CAMPOS, Z., LLOBET, A., PIÑA, C.I. & MAGNUSSON, W.E. (2010)
Yacare Caiman - Caiman yacare.
In: Crocodiles.Status Survey and Conservation Action Plan: 23-28.
Third Edition, ed. by S.C. Manolis and C. Stevenson. Crocodile Specialist Group: Darwin
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The Yacare caiman is found in the lowlands of northern and eastern Bolivia and western Brazil, from the Amazon southwards through the Guaporé/Madeira and Paraguay/Paraná River systems and into northern Argentina. Morphologically and ecologically, this species is similar to the common caiman (Caiman crocodilus crocodilus), and integrates with that subspecies along a large area (probably more than 1000 km) of the Madeira River in Amazonia. As with the common caiman, C. yacare is found in a wide spectrum of habitat types. Most ecological studies have been carried out in the Pantanal region of southern Brazil.
Resolution of the systematic relationships within the very widespread C. crocodilus complex is needed. Extensive surveys and specimen collection in southern Brazil, northern Bolivia and Paraguay suggest a ery complex gradient of morphological features between C. c. crocodilus and the C. yacare. As there are no fixed differences between the two taxa, they have to be defined geographically, rather than morphologically, which obviously poses legal difficulties if an individual crosses the hypothetical line and changes “species”.
Morphological and genetic analyses to resolve the relationships between these taxa are incomplete and inconclusive, mainly because data from the zone of hybridization between the two taxa was not included.
Caiman yacare is still, and always has been, listed technically as a full species. Some authors do not recognize it as being distinct from the common caiman and use the subspecies C. c. yacare. Recent molecular data provide evidence for long-term biological separation of large populations of caimans in Central and South America.
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