Examining competition during the agnathan/gnathostome transition using distance-based morphometrics release_yrnqb4pherghjenqb3h5tokezy

by Bradley Scott, Philip Anderson

Published in Paleobiology by Cambridge University Press (CUP).

2022   p1-16


<jats:title>Abstract</jats:title> The rise of jawed vertebrates (gnathostomes) and extinction of nearly all jawless vertebrates (agnathans) is one of the most important transitions in vertebrate evolution, but the causes are poorly understood. Competition between agnathans and gnathostomes during the Devonian period is the most commonly hypothesized cause; however, no formal attempts to test this hypothesis have been made. Generally, competition between species increases as morphological similarity increases; therefore, this study uses the largest to date morphometric comparison of Silurian and Devonian agnathan and gnathostome groups to determine which groups were most and least likely to have competed. Five agnathan groups (Anaspida, Heterostraci, Osteostraci, Thelodonti, and Furcacaudiformes) were compared with five gnathostome groups (Acanthodii, Actinopterygii, Chondrichthyes, Placodermi, and Sarcopterygii) including taxa from most major orders. Morphological dissimilarity was measured by Gower's dissimilarity coefficient, and the differences between agnathan and gnathostome body forms across early vertebrate morphospace were compared using principal coordinate analysis. Our results indicate competition between some agnathans and gnathostomes is plausible, but not all agnathan groups were similar to gnathostomes. Furcacaudiformes (fork-tailed thelodonts) are distinct from other early vertebrate groups and the least likely to have competed with other groups.
In application/xml+jats format

Archived Files and Locations

application/pdf  830.6 kB
www.cambridge.org (publisher)
web.archive.org (webarchive)
Read Archived PDF
Preserved and Accessible
Type  article-journal
Stage   published
Date   2022-09-16
Language   en ?
Container Metadata
Not in DOAJ
In Keepers Registry
ISSN-L:  0094-8373
Work Entity
access all versions, variants, and formats of this works (eg, pre-prints)
Catalog Record
Revision: 71304392-0d4c-48ef-bad3-594764e514ab