The Skeletal Characteristics of Limb of Two endemic Lizard Species )Acantocercus adramitanus and Chamaeleo calyptratus( in Yemen

Abstract

Lizards have the broadest geographical distribution encompassing a wide range of locomotor habitats. This is reflected in a large morphological diversity of the general body form and of the locomotory apparatus among these animals. So, the present study aimed to clarify the osteological characteristics of the limb skeleton of two endemic species sharing the same environment but differ in microhabitat and mode of their locomotion. Under a dissecting microscope, the fore and hindlimbs of each animal were excised by using iris scissors after narcotizing by doses of anesthetic. The specimens were processed for staining with Alcian blue and alizarin stains to stain the skeletal limbs. In the current study, intra- and interspecific variations were observed in 2 species studied in measurements of limb elements. In Chamaeleo calyptratus both the fore- and hind limbs were relatively equal in length. While, the FOL, MAL, TOFL2, TOFL3, TOFL4 and TOFL5 were significantly shorter than the hindlimb in Acantocercus adramitanus (t= -5.60, -8.59, -3.84, -6.69, -6.12 and -8.35 respectively P= 0.000). A significant pronounced variation in the length of the long bone in lizard studied. Meanwhile, high significant variations were noticeable for metacarpus and metatarsus measurements in A. adramitanus (F4,45= 88.66, P< 0.0001 and F4,45= 32.07, P <0.0001 respectively). Slightly significant variations were observed in metacarpus and metatarsus measurements of C. calyptratus (F4,45= 3.34, P<0.02 and F4,45= 3.42, P<0.02 respectively). Except the centrale, the width of elements composing the wrist and ankle is larger than length in A. adramitanus. High significant variations were noticeable in the autopodium of C. calyptratus. The radiale and centrale had larger length than width. However, C. calyptratus have relatively short ulnare, distal carpus 5 and proximal tarsus. These variations in limb elements of A. adramitanus and C. calyptratus may be due to the difference in microhabitat.