MOLECULAR SYSTEMATICS AND PATTERNS OF DIVERSIFICATION IN PYRRHURA (PSITTACIDAE), WITH SPECIAL REFERENCE TO THE PICTA-LEUCOTIS COMPLEX

Auk, The, Jul 2006 by Ribas, Camila C, Joseph, Leo, Miyaki, Cristina Y

ABSTRACT.-

Parakeets in the genus Pyrrhura occur in Amazonia and in almost all other major Neotropical forests. Their uneven distribution (with some widespread and several geographically restricted endemic taxa) and complex patterns of plumage variation have long generated a confused taxonomy. Several taxonomically difficult polytypic species are usually recognized. Here, we present a mitochondrial DNA (mtDNA) phylogenetic analysis of Pyrrhura, with emphasis on the especially problematic picta-leucotis complex, to provide a more robust basis for interpreting the systematics and historical biogeography of the group. Our main findings are that (1) Pyrrhura can be divided into three main evolutionary lineages, one comprising P. cruentata, an Atlantic Forest endemic, the second comprising the picta-leucotis complex, and the third comprising the remaining species; (2) the traditionally recognized species P. picta and P. leucotis are not monophyletic; and (3) most of the species recognized by Joseph (2000, 2002) are diagnosable as independent evolutionary units, with the exception of the following species pairs: P. snethlageae and P. amazonum, P. leucotis and P. griseipectus, and P. roseifrons and P. peruviana. Other than P. cruentata, the two clades that constitute Pyrrhura appear to have radiated and evolved their present mtDNA diversity over short periods during the Plio-Pleistocene.

Received 30 September 2004, accepted 30 September 2005.

Key words: Amazonia, diversification, mitochondrial DNA, molecular systematics, Neotropics, parakeets, Pyrrhura.

Sistem�tica Molecular y Patrones de Diversificaci�n en Pyrrhura (Psittacidae), con �nfasis en el Complejo Picta-Leucotis

RESUMEN.-Los pericos del g�nero Pyrrhura se encuentran en la Amazon�a y en la mayor�a de los dem�s bosques neotropicales principales. Su distribuci�n desigual (con algunos taxa de amplia distribuci�n y otros end�micos a regiones geogr�ficas estrechas) y los patrones complejos de variaci�n en el plumaje, han conducido a que la taxonom�a del grupo sea confusa. Usualmente se reconocen varias especies polit�picas y taxon�micamente dif�ciles. Con el fin de proveer informaci�n b�sica robusta para interpretar la sistem�tica y la biogeograf�a hist�rica del grupo, en este estudio presentamos un an�lisis filogen�tico de Pyrrhura con �nfasis en el complejo de picta-leucotis basado en ADN mitocondrial (ADNmt). Encontramos que Pyrrhura puede dividirse en tres linajes evolutivos principales: P. cruentata (una especie end�mica del bosque atl�ntico), el complejo de picta-leucotis y las especies restantes. Las especies reconocidas tradicionalmente como P. picta y P. leucotis no son monofil�ticas. La mayor�a de las especies reconocidas por Joseph (2000, 2002) pueden diagnosticarse como unidades evolutivas independientes, a excepci�n de los siguientes pares de especies: P. snethlageae y P. amazonum, P. leucotis y P. griseipectus, y P. roseifrons y P. peruviana. Aparte de P. cruentata, los dos clados que conforman el g�nero parecen haberse diversificado y haber evolucionado su diversidad actual en el ADNmt durante per�odes cortos en el Plio-Pleistoceno.

THE ORIGIN OF the high species diversity in lowland Neotropical forests has long been a major topic in evolutionary biology (Wallace 1852; Haffer 1969, 1993; Endler 1977; Salo et al. 1986; Cracraft and Prum 1988; Bush 1994; Tuomisto et al. 1995). Most authors agree that a fruitful way to address this issue is through linking phylogenetic relationships and geographic distributions of extant taxa (Moritz et al. 2000). Accordingly, numerous papers have studied patterns of phylogenetic relationships of species complexes found in Neotropical forests. Some examples in which molecular approaches have been taken concern snakes (Zamudio and Greene 1997), amphibians (Slade and Moritz 1998, Lougheed et al. 1999), rodents (Patton et al. 1994, 1996, 2000; da Silva and Patton 1998; Matocq et al. 2000; Costa 2003), cats (Eizirik et al. 1998), birds (Cracraft and Prum 1988, Marks et al. 2002, Aleixo 2004, Pereira and Baker 2004, Ribas and Miyaki 2004, Cheviron et al. 2005), and primates (Cort�s-Ortiz et al. 2003). Clearly, this approach to understanding species diversification and distribution patterns depends on a sound systematic framework. Here, we provide such a framework for the genus Pyrrhura.

Pyrrhura occur in all Neotropical forests, including the Amazon, the Atlantic, and the west Andean and Central American forests. Though distinctive and easily recognizable at the generic level, several species of Pyrrhura show subtle, taxonomically difficult patterns of variation, typically involving a small number of plumage characters. Further, taxa within a given species complex are often narrowly distributed geographic endemics. As a result, species-level systematics has long been problematic (Forshaw 1989; Collar 1997; Juniper and Parr 1998; Joseph 2000, 2002).

The Painted Parakeet (Pyrrhura picta) and Maroon-faced Parakeet (P. leucotis) complex, in particular, highlights these problems, some of which arise from the group's taxonomic history. Most authors have followed Peters (1937), who reduced the group to two species with no accompanying arguments. Thus, it has been conventional to recognize two polytypic species: P, picta (subspecies: picta, eisenmanni, roseifrons, lucianii, subandina, caeruleiceps, pantchenkoi, and amazonum) and P. leucotis (subspecies: leucotis, emma, auricularis, pfrimeri, and griseipectus). Joseph (2000, 2002) and Joseph and Stockwell (2002) reviewed geographic variation and taxonomy in the group and recognized 13 different species in the complex, including two new taxa for the east and west Amazon basin (P. snethlageae and P. peruviana, respectively; see Fig. 1). Joseph (2000, 2002) highlighted several problems needing further study. One of them concerns relationships among taxa within the complex. Another concerns finer-scale relationships among eastern and western Amazonian taxa recognized by Joseph (2002).