Ophiopetagno paicei Thuy, Eriksson & Numberger-Thuy, 2022

Thuy, Ben, Eriksson, Mats E., Kutscher, Manfred & Numberger-Thuy, Lea D., 2024, The beginning of a success story: basalmost members of the extant ophiuroid clade from the Silurian of Gotland, Sweden, European Journal of Taxonomy 947 (1), pp. 216-247 : 237

Ophiopetagno paicei Thuy, Eriksson & Numberger-Thuy, 2022

Figs 5K–N , 7

Diagnosis (emended from Thuy et al. 2022)

Species of Ophiopetagno with lateral arm plates showing a concave dorsal edge, fine outer surface tuberculation, a deep tentacle notch incision, three relatively large, prominent lateral spine articulations in a continuous row, and ambulacral groove spine articulations in a continuous row along the entire ventral edge with a weak offset from the latter.

Remarks

Ophiopetagno paicei was described by Thuy et al. (2022) as part of the species pair shown to be at the origin of the modern ophiuroid clade. The lateral arm plates of O. paicei differ from those of its congeners described herein in having a concave dorsal edge and three relatively large spine articulations in a continuous row along the distal plate edge.

Figures

Fig. 5. Dissociated lateral arm plates of ophiuroids from the Silurian of Gotland. A–B. Ophiopetagno bonzo sp. nov, holotype, NRM PAL Ec38336, proximal lateral arm plate in external (A) and internal (B) views. C–D. O. bonzo, paratype, NRM PAL Ec38337, median to distal lateral arm plate in external (C) and internal (D) views. E–F. Ophiopetagno kansas sp. nov, holotype, NRM PAL Ec38338, proximal lateral arm plate in external (E) and internal (F) views. G–H. O. kansas, paratype, NRM PAL Ec38339, median lateral arm plate in external (G) and internal (H) views. I–J. O. kansas, paratype, NRM PAL Ec38340, distal lateral arm plate in external (I) and internal (J) views.K–L. Ophiopetagno paicei Thuy, Eriksson & Numberger-Thuy, 2022, from Thuy et al. (2022), proximal lateral arm plate in external (K) and internal (L) views. M–N. O. paicei, from Thuy et al. (2022), distal lateral arm plate in external (M) and internal (N) views. Abbreviations: AGSA = ambulacral groove spine articulations; di = distal; do = dorsal; LSA = lateral spine articulations; TN = tentacle notch; VAK = vertebral articular knob.

Fig. 7. Stratigraphic position of the taxa described in the present paper with their assumed evolutionary relationships and the nesting of the clades Ankhurida clade nov., Ophiovalida clade nov. and Metophiurida Matsumoto, 1913. Note that some lateral arm plates are mirrored to allow comparison in similar orientation.