Macroevolutionary diversification of feeding structures in echinoids
Macroevolutionary diversification of feeding structures in echinoids
Sea urchins (Echinoidea) have one of the most complete and well-preserved fossil records of any animal, presenting an ideal model system to answer a fundamental question in evolutionary biology: how does functional performance influence macroevolution across deep time? Crown group echinoids are characterized by a distinct structure – the perignathic girdle – which serves as the attachment site for the muscles that move their feeding apparatus. A wide diversity of perignathic girdle morphologies exists, ranging from small, gracile pegs to robust wing-like ridges. While the perignathic girdle has been recognised as a crucial feature underlying echinoid systematics, the functional roles of the different morphologies are unknown, making its role in echinoid diversification unclear. Combining new deep learning approaches to microCT segmentation with 3D geometric morphometrics, we have quantified perignathic girdle shape for over 100 taxa, forming the largest growing databases of 3D echinoid morphology to date. The resulting morphospace is analysed in relation to differences in feeding modalities (e.g., sediment, grazing, predation), habitat type (e.g., epifaunal, infaunal) and important events in echinoid evolutionary history (e.g., Permo-Triassic mass extinction, diversification of irregular body plans). Utilising modern phylogenetic comparative methods, preliminary results indicate that convergent evolution of perignathic girdle shapes is occurring across evolutionarily distinct lineages, suggesting that there may be strong responses to selective pressures related to feeding performance. Specifically, adaptive optima may be driving the evolution of different perignathic girdle morphologies. Overall, this work is providing insight into how changes in the functional performance of feeding morphology have influenced morphological and ecological diversification over the last 300 million years.
Leavey, Alice
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Madappuli Arachchige, Gayashan
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Felice, Ryan
87807260-3b9d-44ab-aa60-fa4290c6357c
Hebdon, Nicholas
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Petsios, Elizabeth
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Thompson, Jeffrey R.
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4 March 2026
Leavey, Alice
2abe23e1-f3c9-47e3-83b7-c3a9fc60a5e9
Madappuli Arachchige, Gayashan
fd4a1f59-7c16-4e4b-9e8e-923d55acd577
Felice, Ryan
87807260-3b9d-44ab-aa60-fa4290c6357c
Hebdon, Nicholas
3cd21bce-f30a-4ebb-aaca-d344de76e191
Petsios, Elizabeth
a5cdbcb2-f8b8-4ee4-8e75-8fa9271a08d6
Thompson, Jeffrey R.
d2c9b7bb-3e33-4918-97c8-0c36e7af30a4
Leavey, Alice, Madappuli Arachchige, Gayashan, Felice, Ryan, Hebdon, Nicholas, Petsios, Elizabeth and Thompson, Jeffrey R.
(2026)
Macroevolutionary diversification of feeding structures in echinoids.
Virtual Conference for Women Archaeologists and Paleontologists (VCWAP) 6th conference, Virtual, Virtual.
04 - 06 Mar 2026.
1 pp
.
Record type:
Conference or Workshop Item
(Poster)
Abstract
Sea urchins (Echinoidea) have one of the most complete and well-preserved fossil records of any animal, presenting an ideal model system to answer a fundamental question in evolutionary biology: how does functional performance influence macroevolution across deep time? Crown group echinoids are characterized by a distinct structure – the perignathic girdle – which serves as the attachment site for the muscles that move their feeding apparatus. A wide diversity of perignathic girdle morphologies exists, ranging from small, gracile pegs to robust wing-like ridges. While the perignathic girdle has been recognised as a crucial feature underlying echinoid systematics, the functional roles of the different morphologies are unknown, making its role in echinoid diversification unclear. Combining new deep learning approaches to microCT segmentation with 3D geometric morphometrics, we have quantified perignathic girdle shape for over 100 taxa, forming the largest growing databases of 3D echinoid morphology to date. The resulting morphospace is analysed in relation to differences in feeding modalities (e.g., sediment, grazing, predation), habitat type (e.g., epifaunal, infaunal) and important events in echinoid evolutionary history (e.g., Permo-Triassic mass extinction, diversification of irregular body plans). Utilising modern phylogenetic comparative methods, preliminary results indicate that convergent evolution of perignathic girdle shapes is occurring across evolutionarily distinct lineages, suggesting that there may be strong responses to selective pressures related to feeding performance. Specifically, adaptive optima may be driving the evolution of different perignathic girdle morphologies. Overall, this work is providing insight into how changes in the functional performance of feeding morphology have influenced morphological and ecological diversification over the last 300 million years.
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Published date: 4 March 2026
Venue - Dates:
Virtual Conference for Women Archaeologists and Paleontologists (VCWAP) 6th conference, Virtual, Virtual, 2026-03-04 - 2026-03-06
Identifiers
Local EPrints ID: 510604
URI: http://eprints.soton.ac.uk/id/eprint/510604
PURE UUID: 9d5cc157-33ed-4a06-916b-ea2eafb04833
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Date deposited: 14 Apr 2026 16:32
Last modified: 16 Apr 2026 02:19
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Contributors
Author:
Alice Leavey
Author:
Gayashan Madappuli Arachchige
Author:
Ryan Felice
Author:
Nicholas Hebdon
Author:
Elizabeth Petsios
Author:
Jeffrey R. Thompson
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