Skull anatomy of the endangered Patagonian huemul deer(Hippocamelus bisulcus)

Abstract

Studies of the normal skull anatomy of the Patagonian Huemul deer are scarce.Currently, the findings of bone lesions in the skull associated with metabolic imbalances are frequent in the literature. The objective of this study was to provide anatomical and morphometric data of the cranium and facies including a morphofunctional interpretation as a reference for clinical, ecomorphological and educational purposes.Five skulls were described, measured, scanned and digitally reconstructed. The presence of a caudal projection of the vomer bone, the absence of the facial tubercle and thin bones forming the cranial cavity were observed. Linear measurements allowed the skull to be classified as dolichocephalic, hyperlepten and ultra-dolichocranial. In conclusion, the Patagonian Huemul has a long head, an extremely long skull and a very narrow face. The thickness of the bones that made up the walls of the cranial cavity suggests chronic metabolic imbalances in response to mineral deficiency. The anatomical and morphometric data obtained in this study strongly emphasizes the relevance of considering the implementation of such management policies that aim at promoting an optimal nutritional context.

Foramina and canals of the skull base in Holstein cow: a computed tomography study

“…This foramen, which is present in pigs and ruminants, has been described in classical sources [1,21,32] as the equivalent of the f round foramen, orbital fissure and trochlear foramen in the horse. In deer (Hippocamelus bisulcus), the ORF is divided into two compartments, dorsal and ventral [33]. In the present study, the ORF was observed as a smooth-walled canal with a triangular intracranial opening and a vertical oval orbital opening, bounded by the pre-basisphenoid bone as described in the literatüre (Fig.…”

Anatomy and computed tomography of the nasal cavity, nasal conchae, and paranasal sinuses of the endangered Patagonian huemul deer (Hippocamelus bisulcus)

“…In addition, the extension of the frontal sinus within the pedicles—the cylindrical excrescences of the frontal bone—possibly suggests their function in absorbing and releasing mechanical energy, as has been described in the goat (Alsafy et al, 2021). This function of mechanical dissipation by the frontal sinus is usually greater in skulls with a convex frontal bone (Curtis et al, 2015), as reported in the Patagonian huemul deer (Núñez‐Cook et al, 2022).…”

“…Despite the clinical importance and the presentation of diseases that involve the paranasal sinuses and nasal conchae in our deer study, little is known of its anatomy. In previous anatomical descriptions, we have reported differences in thickness between bones of the appendicular skeleton and bones of the neurocranium (Núñez-Cook et al, 2022), suggesting a possible unequal nutritional food chain among the geographic locations inhabited by the individuals studied. Following from this study, what the morphological effect of nutritional deficiency has on the nasal cavity, nasal conchae and paranasal sinuses is currently unknown.…”

“…Our volumetric data in males suggest an association between the increase in the total volume of the frontal sinus and the passage of time (age), assuming that this phenomenon is related to body growth. Previously, we have reported evidence of the likely detrimental effect on bone quality (Núñez‐Cook et al, 2022) induced by chronic metabolic imbalances as a response to the mineral deficiency reported in the huemul deer (Flueck, 2018). Therefore, the volumetric data reported in the present study are relevant from a conservation perspective, since osteopathies and secondary infections (like sinusitis) could explain the limited ability of the Patagonian huemul deer to avoid predators and optimize the development of its ecology and, therefore, explain the population's lack of recovery (Flueck, 2018; Flueck & Smith‐Flueck, 2017).…”

“…The cancellous bone formation of the frontal bone and the presence of bony septa in the frontal sinus demonstrate the properties of the skull to resist multidirectional forces when dissipating the energy in large areas (Márquez, 2008), which could be a consequence of the ecological needs associated with the mechanical impacts on their heads (Núñez‐Cook et al, 2022) and not only olfactory needs (Zárate, 2014). In addition, the extension of the frontal sinus within the pedicles—the cylindrical excrescences of the frontal bone—possibly suggests their function in absorbing and releasing mechanical energy, as has been described in the goat (Alsafy et al, 2021).…”