Comparative karyological analysis of three species of Bothriocephalus Rudolphi 1808 (Cestoda: Pseudophyllidea)

Abstract

The diploid complements of mitotic metaphase plates of three species of Botriocephalus were studied using conventional Giemsa staining and karyometric analysis. Botriocephalus claviceps and Botriocephalus gregarius showed a karyotype with 2n=14 chromosomes. All chromosomes of B. claviceps were biarmed, metacentric or meta-submetacentric. The two first pairs of homologues were markedly larger than the remaining elements and represented 48.62% of the total chromosome length. The karyotype of B. gregarius had similar metric values for the chromosomes, but clearly differed in the chromosome morphology of pairs 5, 6 and 7, which had terminally located centromeres. The diploid number 2n=12 was found in Botriocephalus scorpii. The karyotype consists of five pairs of metacentric and one pair of submeta-metacentric chromosomes. The possible pathways of karyotype evolution within Bothriocephalus spp. and their phylogenetic relations with the other karyologically studied groups in the order Pseudophyllidea are discussed.

New cytogenetic data on Caryophyllaeus laticeps and Paracaryophyllaeus gotoi, parasites of evolutionary interest

“…In all species, the difference in centromere position between the corresponding chromosomes within genera is probably due to intrachromosomal changes such as pericentric inversions. This pattern of chromosomal rearrangements is common in all major animal groups, including some tapeworm genera (Petkevičiūtė, 1996, 2003; Petkevičiūtė and Bondarenko, 2001; Naseeb et al ., 2016; Hooper and Price, 2017; Wellenreuther and Bernatchez, 2018). Similar to the family Caryophyllaeidae, the haploid chromosome number of n = 10 occurs in both main sister clades of the family Capingentidae (in the clade Glaridacris + Promonobothrium and the clade comprising the other groups).…”

Diversity of Dilepididae (Cestoda: Cyclophyllidea) revealed by cytogenetic analysis

“…In our viewpoint, if karyotype features are plotted over a phylogenetic tree reconstructed on molecular or morphological data, the processes involving chromosome evolution might be clarified. The congruence between chromosomal and molecular data obtained on diphyllobothriids, characterizing them as a distinct clade within the Pseudophyllidea (see Petkevičiū tė , 2002Petkevičiū tė , , 2003, shows that chromosomal changes could be valuable phylogenetic characters. It is notable that phylogenetic analysis of families of the Cyclophyllidea based on comparative morphology revealed extensive polymorphism within the Dilepididae sensu Bona (1994) (Hoberg et al, 1999).…”

Tapeworm chromosomes: their value in systematics with instructions for cytogenetic study

“…The question that arises is to what extent karyotype features could help us to resolve problematic relationships within the Cestoda. Congruence between chromosomal and molecular data from tapeworm species shows that chromosomal changes can be valuable phylogenetic characters and have phylogenetic significance (Petkevičiūtė 1992, 2002, 2003, Petkevičiūtė and Bondarenko 2001, Petkevičiūtė et al 2006.…”