Glyphodiscus Fisher, 1917

Mah, Christopher, 2005, A phylogeny of Iconaster and Glyphodiscus (Echinodermata, Asteroidea, Valvatida, Goniasteridae) with descriptions of four new species, Zoosystema 27 (1), pp. 137-161 : 144

Genus Glyphodiscus Fisher, 1917

Iconaster – Fisher 1913: 642 (in part).

Iconaster (Glyphodiscus) Fisher, 1917: 173 ; 1919: 306. — Spencer & Wright 1966: U58.

Glyphodiscus – Rowe 1989: 273. — Rowe & Gates 1995: 65. — Clark & McKnight 2003: 52.

TYPE SPECIES. — Iconaster perierctus Fisher, 1917 .

DIAGNOSTIC SUMMARY. — Disk sunken. Primary circlet plates enlarged. Abactinals and superomarginals smooth, bare. Abactinal plates with complete ring of peripheral accessories.

APOMORPHY LIST. — 5, primary circlet plates enlarged. 6, interradial disk plates enlarged. 7, disk sunken. 11, few marginal plates in interradius. 15, actinal plates bare. 17, furrow spines short, squat. 18, furrow spines round to polygonal in cross section. 19, furrow spines crowded. 23, subambulacrals round to polygonal in cross section. 24, subambulacral-furrow spine space absent. 31, narrow flaps on ambulacral base.

Glyphodiscus perierctus ( Fisher, 1913) ( Fig. 2 )

Iconaster perierctus Fisher, 1913: 642 .

Iconaster (Glyphodiscus) perierctus – Fisher 1917: 173; 1919: 306, pls 79, 81, 83, 93.

Glyphodiscus perierctus – A. M. Clark 1993: 254.

Glyphodiscus mcknighti – Rowe 1989: 273, figs 8A, B, 9A, 9B. — A. M. Clark 1993: 254 (checklist). — Rowe

& Gates 1995: 65. — Clark & McKnight 2003: 53.

HOLOTYPE. — Philippines. Sulu Archipelago, Tawitawi Grosimunul Island, Sibutu Passage , 4°56’10’’N, 119°46’00’’E, 177 m, 24.II.1908 ( NMNH 30554 ).

OTHER MATERIAL. — New Caledonia. SMIB 5, stn DW 102, 23°19.6’S, 163°4. 7’E, 290-305 m, 9.IX.1989, 1 dry specimen with rough marginals, R = 2.3 cm, r = 1.2 cm ( MNHN EcAs 11698). — SMIB 4, stn DW 61, 23°00’S, 167°22’E, 520-550 m, 3 dry specimens, R = 3.3 cm, r = 1.6 cm, R = 1.8 cm, r = 1. 0 cm, R = 1. 9 cm, r = 1. 1 cm ( MNHN EcAs 11696). — SMIB 5, stn DW 104, 23°15.7’S, 168°4.4’E, 305-335 m, 2 dry specimens, R = 1.7 cm, r = 0.9 cm, R = 0.8 cm, r = 0.4 cm ( MNHN EcAs 11697). — SMIB 5, 13.IX.1989, rocks (= “roche”), 1 dry juvenile specimen, R = 7.0 mm, r = 4.0 mm ( MNHN EcAs 11686).

Western Australia. NW of Cape Leveque, Western Australia, 14°57.6’S, 121°40.5’E to 14°56.4’S, 121°42.5’E, 200-235 m, Engel trawl on coral rock bottom, 16.II.1984, 1 specimen, R = 3.7 cm, r = 1.5 cm (WAM Z-20875). — S of Bedwell Is., Clerke Reef, sled stn #LB7, 17°54.2’S, 119°17.5’E to 17°53.3’S, 119°17. 1’E, 200 m, rocks and hard sponges, 18.VIII.1995, 1 specimen, R = 4.2 cm, r = 1.5 cm (WAM Z-20944).

DISTRIBUTION. — Philippines to Norfolk Island / New Zealand and to Indian Ocean, Western Australia. 178- 550 m.

DIAGNOSTIC SUMMARY. — Body stellate with tapering arms. Marginal plate surfaces smooth to rough. Arms with superomarginal plates abutted across radius.

APOMORPHY LIST. — 12, marginal plates elongate. 27, arms short. 30, ambulacral waist with rounded surface.

REMARKS

The juvenile demonstrates a number of features permitting identification, including smooth, wide marginal plates and relatively short arms. Larger specimens add abactinal, marginal, and actinal plates as well as a greater number of furrow and subambulacral spines.

Figures

FIG. 2. — A-C, Glyphodiscus perierctus (Fisher, 1917), New Caledonia, SMIB 4, stn DW 61, dry (MNHN EcAs 11686); A, abactinal surface, larger specimen with roughened marginal plates; B, roughened superomarginal plate; C, ambulacral furrow, furrow spines, and adambulacral plates; D, E, Glyphodiscus mcknighti Rowe, 1989 (= G. perierctus), New Caledonia, SMIB 5, stn DW 104, dry (MNHN EcAs 11697); D, abactinal surface, smaller specimen with smooth marginal plates; E, actinal surface. Scale bars: A, B, D, E,