Data from: Rigorous approaches to species delimitation have significant implications for African crocodilian systematics and conservation

Accurate species delimitation is a central assumption of biology that, in
groups such as the Crocodylia, is often hindered by highly conserved
morphology and frequent introgression. In Africa, crocodilian systematics
has been hampered by complex regional biogeography and confounded
taxonomic history. We used rigorous molecular and morphological species
delimitation methods to test the hypothesis that the slender-snouted
croco- dile (Mecistops cataphractus) is composed of multiple species
corresponding to the Congolian and Guinean biogeographic zones. Speciation
probability was assessed by using 11 mitochondrial and nuclear genes, and
cranial mor- phology for over 100 specimens, representing the full
geographical extent of the species distribution. Molecular Bayesian and
phylogenetic species deli- mitation showed unanimous support for two
Mecistops species isolated to the Upper Guinean and Congo (including Lower
Guinean) biomes that were supported by 13 cranial characters capable of
unambiguously diagnos- ing each species. Fossil-calibrated phylogenetic
reconstruction estimated that the species split + 6.5 – 7.5 Ma, which is
congruent with intraspecies diver- gence within the sympatric crocodile
genus Osteolaemus and the formation of the Cameroon Volcanic Line. Our
results underscore the necessity of com- prehensive phylogeographic
analyses within currently recognized taxa to detect cryptic species within
the Crocodylia. We recommend that the com- munity of crocodilian
researchers reconsider the conceptualization of crocodilian species
especially in the light of the conservation ramifications for this
economically and ecologically important group.