Mitotic karyotype of the tropical freshwater crayfish Procambarus (Austrocambarus) llamasi (Decapoda: Cambaridae)

Jeane R Indy,Lenin Arias-Rodriguez,Wilfrido M Contreras-Sánchez,Salomón Páramo-Delgadillo,Carlos A Álvarez-González,Ulises Hernández- Vidal

doi:10.15517/rbt.v58i2.5236

Abstract

In Mexico, the biology of Procambarus has been more studied than the biology of other Cambarids because of its diversity and potential use in aquaculture. We determined the karyotype of the Mexican tropical freshwater crayfish Procambarus (Austrocambarus) llamasi from 189 metaphase spreads from gill tissues of 17 adults. They had 98-120 chromosomes (mode 2n=120 chromosomes). There are 60 pairs of monoarm, telocentric chromosomes. Sex chromosomes were not detected and we propose that the P. llamasi karyotype can be used to distinguish this species from other Mexican crayfish. Additionally, we suggest using karyological data in aquaculture and conservation biology.

Highlights

There are three genera and about 50 species of cambarids in Mexico: Procambarus with 39 species, Cambarellus with 10 and Orconectes with only one species (VillalobosFigueroa 1983)
A total of 189 well-spread metaphases were scored from 70 analyzed chromosome slides from 17 adult specimens of the tropical crayfish P. llamasi
A typical diploid mitotic chromosome spread of the tropical crayfish P. llamasi is shown in figure 2-A, and the most parsimonious karyotype of the species in figure 2-B

Summary

Introduction

There are three genera and about 50 species of cambarids in Mexico: Procambarus with 39 species, Cambarellus with 10 and Orconectes with only one species (VillalobosFigueroa 1983). Cytogenetics studies of crustaceans are relatively few and very difficult to perform because their chromosome numbers are large (Niiyama 1962, Roberts 1969, Mittal & Dhall 1971, Campos-Ramos 1997, Dumas & Campos-Ramos 1999, Zhang et al 2003, Lee et al 2004), chromosomes are small and theirs shapes are very variable including metacentric, submetacentric, and acrocentric chromosomes (Tan et al 2004, Salema & Heino 1990, Damrongphol et al 1991) Such distinctiveness makes them difficult to karyotype in comparison with the chromosomes of insects and some vertebrate species (White 1973). The main aim of this study was to describe the mitotic chromosome number and karyotype of the tropical freshwater crayfish P. llamasi that inhabits the Grijalva River in Tabasco, southern of México

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