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Use of continuous cranial shape variation in the identification of divergent crocodile species of the genus Mecistops
Author(s) -
Carr Amanda N.,
Nestler Jennifer H.,
Vliet Kent A.,
Brochu Christopher A.,
Murray Christopher M.,
Shirley Matthew H.
Publication year - 2021
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.21365
Subject(s) - crocodile , biology , snout , skull , extant taxon , evolutionary biology , identification (biology) , morphometrics , zoology , variation (astronomy) , biodiversity , genus , anatomy , ecology , physics , astrophysics
The discovery of cryptic biodiversity has blossomed under the advancements of genetic techniques, but species identification via morphology remains crucial to effective conservation efforts. In this study, we tested the use of continuous cranial shape variation in distinguishing the two living species of Mecistops : the West African slender‐snouted crocodile ( M. cataphractus ) and the Central African slender‐snouted crocodile ( M. leptorhynchus ). Using a combination of geometric morphometric characters and ratios of linear measurements, we identified statistically significant variation in cranial bone and overall skull shape of mature individuals that corroborates existing molecular and discrete morphological evidence for two distinct, extant species within Mecistops . Specifically, variation in the shape of the nasal appears particularly diagnostic, while ratios involving metrics of snout length to snout width at the premaxillary notch offer distinguishing features easily measured in the field. Because of the complementary results and applications of the morphometric and cranial ratio analyses, we argue that both methodologies remain relevant to species identification. Moreover, we recommend continued cooperation between geneticists and morphologists in diagnosing species of conservation concern.