Benthodytes sp.

Benthodytes sp. MoV. 7319

Material examined. NMV F308186 About NMV * (1) , NMV F308192 About NMV (1) and NMV F308193 About NMV * (1) [IN 2022 V08 115] .

Diagnosis of IOT material. Medium-sized flaky, purple Benthodytes covered in patches of matted bryozoan. From solid and “chunky” to soft and gelatinous, with specimens damaged and some twisted. Elongate, and dorsally raised, up to 21 cm long, 4 cm wide ( NMV F308192 About NMV , live, excluding brim), and 15.5 cm long, 4.5 cm wide and 2.5 cm high (same specimen preserved, excluding brim). Dark purple remnant “skin” in patches over lighter purple to white colour, more uniformly dark purple ventrally. Wide wispy lateral brim of very filamentous double rows of tube feet, exposed for most of their length. Anus dorsal to subterminal. Mouth ventral and dark purple with up to ~11 retracted tentacles ( NMV F308192 About NMV ). Tentacle discs can be large, ~ 5 mm diameter. Circumoral papillae long, well defined, and filamentous in NMV F308192 About NMV (few remaining in others). Dorsal surface “fluffy” and looks stripped of skin. Some evidence of short (~ 10 mm) horn-like dorsal papillae at anterior end in one specimen, but remaining papillae lost. No obvious ventral tube feet seen. Dorsal body wall ossicles are crosses, thick to thin, variably straight to curved and most with arms distally spinous and central bifurcate apophyses, often broken off, sometimes with additional irregular projections. Rare crosses with horizontal rather than bifurcate top to spire (fig. 17g). Papillae often same. Tentacles straight to curved rods with spinous ends .

Remarks. Not a good match for species key and descriptions in the Galathea Report ( Hansen, 1975) , though absence of dorsal and ventral appendages in these specimens make this hard to judge. Brim of filamentous tube feet exposed for most of their length keys to B. superba , but ossicles do not match. Crosses with bifurcate apophyses (often broken off) and ossicles with horizontal top are like those reported for B. incerta in Hansen (1975), and for B. marianensis in Li et al. (2018), but body forms differ. We identify our specimens here as Benthodytes sp. MoV. 7319, noting that additional morphological and genetic samples and more thorough literature review are required before confirming whether this is a new or existing species.

Distribution. These specimen lots only: Indian Ocean, Australian IOT, Cocos (Keeling) Islands Territory, Scrooge Seamount, 2973–2974 m.

References. Hansen (1975), Li et al. (2018).