Translator Disclaimer
1 December 2001 A STATISTICAL ANALYSIS OF A GROWTH SERIES OF THE PERMIAN NECTRIDEAN DIPLOCAULUS MAGNICORNIS SHOWING TWO-STAGE ONTOGENY
Author Affiliations +
Abstract

We use probability plots to compare metric data for a growth series of the Permian nectridean Diplocaulus magnicornis Cope to a normal (Gaussian) probability distribution function and demonstrate that the ontogeny of Diplocaulus is not a single continuous process. The plots are bimodal, revealing a population of small, ontogenetically young animals whose growth is governed by a distinct process. This population, which comprises ∼20% of the growth series, is not evident in allometric studies. These young animals have a mean mid-line skull length of ∼21 mm, and their orbits are relatively larger, and rounder, than the orbits of the older animals, whose mean skull length is ∼94 mm. Although there is no evidence of lissamphibian-type metamorphosis in the Nectridea, the probability plots clearly demonstrate a two-stage ontogeny, best described as an ontogenetic morphological saltation. This saltation may have been an alternative strategy to the metamorphic heterochrony found in lissamphibians and their relatives.

LARRY F. RINEHART and SPENCER G. LUCAS "A STATISTICAL ANALYSIS OF A GROWTH SERIES OF THE PERMIAN NECTRIDEAN DIPLOCAULUS MAGNICORNIS SHOWING TWO-STAGE ONTOGENY," Journal of Vertebrate Paleontology 21(4), (1 December 2001). https://doi.org/10.1671/0272-4634(2001)021[0803:ASAOAG]2.0.CO;2
Received: 14 November 2000; Accepted: 24 July 2001; Published: 1 December 2001
JOURNAL ARTICLE
4 PAGES


SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top