Sclerothyone neofusus ( Deichmann, 1941 ) Thandar & Arumugam, 2022

Thandar, A. S. & Arumugam, P., 2022, Referral of Thyone neofusus Deichmann, 1941, Thyone adinopoda (Pawson & Miller, 1981 and Havelockia obunca (Lampert, 1885) to the genus Sclerothyone Thandar, 1990, and a replacement name for the preoccupied genus Neothyone Deichmann, 1941 (Echinodermata: Holothuroidea: Dendrochirotida), Zootaxa 5219 (1), pp. 65-71 : 66

Sclerothyone neofusus ( Deichmann, 1941) comb. nov.

Although the holotype is now devoid of the calcareous ring and ossicles, perhaps completely decalcified, a dissected paratype demonstrated a well-developed calcareous ring ( Figure 1A ) typical of the Sclerothyonidae and the body wall ossicles ( Figure 1B ) as delicate 2-pillared tables but on their way to corrosion. The paratype corresponds well with Deichmann’s (1941) description of the species except that the pedicel ossicles are badly affected and appear as corroded rods (?plates) with central and terminal perforations ( Figure 1C ). The tentacle ossicles comprise slender, curved, perforated rods ( Figure 1D ) and open rosettes ( Figure 1E ). No ossicles were detected in the introvert. From this we conclude that the calcareous ring and ossicles of the examined paratype are close to the type species of Sclerothyone [(i.e. S. velligera (Ludwig & Heding, 1935) ] and also closely resemble those of S. unicolumnus Thandar, 2006 . However, Martins and Tavares (2019) opined that Thyone neofusus may belong in Temparena (also in Sclerothyoninae ), rather than in Sclerothyone , as they mistook the plate-like ossicles illustrated by Deichmann (1941), to have also come from the body wall. This observation is erroneous because of misinterpretation of Deichmann’s (1941) figure legend. It is here noted that the so-called plates are actually supporting plates, labelled as such in Deichmann’s legend, while in the description she herself stated that the plates may be reduced tables from the tube feet. However, it is noteworthy that Deichmann mentioned only rosettes in the introvert, but her figure clearly illustrates a “disc of table from introvert”. This may perhaps be contamination from another preparation. Hence, Deichmann’s description of the introvert deposits require clarification from a study of more material.

Figures

FIGURE 1. Sclerothyone neofusus comb. nov. (Deichmann, 1941), paratype (MCZ,AHF no. 30).A. calcareous ring of paratype (mid-dorsal view); B. tables of body wall; C. corroded rods of tube feet; D. rods of tentacles; E. rosettes of tentacles. (A—scale 1; B–E scale 2). Sclerothyone obunca comb. nov. (Lampert, 1885), F. calcareous ring, mid-dorsal view; G. tables of body wall; H. tables of tentacles; I. tables of introvert [(all copied from Östergren (1938), perhaps from holotype)]. (r = radial plate; ir = interradial plate); A. Scale 1; B–E Scale 2; F. Scale 3; G. Scale 6; H. Scale 4; I. Scale 5).