers
Printed versions of all papers are also deposited in the libraries of the institutes that are members of
the EJT consortium: Muséum national d’Histoire naturelle, Paris, France; Meise Botanic Garden,
Belgium; Royal Museum for Central Africa, Tervuren, Belgium; Royal Belgian Institute of Natural
Sciences, Brussels, Belgium; Natural History Museum of Denmark, Copenhagen, Denmark; Naturalis
Biodiversity Center, Leiden, the Netherlands; Museo Nacional de Ciencias Naturales-CSIC, Madrid,
Spain; Real Jardín Botánico de Madrid CSIC, Spain; Zoological Research Museum Alexander Koenig,
Bonn, Germany.
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