Chromosomal Evidences of Adaptive Convergence in the Tail Morphology of Neotropical Psittacidae (Aves, Psittaciformes).

Abstract

Summary Behavioral and morphological characters, as well as DNA hybridization and sequencing data strongly suggests that New and Old World Psittacidae evolved independently, supporting the tribe status for the American species (Arini). However, species and genera relationships within this group remain poorly known, and convergence was detected in various morphological characters, which could lead to artificial classifications. Most authors have subdivided Arini tribe in 2 monophyletic groups based on the comparative length of the tail, what is still controversial. In this paper we are describing for the first time the karyotypes of Pionites leucogaster and Pionopsitta pileata, both short-tail species which presented the same karyotypical pattern only previously observed to the long-tail genera. The remarkable karyotypical dichotomy presented by the Neotropical Psittacidae emphasize the existence of 2 distinct monophyletic groups within the Arini tribe. Nevertheless, the karyotypes of P leucogaster and P pileata short-tail species, suggests that the generalization long and short-tail is not valid to represent these both monophyletical groups, and there could occurs convergence in tail morphology character.

Chromosomal similarity between the Scaly-headed parrot (Pionus maximiliani), the Short-tailed parrot (Graydidascalus brachyurus) and the Yellow-faced parrot (Salvatoria xanthops) (Psittaciformes: Aves): a cytotaxonomic analysis

“…The Z-chromosome appears to be conserved in all the remaining New World parrots as it is metacentric and similar in size, corresponding to chromosome pair 4 or 5. The W-chromosome is morphologically more variable among the New World parrots than the Zchromosome, the W-chromosome having been identified as metacentric in most of the New World parrots, submetacentric in Anodorhynchus hyacinthinus (Lunardi et al, 2003), subtelocentric in Aratinga leucophthalmus (Lucca, 1984) and telocentric in Propyrrhura maracana, Aratinga auricapilla and Deroptyus accipitrinus (Francisco and Galetti, 2001;Lunardi et al, 2003). However, the W-chromosome showed a size similar to the smallest macro-autosomes in all the species studied.…”

“…One karyotype pattern is predominant in the genera Anodorhynchus (Lunardi et al, 2003), Ara (Van Dongen and De Boer, 1984;Francisco and Galetti-Jr, 2001), Cyanopsitta (Duarte and Giannoni, 1990), Aratinga (Lucca, 1984;Lucca et al, 1991;Goldschmidt et al, 1997), Guaruba (Goldschmidt et al, 1997), Nandayus (Francisco and Galetti-Jr, 2001), Propyrrhura (Francisco and Galetti-Jr, 2001), Pionites (Francisco et al, 2001) and Deroptyus (Lunardi et al, 2003). This karyogram is characterized by the presence of predominantly biarmed macrochromosomes consisting of about 10 autosomic pairs of which pair 1 is a metacentric conserved both in terms of morphology and size, pairs 2, 3, 4 and 5 vary from submetacentric to subtelocentric, pair 6 from submetacentric to telocentric, pairs 7 and 8 from metacentric to submetacentric and pairs 9 and 10 metacentric to telocentric.…”

“…Generally, where structural differences in karyotypes exist between various species of a group it is possible to form hypotheses as to their phylogenetic relationships (Van Dongen and De Boer, 1984). The American parrots is one of the most cytogenetically studied groups of New World birds (Lucca, 1974(Lucca, , 1984(Lucca, , 1985De Boer and Belterman, 1980;Van Dongen and De Boer, 1984;Schmutz and Prus, 1987;Valentine, 1987;Ferrari, 1985, 1990;Duarte and Giannoni, 1990;Lucca et al, 1991;Archangelo et al, 1995;Duarte and Caparroz, 1995;Rocha et al, 1995;Goldschmidt et al, 1997;Francisco et al, 2001;Lunardi et al, 2003), the species so far analyzed exhibiting a heterogeneous karyotypic morphology among some genera in contrast with several other avian groups in which very uniform karyotypes are found. Duarte and Caparroz (1995) showed that the Yellow-faced parrot (Amazona xanthops Spix, 1824), a species endemic to eastern and central Brazil (Forshaw, 1989), exhibited large karyotypic differences not only with the other species of the genus Amazona but also all the other New World parrots that have so far been described, while the morphological analysis conducted by Sick (1984) led him to state that the`inclusion of (A. xanthops) in the Amazona genus may not be correct.…”