Studies on chromosomal characteristics of Ctenus indicus (Gravely 1931) (Araneae: Ctenidae)

• Published in: Nucleus (Calcutta) 2017-04, Vol.60 (1), p.17-23
• Main Authors: Kumar, Sreeramulu Arun, Venu, Govindappa, Jayaprakash, Gowda, Venkatachalaiah, Govindaiah
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Cell Biology; Chromosomes; Heterochromatin; Life Sciences; Meiosis; Original Article; Silver nitrate; Spiders
• ISSN: 0029-568X; 0976-7975
• DOI: 10.1007/s13237-016-0191-2

The karyological information gathered for the Indian spiders taxa thus far were cytologically derived from only few species but none for the representatives belonging to the genus Ctenus . Ctenus indicus (Gravely 1931), an Indian ctenid spider was cytogenetically analyzed following conventional, C- and NOR-banding techniques so as to gather substantial data for future course of understanding of karyotypic evolution among spider species. The karyotypic data for Ctenus indicus revealed the complement consisting of (2n = 28) 26AA + X 1 X 2 ♂ and (2n = 30) 26AA + X 1 X 1 X 2 X 2 ♀ acrocentric chromosomes. A closer scrutiny of meiotic progression disclosed many male pachytenic cells displaying the occurrence of ‘bouquet’ formation. The results of C-banding enabled in identifying centromeric constitutive heterochromatin locales, and in some chromosomes also the distal ends of telomeric regions. Silver nitrate stained NOR-specifications were noticed at the distal telomeric regions of two pairs of chromosomes (#8 and #10) in the complement. Cytological evidence procured from the present study not only adds to the ever-growing list of the spider cytogenetic assessments but also offers as a baseline data towards establishing evolutionary relationships within this important group.