Cytogenetics of two Species of Paratelmatobius (Anura: Leptodactylidae), with Phylogenetic Comments

Abstract

In this paper we provide a cytogenetic analysis of Paratelmatobius cardosoi and Paratelmatobius poecilogaster. The karyotypes of both species showed a diploid number of 24 chromosomes and shared some similarity in the morphology of some pairs. On the other hand, pairs 4 and 6 widely differed between these complements. These karyotypes also differed in their NOR number and location. Size heteromorphism was seen in all NOR-bearing chromosomes of the two karyotypes. In addition, both karyotypes showed small centromeric C-bands and a conspicuous heterochromatic band in the short arm of chromosome 1, although with a different size in each species. The P. curdosoi complement also showed other strongly stained non-centromeric C-bands, with no counterparts in the P. curdosoi karyotype. Chromosome staining with fluorochromes revealed heterogeneity in the base composition of two of the non-centromeric C-bands of P . curdosoi.Comparison of the chromosomal morphology of these Parutelmatohius karyotypes with that of P. Iutzii showed that the P . poeciloguster karyotype is more similar to that of P . lutzii than P. cardosoi. These cytogenetic results agree with the proposed species arrangements in the P. curdosoi and P. lutzii groups based on morphological and ecological data. SP, The genus Paratelmatobius Lutz and Carvalho is endemic to Brazil and comprises the species P. lutzii, P. gaigeae, P. poecilogaster, P. cardosoi and P. mantiqueira (see review by POMBAL JR. and HADDAD 1999). Paratelmatobius species are usually rare, and P. gaigeae, P. lutzii and P. mantiqueira may be considered as missing species (POMBAL JR. and HADDAD 1999). Based on morphological and ecological data, POMBAL JR. and HADDAD (1999) recognized two species groups, the P. cardosoi group and the P. lutzii group, in this genus. The former group contains P. cardosoi and P. mantiqueira and the P. lutzii group encompasses P. lutzii, P. poecilogaster, and probably P. gaigeae. Shirlei Muriu Recco-Pimentel, Departamenin de Biologia Cellular, IB Universidude Esradual de Cumpinas (UNICAMP)The intergeneric phylogenetic relationships of this group are not yet clear. LYNCH (1971) considered Paratelmatobius a member of the subfamily Leptodactylinae and pointed out some morphological similarities among Paratelmatobius, Scythrophrys, Physalaemus and, to a lesser extent, Zachaenus. This classification was followed by FROST (1999). HEYER (1975) Paratelmatobius grouped together with the genera Scythrophrys, Zuchaenus, Thoropa, Megaelosia, Hylodes, Cycloramphus, Crossodactylus, Crossodactylodes and Craspedoglossa. The proximity between the genera Paratelmatobius and Scythrophrys, suggested by LYNCH (1971) andHEYER (1975), was also indicated by GARCIA (1996). Based on ecological and morphological characters, GARCIA (1 996) suggested a closer relationship between Scythrophrys and P. gaigeae ( = P. cardosoi sensu POMBAL JR. and HAD-DAD 1999) than between this species of Paratelmatobius and P. lutzii, and suggested a revision of both of these genera.The cytogenetic informatio...

Molecular cytogenetics of nucleolar organizer regions in Phyllomedusa and Phasmahyla species (Hylidae, Phyllomedusinae): a cytotaxonomic contribution

“…However, an explanation for differences among species in their susceptibility to molecular reorganization of rDNA clusters is still lacking. Results of the present study contrast with the major pattern of only one chromosome pair with NOR that is found in the other Phyllomedusa and related species studied so far; however, multiple NORs have been described in several other anuran species (e.g., Wiley et al, 1989;Lourenço et al, 1998Lourenço et al, , 2000Veiga-Menoncello et al, 2003;Amaro-Ghilardi et al, 2006;Silva et al, 1999, indicating that this variation is common in this group.…”

“…Similar NOR-length heteromorphisms were found in other anurans (Schmid, 1982;Lourenço et al, 2000;Busin et al, 2000;Bruschi et al, 2012), and this variation has been formerly attributed to tandem amplification of rRNA genes or of a whole NOR segment (Schmid, 1982;King et al, 1990). Schmid (1982) suggested that amplified NORs would be lethal in their homomorphic state, since the chromosome rearrangement could cause additional structural alterations in the NOR-adjacent segments that contain some functionally important genes.…”

Karyotypes of eight species of Leptodactylus (Anura, Leptodactylidae) with a description of a new karyotype for the genus

“…The karyotype of Lithodytes lineatus, another taxon included in Leptodactylus by Frost et al (2006), are composed of 18 biarmed chromosomes (Bogart 1970) and Vanzolinius discodactylus has a 2n=22 karyotype very similar to the other Leptodactylus above referred (Heyer and Diment 1974). Results of Frost et al (2006) and Grant et al (2006) suggest that the clade including Paratelmatobius and Scythrophrys is the sister group of Leptodactylus, and in both genus karyotypes with 24 chromosomes were observed (De Lucca et al 1974, Lourenço et al 2000, 2001, 2003. Taking a conservative approach to the contents of Leptodactylus (i.e., excluding Adenomera, Lithodytes, and Vanzolinius) the distinct diploid number of L. silvanimbus could be interpreted according to two different hypotheses.…”

Restriction fragment analysis of the ribosomal DNA of Paratelmatobius and Scythrophrys species (Anura, Leptodactylidae)

“…It is also interesting to note that there was no intraindividual variability in P. poecilogaster, despite the two NOR-bearing chromosome pairs in this karyotype (chromosome pairs 8 and 10; Lourenço et al, 2000). Moreover, all the species studied, as well as the individuals from the two group I Scythrophrys populations, could be distinguished from each other by the size of the digested fragments.…”

“…The available information about Paratelmatobius and Scythrophrys includes cytogenetic analyses showing interspecific variation in the NOR location in three karyotypes of Paratelmatobius (Lourenço et al, 2000;Lourenço et al, 2003) and two of Scythrophrys (Lourenço et al, in press). However, the organization of the rDNA genes in these genera is not known yet.…”