Panningia trispicula Thandar 2008, sp. nov
| Main Author: | Thandar, Ahmed S. |
|---|---|
| Format: | info publication-taxonomictreatment Journal |
| Terbitan: |
, 2008
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/5107129 |
Daftar Isi:
- 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).
- Published as part of Thandar, Ahmed S., 2008, Additions to the holothuroid fauna of the southern African temperate faunistic provinces, with descriptions of new species, pp. 1-57 in Zootaxa 1697 (1) on pages 29-30, DOI: 10.11646/zootaxa.1697.1.1, http://zenodo.org/record/5107079