Ophiologimus rugosus ( Kutscher & Jagt, 2000 ) Thuy, 2013

Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), European Journal of Taxonomy 48, pp. 1-242 : 55-56

Ophiologimus rugosus ( Kutscher & Jagt, 2000) comb. nov. Fig. 11 : 7-8

Ophiacantha? rugosa Kutscher & Jagt, 2000 in Jagt 2000: 11, pl. 13 fig. 1.

Ophiacantha? rugosa Kutscher & Jagt, 2000: 63, pl. 25 fig. 7.

Ophiacantha ? n. sp. – Jagt 1999a: 200, pl. 2 fig. 5.

Diagnosis

Species of Ophiologimus with large LAPs displaying well-developed vertical constriction on outer surface composed of coarse, strongly overlapping lamellae; up to seven large, ear-shaped spine articulations; ventral portion of LAP relatively narrow; inner side of LAP with two widely separate short ridges or knobs; tentacle notch deeply incised.

Material examined

GZG.INV.78539 and GZG.INV.78540 (leg. Manfred Kutscher) 50 dissociated LAPs, original material listed by Kutscher & Jagt (2000); dissociated LAP ( NHMM JJ 10600/12e) from the upper Campanian Zeven Wegen Member (Gulpen Formation) of Haccourt, northeast Belgium, the original material of Jagt (2000).

Description

Relatively large LAPs, proximal ones nearly 1.5 times higher than wide, distal ones slightly wider than high; ventral fifth (proximal LAPs) to third (distal LAPs) strongly protruding ventro-proximalwards; ventro-distal tip of LAPs tongue shaped, conspicuously protruding; dorsal edge straight to slightly concave as a result of a very weak constriction; distal edge evenly convex; proximal edge undulose, with convex central part and protruding ventral fifth to quarter, separated by kink; no spurs on proximal edge; outer surface with conspicuous irregular striation composed of broad, flattened, distalwards slightly overlapping stripes loosely following outline of proximal edge of LAP; striation restricted to central band, proximally bordered by band of very finely meshed stereom and distally bordered by confluent areoles of finely meshed stereom surrounding all spine articulations. Four (distal LAPs) to seven (proximal LAPs) relatively large, ear-shaped, equal-sized spine articulations; dorsalward increase in size of gaps separating spine articulations; dorsal and ventral lobes forming continuous volute in all spine articulations. Ventral edge of LAPs with extremely large, deeply concave tentacle notch.

Inner side of LAPs with two separate ridges or knobs; ventral ridge consisting of a short, prominent dorsalward protrusion of the slightly thickened ventral portion of the LAP, with well-defined, widened, rounded dorsal tip; second ridge near centre of inner proximal edge of the LAP, consisting of a welldefined, prominent, reversed V-shaped knob with a ventro-proximally pointing branch and slightly shorter and narrower ventro-distalward pointing branch; in distal LAPs poorly defined and only slightly prominent connection between both ridge-like structures; inner side of ventro-distal tip of LAP strongly protruding but not thickened and devoid of spurs. Inner side of tentacle notch with coarsely meshed, horizontally stretched stereom. Very faint, irregular vertical row of small perforations on inner side of proximal LAPs.

Remarks

This species was originally described by Kutscher & Jagt (in Jagt 2000) on the basis of dissociated LAPs from the early Maastrichtian of Germany and Denmark and tentatively assigned to the genus Ophiacantha . Reassessment of the type specimens has revealed that the species is assignable to Ophiologimus . Within this genus, it is unambiguously recognisable on account of the high number of spine articulations.

Occurrence

Late Campanian of northeast Belgium and early Maastrichtian of northeast Germany and Denmark.

Figures

Fig. 11. Lateral arm plates (LAPs) of fossil and Recent ophiacanthid brittle stars in external (a) and internal (b) views. 1. Ophiologimus hexactis H.L. Clark, 1911, Recent, median LAP in external view. 2-4. Ophiologimus martynovi sp. nov. from the latest Aptian to earliestAlbian (Early Cretaceous) of Blake Nose, NE Atlantic. 2. GZG.INV.78532 (holotype), proximal LAP. 3. GZG.INV.78533 (paratype), median LAP. 4. GZG.INV.78534 (paratype), distal LAP. 5-6. Ophiologimus aiodipius sp. nov. from the latest Aptian to earliest Albian (Early Cretaceous) of Blake Nose, NE Atlantic. 5. GZG.INV.78536 (holotype), proximal LAP. 6. GZG.INV.78537 (paratype), median LAP. 7-8. Ophiologimus rugosus (Kutscher & Jagt, 2000) comb. nov. from the early Maastrichtian (Late Cretaceous) of Rügen, Germany. 7. GZG. INV.78539, proximal LAP. 8. GZG.INV.78540, median LAP. One common scale bar per species is given.