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  • The early actinopterygian genus Rhadinichthys redefined, the type species ornatissimus redescribed, and the species bearsdeni introduced
Title: The early actinopterygian genus Rhadinichthys redefined, the type species ornatissimus redescribed, and the species bearsdeni introduced
ABSTRACT Rhadinichthysis one of the most wide-ranging and speciose genera of Palaeozoic actinopterygians. A classic variety of ‘palaeoniscoid’,Rhadinichthysspecies are generally small (~10–15 cm) and known mostly from dermal skeletal remains that show features commonplace among early ray-finned fishes. For this reason, the genus has long been considered a poorly diagnosed wastebasket taxon in need of revision and rarely included in systematic analyses. In the present work, syntypes ofRhadinichthys ornatissimus, the type species, are re-examined and supplemented with better-preserved material from other localities in the Scottish Midland Valley. A neotype is nominated and a more precise diagnosis presented with a suite of genus-level apomorphies. Unexpectedly, these traits are also evident in the monotypic Lower Carboniferous actinopterygian genusWoodichthys, which the neotype ofR. ornatissimusclosely resembles. As a result, the genusWoodichthysis subsumed within the redefinedRhadinichthys, and the singleWoodichthysspecies is reassigned asR. bearsdeni, comb. nov., bringing with it a set of endoskeletal data. Some of these data are new, derived from μCT scans of the skull of theR. bearsdeniholotype, yielding renderings that update the original description of its skull table, parasphenoid, neurocranium, and otoliths. Further new data concerning the hyoid arch are obtained from a new specimen ofR. bearsdenifrom a site close by the original Bearsden locality. Redefined in this way,Rhadinichthyspresents a data-rich operational taxonomic unit better suited for systematic studies. However, in so doing, it also releases a cluster of fossil species no longer anchored to a genus and now in need of rediagnoses.  more » « less
Award ID(s):
2218892
PAR ID:
10649464
Author(s) / Creator(s):
; ;
Publisher / Repository:
Cambridge University Press
Date Published:
Journal Name:
Earth and Environmental Science Transactions of the Royal Society of Edinburgh
Volume:
115
Issue:
3-4
ISSN:
1755-6910
Page Range / eLocation ID:
113 to 129
Subject(s) / Keyword(s):
Actinopterygii, palaeontology, Scotland, systematics, wastebasket taxa, microCT
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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