Pleurobranchus iouspi, Ev. Marcus, 1984

Grzelak, Katarzyna & Sørensen, Martin V., 2022, Echinoderes galadrielae Grzelak & amp; Sørensen 2022, sp. nov., Zoological Studies 55 (15), pp. 1-31 : 28

publication ID

https://doi.org/ 10.5281/zenodo.7225407

persistent identifier

https://treatment.plazi.org/id/7B5BA125-7B58-027A-4D95-7889FC212890

treatment provided by

Valdenar

scientific name

Pleurobranchus iouspi
status

 

Synonymy between Pleurobranchus iouspi View in CoL and

P. emys

The spicule layer in the mantle suggest that Pleurobranchus emys and P. iouspi are potentially synonyms. A dense layer of radiating spicules was observed in the specimens analyzed here. Such a layer was previously described only for P. emys in the western Atlantic ( Dall and Simpson 1901; Verrill 1901; Thompson 1977; Ev. Marcus 1984). The analysis of transverse cuts of the mantle of the holotype of P. iouspi and P. emys showed that there is a dense layer of stellate spicules ( Figs. 17D View Fig , 13 View Fig B-D). Beneath it is another less dense layer of linear spicules ( Fig. 13A View Fig ). Ev. Marcus (1984) believed that the jaw platelets of P. emys differ sharply from other pleurobranchines in their narrow anterior part and the much wider posterior part; however, the type material (MZSP 119934) shows this difference only in a few parts of the jaw. This could be an artifact of preservation, because most of the jaw follows the same pattern as the genus, with 2-5 denticles on each side of the main cuspid ( Fig. 17C View Fig ). The radula teeth are all hook-shaped, and as stated above, the mantle is composed by stellate spicules ( Fig. 17D View Fig ). Since living specimens of P. iouspi vary widely in coloration ( Figs. 1 View Fig E-F), and the descriptions of P. emys and P. iouspi do not differ significantly (Ev. Marcus 1970, 1976b, 1984), it is considered that P. emys and P. iouspi in the present study.

The placement of P. emys into synonymy under P. areolatus made by Goodheart et al. (2015) seems arbitrary since the types were not examined not even specimens from the type locality, Colombia, and the authors did not provide a discussion about this synonymy. If P. emys is synonym of other species is P. iouspi due the similarities discussed above. Pleurobranchus areolatus differs from P. emys in relation to the general color of the body ( Table 1); the size and shape of the tubercles of the dorsum, in P. emys it is large and pointed, while in P. areolatus is low; and, due the dense layer of stellate spicules found in P. emys .

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