The indeterminate parrot of Nuevo León
The paleoavifauna of San Josecito Cave, Nuevo León, northeast Mexico, includes seventeen osteological elements of parrots. The late Pleistocene deposit has been radiocarbon-dated at 25,000–12,500 years B.P. The material is all assignable to the genus Rhynchopsitta, a pinecone specialist. Three species are recognizable on the basis of qualitative and quantitative characters: the smaller extant western Thick-billed Parrot, R. pachyrhyncha, the larger extant eastern Maroon-fronted Parrot, R. terrisi, and the still larger heavier-billed parrot here named R. phillipsi. Because of distinctive character differences in all elements represented (rostrum, ulna, carpometacarpus, humerus), the extinct R. phillipsi is not considered ancestral to R. terrisi but contemporaneous with it in the late Pleistocene. With the conversion of pinyon-juniper woodland of northern Mexico to Chihuahuan desert scrub and the restriction of coniferous forests to relictual populations 1,000 m upslope at the end of the Pleistocene, the Large-billed Parrot was lost from the local avifauna.