Ophiotreta, Verrill, 1899

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 : 87

Ophiotreta sp. nov. innom. 1

“ Ophiacanthid A” – Thuy & Kroh 2011: 781, pl. 1 figs 1-2.

Remarks

A re-examination of the four LAPs described and illustrated by Thuy & Kroh (2011) as an indeterminate record of an ophiacanthid (“Ophiacanthid A”) from the Barremian of France has revealed that those LAPs are assignable to Ophiotreta mainly on account of the highly distinctive shape of the ridge on their inner side and the moderately well-developed connecting ridge between the spine articulations and the outer surface. Greatest similarities are shared with the LAPs of Ophiacantha jaegeri sp. nov. (see below), especially with respect to the ventral part of the ridge, missing or reduced to a knob on the ventral portion of the inner side of the LAP and widely separated from the remaining ridge in all other fossil species of Ophiotreta . The LAPs described by Thuy & Kroh (2011) differ from those of Ophiacantha jaegeri sp. nov. in lacking the spur on the outer proximal and inner distal edges. They most probably represent a new species, the formal description of which, however, requires additional, less fragmentary specimens. It is remarkable that this Barremian species of Ophiotreta is morphologically closer to Ophiacantha jaegeri sp. nov., its Jurassic congener and oldest currently known species of the genus, than to O. striata ( Kutscher & Jagt, 2000) comb. nov. from the early Maastrichtian and all other, younger records. This supports the observation by Thuy & Kroh (2011) that the Barremian ophiuroid assemblage they described was closer to Jurassic equivalents than to Late Cretaceous ones in terms of faunal spectrum.