Cytogenetics of Australian scorpions. II. Chromosome polymorphism in species of Urodacus (family Scorpionidae)

Abstract

The cytogenetic features of six species of scorpion from the Australian genus Urodacus (family Scorpionidae) were examined. Australian scorpionids possess monocentric chromosomes and male meiosis is achiasmate. Chromosome numbers are generally high and in some species extremely variable. Chromosome variation in one species, U. manicatus, was found to be due to fusion – fission polymorphism and variation in the number of small telocentric chromosome pairs. Additionally two populations exhibited extensive inversion heterozygosity. Available evidence suggests that female meiosis may also be achiasmate. The extensive numerical and structural heterozygosity found in U. manicatus may be related to the achiasmate meiosis, which allows regular pairing and disjunction of the multiple chromosome associations.Key words: achiasmate meiosis, chromosome polymorphism, structural heterozygosity, Robertsonian fusions.

Chromosomal characteristics of a Brazilian whip spider (Amblypygi) and evolutionary relationships with other arachnid orders

“…Furthermore, among the Tetrapulmonata, high diploid numbers were recorded in basal groups of Araneae (2n = ± 96 in Mesothelae). In certain other groups of Arachnida, for instance, high chromosome numbers were recorded in derivative groups of all Scorpiones (2n = 56-175 in Urodacidae) and Pseudoscorpiones (2n = 61-73 in Chernetidae) (Suzuki, 1954;Shanahan, 1989;Štáhlavský et al, 2005). Considering this karyotype information, it is possible to suggest that the evolution of the diploid number in the distinct arachnid orders certainly evolved independently to an increase or decrease in chromosome number.…”

Conventional and ultrastructural analyses of the chromosomes ofDiscocyrtus pectinifemur(Opiliones, Laniatores, Gonyleptidae)

“…The wide diversity of chromosome numbers found in Opiliones also occurs in two related orders, Pseudoscorpiones and Scorpiones (Shanahan 1989; Šáhlavský et al. 2006).…”

Karyotype for <i>Nebo hierichonticus</i> (Simon 1872) from the Palestinian Territories (Scorpiones: Scorpionidae)

“…However, our data on Nebo hierichonticus and a review of available data shows an interesting pattern the karyotype of the Buthidae sensu lato ranges from 2n=6 to 2n=48, while that of the Scorpionidae sensu lata range from 2n=29 to 2n=175 (Shanahan 1989a, 1989b, Mattos et al 2013. Schneider et al (2009) stated that the low diploid numbers were restricted to the most cytogenetically investigated family (Buthidae) and in Opiliones, but not in the Scorpiones groups.…”

“…However, Soleglad and Fet (2003) abolished this family and downgraded it to a subfamily rank in the family Scorpionidae. The karyotype of 15 species of this family was investigated, with 2n ranging from 52 in Scorpio marus fuscus (Qumsiyeh et al 2013) to 175 in Urodacus novaehollandiae (Shanahan 1989b).…”