Havelockia versicolor ( Semper, 1867 )

Thandar, Ahmed S., 2019, On some lesser known sea cucumbers in the Natural History Museum, UK (Echinodermata: Holothuroidea), Zootaxa 4688 (3), pp. 361-381 : 371-373

Havelockia versicolor ( Semper, 1867)

Figure 6

Cucumaria versiclor Semper, 1867: 49 , pl. XII, fig 11, pl. XIV, fig. 8; Utinomi, 1955: 273.

Thyone mirabilis Ludwig, 1875: 93 pl. 6, fig. 18; Lampert, 1885: 162;; Sluiter, 1901: 93; Kalk, 1958: 216 (passim).

Non Thyone mirabilis Théel, 1886:138 [(= Thyone theeli (jun. sec. homonym of H. versicolor (Semper) ].

Thyone mirabilis? Bell, 1884: 149 .

Thyone (?) calcarea Pearson, 1903: 194.

Havelockia herdmani Pearson, 1903: 197 ; Koehler and Vaney, 1908: 25; Panning, 1949: 466; Clark and Rowe, 1971: 180.

Cucumaria areolata Ekman, 1918: 35 .

Pentathyone mirabilis H.L. Clark, 1938: 459 , pl. 6, fig. 3; Panning, 1949: 459, text-fig 55.

Pentathyone versicolor Panning, 1949: 460 .

Thyone herdmani James, 1969: 60 .

Havelockia mirabilis Clark and Rowe, 1971: 180 .

Havelockia versicolor Clark and Rowe, 1971: 180 , text-fig 91b, 92h, pl. 29, fig. 13; James, 1976: 55, text-fig 1a–f; Thandar, 1989: 294; Liao and Clark, 1995: 484, text fig. 292.

Name-bearing types. NHMUK 1884.3 .8.32 (lectotype); Hamburg Museum E 2873 (paralectotypes); (type designations by Arumugam 2012, unpublished) .

Type locality. Bohol, Philippines .

Material examined. NHMUK 1981.2.6.76-77, Ninepins ls, Hong Kong, 2 spec.

NHMUK 1884.3 .8.32 (lectotype); Hamburg Museum E 2873 (paralectotypes) .

Habitat. Coral

Description. Specimens cylindrical, barrel-shaped. Colour greyish, darker in ambulacra. Larger specimen eviscerated but calcareous ring intact, length of larger specimen 51 mm, breadth in mid-body 11 mm; smaller specimen 36 mm in length, 12 mm in breadth in mid-body. Tentacles 10, mid-ventral two reduced. Tube feet scattered, retractile, more numerous in ambulacra, thick with suckers of more or less same diameter but appearing larger when tube feet retracted. Ventral tube feet more developed than dorsal; dorsal often papilliform and fewer. No anal teeth. Genital papilla prominent, situated dorsally between extended introvert and body wall. Calcareous ring clearly of the sclerodactylid type, with radial and interradial plates fused and unfragmented. Processes of radial plates not obviously fragmented except for one or two of which do show some incipient subdivision or fragmentation. Radial plates not obviously bifid anteriorly. Stone canal free, short. Madreporite sub-spherical, and brain coral-like. Polian vesicle single, elongated, sac-like.

Ossicles of body wall as two-pillared tables with an oblong, oval to irregular disc (29–81 µm, average 51 µm) with smooth margins, perforated by usually four large central and approximately 10 marginal holes smaller than the central holes. Spire low or of moderate height (ca. 24 µm), sometimes elongated, always of two pillars with one or two cross-bars, terminating in a few ill-defined teeth. Tube feet deposits comprise arched tables (29–100 µm, average 63 µm); end plates (ca. 193 µm in diam.), well developed with minute medial holes and much larger ones outside these in two or three concentric circles. Introvert deposits only common at the base of tentacles comprising, in the larger individual, only tables with rather deformed and partially corroded disc and tall spire comprising two pillars usually separated by one or two cross-bars and terminating in 1–3 teeth. Rosettes absent in larger specimen but smaller specimen endowed with both well-developed tables and rosettes with the former composed of tall, usually completely or terminally fused pillars ending in 1–3 teeth. Tentacle stalks without ossicles, but branches comprise rods and finely branched rosette-like rods (24–49 µm; average 36 µm).

Distribution. Central Indo-West Pacific.

