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| Melanedaphodon hovaneci Mann, Henrici, Sues & Pierce, 2023 Life reconstruction by Henry Sutherland Sharpe |
Abstract
Herbivory evolved independently in several tetrapod lineages during the Late Carboniferous and became more widespread throughout the Permian Period, eventually leading to the basic structure of modern terrestrial ecosystems. Here we report a new taxon of edaphosaurid synapsid based on two fossils recovered from the Moscovian-age cannel coal of Linton, Ohio, which we interpret as an omnivore–low-fibre herbivore. Melanedaphodon hovaneci gen. et sp. nov. provides the earliest record of an edaphosaurid to date and is one of the oldest known synapsids. Using high-resolution X-ray micro-computed tomography, we provide a comprehensive description of the new taxon that reveals similarities between Late Carboniferous and early Permian (Cisuralian) members of Edaphosauridae. The presence of large bulbous, cusped, marginal teeth alongside a moderately-developed palatal battery, distinguishes Melanedaphodon from all other known species of Edaphosauridae and suggests adaptations for processing tough plant material already appeared among the earliest synapsids. Furthermore, we propose that durophagy may have provided an early pathway to exploit plant resources in terrestrial ecosystems.
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| Holotype of Melanedaphedon hovaneci gen. et sp. nov., CM 93778. (A) Photograph showing the negative relief/natural mould. (B) Digital three-dimensional rendering of the CT data in positive relief. (C) Interpretative drawing of specimen based on micro-CT data and original fossil. Top left corner shows a reconstruction of the skull in lateral view with the preserved cranial elements highlighted. Anatomical abbreviations: ang angular, art articular, d dentary, j jugal, mx maxilla, pt pterygoid, sur surangular, sp splenial. |
Systematic palaeontology
Synapsida Osborn, 1903
Sphenacomorpha Ivakhnenko, 2003 sensu Spindler et al., 2015.
Edaphosauridae Cope, 1882.
Melanedaphodon hovaneci gen. et sp. nov.
Diagnosis: An edaphosaurid synapsid with the following autapomorphies: long maxilla with 20 tooth positions; marginal dentition consisting of tall teeth with bulbous crowns that have pointed apices; and cutting edges of tooth crowns without serrations. Further differential diagnosis includes: an elongate pterygoid shared with Ianthasaurus but not Edaphosaurus. Palatal shagreen with enlarged teeth on the anterior (palatal) ramus of pterygoid shared with Ianthasaurus but not Edaphosaurus. Differs from Ianthasaurus but shares with Edaphosaurus in having a tooth battery instead of enlarged single tooth row on the transverse flange of the pterygoid. Differs from Gordodon in the absence of a diastema on the anterior end of the maxilla.
Etymology: Generic name derived from the combination of the Greek ‘melanos’ meaning ‘black’ and ‘edaphon’ meaning ‘pavement’ and ‘odon’ meaning ‘tooth’, referring to the dense shagreen on the pterygoid and to the position of the taxon among Edaphosauridae. The specific epithet hovaneci honors George Hovanec who generously donated funds to facilitate the CT scanning of Linton fossils.
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| Life reconstruction of Melanedaphedon hovaneci gen. et sp. nov. (created by Henry Sutherland Sharpe). |
Arjan Mann, Amy C. Henrici, Hans-Dieter Sues and Stephanie E. Pierce. 2023. A New Carboniferous edaphosaurid and the Origin of Herbivory in Mammal Forerunners. Scientific Reports. 13: 4459. DOI: 10.1038/s41598-023-30626-8
