Translator Disclaimer
16 May 2019 Deciphering the roles of environment and development in the evolution of a Late Triassic assemblage of conodont elements
Pauline Guenser, Louise Souquet, Sylvain Dolédec, Michele Mazza, Manuel Rigo, Nicolas Goudemand
Author Affiliations +
Abstract

To assess evolutionary processes in deep time, it is essential to understand the roles of development and environment, both recorded through the morphological variability of fossil assemblages. Thanks to their great abundance and the high temporal resolution of their fossil record, conodont elements are ideal to address this issue. In this paper, we present the first quantitative study of a Carnian–Norian (Late Triassic) assemblage of closely related P1 conodont elements. Using geometric morphometrics (landmarks, sliding landmarks, and elliptic Fourier analysis), we explore the main axes of phenotypic variation and relate them to classically used taxonomic characters. We show that some important taxonomic features follow laws of covariation, hence highlighting developmental constraints. Furthermore, the intraspecific variation within all considered species, either Carnian or Norian forms, is similarly restricted, emphasizing, for the first time in conodont P1 elements, a common line of least resistance to evolution, which means that similar intrinsic (developmental) factors were acting on these taxa and likely biased the evolutionary trajectories of all these taxa in a similar way. Because the evolution between Carnian and Norian forms is known to have followed a trajectory that is significantly different from the line of least resistance, strong extrinsic pressures, such as environmental disturbances, were probably at play around the Carnian/Norian boundary to counteract the effects of these intrinsic, developmental constraints.

© 2019 The Paleontological Society. All rights reserved.
Pauline Guenser, Louise Souquet, Sylvain Dolédec, Michele Mazza, Manuel Rigo, and Nicolas Goudemand "Deciphering the roles of environment and development in the evolution of a Late Triassic assemblage of conodont elements," Paleobiology 45(3), 440-457, (16 May 2019). https://doi.org/10.1017/pab.2019.14
Accepted: 9 April 2019; Published: 16 May 2019
JOURNAL ARTICLE
18 PAGES


Share
SHARE
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top