Filling the Silurian knowledge gap: A new occurrence of solutans in the Wenlock of Wales

 

Authors: Nohejlová M, Dupichaud C, Lefebvre B

Published in: Bulletin of Geosciences, volume 101, issue 1; pages: 111 - 121; Received 19 November 2025; Accepted in revised form 3 March 2026; Online 3 May 2026

Keywords: Soluta, Echinodermata, palaeoecology, palaeobiogeography, Silurian, Wales,

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Abstract

Soluta is a long-ranging, low-diversity class of Palaeozoic echinoderms with a particularly discontinuous fossil record. This study describes their second worldwide occurrence in the Silurian, and their earliest record after the Late Ordovician mass extinction. The new material from the Nantglyn Flags Formation (Wenlock Series) in Wales (UK) is herein assigned to Dehmicystis aff. ariasi, based on characteristic morphological features, such as a globose, rounded theca made of smooth, unornamented plates; a non-apical brachiole inserted on the lower thecal surface; and a large periproct located on the upper thecal side. This new occurrence extends the stratigraphic and palaeobiogeographic distribution of the genus Dehmicystis, previously known from the Ludlow of Spain, the early Emsian of Germany, and possibly the Pragian of Belgium. Dehmicystis aff. ariasi provides crucial data for deciphering the evolutionary patterns and recovery of solutans after the Hirnantian mass extinction. Their cryptic fossil record may result, at least partly, from their restriction to deep environments (outer shelf, slope), which are less frequently preserved than more proximal settings.