Cytogenetics studies in Brazilian species of Pseudophyllinae (Orthoptera: Tettigoniidae): 2n(♂)=35 and fn=35 the probable basic and ancestral karyotype of the family tettigoniidae

The karyotypes of five species of Brazilian Pseudophyllinae belonging to four tribes were here studied. The data available in the literature altogether with those obtained with species in here studied allowed us to infer that 2n(♂)=35 is the highest chromosome number found in the family Tettigoniidae and that it is present in species belonging to Pseudophyllinae, Zaprochilinae and in one species of Tettigoniinae. In spite of that all five species exhibit secondary karyotypes arisen surely by a mechanism of chromosomal rearrangement of centric fusion, tandem fusion and centric inversion types from those with 2n(♂)=35 and FN=35, they share some common traits. The X chromosome is submetacentric (FN=36), heteropicnotic during the first prophase, the largest of the set but its size is rather variable among the species and the sex chromosomal mechanism is of the XO( ♂ ), XX( ♀ ) type. The chromosomal rearrangements involved in the karyotype evolution of the Pseudophyllinae and its relationship with those of the family Tettigoniidae are discussed and we propose that the basic and the ancestral karyotype of the Tettigoniidae is formed by 2n(♂)=35, FN=35 and not by 2n(♂)=31, FN= 31, as usually accepted.

Cytogenetics studies in thirteen Brazilian species of Phaneropterinae (Orthoptera: Tettigonioidea: Tettigoniidae): main evolutive trends based on their karyological traits

The thirteen species of Phaneropterinae here studied can be arranged in four different groups according to their basic karyological traits. All of them share the same kind of chromosomal sex determining mechanism with X0(male) and XX(female). The X chromosome differs among species and always appears heteropycnotic during prophase I, it is the largest in the set and segregates precociously during anaphase I. Among the species, the karyotypes varies in fundamental number between 31 to 21. The meaning of these significant changes in the karyotypes in relation to the phylogeny within some large taxonomic group of species is discussed.

As treze espécies de Phaneropterinae estudadas neste trabalho podem ser organizadas em quatro diferentes grupos tomando como referência suas características cariotípicas. Todas possuem sistema cromossômico de determinação sexual do tipo X0(masculino), XX(feminino). O cromossomo X é sempre heteropicnótico durante a prófase I, tem dimensões e morfologias variáveis nas diferentes espécies mas é sempre o maior elemento do cariótipo, além de apresentar segregação precoce durante a anáfase I. O número cromossômico fundamental (NF) varia de 21 a 32. Neste trabalho, são discutidos os significados evolutivos das variações cariotípicas encontradas e suas correlações filogenéticas com outros grupos de espécies pertencentes à mesma subfamília.