Comparative anatomical study of the hyoid apparatus of Bosk’s fringe-toed lizard and spotted fan-toed gecko (Squamata: Lacertidae and Phyllodactylidae)

Background The present study aimed to illustrate comparative morphological, histological, and functional variations of the hyoid apparatus of Acanthodactylus boskianus and Ptyodactylus guttatus. Result The hyoid apparatuses and musculature of the two investigated species are well-developed. The hyoid apparatuses exhibit high mobility with different articulation sites between their skeletal elements. The degree of ossification of the hyoid apparatus of gecko is more developed than that of the lacertid lizard. In P. guttatus, a well-developed synchondrosis articulation appears between the basihyoid and ceratobranchialis of the hyoid apparatus. Meanwhile, in A. boskianus, the articular ligament which appears between basihyoid and ceratobranchialis is less developed and also appears as a ligament connection between the two parts of hyoid cornua in which ligaments provide more mobility to the hyoid of lacertid lizard. Conclusion The results reflect a phylogenetically informative character about these clad and explain the different functional demands imposed on the hyoid apparatus as well as confirm the important role of hyoid apparatus in the movement of the tongue during the prey transport.