Karyotypic differentiation via 2n reduction and a finding of a case of triploidy in anurans of the genus Engystomops (Anura, Leiuperidae)

Abstract

The genus Engystomops is divided into two groups, namely the Duovox clade and the Edentulus clade. The species of Edentulus clade have karyotypes with 2n = 22, while E. pustulatus and E. puyango, which belong to Duovox clade, have 2n = 20. To investigate if 2n = 20 is a synapomorphy of Duovox clade, we cytogenetically analyzed all the species of this group, except for E. puyango, in the present study. All of them had 2n = 20, differing from the species of Edentulus clade. Since the species already karyotyped of the genus Physalaemus, which is considered to be the sister group of Engystomops, also have 2n = 22, we conclude that the 2n reduction is a synapomorphy of Duovox clade. Despite the karyotypes of all the species of Duovox clade were very similar, they varied in the NOR pattern. In E. coloradorum, an additional NOR was found in one homologue of the chromosome pair 10 exclusively in all females, indicating that this could possibly be a sexual pair of the ZZ/ZW system. Also in this species, it was found the first case of natural polyploidy of the genus Engystomops.

Larval morphology of Amazonia foam‐nesting frogs of the genus Engystomops (Anura: Leptodactylidae: Leiuperinae)

“…A distinctive feature of tadpoles of E. guayaco is the presence of a conspicuous brown spot on the tail tip (Ron et al, 2005). We confirmed this character in our analyses for this species, but also found a similar pattern in tadpoles of E. randi , considered a very similar species to E. guayaco (Targueta et al, 2011). These two species, along with E. coloradorum and E. montubio , formed the clade Brevivox (Ron et al, 2006), characterized by small‐sized and morphologically conservative species, except for E. coloradorum (Cannatella & Duellman, 1984; Ron et al, 2004, 2005, 2006).…”

“…Engystomops guayaco and E. randi are cryptic species that occur in sympatry (Ron et al, 2005) but differ in their calls. Additionally, Targueta et al (2011) found distinctive cytogenetic patterns in E. randi , such as an interstitial C‐band in chromosome 10, that is absent in E. guayaco . Interesting, these two species exhibit distinctive diagnoses in the buccal cavities.…”

Chromosome evolution in Cophomantini (Amphibia, Anura, Hylinae)

“…This report is the first record of spontaneous autopolyploidy in a natural population of a diploid hylid species. This phenomenon is infrequent among anurans and has been observed only in eight species, Amietophrynus poweri (Bufonidae, [ 83 ]), Engystomops coloradum (Leptodactylidae, [ 84 ]), Eupsophus vertebralis (Alsodidae, [ 85 ]), Holoaden luederwaldti (Craugastoridae, [ 86 ]), Leiopelma hochstetteri (Leiopelmatidae, [ 87 ]), Lithobates palustris and L . pipiens (Ranidae, [ 88 , 89 ]), Odontophrynus americanus (Odontophrynidae, [ 90 ]), and Xenopus tropicalis (Pipidae, [ 80 ]).…”

Comparative cytogenetics of nine populations of the Rhinella genus (Anura, Bufonidae) with a highlight on their conservative karyotype

“…Cytogenetic data provide a powerful tool for the evaluation of the taxonomic (Cuevas, 2008; Fávero et al , 2011; Funk et al , 2012) and evolutionary relationships (Veiga-Menoncello et al , 2014) among anuran species. The understanding of chromosomal characters helps to identify synapomorphies (Cunningham and Cherry, 2004; Targueta et al , 2012; Suárez et al , 2013; Ferro et al , 2018) and homoplasies (Cardozo et al , 2011), and when combined with molecular phylogenetic inferences, these can contribute to the understanding of the role of chromosomal rearrangements in the diversification of a lineage (Veiga-Menoncello et al , 2014).…”