Amazona, Lesson, 1830

Smith, Brian Tilston, Thom, Gregory & Joseph, Leo, 2024, Revised Evolutionary And Taxonomic Synthesis For Parrots (Order: Psittaciformes) Guided By Phylogenomic Analysis, Bulletin of the American Museum of Natural History 2024 (468), pp. 1-87 : 34

Amazona

Amazona is a diverse yet easily recognizable clade of mid- to large-sized stocky birds with relatively short tails, large heads, and barred plumage. Most species are green with colorful patterning on the head but a few Caribbean species have plainer or more elaborate plumage. The concatenated and species trees are largely concordant and indicate at least three independent colonizations of the Caribbean. The main discrepancy between them arises from the relatively high number of lower-quality samples that were not accurately placed in the species tree. Our topology was generally concordant with that of Rusello and Amato (2004) with the exception of the position of two clades (1, 2) that stemmed from short internodes and were placed in our tree with high support: (1) A. festiva , A. pretrei , A tucumana , and A. vinacea ; and (2) A. amazonica , A. guildingii , A. brasiliensis , and A. imperialis . The basal divergence in Amazona dated to 9.9 Mya (4.7–13.1; fig. 7). It separates a clade of smaller bodied Caribbean ( A. agilis , A. vittata , A. ventralis , A. leucocephala , and A. collaria and Central American/ Mexican ( A. xantholora and A. albifrons ) species from all other Amazona , a phylogenetic position recovered previously by Russello and Amato (2004). This clade includes dichromatic species ( A. agilis , A. xantholora , and A. albifrons ), a character state that is generally lacking in Amazona . Ancient DNA and archaeological evidence show that Amazona in the Greater Antilles, specifically A. leucocephala and A. ventralis , were translocated across the Caribbean and had natural, more widespread ranges in the past ( Oswald et al., 2023). Amazona leucocephala was also found to have intraisland divergences throughout the Pleistocene. The next divergence results in two sister clades whose short node now has more support (UFBS = 91% vs. BS = 53%) than that in Russello and Amato (2004). The first clade had a crown age of 9.2 Mya (4.4–12.1) and includes a heterogeneous group of species spanning from Mexico (e.g., A. viridigenalis , A. finschi ) to Brazil ( A. diadema , A. amazonica ; fig. 7). It also represents a colonization of the Caribbean ( A. imperialis and A. guildingii ). Amazon guildingii is polymorphic, having yellow-brown and green plumage morphs ( Forshaw and Knight, 2010). The second of the major sister clades is also geographically widespread and consists of two independent colonizations of Central America. The first was seen in the divergence within what was formerly treated as a single species A. farinosa . It supports species rank for its Central American populations now recognized as A. guatemalae with two subspecies A. g. guatemalae and A. g. virenticeps. This accords with Wenner et al.’s (2012) phylogeographic study on the A. farinosa complex in which they detected a deep divergence between Central and South American lineages (1.75–2.70 Myr split in mtDNA). Our estimate was comparable but older. Together, the two data sets support divergence that reflects independent evolution of A. farinosa and A. guatemalae irrespective of a potential contact zone, vocal differences, or morphological distinctiveness. Chesser et al. (2023) did not recognize A. guatemalae as a species, arguing that a more thorough population-level study is necessary to better understand species limits. The second divergence across the Isthmus of Panama involves the yellow-headed Amazons and the split of A. ochrocephala from A. oratrix and A. auropalliata of Central America and Mexico, and A. tresmariae of the Tres Marias Islands of the Pacific Coast of Mexico. The recognition of these lineages as species (as opposed to subspecies) was in part due to phylogeographic studies that found deep genetic divisions within the yellow-headed Amazon complex ( Eberhard and Bermingham, 2004; Ribas et al., 2007b). Amazona tresmariae , as with A. guatemalae , was not recognized as a species by the North American Checklist Committee for similar reasons of inconclusive data ( Chesser et al., 2023). This clade was sister to the third colonization of the Caribbean where A. barbadensis of Venezuela and neighboring islands was sister to A. versicolor of St. Lucia and A. arausiaca of Dominica. The final clade was a group of three species, A. vinacea , A. tucumana , and A. pretrei , that have a southern distribution in Bolivia, Argentina, Brazil, and Paraguay.