Aratinga

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 : 43-45

Aratinga and Gymnopsittacus

Aratinga are small to medium-sized parakeets that are mostly green, but several species have extensive yellow and orange plumage. They have long, attenuated tails. We included the first genetic data for A. maculata , which was recently separated from the closely related A. solstitialis ( Silveira et al., 2005; Nemésio et al., 2009). Phylogenomic results confirm previously proposed relationships from mtDNA ( Ribas and Miyaki, 2004). That is, Aratinga auricapillus , A. jandaya , A. maculata , and A. solstitialis , hereafter the core A. solstitialis group, are closely similar in plumage and form a well-supported clade in the concatenated and species tree. As suspected, based on genetic distances in mtDNA within the core A. solstitialis group, their divergences from one another occurred in the past two million years. We further confirmed a sister species relationship between A. maculata and A. solstitialis , the two taxa sharing an estimated common ancestor 1 Mya (0.3–1.7; fig. 9).

Also reinforcing Ribas and Miyaki’s (2004) mtDNA findings, we recovered a further species, A. nenday , as sister to the core A. solstitialis group. This species has often been placed in monotypic Nandayus, Bonaparte 1856 . Its phenotypic distinctiveness is undeniable due to its black head, differently colored and sharply demarcated chest and abdominal plumage, and red confined to the tibial feathers. A close relationship between A. nenday and the core A. solstitialis group, however, was first proposed by Miranda-Ribeiro (1920) who placed them all in Nendayus [sic] Bonaparte, 1856. Most phenotypic similarities of nenday to the brightly colored core A. solstitialis group, possibly synapomorphic and thus consistent with a sister relationship, are not readily apparent in a typical museum specimen or a perched living individual. However, Silveira et al. (2005) outlined this similarity as follows: “The most remarkable characters shared by the members of the group [i.e., the core A. solstitialis group] are found in the wings and tail. Remiges are dorsally green, with middle and distal portions deep blue and black, respectively. They are black ventrally, and the greater wing coverts are mostly deep blue. Upper side of tail is mostly green with deep blue in the tip; underside is mostly black. Nandayus nenday (Nanday Parakeet) also shares the characters that otherwise diagnose the A. solstitialis group and probably belongs to the same clade” ( Silveira et al., 2005). To these we can add a black bill.

The impetus to move nenday to Aratinga involved a further species, weddellii . That is, although nenday is sister to the core A. solstitialis group ( Ribas and Miyaki, 2004; this study), weddellii is in turn that larger group’s sister (see South American Checklist Committee [SACC] proposal 578). Retaining all these species in Aratinga is simple and expedient (e.g., Remsen et al., 2013); it even has biogeographic cohesion in that the group is distributed around the lowland periphery of most of Amazonia. It obviates the need to recognize three genera, which is necessitated if nenday , nested within the group, is assigned to monotypic Nandayus . However, we do recommend assigning weddellii to its own genus (see below), so the issue returns to one of whether to generically recognize the two sister lineages, i.e., nenday and the core A. solstitialis group. Like so many similar decisions involving sister lineages, this ultimately is arbitrary. How might we resolve it here?

The divergence between A. nenday and the core A. solstitialis group had a mean estimate of 3.2 Mya (1.1–4.8; fig. 9). This age was younger than the majority of intrageneric divergences in parrots (only the Diopsittaca and Guaruba split at 2.5 Mya [0.9–3.8] was younger), and it is comparable with that of intraspecific divergences frequently observed within Neotropical birds ( Smith et al., 2017). We conclude that relative to the core A. solstitialis group, phenotypic differences of nenday have evolved rapidly while plumage similarities ( Silveira et al., 2005) likely are synapomorphic. We advocate retention of nenday in Aratinga .

Further research might usefully focus on the evolution of plumage color in the core A. solstitialis group complex, which presumably uses blue structural color and psittacofulvins to produce the greens and yellows in plumage of the entire head (reviewed in Berg and Bennett, 2010), whereas nenday has a melanin-producing pathway in its dark crown. Mutations in the gene SLC45A 2 in captive color morphs of Psittacula sensu lato parakeets were shown to lead to a loss of melanin and produce a yellow phenotype ( Roy et al., 2024). Identifying the reverse molecular pathway, a gain in melanin production, would help clarify the taxonomic relevance of the dark crown in nenday . Qualitatively, evolution to melanin-producing plumage color was infrequent in parrots, but it has independently evolved multiple times outside of nenday .

The final species to be discussed in the genus is A. weddellii of western lowland Amazonia. In our analyses, it is strongly supported as sister to all other Aratinga and on a relatively long branch (fig. 9), corroborating previous work ( Kirchman et al., 2012). The disparity in plumage and skin color and patterning between A. weddellii and all other Aratinga is striking. It is reflected in the deep split at 6.6 Mya (2.7–9.4; fig. 9), separating these two lineages. The estimated timing of this divergence is largely overlapping with the split of the extinct Conuropsis carolinensis from the whole subclade (fig. 9).

The combined phenotypic and phylogenetic distinctiveness of Aratinga weddellii strongly suggests the merit of its generic separation (cf. distinctiveness of Psephotellus varius relative to other Psephotellus spp. ). A genus group name, Gymnopsittacus Miranda-Ribeiro, 1920 , is available for A. weddellii . We advocate for and suggest the reintroduction of its status as a monotypic genus.

Miranda-Ribeiro (1920) designated Aratinga weddellii (see note below on orthography) as the type species and Eupsittula cactorum as what he termed a cotype species. Peters (1937) as first reviser fixed Conurus weddellii Deville, 1851 , as the type species of Gymnopsittacus . Further, Miranda-Ribeiro (1920) included a third taxon, aeruginosa, in Gymnopsittacus but it has long since been recognized as a subspecies within the polytypic Eupsittula pertinax complex. Similarly, Eupsittula also holds E. cactorum .

It is beneficial to reiterate the diagnostic phenotypic traits of Gymnopsittacus as follows: rosepink (côr de carne = color of flesh sensu Miranda-Ribeiro, 1920) colored nares and lateral gular skin along the base of the bill; frequently very pale iris, albeit possibly bicolored; large, broadly circular area of naked, pale periophthalmic skin that is proportionally larger relative to the eye than in closely related Aratinga sensu stricto but that resembles in its extent that of Thectocercus acuticaudata , for example; the highly variable dusky blue-gray coloring of the feathering of the head that results from individual feathers being brownish proximally and bluish gray distally. The overall color of the head is thus highly variable due, we posit, to combined factors of wear and perhaps individual variation; we know of no evidence that there are sexual differences in its intensity, although this may warrant study.

Lastly, we note that Miranda-Ribeiro (1920) consistently misspelled the epithet weddellii as weddelli. The orthography introduced by Deville (1851) was indeed the former, i.e., weddellii , having double d, double l, and double i.

Cyanopsitta Cyanopsitta is a small blue macaw of northeastern Brazil. It is one of the rarest birds in the world and the subject of intense in situ and ex situ conservation management ( Hammer and Watson, 2012). It was sister to a clade containing the majority of other macaws (except Anodorhynchus and Diopsittaca ), diverging 8.1 Mya (3.5–11.4; fig. 9). Its phylogenetic position is stable across multilocus phylogenies (e.g., Tavares et al., 2006; Wright et al., 2008; Schirtzinger et al., 2012) and the concatenated and species trees.