Trachythyone flaccida Thandar, 2013, n. sp.

• Main Author: Thandar, Ahmed S.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2013
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Holothuroidea; Dendrochirotida; Cucumariidae; Trachythyone; Trachythyone flaccida; Fridtjof Nansen
• Online Access: https://doi.org/10.5281/zenodo.6158749; http://treatment.plazi.org/id/B63B87B5FFB8FF8A54C64F664187A6DB

Trachythyone flaccida n. sp. (Figures 1 & 2) Diagnosis. A plump, soft-bodied, barrel-shaped species of Trachythyone , up to 50 mm in length when preserved. Colour in alcohol light greyish brown. Mouth and anus terminal. Anal teeth absent. Tube feet non-retractile, scattered, slightly more numerous ventrally. Body wall ossicles comprising a superficial layer of irregular, cup-like baskets, often accompanied by cross-shaped deposits, and a deeper layer of smooth, elongated to irregular, multilocular plates, aggregated at base of tube feet. Tube feet and tentacles with rods; introvert without ossicles; end-plates absent. Etymology. The specific name refers to the soft, limp body. Material examined. Holotype SAM A28116, Dr. Fridtjof Nansen Demersal Survey, Stn. 3924, off southern Angola, 16º 11´S, 11º 46´E, 6 III 2006, 36 m.; Paratypes —SAM A28117, same data as holotype, 4 spec. Description of holotype. Holotype slightly damaged, deflated, tentacles retracted. Body soft, flabby; form barrel-shaped (see paratype—Figure 1A), bent upwards at both ends but ends never attenuated. Length about 50 mm, breadth in mid-body 23 mm. Preserved colouration a dull greyish brown. Mouth and anus terminal. Tentacles bushy, 10, ventral two much reduced, arising close together. Tube feet small, rigid, non-retractile, scattered throughout body with no regular arrangement but slightly more numerous ventrally and in the radii than elsewhere, suckers much reduced, of equal diameter to tube feet. Anal teeth absent. Calcareous ring (Figure 1 E) simple, no posterior bifurcations or processes on radial plates; each radial plate with long anterior projection and a notched posterior margin; interradial plate triangular, also anteriorly prolonged. Polian vesicle single, saccular; stone canal short, free, madreporite bean-shaped. Gonad (testis) mature, tubules unbranched. Respiratory trees well branched, left shorter than right, both arising from cloaca independently. Retractor muscles arise at mid-body. Body wall thin, soft except in region ...