Phylogeny and taxonomy of the Socorro parakeet (Psittacara holochlorus brevipes): recent speciation with minor morphological differentiation

Abstract

The Socorro parakeet (Psittacara holochlorus brevipes), endemic to Socorro Island has long been treated as a subspecies by several authorities while others considered it to be a full a species based on different types of evidence. We reviewed the phylogenetic placement of the Socorro parakeet using molecular techniques adding newly derived information from several fresh and museum specimens to available sequences in GenBank. We obtained revised phylogenies from NADH dehydrogenase 2 (ND2) and cytochrome oxidase I (COI) mitochondrial genes. Maximum likelihood and Bayesian phylogenetic analysis recovered the phylogeny of Psittacara. This clade has strong support for both genes and taxa within the clade show reciprocal monophyly. Based on this phylogenetic placement and geographical isolation, we recommend recognizing the Socorro parakeet as a distinct species (Psittacara brevipes). Psittacara h. rubritorquis should be treated as a distinct species as well. This taxonomic arrangement also will draw more attention to this parakeet from the conservation community considering the restricted distribution and small population size of the Socorro parakeet.