Cytotaxonomy of Eurypyga helias (Gruiformes, Eurypygidae): First Karyotypic Description and Phylogenetic Proximity with Rynochetidae

Abstract

The sunbittern (Eurypyga helias) is a South American Gruiformes, the only member of Family Eurypigidae. In most phylogenetic proposals, it is placed in a more distant position than other families of the so-called “core Gruiformes”. Different studies based on molecular, morphological and biogeographical data suggest that the Eurypigidae is closely related to the kagu (Rhynochetos jubatus), the only species in Rynochetidae, another family not included in the core Gruiformes. Here, the karyotype of the sunbittern is described for the first time, by classical and molecular cytogenetics, using whole chromosome probes derived from Gallus gallus and Leucopternis albicollis. We found a diploid number of 80, with only one pair of biarmed autosomal macrochromosomes, similar to that observed in the kagu. Chromosome painting revealed that most syntenies found in the avian putative ancestral karyotype (PAK) were conserved in the sunbittern. However, PAK1, PAK2, and PAK5 corresponded to two chromosome pairs each. Probes derived from L. albicollis confirm that fissions in PAK1 and PAK2 were centric, whereas in PAK5 the fission is interstitial. In addition, there is fusion of segments homologous to PAK2q and PAK5. From a phylogenetic point of view, comparisons of our results with two other Gruiformes belonging to family Rallidae suggest that the PAK5q fission might be a synapomorphy for Gruiformes. Fissions in PAK1 and PAK2 are found only in Eurypigidae, and might also occur in Rynochetidae, in view of the similar chromosomal morphology between the sunbittern and the kagu. This suggests a close phylogenetic relationship between Eurypigidae and Rynochetidae, whose common ancestor was separated by the Gondwana vicariancy in South America and New Caledonia, respectively.

The Karyotype of the Hoatzin (<b><i>Opisthocomus hoazin</i></b>) - A Phylogenetic Enigma of the Neornithes

“…Some species of Gruiformes and Charadriiformes, which form a clade with Opisthocomiformes according to whole-genome analysis [Jarvis et al, 2014;Cracraft et al, 2015], have been analyzed by chromosome painting. These studies revealed the presence of a few chromosome synapomorphies which reinforced the monophyly of each order [Nanda et al, 2011;Furo et al, 2015b;Kretschmer et al, 2015b]. For instance, the fission of the syntenic group corresponding to GGA5q represented a synapomorphy for Gruiformes species.…”

“…This is also the case for species that have been placed as sister groups of Opisthocomiformes, including turacos [Van Tuinen and Valentine, 1986], cuckoos [Stock and Mengden, 1975; Wald- Ferrari, 1980Ferrari, , 1982, Charadriiformes [Hammar, 1970;Ledesma et al, 2005;Kretschmer et al, 2015b], and Gruiformes [Furo et al, 2015b]. However, there are a number of chromosomal rearrangements involving syntenic groups corresponding to chicken macrochromosomes.…”

Comparative analyses of three swallow species (Aves, Passeriformes, Hirundinidae): Insights on karyotype evolution and genomic organization

“…The chromosome painting patterns found in swallows are very distinct when compared to distant bird orders, such as Galliformes and Anseriformes, which in general present chromosomal structure similar to PAK1-10 ( Guttenbach et al, 2003;Shibusawa et al, 2003;Kretschmer et al, 2018a). The same occurs when compared with Gruiformes, Eurypygiformes and Trogoniformes, which show fusions in distinct macrochromosomes pairs and also some peculiar chromosomal fission for each order (Nanda et al, 2011;Furo et al, 2015;Degrandi et al, 2017).…”

Phylogenetic Analysis and Karyotype Evolution in Two Species of Core Gruiformes: Aramides cajaneus and Psophia viridis

“…In our previous study with Eurypyga helias (Eurypygidae), formerly included in Gruiformes, but now regarded as belonging to a different order (Eurypygiformes) with only two families (Rynochetidae and Eurypygidae), we had proposed that the putative common ancestral karyotype of core Gruiformes would have a fission of GGA4p, since it had been found in the three species studied (P. viridis, F. atra and G. chloropus) ( Table 1; Table 2) [10,17]. If this hypothesis was correct, A. cajaneus would have regained the ancestral character.…”

“…The advances in comparative chromosome mapping with the use of chromosome painting has provided important information for inferences about phylogenetic relationships in some groups of birds, clarifying some problems left by the analyses of molecular biology [9][10][11][12][13][14]. Furthermore, despite the apparent karyotypical conservation among birds observed by conventional staining, comparative chromosome painting has revealed many rearrangements, such as fusions and fissions in several macrochromosomes; this information allowed the inference of a putative ancestral karyotype (PAK) of birds, which is actually highly similar to the chromosomal complement of Gallus gallus, with the exception of pair 4, which corresponds to two distinct pairs in the proposed ancestral karyotype [9][10][11]15,16].…”