Ophiopetagno doro, Thuy & Eriksson & Kutscher & Numberger-Thuy, 2024

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 : 237-238

Ophiopetagno doro sp. nov.

urn:lsid:zoobank.org:act:701D078F-2F68-47ED-949A-5AE59490362E

Figs 6A–F , 7

Diagnosis

Species of Ophiopetagno with lateral arm plates showing a weakly convex dorsal edge, a conspicuously oblique proximal edge with a proximalwards pointing ventro-proximal tip, a moderately coarse outer surface ornamentation, three large, prominent lateral spine articulations showing a gap between the dorsal and the median articulation, and a row of ambulacral groove spine articulations with a sharp offset with respect to the ventral edge.

Etymology

Species named after heavy metal singer Dorothee Pesch, also known as ‘Doro’, to honor her commitment, musical career and role as a pioneer and gate opener for female vocalists in metal music.

Type material

Holotype

SWEDEN • Gotland, Petsarve ; NRM PAL Ec38341 .

Paratypes

SWEDEN • 2 specs; same data as for holotype; NRM PAL Ec38342 , NRM PAL Ec38343 .

Type locality and stratum

Ludlow Series, Ludfordian Stage, Upper Icriodontid conodont subzone sensu Jeppsson (2005), Eke Formation, upper part; Petsarve, Gotland, Sweden.

Description

Holotype ( Fig. 6A–B )

NRM PAL Ec38341 is a dissociated proximal lateral arm plate approximately 1.7 times as long as high, relatively thin, with weakly concave dorsal edge, convex distal edge and oblique proximal edge showing proximalwards protruding ventro-proximal tip and lined by shallow groove followed by slightly raised band of more finely-meshed stereom; ventral portion long, weakly protruding ventro-proximalwards, with weakly convex ventral edge with four slightly protruding protrusions for ambulacral groove spine articulations lined by sharp offset along ventral edge, and small, deep tentacle notch incision; outer surface with moderately fine tuberculation covering entire outer surface except for groove and raised band along proximal edge and shelf distally bordering spine articulations; three large, conspicuous and prominent lateral spine articulations composed of round opening surrounded by elevated, relatively regular ring, with dorsalward increase in size and with larger gap between dorsal and middle articulations, separated from distal plate edge by very large shelf. Inner side of lateral arm plate ( Fig. 6B ) with large, rounded triangular, well-defined and prominent vertebral articular surface in centre of proximal plate portion at some distance from inner dorso-proximal corner and separated from inwards protruding dorsal edge; tentacle notch very large, deep, well-defined, with small but deep incision in ventral edge, proximally bordered by thickened ventro-proximal plate portion; four relatively large but inconspicuous ambulacral groove spine articulations along entire ventral edge.

Paratype (supplements)

NRM PAL Ec38342 ( Fig. 6C–D ) is a dissociated median lateral arm plate approximately 1.9 times as long as high, similar to holotype but with sharper and more conspicuous offset between row of ambulacral groove spine articulations and ventral plate edge; distalward increase in size of ambulacral groove spine articulations; three lateral spine articulations as in holotype but with larger gap between dorsal and middle spine articulations. Inner side as in holotype.

NRM PAL Ec38343 ( Fig. 6E–F ) is a dissociated distal lateral arm plate two times as long as high, similar to holotype but with slightly concave dorsal edge, with sharper offset between row of six ambulacral groove spine articulations. Inner side as in holotype.

Remarks

Ophiopetagno doro sp. nov. is characterized by having lateral arm plates with large, conspicuous lateral spine articulations with a marked gap between the dorsal and median ones. It furthermore differs from its congeners in having a strongly oblique proximal edge with a proximalwards pointing ventro-proximal tip.

Occurrence

Petsarve.

Figures

Fig. 6. Dissociated lateral arm plates of ophiuroids from the Silurian of Gotland. A–B. Ophiopetagno doro sp. nov, holotype, NRM PAL Ec38341, proximal lateral arm plate in external (A) and internal (B) views. C–D. O. doro, paratype, NRM PAL Ec38342, median lateral arm plate in external (C) and internal (D) views. E–F. O. doro, paratype, NRM PAL Ec38343, distal lateral arm plate in external (E) and internal (F) views. G–H. Ophiopetagno sp. 1, NRM PAL Ec38344, proximal to median lateral arm plate in external (G) and internal (H) views. I–J. Ophiopetagno sp. 2, NRM PAL Ec38345, median to distal lateral arm plate in external (I) and internal (J) 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.