Comparative cytogenetics of Physalaemus albifrons and Physalaemus cuvieri species groups (Anura, Leptodactylidae)

Abstract

Recently, Physalaemus albifrons (Spix, 1824) was relocated from the Physalaemus cuvieri group to the same group as Physalaemus biligonigerus (Cope, 1861), Physalaemus marmoratus (Reinhardt & Lütken, 1862) and Physalaemus santafecinus Barrio, 1965. To contribute to the analysis of this proposition, we studied the karyotypes of Physalaemus albifrons, Physalaemus santafecinus and three species of the Physalaemus cuvieri group. The karyotype of Physalaemus santafecinus was found to be very similar to those of Physalaemus biligonigerus and Physalaemus marmoratus, which were previously described. A remarkable characteristic that these three species share is a conspicuous C-band that extends from the pericentromeric region almost to the telomere in the short arm of chromosome 3. This characteristic is not present in the Physalaemus albifrons karyotype and could be a synapomorphy of Physalaemus biligonigerus, Physalaemus marmoratus and Physalaemus santafecinus. The karyotype of Physalaemus santafecinus is also similar to those of Physalaemus marmoratus and Physalaemus biligonigerus owing to the presence of several terminal C-bands and the distal localization of the NOR in a small metacentric chromosome. In contrast, the Physalaemus albifrons karyotype has no terminal C-bands and its NOR is located interstitially in the long arm of submetacentric chromosome 8. The NOR-bearing chromosome of Physalaemus albifrons very closely resembles those found in Physalaemus albonotatus (Steindachner, 1864), Physalaemus cuqui Lobo, 1993 and some populations of Physalaemus cuvieri Fitzinger, 1826. Additionally, the Physalaemus albifrons karyotype has an interstitial C-band in chromosome 5 that has been exclusively observed in species of the Physalaemus cuvieri group. Therefore, we were not able to identify any chromosomal feature that supports the reallocation of Physalaemus albifrons.

Chromosomal analysis of Physalaemus kroyeri and Physalaemus cicada (Anura, Leptodactylidae)

“…This is because the morphology of pairs 1–7 is highly similar in the karyotypes analyzed, despite some differences in size (e.g., Physalaemus albonotatus in Vittorazzi et al 2014b). Even so, it is possible that some of these inferences are erroneous, given that some pairs of chromosomes (pairs 3 and 4, for example, and 5 and 6) are very similar.…”

“…The (FN)fundamental number of these karyotypes is 44, which is characteristic of most of the Physalaemus species for which cytogenetic data are available, such as Physalaemus cuvieri (Beçak et al 1970, Silva et al 1999, Quinderé et al 2009), Physalaemus soaresi Izecksohn, 1965 (De Lucca et al 1974), Phyllodactylus marmoratus (Reinhardt & Lütken, 1862) (Beçak et al 1970, Amaral et al 2000), Physalaemus biligonigerus (Cope, 1861) (Amaral et al 2000, Silva et al 2000), Physalaemus henselii (Peters, 1872), Physalaemus riograndensis Milstead, 1960 (Tomatis et al 2009), Physalaemus olfersii (Lichtenstein & Martens, 1856) (De Lucca et al 1974; Silva et al 2000, Milani et al 2011), Physalaemus ephippifer (Nascimento et al 2010), Physalaemus barrioi Bokermann, 1967 (Provete et al 2012), Physalaemus albifrons , Physalaemus centralis (Denaro 1972, Vittorazzi et al 2014b), Physalaemus albonotatus , Physalaemus cuqui , and Physalaemus santafecinus Barrio, 1965 (Vittorazzi et al 2014b). However, the species of the Physalaemus signifer clade and Physalaemus fernandezae (Muller, 1926) (part of the Physalaemus henselii group of the Physalaemus cuvieri clade) (see Lourenço et al 2015) have FN=42, due to the presence of a telocentric pair classified as pair 11.…”

“…All the Physalaemus species karyotyped up until the present time show 2n = 22 (Beçak et al 1970, Denaro 1972, De Lucca et al 1974, Silva et al 1999, Silva et al 2000, Amaral et al 2000, Lourenço et al 2006, Ananias et al 2007, Tomatis et al 2009, Milani et al 2010, Nascimento et al 2010, Provete et al 2012, Vittorazzi et al 2014b). The species of the Physalaemus cuvieri group studied by C-banding (Silva et al 1999, Quinderé et al 2009, Nascimento et al 2010, Vittorazzi et al 2014b) all present a block of interstitial heterochromatin in the metacentric chromosome 5, which is a potential cytogenetic marker of the Physalaemus cuvieri group (Vittorazzi et al 2014b, Lourenço et al 2015).…”

“…The species of the Physalaemus cuvieri group studied by C-banding (Silva et al 1999, Quinderé et al 2009, Nascimento et al 2010, Vittorazzi et al 2014b) all present a block of interstitial heterochromatin in the metacentric chromosome 5, which is a potential cytogenetic marker of the Physalaemus cuvieri group (Vittorazzi et al 2014b, Lourenço et al 2015). The chromosomal location of the PcP190 satellite DNA is known for Physalaemus cuvieri , Physalaemus centralis , Physalaemus albonotatus , Physalaemus albifrons and Physalaemus ephippifer (Vittorazzi et al 2011, Vittorazzi et al 2014a).…”

“…Given this, the objective of the present study was to evaluate the chromosomal features of these two species, in particular the presence of an interstitial heterochromatic band on chromosome 5, which is recognized as a chromosomal synapomorphy in the Physalaemus cuvieri group (Vittorazzi et al 2014b, Lourenço et al 2015). …”