Parathyone itapuaensis, Martins & Tavares, 2021

Martins, Luciana & Tavares, Marcos, 2021, A new species of Parathyone (Holothuroidea: Dendrochirotida: Cucumariidae) from northeastern Brazil, with a key to species, Zootaxa 4985 (2), pp. 245-252 : 246-250

publication ID	https://doi.org/ 10.11646/zootaxa.4985.2.7
publication LSID	lsid:zoobank.org:pub:422F6D31-D243-4051-82E6-6880F7090FD3
DOI	https://doi.org/10.5281/zenodo.5056432
persistent identifier	https://treatment.plazi.org/id/496787AA-FFF2-FF93-B691-F8FD77985693
treatment provided by	Plazi
scientific name	Parathyone itapuaensis
status	sp. nov.

Treatment

Parathyone itapuaensis sp. nov.

( Figures 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Type material. Holotype: 40 mm ( MZUSP 2089 View Materials ), 12°57’ S; 38°21’ W, Itapuã beach, Salvador, Bahia, Brazil, L.R. GoogleMaps Martins coll., 21.iv.2011, intertidal, found burrowed into soft sediments, underneath rocks. GoogleMaps Paratypes: 1 spec 40 mm ( UFBA 631 ), same data as holotype. GoogleMaps 1 spec 40 mm ( UFPB ECH 438 ), 07°04’ S; 34°49’ W, João Pessoa , Paraíba, Brazil GoogleMaps . 1 spec 100 mm ( MZUSP 2103 View Materials ), Ubatuba , São Paulo, Brazil . 5specs 10–25 mm ( MZUSP 2756 View Materials ), 12°57’ S; 38°21’ W, Itapuã beach, Salvador, Bahia, Brazil GoogleMaps . 5specs 10–25 mm ( MZUSP 2756 View Materials ), 12°57’ S; 38°21’ W, Itapuã beach, Salvador, Bahia, Brazil GoogleMaps .

Comparative material examined. Aslia pygmaea (Théel, 1886) , 2 specs 50–70 mm ( CASIZ 117956) [originally labeled as Ocnus pygmaeus ], 13.viii.1977, intertidal, Venezuela. 1 spec 50 mm ( USNM E 30519) [originally labeled as Ocnus pygmaeus ], 29.iv.1981, 27m, Georgia, EUA. Parathyone braziliensis ( Verrill, 1868) , Praia da Figueira, São Sebastião, São Paulo, Brazil: 1 spec 70 mm long ( MZUSP 1095), coll 14 October 1997. Ilha de Boipeba, Bahia, Brazil: 1 spec 40 mm ( MZUSP 1207), coll 22 June 2015. Prado, Bahia, Brazil: 1 spec. 40 mm long ( MZUSP 1147), coll 10 January 2015.Itapuã beach, Salvador, BA, Brazil, (12°57’ S; 38°21’ W), intertidal: 72 spec 10–60 mm long ( UFBA 0180), coll 03 November 2006. Itapuã beach, Salvador, BA, Brazil, (12°57’ S; 38°21’ W), intertidal, 1 spec 35 mm long ( MZUSP 1354), coll 05 April 2006. Itapuã beach, Salvador, BA, Brazil, (12°57’ S; 38°21’ W), intertidal, 24 spec 15–50 mm long ( MZUSP 1143), coll 31 January 2015.Itapuã beach, Salvador, BA, Brazil (12°57’ S; 38°21’ W): intertidal, 3 spec 35–40 mm long ( MZUSP 1383), coll 05 April 2008. Alagoas, Maceio, Brazil 1 spec 30 mm long ( MZUSP 1100), coll 31 May 2011.Passo do Camaragibe, Alagoas, Maceio, Brazil. 3 spec 25–30 mm long ( MZUSP 1094), coll 11 January 2011. MNHN-IE-2005 1237, 1238, 1239 [Slides of body wall and tentacles]. Parathyone surinamensis ( Semper, 1867) , 1 spec 40 mm ( USNM E27248) [originally labeled as Ocnus surinamensis ], 6.ii.1977, Limon Bay, Canal Zone, Panamá, Caribe. Parathyone suspecta ( Ludwig, 1875) , 2 specs 20–35 mm ( USNM E22299 View Materials ) [originally labeled as Ocnus (Urodemella) suspectus , 28.ii.1966, Andros island, Bahamas. 1 spec 40 mm ( ZBM – ECH 5687), Barbados. MNHN-IE-2005 3378, 33576 [Slides of body and tentacles].

Etymology. The specific name refers to the type locality: Itapuã.

Diagnosis. Length of anterior process (radial plate of the calcareous ring) larger than length of base of radial plate. Body wall buttons with triangular knobs; knobbed multiperforated plates in anal region. Two Polian vesicles and single madreporite.

