Polytelis, Wagler, 1832

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 : 49-50

Polytelis

Polytelis comprises three species endemic to Australia. They are long-tailed, slender-bodied parrots and have vocalizations that are as notably unique to the genus as they are similar among the three species themselves. Phenotypically disparate relative to each other, they share at least one plumage trait, a distinctively colored wing-covert patch. Notably, however, this patch is most easily visible in one species, P. swainsonii when safely viewed under a “black” light where ultraviolet pigments reflect as yellow (L.J., personal obs.). Similarly, P. swainsonii is sexually dimorphic in its coronal plumage but UV-fluorescent pigments are again only visible when safely viewed under a “black” light (L.J., personal obs.).

Previous multilocus phylogenetic studies analyzed only two of the three species, P. anthopeplus and P. alexandrae , and not P. swainsonii ( Wright et al., 2008; Schweizer et al., 2010, 2011). Further, these earlier multilocus studies sampled only single individuals each of P. anthopeplus and P. alexandrae that, moreover, had been reared in captivity either in Europe or North America and presumably were descended from many generations bred in captivity. Wild-collected specimens of Polytelis alexandrae are rare in museum collections, and we know of no cryofrozen tissue samples of it from natural populations. Given that background and taxon sampling, we note that the earlier multilocus studies consistently and unexpectedly found that P. anthopeplus and P. alexandrae were not each other’s closest relatives. In particular, P. alexandrae consistently was more closely related to Aprosmictus erythropterus than to P. anthopeplus (reviewed in Provost et al., 2018).

In an ongoing phylogenomic study of this unexpected result, we have sequenced all three species using multiple samples, whether toe pads of older museum specimens or cryofrozen tissue samples, from the natural ranges of all species, as well as captive-bred samples of P. alexandrae (note again that there are no cryofrozen tissue samples of wild P. alexandrae ). We specifically probed the unexpected paraphyly of Polytelis . We wished to test, for example, whether it was due to the use in earlier work of captive birds in Europe and North America. Specifically, such birds could have been descended, albeit by many generations, from well-known hybridization between P. alexandrae and A. erythropterus in captivity, although there is no evidence of backcrossing after such hybridization ( Forshaw, 2002; Sindel and Gill, 2003) during the 20th century. The concatenated tree found that P. alexandrae was sister to P. anthopeplus and P. swainsonii with 93% UFBS (fig. 10). In contrast, the species tree affirmed earlier multilocus work showing P. alexandrae as sister to Aprosmictus with 100% support. The divergence time estimate for P. alexandrae was approximately 7.9 Mya (4.7–11). This phylogenetic discordance could indicate several possibilities: ancient introgression occurred between between P. alexandrae and A. erythropterus (or their ancestral lineages); P. alexandrae is of hybrid origin; or P. alexandrae warrants full generic, not subgeneric, separation from Polytelis . Concerning the last alternative, we note that Spathopterus North, 1895, was erected solely for this species based on the spatulate tip of one primary feather in males. Mathews (1912) noted, however, that the name is preoccupied by Spathoptera Audinet-Serville, 1835 , in the Coleoptera (see Schodde and Mason, 1997). Northipsitta Mathews, 1912 , is available for it if Spathoptera is truly unavailable. Currently, we do not favor its generic separation from Polytelis (pace Provost et al., 2018). We instead argue that ancient introgression within the past natural ranges of these birds, not in captive populations, is potentially an equally good explanation of the data bearing on this problem. We are planning a separate publication specifically to address this surprisingly intransigent conundrum in more detail and our approach to its resolution.