Published online: 2019-08-09 THIEME 174 Original Article Anatomical and Radiographic Study on the Skull and Mandible of the African Lion (Panthera leo) Reda Mohamed1,2 1 Department of Basic Veterinary Sciences, School of Veterinary Address for correspondence Reda Mohamed, PhD, Department of Medicine, Faculty of Medical Sciences, The University of the West Basic Veterinary Sciences, School of Veterinary Medicine, Faculty of Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago Medical Sciences, The University of the West Indies, St. Augustine 2 Anatomy and Embryology Department, Faculty of Veterinary Campus, St. Augustine, Trinidad and Tobago Medicine, Beni-Suef University, Beni-Suef, Egypt (e-mail: [email protected]). J Morphol Sci 2019;36:174–181. Abstract Objective The taxonomic affiliations can be detected via the skull morphology. The objective of this study was to give a detailed gross anatomical and radiographic description of the bones and foramina of the skull and mandible of the lion. This information could be used in the identification of the skull and mandible of the lion, which is of great importance in taxonomic affiliation and to help the zoo veterinarians to detect, diagnose, and treat head conditions. Materials and Methods The current work was conducted on two skulls and mand- ibles of lions. The skulls and mandible were prepared using standard boiling and maceration technique. The gross and radiographic photos of the bones and foramina of the skull and mandible were taken using a Kodak digital camera and Siemens mobile full wave X-ray machine (Siemens Medical Solutions, Erlangen, Germany). Results The skull of the lion comprised of facial and cranial parts. The nasal openings were large, and the bony orbit was incomplete. The supraorbital foramen was absent. The zygomatic arch was large. The frontal region had a deep longitudinal depression dorsally. The mandible was a paired bone with movable articulation, and it had strongly Keywords excavated masseteric fossa with a well-developed crest. The dental formula was 30 ► anatomy teeth consisting of small incisors, long canines and carnassial premolars. ► radiography Conclusion The current study showed that the osteology and foramina of the skull ► skull and mandible of the lion were similar to those of other mammals. The information is ► mandible important for taxonomic affiliation, and wildlife forensic as well as to help the zoo ► lion veterinarians to manage clinical head diseases in this species. Introduction kept in zoos throughout the world.3 Over the years, there were The lion is part of the Felidae family, and one of the four large reports of abnormalities in the skulls of the lions at these zoo- cats of the Panthera species, along with the tiger, panther, and gardens of Europe,4 South Africa,5 Australia,6 the United wild leopard. Europe, Asia, the Middle East, and large parts of States,7 and Asia.8 The skull forms the head skeleton, which Africa were once the main regions of habitat for the lion protects the brain and organs of special sense, such as the eyes, (Panthera leo).1,2 Now, they are mostly found in savannah ears and nose, besides housing teeth for mastication. The head and grasslands throughout sub-Saharan Africa, while many are is important in body coordination and defense as well as olfaction and deglutition.9 The skull of an animal contributes Reda Mohamed’s ORCID is https://orcid.org/0000-0002-5512-6175. to the phylogenetic structure of the head of animal species, as received DOI https://doi.org/ Copyright © 2019 by Thieme Revinter January 15, 2019 10.1055/s-0039-1691756. Publicações Ltda, Rio de Janeiro, Brazil accepted ISSN 2177-0298. April 14, 2019 Skull of African Lion Mohamed 175 seen in the feline or in the camel.10 Further, the morphology of three upper incisors were observed along with a well- the skull gives rise to the animal’s taxonomic affiliations,11,12 defined space for the lower canine tooth frame (►Figs. 1–3). and the occipital bone of the skull can be used in forensic The cranial rim of the orbit of the lion was bounded by the medicine to determine its gender.13 The foramen magnum of lacrimal bones, which articulated with the zygomatic, max- the skull has scientific importance due to its clinical and illary and frontal bones. They presented the lacrimal segment variant morphological importance,14 and any deviation in its only, and they also presented the orifice of the nasolacrimal form and structure can lead to neurological indications.15 duct. The zygomatic bones were well developed with a quad- There are no available literatures describing the osteology of rilateral shape, and they had the frontal processes, which, with the skull and mandible of the lion. Thus, the main purpose of the well-developed zygomatic processes of the frontal bones, this article is to give a detailed description of the gross anatomy tended to close the orbital