The chromosomes of Biomphalaria tenagophila (Gastropoda-Basommatophora-Planorbidae).

Abstract

Mitotic and meiotic chromosomes of the fresh water snail B. tenagophila were studied. Three populations, 2 from Argentina (Buenos Aires and San Miguel de Tucuman) and 1 from Uruguay (Carrasco), were investigated. The haploid number of the species is n = 18 and the diploid number is 2n = 36. The fundamental number is FN = 68. The karyotype is composed of 8 pairs of metacentrics, 8 pairs of submetacentrics and 2 pairs of acrocentrics. Secondary constrictions were apparent in some of the snails from the carrasco population.