Estudo cariotípico de duas espécies brasileiras do gênero Micrurus (Ophidia: Elapidae)

Abstract

The karyotypes of two brazilian species of coral snakes (Ophidia: Elapidae): Micrurus corallinus and M. ibiboboca are described for the first time. Cytological preparations were obtained through the technique of squashing, followed by conventional Giemsa staining. The diploid number for Micrurus corallinus was 40 chromosomes with a karyotype formulae 40 (4; 16; 20) with a secondary constriction in the second pair of subtelocentric macrochromosomes. Micrurus ibiboboca is described by the formulae 42 (2; 20; 20) with 2n = 42 with a secondary constriction in the first pair of telocentric macrochromosomes. The karyotypes of M. corallinus and M. ibiboboca present aspects similar to M. lemniscatus and M. surinamensis, the only previously analyzed species of this genus in South America. These four species have the same number of microchromosomes (20), the largest number of telocentric or subtelocentric macrochromosomes and the largest diploid numbers (2n) ever found in the genus Micrurus. These characteristics differ from those of the nine known species of Central America.Keywords

Cytogenetics and Molecular Data in Snakes: A Phylogenetic Approach

“…Contrarily, in South America M. surinamensis surinamensis has 2n = 38 [Gutiérrez et al, 1988], M. lemniscatus car valhoi presents 2n = 42 [Beçak and Beçak, 1969], M. corallinus has 2n = 40 and M. ibiboboca has 2n = 42 [Serafim et al, 2007]. Serafim et al [2007] formulated the hypothesis that the chromosome number in the genus tends to increase in South America and decrease in Central America, changes that especially involve the microchromosomes in Central America and the macrochromosomes in South America, probably due to fusion and fission processes. The high chromosome variability is also true for Bungarus and Naja and other species in the family.…”

Karyotypes of Coralsnakes (Reptilia: Elapidae) from the Western Hemisphere, with Comments on Intraspecific Variation and Centric Fission of Chromosomes

“…The apparent occurrence of the conservative ancestral snake karyotype in the diverse elapids listed above strongly suggests that it is the ancestral karyotype for the family Elapidae (Mengden, 1985;Mengden et al, 1986). Nevertheless, the family has considerable karyotypic variation, as shown in the following papers: Singh (1972Singh ( , 1974; Graham (1977); Gutiérrez and Bolaños (1979, 1980; Gorman (1981); Toriba (1987); Gutiérrez et al (1988); Luykx et al (1992); and Serafim et al (2007).…”