Gorgocephalus pustulatum (H.L. Clark, 1916 )

Calero, Belén & Ramil, Fran, 2023, Euryalida (Echinodermata, Ophiuroidea) from Northwest Africa, European Journal of Taxonomy 870, pp. 46-75 : 67-68

Gorgocephalus pustulatum (H.L. Clark, 1916)

Figs 10–11

Astrodendrum pustulatum Clark, 1916: 84–85 , pl. XXXIV figs 1–2.

Gorgonocephalus pustulatum Baker, 1980: 54–56 , figs 18B, 20, 30.

Gorgonocephalus pectinatus Mortensen, 1933: 281–285 , figs. 16–17, pl. XVIII figs. 1–2.

Gorgonocephalus pustulatum – Rowe & Gates 1995: 368. — Calero et al. 2018: 3, 8. Gorgonocephalus pectinatus – Clark & Courtman-Stock 1976: 133.

Material examined

GUINEA BISSAU • 1 spec., 30.45 mm dd; 10°01′18″– 10°00′24″ N, 17°24′56″– 17°25′05″ W; depth 902–908 m; 24 Oct. 2008; Bissau-0810 exped.; stn BS166; Bissau-0810-18012 ; LZM-UV .

Distribution

This species has an Indo-Pacific distribution. It has been recorded in South Africa from Cape Province to East London ( Mortensen 1933), the Indonesian region ( Döderlein 1927) and Flinders Islands (Bass Strait, Australia) ( Clark 1916); its bathymetric range extends from 182 ( Clark 1916) to 860 m ( Clark & Courtman-Stock 1976).

Our material was recorded in one station in Guinea-Bissau waters, between 902 and 908 m. This material is the same as that reported by Calero et al. (2018).

Description

The dorsal side of disc covered by a skin with some scattered tubercles, ending in some small thorns. The same type of tubercles were found on the marginal belt of plates.

Radial shields long and bar-shaped, nearly reaching the centre of the disc ( Fig. 11A ). They are almost completely covered by tubercles similar to those from the interradial areas but slightly bigger ( Fig. 11C ). The ventral interradial areas are almost fully covered by small granules.

Plates of the oral frame swollen and obscured by a thick skin. Oral shields with some scattered small granules. There is a cluster of slender apical papillae flanked on each side by smaller oral papillae.

Arms also covered by a skin concealing the plates. First pair of tentacle pores outside the mouth edge, without arm spines. Two arm spines from the second to fifth or sixth pores; afterwards, from the first fork on, three spines. Arm spines are small, less than one arm segment, and with some thorny ends.

First fork within the edge of the disc. Dorsally, arms covered by flat granules, and with a longitudinal median furrow ( Fig. 11F ). Pedicellarial bands along the arms, appearing from the first segments.

Remarks

Even though the single specimen collected was badly damaged, the presence of the main distinctive features of Gorgonocephalus pustulatum (H.L. Clark, 1916) , like the number of spines (max. 4), disc coverage (sparse and low tubercles) or the thin peripheral ring, legitimate our identification to species level.

Our finding in Guinea-Bissau represents the first record of G. pustulatum in the Tropical East Atlantic Ocean, extending its geographical distribution to the north, from south Africa to Guinea-Bissau. This station also represents the deepest record for this species (908 m).

Figures

Fig. 10. Map from the study area with the location of the stations where specimen of Gorgonocephalus pustulatum (H.L. Clark, 1916) was collected during the ten surveys off Northwest Africa.

Fig. 11. Gorgonocephalus pustulatum (H.L. Clark, 1916) (LZM-UV Bissau-0810-18012). A. Dorsal view. B. Ventral view. C. Detail of dorsal view. D. Detail of ventral view. E. Detail of ventral disc and arm base. F. Arm tip. G–H. Arm spine. I–J. Spine of disc.