Cytogenetic analysis of the Mediterranean Palinuridae Palinurus elephas and P. mauritanicus (Crustacea, Decapoda).

Cytogenetic analysis of the Mediterranean Palinuridae Palinurus elephas and P. mauritanicus (Crustacea, Decapoda) E. Coluccia, A. Cau, S. Salvadori, R. Cannas, A.M. Deiana Dipartimento di Biologia Animale ed Ecologia, Università di Cagliari, V.le Poetto, 1- 09126 Cagliari, Italy - email: coluccia@unica.it Palinurus elephas (Fabricius, 1787) and P. mauritanicus Gruvel, 1911 are two Mediterranean spiny lobster species living at different depths.. The knowledge on the karyology of Decapoda are scanty owing to technical constraints in obtaining good chromosomal preparations. To date cytogenetic analysis by chromosome banding are very few. In the contest of a cytogenetic and molecular study on the two Mediterranean Palinuridae we present a characterization of mitotic and meiotic chromosomes of these species by different staining techniques. Chomosomal preparations have been obtained from testicular and somatic tissues by a direct method. Heterochromatin has been localized by C-banding. This technique allowed also a sharp differentiation of chromosomes, a clear identification of meiotic figures and the detection of supernumerary chromosomes in both species. B chromosomes are variable in number, very small, completely heterochromatic and in meiosis I they are often asynaptic. Their presence could account for the variability recorded in determining the chromosome number. The heterochromatin analysis has been deepened by fluorochrome banding. Quinacrine and DAPI localized AT-rich clusters in several centromeric and paracentromeric regions; chromomicin A3 localized GC-rich DNA in centromeric and paracentromeric regions and in some small chromosomes, entirely fluorescent.