arches. They had the temporal of the bones and foramina of the lion’s skull and mandible. This processes, which contributed to form the massive zygomatic description would be useful in the identification of the skull arch with zygomatic processes of the temporal bones (►Fig. 1). and mandible of the lion, as well as to help the zoo veterinar- The maxillae were the most developed and largest bones ians in the detection, diagnosis, and treatment of head affec- in the face. They were attached to the premaxilla, nasal, tions in this species. lacrimal and frontal bones, and formed the wall of the hard palate. The dental edges of the maxillary bones presented the Materials and Methods dental alveoli for one canine, three premolars, and one molar. The paired palatine bones were observed in the palate and The heads of two lions that died in the zoo in Trinidad and orbit and circumscribing the choanae. They had the perpen- Tobago were brought to the department of basic veterinary dicular and horizontal processes. The horizontal process and sciences, School of Veterinary Medicine, Faculty of Medical the palatine process of the maxilla formed the oral palatine Sciences, University of the West Indies, Trinidad and Tobago. foramen. The pterygoid bones were delicate bones, which No skeletal deformities were detected upon inspection of the had a very developed hamulus in their caudal aspect. They heads, which were then boiled and treated to remove the formed the roof and lateral walls of the nasopharyngeal skin and muscles, then bleached in 3% hydrogen peroxide passage, while the vomer bone was an elongated, thin and then left to dry.16 The different standard views of the unpaired bone, which contributed to the nasal cavity cra- skull and mandible were then photographed, followed by nially and articulated with the premaxilla, presphenoid and radiographic photography taken for documentation using a maxilla bones. In the nasal cavity, the turbinate bones were Kodak digital camera and Siemens mobile full wave X-ray attached to its lateral walls as delicate, scroll-like, complex machine (Siemens Medical Solutions, Erlangen, Germany), bony plates. The foramina of the facial region of the skull respectively. The bones and foramina of the skull were were the large infra-orbital foramen representing the max- named according to Nomina Anatomica Veterinaria.17 illo-incisive or infraorbital canal opening, the sphenopala- tine foramen, the oral palatine fissures, the orifice of the ► – Results nasolacrimal duct and the choanae ( Figs. 1 3). The Bones and Foramina of the Facial Region The Bones and Foramina of the Cranial Region The facial part of the skull of the lion was relatively large and The cranium was moderately compressed latero-medially and compressed laterally. The bony part of the dorsal, lateral and slightly flattened dorsoventrally in the fronto-orbital region. medial aspect of the face was made up of the nasal, premaxilla, Thefrontal, parietal, temporal, basioccipital, basisphenoid, and lacrimal, zygomatic, maxilla, palatine, pterygoid, vomer and presphenoid bones formed the bony part of the dorsal, lateral, turbinate bones. In the ventral part of the skull, the hard palate ventral, and caudal aspects the basicranial region in the lion. was observed and was made up of the palatine processes of the Thefrontal bone formed the roofof the skull and contributed to premaxilla and palatine bones. It appeared as V-shaped at its the temporal fossae and orbital cavities. It had the short caudal margin. In the ventral view, the choanae were seen at zygomatic processes with neither supraorbital groove nor the terminal part of the hard palate, and the cribriform plate foramen, and it attached to the nasal bones cranially. A deep served to separate the nasal cavity from each of the cranium. longitudinal depression was seen in the frontal region. The The nasal bones were paired, and flattened and triangular bulk of the roof of the skull was formed by the parietal bones, in shape in the nasal cavity. They articulated with the frontal, which had a less prominent temporal line and a well-devel- maxillary and incisive bones, and their oral end was comma oped external sagittal crest. The presphenoid bone was seen in shaped. The nasal bones were free from notches and for- the nasopharyngeal passage as a single bone and consisted of a amina. A deep longitudinal depression was seen in the dorsal body and two orbital wings. The basisphenoid bone was a aspect of the nasal bones. The caudal projection of the nasal- single bone between the presphenoid bones and the basilar frontal suture extended more caudal than that of the max- part of occipital bone and it consisted of a body, two wings. The illary-frontal suture. The lateral and ventral walls of the nasal nuchal crest of the occipital bone was prominent, angular and cavity were formed by the premaxillae or incisive bones, directed caudally.