Background: The anatomical information about the structure of the choana is lacking in literature, and its role in the olfactory and feeding mechanism is still unknown Results: The present study discusses the adaptation of choana to cranial kinesis during feeding process in different bird species: kestrel, common moorhen, and hoopoe. Kestrel possesses a kinetic skull while the hoopoe and common moorhen have kinetic one; however, the common moorhen skull seems highly kinetic more than that of the hoopoe that properly effect on the choanal epithelium. The choana of kestrel and hoopoe are lined by pseudostratified ciliated columnar epithelium, while choana of common moorhen have transitional epithelium beside pseudostratified ciliated columnar epithelium. The choana epithelium of each bird species provides with simple alveolar glands and numerous goblet cells. In kestrel and hoopoe, the secretion products of choanal glands contain neutral and sulfated mucin, while in the common moorhen, these glands secret neutral and carboxylate mucopolysaccharides. Conclusion: The choana of the three studied bird species apparents adaptation to the olfaction process but also affects the movement of skeletal elements of the skull during the feeding process

The current observations focused on the ultrastructure comparison between the tongue of two reptile species endemic the Egyptian fauna; Bosc's fringe‐toed lizard Acanthodactylus boskianus and Sinai fan‐fingered gecko Ptyodactylus guttatus to exhibit the relationship between the lingual epithelium and its function according to their specific feeding strategy. A. boskianus possessed triangular elongated tongue with bifurcated tapering apex and wide base while; the P. guttatus had a triangular flattened tongue with conical shallow bifurcated apex and broad base. The ventral surface of the lingual apex of A. boskianus had transverse while in P. guttatus had two oval pads and median ventral groove. Both surfaces of the tongue of both examined species are covered by stratified squamous epithelium with great variability of degree of keratinization. The dorsal epithelium formed flattened and conical filiform papillae in A. boskianus, while in P. guttatus formed cylindrical papillae, conical, and tall filiform ones. Few taste buds are observed on the fore‐tongue but increase on the mid‐tongue of A. boskianus, while in P. guttatus, numerous taste buds are distributed on the fore‐tongue and mid‐tongue. Both surfaces of the laryngeal mound of both examined species provided with numerous of cilia and orifices of laryngeal gland. The present results confirmed that the tongue of A. boskianus acts as a chemoreceptor organ to follow pheromone trails of prey and mates. While in P. guttatus the tongue may play an important role in the feeding mechanism and act as a chemoreceptor organ.

In this study, atrazine has been shown to act as a potent endocrine disruptor in amphibians either alone or in combination with nitrate under stable laboratory conditions, causing altered gonadal development at the sub-lethal concentrations. A control group and three treatments were tested; atrazine, nitrate, atrazine-nitrate treatments with doses of 300 µg/L, 200 mg/L and their combination, respectively. Atrazine exhibited increase the presence of testicular oocytes TOs in most treated specimens; furthermore, the sizes of seminiferous tubules were decreased compared to control group. Conversely no intersex individuals were detected in the nitrate treatment alone. The combined effects of nitrate and atrazine were not additive or synergistic but were similar to the effects of atrazine in raising the percentage of intersex but with increasing the size of testicular oocyte compared to atrazine alone. On the other hand, the control group in the present study did not contain the rudimentary testicular oocytes and showed normal structures. These gonadal abnormalities may reduce reproductive success and could be a major factor behind amphibian declines. Also, these negative impacts may be a bioindicator alarming the ecosystem disrupting caused by the uncontrolled apply of these chemicals in agriculture.

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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.