Paroriza prouhoi Hérouard, 1902

Paroriza prouhoi Hérouard, 1902 View in CoL

Paroriza prouhoi Hérouard, 1902: 24–25 View in CoL , pl. 7: 1–2, pl. 8: 30. — Hérouard, 1923: 29–30, pl. 2: 3–4. — Mortensen, 1927: 386. — Deichmann, 1930: 112–113. — Hansson, 2001 (list). — Gebruk et al., 2014: 166–167.

Mesothuria expectans .— Perrier, 1899: 245. — Perrier, 1902: 317– 320. — Deichmann, 1930: 92. — Tortonese, 1949: 11 (list). — Madsen, 1953: 168 (list).

Material examined. NMV F308312 About NMV * (1) [IN 2022 V 08 183] .

Diagnosis of IOT material. Elongate, subcylindrical specimen, slightly raised dorsally and flattened ventrally, rounded at anterior and posterior ends but otherwise a relatively even width throughout body. Body not obviously curved or tapered and small at 57 mm long, 16 mm wide and 10 mm high (preserved). Skin firm and light brown with a complete dorsal cover of tightly packed white-opaque filiform papillae giving the specimen an almost mauve-grey appearance once preserved. Longer and shorter papillae, slightly more condensed on radii, often with a shorter cylindrical tube foot at the base (fig. 30e), these are of variable size and scattered throughout. Papillae up to 8 mm long (dorsal, live) and 6 mm long once preserved, shorter on ventrolateral, wide at base tapering to a rounded tip. Papillae and tube feet extend to ventrolateral and encroach on ventral, with cream to light-brown tube feet continuing across the whole ventral surface, smaller along the midventral line. Anus subventral and dark brown with pygal furrow. Mouth ventral with dark brown to purple tentacles, mostly retracted, two visible on thick stalks and with discs with at least five rounded (not bifid) digit-like processes on edges (fig. 30c). Longitudinal muscles are flat. White and light brown grit caught between papillae and tube feet on surface of the animal. No ossicles present in body wall.

Remarks. This IOT specimen is currently distinguished from Paroriza prouhoi Hérouard, 1902 sensu stricto by being noticeably crowded dorsally, and by the presence of midventral tube feet. It also differs from the WoRMS image of a much larger NHMUK specimen of P. prouhoi from the Porcupine Abyssal Plain in the Northeast Atlantic, which is bare midventrally and a lot less crowded dorsally (WoRMS, 2024). We have judged that this discrepancy is due to specimen size, because other morphology including presence of large and small “tubes” and dark tentacles and anus match the original description. Hansen (1956), when describing a similar species, P. grevei , noted that while larger specimens were bare midventrally, a covering of ventral tube feet was present in smaller specimens. Here we note the same for our small IOT specimen of P. prouhoi , which is only 57 mm long compared with the type material recorded at 23 cm ( Hérouard, 1902). Noting that the IOT specimen is also a perfect match for a genetic sequence of P. prouhoi from the northeast Atlantic, we anticipate a need to revisit species and genus-level descriptions for the group, potentially noting the discrepancies between small and large forms. Distinguished from P. grevei Hansen 1956 by tentacle discs having more than the four diagnostic processes Hansen noted, also less cup shaped. Distinguished from P. pallens by a mixture of long and short tube feet, scattered throughout, rather than uniform and even distribution. Distinguished from P. verrucosa by the presence of a complete dorsal and ventrolateral covering of papillae and scattered tube feet, not just wart-like tube feet, also not smooth or bare ventrally and with different tentacle form.

The single P. prouhoi specimen from the IOT was sequenced for COI. The sequence was similar to a previously sequenced P. prouhoi from the northeast Atlantic Ocean, with only two base pair differences (fig. S4). No other genetic data for other Paroriza species were available at the time of publication.

Distribution. North-East Atlantic, off the Azores, the Bay of Biscay, and the Porcupine Seabight; Mediterranean Sea; Indian Ocean (Australian IOT).

Full bathymetric range: 3948–4880 m (IOT 3948–4047 m).

Type locality. North Atlantic Ocean between Azores and Portugal, 4360 m .

This species not previously recorded from Australia in AFD, and Paroriza only recorded at genus level from Australia in ALA (January 2024). This IOT material extends the geographic range for the species and genus as the first record from the Indian Ocean. It also slightly extends the bathymetric range for the species previously recorded from 4080 m ( Gebruk et al., 2014) and is a new record for the species in Australia .

References. AFD (2024), ALA (2024), Gebruk et al. (2014), Hansen (1956), Hansson et al. (2001), Hérouard (1902), Massin (1987), WoRMS (2024).

Family Molpadiodemidae Miller, Kerr, Paulay, Reich, Wilson, Carvajal and Rouse, 2017 View in CoL

Diagnosis. (see Miller et al., 2017)

Remarks. This family was erected in 2017 when molecular evidence combined with morphological characters supported its individual status within Persiculida ( Miller et al., 2017) . It currentlycomprisesasinglecosmopolitangenus: Molpadiodemas , previously found off eastern, southern and north-western coasts of Australia at depths of 528–4139 m, and in Australian Antarctic waters (WoRMS and ALA, January 2024).