Peniagone sp.

Mackenzie, Melanie, Davey, Niki, Burghardt, Ingo & Haines, Margaret L., 2024, A report of sea cucumbers collected on the first dedicated deep-sea biological survey of Australia’s Indian Ocean Territories around Christmas and Cocos (Keeling) Islands (Echinodermata: Holothuroidea), Memoirs of Museum Victoria (Mem. Mus. Vic.) 83, pp. 207-316 : 219

Peniagone sp. MoV. 7320

Material examined. NMV F308335 * (2) [IN 2022 V 08 196] .

Diagnosis of IOT material. Elongate specimens up to 85 mm long and 15 mm wide, only slightly raised dorsally. Grey-cream with black speckled coating on flakey outer skin (preserved, ethanol). Skin semitranslucent revealing central gut with pink to orange tint. Anterior velum severely damaged but appears short or reduced. No obvious neck tube but mouth curved ventrally with darker maroon to brown semi-retracted tentacles. No tube feet remaining. Images look soft, but after preservation hard and crunchy dorsally, softer ventrally. Ossicles Peniagone - style crosses with smooth central beam, four (4–5) arms, and four (2–4) apophyses. Arms and apophyses spinous distally and for most of their length. One variety of Peniagone -style cross with longer arms and apophyses. Arms variably curve directly down (fig. 8d, e) or horizontally for a short distance before they curve down (fig. 8f, g). Apophyses typically straight and vertical. Second kind of Peniagone -style cross with much shorter arms and apophyses (fig. 8h).

Remarks. Damaged specimens with few external characters. Specimens not the typical Peniagone shape, colour or texture, but this may be an artifact of being collected from a station with manganese nodules. Many specimens from this site were coated with dark residue and were atypical in colouration. Elongate body with no neck-tube closer to P. challengeri , though ossicles show similarities to P. azorica , P. purpurea and P. islandica . Ossicles not a match for original illustrations for P. mus (Djakanov, 1952) which were from the deeper skin layer, though closer to the redescription of P. mus by Kremenetskaia et al. (2021). Dorsal ossicles with only one pair of apophyses (fig. 8e) are also a feature of P. dubia as redescribed in the same paper, though not as obviously dominant here. Combination of external and ossicle morphology make this distinctly different from other Peniagone examined. Here we identify specimen to OTU level as Peniagone sp MoV. 7320; additional review of literature and more complete material required to confirm this as a new species.

Distribution. This specimen lot only: Indian Ocean, Australian IOT, Cocos (Keeling) Islands Territory, Cocos Abyssal Stn., 3431–5414 m.

References (for genus Peniagone ). Djakanov (1952), Hansen (1975), Kremenetskaia et al. (2021), Théel (1882).