Remarks. Judging from the number of synonyms it is obvious that this is a very variable Indo-West Pacific species, extending from the Indo-Malayan region, to Mozambique. It was only in 1976 that James synonymised the different names, and it is not known that he examined all the species he synonymised. However, this synonymy, although too sweeping, has been accepted by subsequent workers, except Rowe (1995) who elevated Théels’s (1886) to a nomen nov. ( Thyone theeli as a junior secondary homonym of Havelockia versicolor ), after examining Théels’s material in the NHMUK. Likewise, all the synonyms established by James (1976) need to be examined or re-examined. It is here noted that the NHMUK material from Hong Kong described above, differs a little from other geographic variants (see that described below from Australia). James (1976) records only rosettes in the introvert and tentacles but no tables but Arumugam (2012), in a yet unpublished work, who examined some materials from both the NHMUK and the Hamburg Museum, reports both tables and rosettes in the introvert and only rosettes in the tentacles and this was confirmed by the writer. In the specimens here studied, introvert deposits were only found at the base of the tentacles, which in the larger specimen represented tables only whereas in the smaller specimen, both tables and rosettes. Arumugam (2012), on my instructions proposed designation of the NHMUK specimen (1884.3.8.32) as lectotype and the Hamburg Museum specimens (E2873 as paralectotypes). These designations are here published for the first time. The tables with their large multilocular disc and a tall spire composed of two fused or partially fused pillars terminating in 1–3 points, closely resemble those illustrated by Arumugam for the lectotype. whereas the tentacle deposits match those illustrated by James (1976) as well as by Arumugam (2012). The calcareous ring of the current material differs slightly from that known for the species, but is clearly of the sclerodactylid type but the plates are distinctly fused and the processes are much shorter. In addition, in the current material, as opposed to that illustrated by Clark and Rowe (1971), the processes are not obviously fragmented and the radial plates likewise not obviously bifid anteriorly. These differences are here judged not valid to separate the current material since in size, colour, form and the general body wall and tube feet deposits it corresponds remarkably well with H. versicolor and its synonyms as well as the lectotype here re-examined.

Other material examined. The NHMUK material also contains four other specimens referable to this species, two from Cape D’ Aquilar (114°15’32” E, 22°12’27” N), south-east Hong Kong, and another two from the Great Barrier Reef. For comparison with the Hong Kong specimens described above the latter specimens are also here briefly described.

1974.12.3.38, GBR, off Queensland coast, 16º 40’ 4”S, 145º 59’ 1” E, 24 m, 1 spec.

1974.12.3.39, off Queensland cost, 14° 24’ 9” S, 144° 50’ 1” E, 16 m, GBR exp., P. Gibb, 1 spec.

Description. Specimen (1974.12.3.38) cream-coloured, cucumber-shaped, larger one 16 mm in length, breadth in mid-body 7 mm. Mouth and anus terminal, the latter with poorly calcified (more or less papilliform) anal teeth. Tentacles retracted. Tube feet long and scattered, mostly in ambulacra but some also in interambulacra. Specimen not dissected and hence introvert, the number of tentacles and their deposits and other associated structures not examined.

Specimen (1974.12.3.39) well preserved. Colour cream to white, with some podia darker than others, perhaps implying that live colouration lost. Length approximately 11 mm, breadth in mid-body 5 mm. Tube feet scattered but more numerous in ambulacra, both dorsally and ventrally, all appreciably long with suckers of same diameter. Anal teeth reduced. Specimen lacks calcareous ring and associated structures. Ossicles of body wall comprise twopillared tables with smooth disc bearing 8–10 holes. Ossicles of tube feet tables with arched disc bearing four holes and a spire ending in 2–3 teeth. End plates with large holes on periphery of plate and smaller holes concentrated in the central region.

Remarks. From the form of body-wall ossicles and tube feet end plates, there is no doubt that these specimens also represent Havelockia versicolor . The four specimens described above add substantially to the single extant record in the NHMUK online catalogue, based on a specimen from Bohol, Philippines, which is perhaps part of the type material.

Figures

FIGURE 6. Havelockia versicolor Semper, 1868. NHMUK 1981.2.6.76. Hong Kong. A. Specimen entire; B. Part of calcareous ring; C. & G. Tables of dorsal body wall; D. Tube foot end-plate; E. Tube feet ossicles, F. Rosette-like rods from tentacles. (All line drawings to same scale); MDIR = mid-dorsal interradial plate.