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Karyological investigation and comparison among tropical lizards (Squamata : Agamidae) and its taxonomic implications
Author
Low, Vivian May Hon
Supervisor
Diong, Cheong Hoong
Abstract
The Family Agamidae (Order: Squamata) in Peninsular Malaysia and Singapore is represented by 7 genera and 25 species of lizards. Nine species of lizards from the 3 genera: Acanthosaura, Calotes, and Gonocephalus, were karyotyped in this study. The karyotypes of five lizards, Acanthosaura armata, Gonocephalus bellii, Gonocephalus liogaster, Gonocephalus chamaeleontinus, and Gonocephalus robinsonii were documented here for the first time. No heteromorphic sex chromosome was evident in the species studied. The karyotypes showed chromosomes of two distinct size groups: macrochromosomes and microchromosomes. The number of macrochrolnosomes within each genus was invariant. Of the 3 genera karyotyped, one genus has diploid numbers more than the ancestral karyotype 2n = 36, while the two other genera had less than the 2n = 36 chromosomes.
Karyological data was used to discuss the taxonomic status of species in the Calotes and Gonocephalus species complex. Calotes cristatellus has a karyotype formula 2n = 34(14M + 20m) while other Calotes species have a karyotype of 2n = 34(12M+20m). In light of the karyological data from this and other published studies, there is justification to reassign Calotes cristatellus to the genus Bronchocela. Karyological results were also used to hypothesize possible modes of speciation of Gonocephalus species on either side of the Wallace line.
Karyological data was used to discuss the taxonomic status of species in the Calotes and Gonocephalus species complex. Calotes cristatellus has a karyotype formula 2n = 34(14M + 20m) while other Calotes species have a karyotype of 2n = 34(12M+20m). In light of the karyological data from this and other published studies, there is justification to reassign Calotes cristatellus to the genus Bronchocela. Karyological results were also used to hypothesize possible modes of speciation of Gonocephalus species on either side of the Wallace line.
Date Issued
1996
Call Number
QL666.L2 Low
Date Submitted
1996