Astrocladus goodingi Baker & Okanishi & Pawson 2018, sp. nov.
Creators: name: Baker, Alan N.
name: Okanishi, Masanori
name: Pawson, David L.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Echinodermata
Ophiuroidea
Euryalida
Gorgonocephalidae
Astrocladus
Astrocladus goodingi

description: Astrocladus goodingi sp. nov.
(Figs. 7A–C, 8–11)
Astrocladus tonganus.— Cherbonnier & Guille, 1978: 14, Pl. II figs. 3–4. Non Astrocladus tonganus Döderlein, 1911: 77, 107, pl. 9 fig.8.
Material Examined. Holotype USNM 1072479, Anton Bruun Cruise 9, Indian Ocean, Comoro Islands, Mayotte Island, Bandeli Reef, 12° 54’S, 45° 16.5’E, inner side of reef, depth approximately 1 m, 23–26 November 1964. Collected by R.U. Gooding (RU-297), 1 specimen, disc diameter 15 mm (Figs. 7–10).
Other material examined. Three specimens from localities in the northwest and south of Madagascar, identified by Cherbonnier & Guille 1978 as Astrocladus tonganus Döderlein (sent to ANB by the late Dr A. Guille, specimens now in Muséum National d’Histoire Naturelle, Paris). The three specimens were referenced by Baker (1980, p. 64). Their current catalogue numbers were unavailable.
Etymology. Named for the collector, the late Dr R.U. “Judge” Gooding of Barbados; our friend and colleague.
Diagnosis. Disc and radial shields with tubercles bearing 2–8 glassy spines; five arm spines bearing 1–5 glassy spinules, present from third arm segment; girdle bands present from disc margin; arm areas between girdles and orally with large polygonal plates, separated by narrow rows of small single plates. Genital slits bordered abradially by a row of tall spines.
Description of the holotype. External morphology. Aboral disc depressed at center, aborally with scattered small <0.3 mm diameter tubercles bearing 2–8 glassy spines averaging 86 µm in length, on a dense background of small, low granules (Fig. 7A, C, 8A–B).
Radial shields prominent, narrow (ratio length to breadth 1:8), slightly divergent, not meeting centrally, covered with small (0.1 mm diameter) tubercles bearing 1–5 glassy spines interspersed with flat plates (Fig. 8A, C).
Oral disc covered by plate-shaped external ossicles, teeth large, spear-shaped; oral papillae small, spiniform (Fig. 8E). One madreporite on the inner border of the soft interbrachium (Fig. 8E).
Oral interradii with a close cover of pustules and scatted large tubercles, a few bearing spines (Fig. 8F). Genital slits narrow and short (0.25 x 2.0 mm), bordered abradially by a row of tall spines (Fig. 8F).
Arms coiled, bifurcated at least 16 times (Fig. 7A–B). Girdles complete between disc edge and first arm branch (Fig. 9A), girdle hooklets with one secondary tooth. Between girdles, arms have a few spines basally, but mostly large flat polygonal plates, bearing low smooth knobs (Fig. 9A), those disappear toward the distal arm tip (Fig. 9D). Oral surface of arms and oral frame covered with flat, smooth polygonal plates surrounded by rows of single, smaller plates (Fig. 8D, 9B–C). Up to 5 arm spines, beginning just before third arm branch, with initially 1 or 2, then 5, glassy-tipped spines (Fig. 9C). Five arm segments to first branch, 4 to next branch.
Ossicle morphology. Hooklet-bearing plates possessing approximately 16 tubercle-shaped articulations for hooklets in the basal portion of the arm (Fig. 10A), approximately 6 articulations in the distal portion (Fig. 10H). The articulations forming two parallel rows (Fig. 10A, H). Each hooklet bears one inner tooth (Fig. 10B–C). Lateral arm plates concave on distal and basal sides, the concavity deeper on distal side (Fig. 10D–E). No perforations visible on lateral arm plates but simple nerve openings on oral-external side (Fig. 10E–F) and on distal portion of the arms; articulations for hooklets only visible on oral surfaces (Fig. 10H). Arm spines in the basal portion of the arm ovoid and having one secondary point, approximately one-third length of the height of the spine (Fig. 10I). All vertebrae with hourglass-shaped streptospondylous articulations (Fig. 11D–E, H–I). Depressions for tube feet openings in the distal part of oral-lateral side of vertebrae (Fig. 11A, G). A pair of radial water canals opening on the lateral side of vertebrae, near depression of the tube feet (Fig. 11A, G) and radial nerve canals opening inside oral furrows (Fig. 11A).
Remarks. The genus Astrocladus contains 10 nominal species, of which five are now know from the Indian Ocean or nearby: A. hirtus Mortensen, A. euryale (Retzius), A. exiguus (Lamarck), A ludwigi (Döderlein), and A africanus Mortensen. Adding a further species to this fauna may seem an unnecessary complication, especially given the intra-species variations and similarity in morphology of A. euryale and Astrodendrum capensis (Mortensen, 1933b) as noted by A. M. Clark (1974) in her account of echinoderms from Southern Africa. We have, however, examined the descriptions of all the Astrocladus species, and cannot reconcile the Comoro and Madagascar specimens with any known taxon.
Cherbonnier & Guille (1978) referred five specimens of an Astrocladus collected in northwestern and southern Madagascar, to A. tonganus Döderlein, 1911 a species previously known only from the Pacific Ocean near the Tonga Islands. Baker (1980, p. 64) compared some of their material with A. tonganus from the Pacific type locality, and found that it represented a “species allied to A. hirtus ”. The Cherbonnier & Guille (1978) material is referred here to A. goodingi sp. nov. A. tonganus has a disc covering of conical tubercles bearing 1–2 glassy spines, but there the external similarity with A. goodingi ends: the arms of A. tonganus are covered above with flat plates and pointed tubercles and below with closely set small plates, the girdle belts are continuous only after the 7th arm bifurcation, and the genital slits are not bordered by tall spines. A. hirtus from “Natal or Mozambique ”, is perhaps closer to A. goodingi sp. nov., but differs mainly in that it has fewer glassy spines on the disc tubercles, radial shields bearing slender papillae, and complete belts of girdle hooklets from the 6th arm bifurcation (Mortensen, 1933b; A. M. Clark & Courtman-Stock, 1976).
The distinguishing features of A goodingi sp. nov. are: Disc and radial shields bearing conical tubercles with 2–8 terminal glassy spines (Fig. 9B–C); Five arm spines bearing 1–5 terminal glassy spinules (Fig. 10I), present from third arm segment; Genital slits narrow and short, bordered abradially by a row of tall spines (Fig. 9F); Girdle bands present from disc margin, and complete between first and second arm branch (Fig. 9A); Arm surface, orally and between girdles covered with large polygonal plates, separated by narrow rows of small single plates (Fig. 9A).
Distribution. Western Indian Ocean including Mayotte Island (type locality) and the Mozambique Channel.
description: Published as part of Baker, Alan N., Okanishi, Masanori & Pawson, David L., 2018, Euryalid brittle stars from the International Indian Ocean Expedition 1963 - 64 (Echinodermata: Ophiuroidea: Euryalida), pp. 1-27 in Zootaxa 4392 (1) on pages 11-14, DOI: 10.11646/zootaxa.4392.1.1, http://zenodo.org/record/1194434