Gekko

Abstract: The foot of gekkonid lizards, because of the wide range of variation it displays within the family, is an ideal system on which to carry out a functional anatomical study. The wide range of variability and adaptation of the foot is unparalleled in other lizard groups. The Tokay (Gekko gecko (Linnaeus) 1785) has been used as a basis for a broader study of the comparative and functional anatomy of the foot within the family Gekkonidae. The acquisition of adhesive pads by Gekko has resulted in the development of a very distinctive mode of locomotion which has become modified both to deploy and, at the same time, protect the delicate subdigital setae. Analysis of the structure and function of the foot has been carried out in two stages: firstly a description of the mechanical units and then an interpretation of their function, with the aid of high speed cinematographic data. The skeletal elements of the foot exhibit several features which reflect the specialized method of locomotion and these are related to remarkable adaptations exhibited by the associated muscular, vascular and tendon systems. The functional significance of scansorial plates is discussed and the relationship between size and locomotory ability within the family Gekkonidae is also considered. Some ideas as to the selective advantage of the particular locomotory modifications under discussion are presented, but further consideration of this topic must wait until subsequent papers deal with a larger proportion of the family.

Abstract: The gekko Phyllodactylus marmoratus has at least three distinct chromosome races; 2n=36, 2n=36 ZZ/ZW and 2n=34. Specimens from these races are morphologically distinguishable, have a degree of habitat specialization and occur in a defined distribution. The 2n=36 race found in Eastern Australia is the presumed primordial type. The 2n=34 race occurs in Western Australia and is regarded as a fusion derivative. The 2n=36 ZZ/ZW race, which is only found on the Murray River system in Eastern Australia has a heteromorphic sex chromosome system present in the female. Giemsa banding suggests that this heteromorphism is the result of a pericentric inversion.

Abstract: An atlas of the forebrain of the lizard Gekko gecko has been provided, which will serve as the basis for subsequent experimental tracing and immunohistochemical studies. Apart from a strongly developed medial cortex and septal area, the Tokay gecko shows all the main features of the forebrain of the lacertid-type lizards. When its convenience as an experimental animal is also taken into account, this species seems to be very suitable for studying the limbic system in reptiles. The atlas comprises topographical reconstructions of the telencephalon and diencephalon and a series of transverse sections of which the levels have been indicated in the reconstructions. The results obtained in the Gekko are briefly compared with those found in other lizards studied.

Abstract: A new species of the Gekko japonicus group is described from Khammouane Province, central Laos, based on morphological characters and molecular data. Morphologically, Gekko nadenensis sp. nov. is differentiated from the remaining congeners by a combination of the following characters: size moderate (SVL 61.0–77.1 mm); nares bordered with rostral; internasals absent; postmentals enlarged; interorbital scales between anterior corners of the eyes 28–30; dorsal tubercles absent; ventral scales between mental and cloacal slit 175–185; midbody scale rows 123–140; ventral scale rows 38–40; subdigital lamellae on first toes 13–15, on fourth toes 14–16; finger and toe webbing present at base; tubercles on dorsal surface of fore and hind limbs absent; precloacal pores six (3+3 or 5+1) in a discontinuous row in males, absent in the female; postcloacal tubercles 1 or 2; tubercles absent on dorsal surface of tail base; subcaudals distinctly enlarged; dorsal surface of body with greyish brown blotches. Molecular analyses demonstrated the new species is closely related to G. bonkowskii and G. thakhekensis , but separated from them by approximately 7% in genetic divergence as shown by a fragment of the mitochondrial ND2 gene.