PHYLOGENETIC RELATIONSHIPS AMONG SOME NEOTROPICAL PARROT GENERA (PSITTACIDAE) BASED ON MITOCHONDRIAL SEQUENCES

ABSTRACT.-The New World tribe Arini includes 30 genera and represents 148 known species of parrots. A previous phylogenetic study examined nine of those genera and suggested the existence of two groups. Our objective was to better understand the relationships among 14 species from 9 genera belonging to one of those groups. We partially sequenced the 12S and 16S ribosomal DNAs, cytochrome b, cytochrome oxidase I, and control region. We improved our understanding of the phylogenetic relationships among Neotropical parrots by adding both taxa and sequences, but the relationships among the deeper lineages were not well resolved. Our results agree with present classifications that place some species formerly in the genus Ara into three additional genera (Primolius, Orthopsittaca, and Diopsittaca). Additionally, we suggest that (1) D. nobilis and Guarouba guarouba are closely related and the genus Aratinga is not monophyletic; (2) diversification of genera may have occurred during the Miocene, and of species within genera during the Pliocene and Pleistocene; and (3) geologic, climatic, and environmental changes in South America may have been related to that diversification. Received 3 May 2002, accepted 7 November 2003.

RESUMEN.- A tribo Arini, que ocorre exclusivamente no Novo Mundo, agrega 140 especies de psitacideos organizadas em 30 generos. Em um estudo filogenetico previo foram analisados nove desses generos e foi sugerida a existencia de dois grupos. Nosso objetivo foi estudar melhor as relacoes entre 14 especies de nove generos pertencentes a um desses grupos. Nos sequeciamos parcialmente os rDNAs 12S e 16S, o citocromo b, o citocromo oxidase I e a regiao controle. Nossos resultados indicam que a adicao de taxons e de sequencias melhorou a compreensao das relacoes filogeneticas entre psitacideos Neotropicais, mas as relacoes entre as linhagens mais antigas continuaram mal resolvidas. Nossos resultados sao concordantes corn a classificacao atual que considera que algumas das especies que pertenciam ao genero Ara devem estar organizadas em tres generos adicionais (Primolius, Orthopsittaca e Diopsittaca). Alem disso, sugerimos que Diopsittaca nobilis e Guarouba guarouba sao proximamente relacionadas e que o genero Aratinga nao e monofiletico. A diversificacao entre generos deve ter ocorrido durante o Mioceno e a divergencia dentro dos generos, durante o Plioceno e Pleistoceno. Mudancas geologicas, climaticas e ambientais na America do Sul podem estar relacionadas com tal diversificacao.

THE ORDER PSITTACIFORMES comprises ~350 species distributed in 84 genera (Collar 1997, Rowley 1997), and ~27% of them are endangered to varying degrees (BirdLife International 2000). They are distributed throughout the southern portion of North America, Central and South America, the Caribbean Islands, Africa, Indian and Pacific islands, the Australasian region, and southern Asia (Forshaw 1989).

The phylogeny of the group is still poorly understood at almost all taxonomic levels. Using DNA-DNA hybridization data, Sibley and Alquist (1990) suggested that the order descended from an ancient lineage and has no close living relatives. The morphological homogeneity of parrots makes them distinct from other avian orders, while rendering further subdivision difficult (Smith 1975). However, Smith (1975) suggested that New World parrots should be set apart from Old World parrots; he grouped all the New World parrots in the tribe Arini on the basis of some exclusive characters, such as chicks hatching with imperforate ear canal and the copulation posture on one leg. The tribe Arini is also recognized by other authors (Forshaw 1989, Sick ?997, Collar 1997). Sibley and Alquist (1990) also suggested that parrots could be separated by their geographical location (i.e. Americas, Africa, and Australasia); but given the limited number of samples studied, they argued that this conclusion may be premature.

Our present study focuses on the tribe Arini. This group belongs to the subfamily Psittacinae, family Psittacidae, and contains the majority of the species of the order (148 of 353; Collar 1997, Rowley 1997). Some authors have attempted to understand the systematics of this tribe on the basis of morphology (Miranda Ribeiro 1920, Smith 1975, Sick 1990) and behavior (Smith 1975, Sick 1990). However, those studies did not try to recover the phytogeny of the taxa studied, and relationships still remain poorly understood.

A phylogeny of nine Arini genera based on 1.7 kilobases (kb) of mitochondrial DNA sequence data (12S rDNA, 16S rDNA, and cytochrome b) supports the presence of two groups: (1) Anodorhynchus hyacinthinus, Ara ararauna, Aratinga aurea, Cyanopsitta spixii, Deroptyus accipitrinus, Guarouba guarouba, and Pyrrhura picta; and (2) Amazona aesiiva and Pionus menstruus (Miyaki et al. 1998). Relationships among the seven species in the first group were poorly resolved. Therefore, we expanded the taxon sampling and increased the number of mitochondrial genes sequenced to answer the following questions: (1) Are those groups supported even with the addition of more taxa? (2) Are the nonmonotypic genera monophyletic? and (3) are there other species more closely related to the species studied by Miyaki et al. (1998)? We also estimate and discuss the dates of divergence of the taxa studied. The scientific names of the species analyzed here follow Collar (1997), with modifications (Penhallurick 2001).