Description. Body barrel-shaped to oval when fixed; tube feet scattered throughout body ( Fig. 1a View FIGURE 1 ). Ten dendritic tentacles, ventral pair reduced ( Fig. 1b View FIGURE 1 ). Anal papillae present ( Fig. 1c View FIGURE 1 ) Longitudinal muscles well developed ( Fig. 1d, e View FIGURE 1 ), split at anterior region ( Fig. 1e View FIGURE 1 ). Retractor muscle short and attached to the middle of radial plate ( Fig. 1g, i View FIGURE 1 ). Stone canal single, short, attached to round madreporite ( Fig. 1g View FIGURE 1 ). Two Polian vesicle ( Fig. 1h View FIGURE 1 ). Colour in ethanol brown

Plates of the calcareous ring lacking posterior processes. The radial and interradial plates of same height and laterally connected to each other for most of their length ( Fig.1i View FIGURE 1 ). MidIR (IR5) is not modified ( Fig.2b View FIGURE 2 ), and the midR (RI) is smaller than the other radials ( Fig.2c View FIGURE 2 ). Radial and interradial plates with pointy anterior region and strongly concave at base ( Fig.1 d–f View FIGURE 1 ). Anterior region of the radial plate slightly depression for attachment the RMA ( Fig. 2d View FIGURE 2 ). AP close together, anterior notch small ( Fig. 2d View FIGURE 2 ). Marginal grooves for AB deep, broad ( Fig. 2d View FIGURE 2 ). GV at inner region of radial plates conspicuous ( Fig. 2d View FIGURE 2 ). TCT X- to H-shaped ( Fig. 2f View FIGURE 2 ). Size of radial plates varies; radial plates usually wider than interradial plates.

Body wall ossicles four holed-knobbed buttons with triangular knobs at the center (60–120 μm long, Fig. 3a–b View FIGURE 3 ; fig 4a–c); four-holed to multilocular shallow cups (35–45 μm long, Fig. 3c–d View FIGURE 3 ); knobbed perforated plates (60–100 μm long, Fig. 3e View FIGURE 3 ) at anal region. Introvert with shallow cups; knobbed in its inner and outer faces (30–40 μm long, Fig. 3f View FIGURE 3 ) and rosettes. Tentacles with three types of perforated rods: elongated with irregular margins (180–240 μm long, Fig. 3g View FIGURE 3 ); large arched rods (600–800 μm long, Fig. 3h View FIGURE 3 ) and knobbed curved rods at base of tentacles (60–180 μm long, Fig. 3i View FIGURE 3 ) sometimes tri-armed (300–400 μm long, Fig. 3j View FIGURE 3 ) and rosettes. Tube feet supporting rods with small perforations at extremities, one central perforation and one central apophysis (250–300 μm long, Fig 3k View FIGURE 3 ); end plate circular; small holes around margin, bigger ones centrally (100–140 μm long, Fig 3l View FIGURE 3 ).

Occurrence. Only known from Brazil (Paraiba, Bahia, and São Paulo).

Taxonomic Remarks. Parathyone itapuaensis sp. nov. is herein assigned to Parathyone , whose diagnostic characters (cf. Deichmann 1957) are recognized in the new species. They are as follow: 1) ambulacral feet stout spreading out into the interambulacral; 2) calcareous ring simple lacking posterior process; 3) dermal ossicles are baskets and knobbed buttons; tube feet with end plates and large supporting rods.

The new species shares with P. braziliensis and P. suspecta , two reduced ventral tentacles. However, differs from both, P. braziliensis and P. suspecta , in having the anterior process of the radial plate longer than the length of base of radial plate (vs anterior process of the radial plate as long as the base of the radial plate in P. braziliensis and P. suspecta ). The new species further differs from P. braziliensis in that the anal region is provided with knobbed multiperforated plates (lacking in P. braziliensis ) and in having two Polian vesicles (vs. one Polian vesicle in P. braziliensis ).

Parathyone itapuaensis sp. nov. superficially resembles P. surinamensis in the general aspects of the calcareous ring. However, the new species stands apart from P. surinamensis in having the body wall buttons slightly knobbed and triangular knobs at the center ( Fig. 4a–c View FIGURE 4 ); two Polian vesicle and the longitudinal muscle split anteriorly and in having tentacles with ventral pair reduced whereas P. surinamensis has body wall buttons strongly knobbed and rounded knobs at the center ( Fig. 4d–f View FIGURE 4 ), one Polian vesicle; longitudinal muscle split before the midlength of the body cavity and in having tentacles of equal size.

Juveniles and adults of the same species can differ in the form of the ossicles ( Cutress 1996). Also, ontogenetic changes in the form of the ossicles or even disappearance of the ossicles have been shown to occur, including in dendrochirotids ( Vaney 1914; Thandar 1989; O’Loughlin and Alcook 2000; O’Loughlin et al. 2012; Martins 2019). However, in Parathyone itapuaensis sp. nov., the only difference found between adults and younger specimens was the number of ossicles, with the younger specimens tended to have more ossicles (stage of development based on size: 10–25mm in length).

UFPB	Departamento de Sistematica e Ecologia
USNM	Smithsonian Institution, National Museum of Natural History
MZUSP	Museu de Zoologia da Universidade de Sao Paulo
ECH	Elmira College