Karyological observations on Polyclads

Abstract

A karyological analysis of eight species of Polyclads has been carried out. A chromosome number of n = 10 for Stylochus alexandrinus and for Stylochus mediterraneus was ascertained on germinal lines.A chromosome number of 2n = 20 was ascertained from metaphasic plates from regenerative blastemas of Notoplana alcinoi and Leptoplana tremellaris. A karyometric analysis of this last species permitted the reconstruction of an idiogram.An idiogram was also prepared from metaphasic plates of Stylostomum ellipse obtained from early embryonic mitoses. The chromosome number of this species also was 2n = 20.Chromosome numbers of n = 8 and 2n = 16 were ascertained on germinal lines and metaphasic plates of blastemas in Echinoplana celerrima and on germinal lines and early embryonic mitoses of Stylochoplana maculata.Finally the diploid number 2n = 18 was ascertained on metaphasic plates from regenerative blastema of Yungia aurantiaca.

Theama mediterranea sp. nov. (Platyhelminthes, Polycladida), the first interstitial polyclad from the Mediterranean

“…In the Acotylea, the haploid chromosome numbers range from 8 to 10, with most species showing n510, and isobrachial chromosomes (Galleni & Puccinelli 1984, 1985. Karyotypes with n510, with mostly meta-submetacentric chromosomes, are also found in the Cotylea (Galleni & Puccinelli 1981;Curini-Galletti & Campus 2007). The karyotype of T. mediterranea thus confirms the prevalence of sets with n510 and isobrachial chromosomes in the Polycladida, which appear particularly conservative with this regard.…”

Karyological observations on Turbellaria Proseriata: karyometric analysis ofMonocelis fusca, M. lineata (Monocelididae) andParotoplana macrostyla (Otoplanidae)

“…Examination of marine groups, mostly dealing with marine triclads and polyclads indicate that in closely related forms speciation has been accompanied by small karyological variations, mainly concerning centromere position (Galleni & Puccinelli, 1979, 1981, 1982.…”

“…At present, the knowledge on the karyology of marine Turbellaria is fairly satisfactory only for polyctads and marine triclads (Galleni & Puccinelli, 1981, 1982. Within the other marine groups, Proseriata are of special interest, mainly due to their phylogenetic position and relation to triclads Sopott-Ehlers, 1984).…”

Chromosomal evolution in marine triclads and polyclads (Turbellaria)

“…in the genus Procerodes (Tricladida) published by Galleni & Puccinelli (1979) and , of the polyclad species Thysanozoon brocchii and Yungia aurantiaca (see Galleni & Puccinelli, 1977, and of the polyclad genera Notoplana and Leptoplana (Galleni & Puccinelli 1975, 1981 .…”