The spectacled caiman (Caiman crocodilus) is currently considered to be a species complex due to the relatively high morphological and molecular diversity expressed across its range. One of the populations of interest, inhabiting the Apaporis River (Colombia), was described based on skull features as an incipient species (C. c. apaporiensis) and has been treated by some authors as a full species. Recent molecular work challenged this hypothesis, because relatively low mitochondrial molecular differentiation was found between the morphologically described Apaporis caiman and C. crocodilus (s.s.) Amazonian populations. Here, we present an update on the topic based on a larger molecular sample size and on analysis of expanded geometric morphometric data that include six newly collected skulls. Morphometric data support the existence of previously recognized morphotypes within the complex in Colombia and demonstrate that the newly collected material can be assigned to the classic Apaporis caiman morphotype. However, our expanded genetic analysis fails to find appreciable mitochondrial molecular divergence of the Apaporis caiman population from the C. c. crocodilus population (COI-CytB: Amazon Peru 0.17 ± 0.06%, CytB-only: Caquetá River Colombia 0.08 ± 0.07%). The Apaporis caiman is interpreted to be a phenotypically distinct member of the cis-Andean C. crocodilus metapopulation that has not yet achieved (or may not be undergoing at all) appreciable genetic differentiation. Thus, it should not be considered a fully independent evolutionary lineage, nor given full species rank.

Conservation efforts have allowed American crocodile (Crocodylus acutus) populations to recover to the point that dispersal movements are beginning to be documented. The environmental authority of San Andres Island in Colombia reported, for the first time, the arrival of two C. acutus from unknown localities in 2012 and 2018. The former was sacrificed, and the latter was captured and kept in captivity to determining its potential origin. We used wildlife forensics to establish the origin of the animal that arrived in 2018 based on two mitochondrial genes (COI and Cytb). Additionally, five other samples from Tayrona National Natural Park (TNNP), and Salamanca Island Road Park (SIRP) were sequenced for molecular attribution of these populations to the currently described lineages. Phylogenetic and phylogeographic analyses showed that the American crocodile found in San Andrés belongs to a continental evolutionary lineage endemic to Colombia, showing also a strong genetic similarity with animals from SIRP. Thus, the most likely origin for this individual was not the nearest continental area but somewhere around the central Colombian Caribbean, located ~700 km from the island. We discuss the implication of our findings in the systematics and conservation of the species and the potential of mitochondrial DNA analysis to identify such migrants.

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