Panningia trispicula, Thandar, 2008

Thandar, Ahmed S., 2008, Additions to the holothuroid fauna of the southern African temperate faunistic provinces, with descriptions of new species, Zootaxa 1697 (1), pp. 1-57 : 29-30

Panningia trispicula sp. nov..

Figure 11

Diagnosis

Presumably a small, barrel-shaped species, holotype (juvenile) 4 mm long. Tentacles 10, mid-ventral two only slightly reduced. Dorsal podia absent, ventral podia few, in single rows. Polian vesicle single, madreporite bean-shaped. Body invested in large, non-contiguous, imbricating, single-layered, multilocular plates/scales, 280-445 µm, faintly to heavily knobbed or smooth, always with short handle-like projection. Cross-shaped deposits also present. Podial deposits as rods with projecting arms and a few holes. Tentacles supported by rods and plates.

Etymology The specific name refers to the three types of spicules (crosses, simple plates, knobbed plates).

Material examined

Holotype, SAM-A28011, UCT Ecol. Surv., off Mossel Bay , St. SCD 186 , 34 o 10' S, 23 o 32' E, 30.11. 1960, 97 m. Paratype, SAM-A28012, same data as holotype.

Type locality Off Mossel Bay , WCP, 34 o 10' S, 23 o 32' E, 97 m.

Description of holotype

Specimen previously dissected, minute, obviously juvenile, judging from its size, distribution of podia and lack of gonad. Length 4 mm, width in mid-body 2 mm. Form barrel-shaped, anterior end broader. Colour uniformly white, including tentacles. Mouth and anus terminal, latter dorsally directed; anal teeth present but difficult to demonstrate. Tentacles 10, clearly dendritic, mid-ventral two only slightly reduced. Dorsal podia absent, ventral podia few, apparently in single row per ambulacrum, not easy to demonstrate as specimen previously dissected through ventral surface. Body invested in large, non-contiguous scales with their narrow, handle-like ends, directed anteriad.

Calcareous ring ( Figure 11J ) typically cucumariid or psolid-like, radial plates with bifid anterior projection and a depression for retractor muscle, posterior end deeply concave; interradial plates triangular with wide posterior concavity. Polian vesicle single, short, situated close to equally short stone canal; madreporite beanshaped ( Figure 11J ). Gonad absent. Respiratory trees poorly developed, each with few terminal branches, right tree slightly longer, reaching anterior third of body. Retractor muscles short, arising from anterior third of longitudinal bands and inserting on radial plates without any subdivision.

Dorsal and ventral body wall deposits comprise plates/scales and cross-like deposits. Plates large, in various stages of development, complete ones ( Figure 11A ) elongate, 280-445 µm (mean 348 µm), imbricating, single-layered, faintly to heavily-knobbed, rarely smooth, multilocular with 10-35 holes and with anterior end prolonged into a thin, handle-like projection; developing plates ( Figure 11B ) 60-200 µm long (mean 157 µm), with fewer (0-7) holes. Crosses ( Figure 11C ) probably represent developing plates, 25-40 µm (mean 31 µm), smooth, with usually dichotomously branched arms but many also asymmetrical. Podial deposits ( Figure 11D ) as irregular rods, 93-200 µm (mean 147 µm), with projecting arms, perforated by varying number (0-6) of large medial and/or smaller terminal holes. End-plates ( Figure 11E ) reduced (ca. 145 µm) with central holes slightly larger than marginal ones, margins irregular. Tentacles supported by rods and plates, rods ( Figure 11G ) with or without terminal perforations, plates of a variety of form, either smooth or with few tiny marginal nodules ( Figure 11F ). Introvert not examined.

Description of paratype

Specimen juvenile, form, colour and tentacles as in holotype. Length 3 mm, width in mid-body 1.5 mm. Anal teeth inconspicuous. Dorsal podia absent, sole absent, ventral podia 4-5 per ambulacrum but with welldeveloped suckers. Body wall spicules as plates and crosses. Plates ( Figure 11H ) as in holotype but heavilyknobbed ones absent, small-knobbed ones the commonest, 235-400 µm (mean 296 µm), holes 12-32, knobs few, small, restricted to margin of plate. Crosses common, 25-40 µm (mean 30 µm). Podial deposits as in holotype, 85-182 µm (mean 145 µm), with 2-10 holes; end-plates about 120 µm ( Figure 11I ).

Distribution Known only from type locality.

Remarks

The new species is here tentatively referred to the east Atlantic genus Panningia because of its cross-like deposits and plates/scales in varying stages of development, with some of them prolonged at one end into a handle-like projection. Such deposits come quite close to P. bispicula Cherbonnier, 1964 from the West African coast, also recently illustrated by Massin (1993). The two specimens are definitely juvenile judging from their size and poor development of podia and, at least in the one dissected, the absence of gonad. However, because of their barrel- and not U-shaped body form, the absence of dorsal podia, only slight reduction of the ventral tentacles and the presence of handle-like projections of plates that are not up-turned at an angle, the specimens are here described as a new species. The new species may deserve another genus but this is not done in order to limit the number of monotypic genera within the Cucumariidae (see Thandar & Samyn 2004).

Figures

FIGURE 11. Panningia trispicula sp. nov. Holotype, SAM-A28011. A. Heavily-knobbed plate from body wall; B. almost smooth plates from body wall; C. cross-shaped deposits from body wall; D. rods from podia; E. end-plate; F. plates from tentacles; G. rods from tentacles; J. madreporite and calcareous ring. Paratype SAM-A28012, H. plates from body wall; I.end-plate. A scale a; B-I scale b.