Synallactes quatrami, Thandar, 2018

Thandar, Ahmed S., 2018, On some miscellaneous sea cucumbers (Echinodermata: Holothuroidea) in the collections of the South African Museum with three new species, Zootaxa 4532 (1), pp. 57-85 : 80-81

Synallactes quatrami n. sp.

( Figure 18 )

Synallactes viridilimus Thandar, 2008: 43 , fig. 17 (non S. viridilimus Cherbonnier, 1952 ).

Etymology. The species is so named because of its four-branched large tables (I. quattro- four, rami- branches).

Material examined. SAMC-A 090929 , A9153-075-084-5082, off Lamberts Bay , Western Cape Province, 32°05.7’ S, 16°19.8’ E, 440 m, 16.VIII.1989, 1 spec .

Diagnosis. A medium-sized species of Synallactes , up to 160 mm in length. Tentacles 18. Dorsal papillae reduced, size and arrangement of papillae not easily distinguishable, about six papillae placed dorsally just behind collar, not arranged in groups but in pairs, perhaps part of dorsal papillae; in addition groups of 3–5 oral papillae surround mouth. Tube feet short, in ventral ambulacra, in about 2–4 rows, reaching level of mouth and anus. Ossicles of body wall as three types of tables: small, with cross-shaped mostly incomplete disc; other small tables with complete lattice-like disc; and large tables mostly with 4-armed disc with arms terminally perforated by one to few holes, but not forming lattice-like festoon of holes. Spire of large tables solid, low, with 3–4 terminal teeth. Crosses with or without spires not observed. Rods of tube feet, papillae and tentacles typically synallactid.

Description. Specimen ( Figure 18A ) 159 mm in length, 45 mm in breadth in mid-body. Specimen poorly preserved, almost macerated. Tentacles 18, yellowish in colour. Dorsal papillae not at all obvious, apparently situated on warts/tubercles in about six longitudinal rows but size and number of papillae not easily distinguishable as they appear minute, about six papillae placed dorsally just behind the collar, not arranged in groups but in pairs, perhaps being part of dorsal papillae; in addition groups of 3–5 oral papillae surround mouth. Tube feet also short, in ventral ambulacra, in about 2–4 rows, decreasing in size in both directions, but reaching level of mouth and anus. Ventral ambulacrum with naked area without tube feet. No special anal papillae, but some ventral podia reach level of anus. Ossicles of body wall comprise three types of tables ( Figure 17B ): small with cross-shaped mostly incomplete disc; other small tables with complete lattice-like disc (spire height of small tables 60–110 µm, arm length 30–100 µm, total disc size of such tables 70–210 µm); and large, mostly 4-armed tables with arms terminally perforated by one to few holes but disc not forming lattice-like or racquet-shaped bodies (disc diam. of large tables 30–50 µm, arm length 160–320 µm, total size of large tables 190–370 µm). Spire of large tables solid, low, with 3– 4 terminal projections. Minute crosses with or without spires not observed. Rods of tube feet ( Figure 17C ) and papillae ( Figure 17D ) typically synallactid, up to 670 µm; tentacle rods up to 570 µm ( Figure 17E ).

Distribution. West coast of South Africa, between Lambert and Hondeklip Bays, 425- 450 m.

Remarks. In the form and texture of the specimen, the occurrence of oral papillae and the form of the ossicles it appears that the current specimen is very close to Synallactes viridilimus Cherbonnier, 1952 and S. challengeri Théel, 1886 and almost identical to S. viridilimus described by Thandar (2008) (non Cherbonnier 1952). However, in the occurrence of 4-armed large tables, the complete lattice-like disc of some small tables and the presence of oral papillae in pairs/groups shows that it is identical with Thandar’s (2008) (non Cheerbonnier’s 1952) S. viridilimus , confirming its status as a new species. It is unlike any other southern African synallactid described to date.

Figures

FIGURE 17. Psolus imperfectus Clark, 1923. SAMC-A090928. A. Specimen (entire); B. Plates from dorsal body wall; C. Rods and plates from tentacles; D. Plates from ventral body wall; E. Developing end-plate from tube foot; F. Developing plate from ventral body wall; G. Baskets from ventral body wall; H. Rods from tube feet of ventral body wall. (B & D same scale; E & F same scale).

FIGURE 18. Synallactes quaterama n. sp. SAMC-A090929 (cf. viridilimus Thandar, 2008). A. Specimen (entire); B. Body wall tables; C. Rods from papilla; D. Rods from tube feet; E. Rods from tentacle.