Deima validum validum Théel, 1879

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 : 262-264

Deima validum validum Théel, 1879

Deima validum Théel, 1879: 5 , figs 36–38.— Théel,1882: 68–70, pls. 18, 19, 31: 4–9, 36: 4, 37: 8, 43: 7, 44: 13, 46: 5.—Sluiter, 1901: 60.— Rowe et al., 2017: 480, fig. 11.18b.

Deima validum validum Théel. — Hansen, 1967: 488–490, fig. 5.— Hansen, 1975: 17–23, figs 1: 1–4, 6, 7, 109, pl. 11: 1.— Rogacheva et al., 2013: 595, fig. 18e.— Gebruk et al. 2014: 165.— O’Hara et al., 2020: add. file 1: sup. table S1 (list).

Deima fastosum Théel, 1879: 5–6 , figs 1–3.— Théel, 1882: 71–73, pls. 20, 21: 1, 31: 10–13, 35: 7–10, 36:7, 37: 3, 43: 2, 3, 5, 46: 8.

Deima blakei Théel, 1886b: 1–2 , figs 1, 2.— Koehler and Vaney, 1905: 55–57, pl. 11: 13–15.— Hérouard, 1923: 40–41, pls. 5: 7, 6: 5.— Deichmann, 1930: 115–116, pls. 10: 7–11, 11: 1–3.— Deichmann, 1940: 198–199.

Deima atlanticum Hérouard, 1898: 88–89 , figs 1, 2.— Hérouard, 1902: 32–35, pls. 3: 3, 4: 18, 5: 1–5, 8: 26–29.— Grieg, 1921: 4, pl. 1: 2, 3.

Deima mosaicum Ohshima, 1915: 233–234 .—Ohshima, 1916– 1919, with 2 figures.

Material examined. NMV F308224 * (1) and NMV F308232 (1) [IN 2022 V 08 122] ; NMV F308279 (1) and NMV F308280 (1) [IN 2022 V 08 151] .

Diagnosis of IOT material. Specimens typically pink to white, or white to grey once preserved. Body elliptical to oval, strongly convex dorsally (almost egg-shaped) and flattened ventrally, with a ratio of length to width ~5:3. Specimens up to 90 mm long and 55 mm wide ( NMV F308279, fig. 36c, d). Long, non-retractile (but often brittle or broken) papillae, in series along each dorsal radii (~4 pairs visible, others broken) and in ventrolateral series above tube feet (~7 pairs). Anus ventral, almost terminal. Mouth ventral, with retractable tentacles terminating in soft discs, sometimes curled into a cup shape or with rounded or digit-like processes visible. Circumoral papillae present but can be minute or hard to detect. Eleven (9–11) pairs of ventrolateral tube feet in single series along each side, smaller at posterior. Some also include smaller post-anal pair (e.g. NMV F308224, NMV F308280). No midventral tube feet or pre-anal tube feet observed. Ossicles consist of mostly large, often multilayered perforated plates (fig. 36e–h), dorsal up to 4.2 mm, ventral up to 1.5 mm, giving a crunchy texture, plus some smaller variable ossicles including dichotomously branching cross-like rods. Two damaged specimens ( NMV F308232 and NMV F308280) had very broken and imbricating plates visible to the eye.

Remarks. Hansen’s (1975) redescription for Deima validum validum Théel, 1879 noted multilayered plates, 10–13 pairs of ventrolateral tube feet, rare pre-anal tube feet, and 3–7 pairs of lateral papillae, all matching the features of IOT specimens. The description included more dorsal papillae (5–10 pairs) than what was seen for IOT specimens, though he noted that these were more variable ( Hansen, 1975). All IOT specimens have many multilayered perforated plates identical to the Challenger illustrations from the original type specimens of D. validum ( Théel, 1879, pl. 31, figs 4–9), which, along with fewer dorsal papillae, distinguished them from the only other subspecies in this genus – D. validum pacificum Ludwig, 1894 . They are also clearly differentiated from the two Deima found only at shallower IOT stations less than 2000 m and described below ( NMV F308242 and NMV F308216). Presence of fewer papillae dorsally along with post-anal tube feet but no pre-anal tube feet in some IOT specimens indicates that our material differs from D. validum validum Théel, 1879 sensu stricto, but we keep it here for now based on the presence of mostly multilayered plates identical to those illustrated in the type material ( Théel, 1879).

Distribution. Worldwide (though absent from many areas).

Full bathymetric range. 724–4990 m (IOT 3053–4990 m).

Type locality (as D. validum ). Mid North Pacific Ocean , 3749 m .

Subspecies not recorded for Australia in AFD or ALA (January 2024), but D. validum is recorded in both and many species-level records were further identified to subspecies on the NMV catalogue ( O’Loughlin, 1998) and published identification lists ( O’Hara et al., 2020), making the current Australian range 1250–4990 m and slightly extending the worldwide depth range, previously 724–4820 m in Gebruk et al. (2014). In Australia this subspecies is now known from Lord Howe Rise, from the eastern abyss off Nowra NSW to just north of Tasmania, from the Great Australian Bight in South Australia and from the Australian IOT.

References. ALA and AFD (2024), Gebruk et al. (2014), Hansen (1975), O’Hara et al. (2020), O’Loughlin in NMV Catalogue (1998), Théel (1879).