Parathyonidium incertum Heding

• Main Authors: O'Loughlin, Mark, Manjón-Cabeza, Eugenia, Ruiz, Francina Moya
• Format: Other/Unknown Material
• Language: unknown
• Published: 2009
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Holothuroidea; Dendrochirotida; Cucumariidae; Parathyonidium; Parathyonidium incertum; Antarctic; Antarctic Peninsula; Antarc*; Icefish; South Atlantic Ocean
• Online Access: https://zenodo.org/record/6219730; https://doi.org/10.5281/zenodo.6219730

Parathyonidium incertum Heding Figure 1 d–f; table 1. Parathyonidium incertum Heding (in Heding & Panning, 1954): 37–39, fig. 3. Material examined. Antarctic Peninsula, Low I., BENTART– 2006, R/V Hesperides, stn LOW 47, 63.4668ºS, 62.2151ºW, 115 m, 12 Feb 2006, MNCN 29.04/ 126 (1 specimen), body wall ossicles slide NMV F 161525; MNCN 29.04/ 127 (2 specimens), posterior body ossicles slide F 161526, tentacle ossicles slide F 161527; South Atlantic Ocean, South Georgia, Icefish 2004, stn 47 BT 25, 114–118 m, 12 Jun 2004, NMV F 104998 (1). Diagnosis. Specimens up to 35 mm long (tentacles partly extended, preserved, NMV F 104998), subcylindrical, elongate, widest diameter 5 mm; soft thick non-calcareous body wall; lacking distinct sole ventrally; oral end sometimes upright, slightly tapered and rounded distally when tentacles withdrawn; anal end slightly tapered and rounded distally; 15 dendritic tentacles (variable; “ type ” has 13; F 104998 has 16), unequal, some undeveloped (buds only); long digitiform genital papilla posterior to dorsal tentacle pair in male specimen (indicative of internal fertilization and brood protection); tube feet confined to radii, spaced single series of large tube feet, uniform in size from base of tentacles to anus; calcareous ring faintly evident, only radial plates evident, wide anteriorly and posteriorly, narrowed in mid-plate, 2 small notches anteriorly, deep rounded notch posteriorly. Ossicles in body wall abundant, thin, bluntly spinous to smooth, single-layered irregular plates, few to many perforations; similar dorsally and ventrally; common form elongate, with 2 large central perforations, 2 small distal perforations, one extended end with few small perforations, short blunt spines on surface and around margin, typically 100 µ m long; small plates intergrade with larger smooth to knobbed, marginally denticulate plates, up to 200 µ m long. Tube foot endplates large, up to 360 µ m diameter, few perforated support plates, not rods. Tentacles ossicles perforated plates, not ...