First observation of intersex in barbel Barbus callensis (Valenciennes, 1842) collected in Soummam River (Algeria)
The presence of intersexuality in a gonochoric species Barbus callensis (Valenciennes, 1842) collected between March and October 2010 in the Soummam River, Algeria, is reported using anatomical and histological investigations. A total of 16 out of 700 dissected specimens (2.28%) were macroscopically classified as intersex, i.e. characterized by the simultaneous presence of both male and female gonads in the same individual. Three different anatomical forms were observed: (1) two gonads with an ovary and a testis clearly individualized (n = 2), (2) four gonads with distinguished pairs of ovaries and testes (n = 8), and (3) four gonads, in which each ovary was completely linked to a testis (n = 6). Different portions of the gonads representing the three macroscopic forms of intersex were studied microscopically using Mayer’s haemalun-eosin and modified azan staining techniques. Histological analysis revealed the simultaneous presence of female and male gametes in each analysed gonad. In the gonads that appeared as ovaries, a majority of female tissue with oocytes at different developmental stages was observed, with cells reaching the final stage of maturation. Within the female tissue, different male germ cells were observed, including maturated spermatozoa. In apparent testes, the same cells were observed, except that male germ cells were predominating. This study reports the first evidence of simultaneous intersexuality in a gonochoric species Barbus callensis, revealed at macroscopic and microscopic levels.