Jaw anatomy ofPotamogale velox(Tenrecidae, Afrotheria) with a focus on cranial arteries and the coronoid canal in mammals

Abstract

Afrotheria is a strongly supported clade within placental mammals, but morphological synapomorphies for the entire group have only recently come to light. Soft tissue characters represent an underutilized source of data for phylogenetic analysis, but nonetheless provide features shared by some or all members of Afrotheria. Here, we investigate the developmental anatomy of Potamogale velox (Tenrecidae) with histological and computerized tomographic data at different ontogenetic ages, combined with osteological data from other mammals, to investigate patterns of cranial arterial supply and the distribution of the coronoid canal. Potamogale is atypical among placental mammals in exhibiting a small superior stapedial artery, a primary supply of the posterior auricular by the posterior stapedial artery, and the development of vascular plexuses (possibly with relevance for heat exchange) in the posterior and dorsal regions of its neck. In addition, the posterior aspect of Meckel’s cartilage increases its medial deflection in larger embryonic specimens as the mandibular condyle extends mediolaterally during embryogenesis. We also map the distribution of the coronoid canal across mammals, and discuss potential confusion of this feature with alveoli of the posterior teeth. The widespread distribution of the coronoid canal among living and fossil proboscideans, sirenians, and hyracoids supports previous interpretations that a patent coronoid canal is a synapomorphy of paenungulates, but not afrotherians as a whole.

Clinical anatomy of coronoid foramina of mandible and review of its implications in maxillofacial surgery

“…The rst description of FN in a live human was associated with the presence of lateral accessory foramina and canal on the mandibular ramus attributing itself to a phylogenetic hypothesis which implied that FN was not observed in humans except for fossilized mammals [11,12]. It was Ferretti and Debruyne [10] mentioning in their article 'Elephas Maximus' as having a foramen and a canal merging with the alveolus at the distal-most erupting molar [3,10]. This canal emerging as the coronoid canal was elaborated as a synapomorphic feature of paenungulates by Tassy and Shoshani [32].…”

“…1) in the Oro-facial region [11]. The foramen in the coronoid process was seen to exist in only fossils including early genera and was recovered as a paenungulate Synapomorphy suggesting a phylogenetic hypothesis [3,10,32].…”

The Skull of Epidolops ameghinoi from the Early Eocene Itaboraí Fauna, Southeastern Brazil, and the Affinities of the Extinct Marsupialiform Order Polydolopimorphia

“…), but these appear to be nutrient foramina that are variable in number and position, and which do not lead into a distinct canal, unlike the single, relatively large foramen observed in paucituberculatans. It is unclear whether the small retromolar foramina in argyrolagids lead into a distinct canal; if they do not, I consider it more likely that the distinct retromolar foramen and canal found in most paucituberculatans is homologous with the retrodental canal of argyrolagids (contra Babot and García-López 2016 ), despite the differences in position and morphology (see Brocklehurst et al 2016 for a discussion of the homology of a morphologically similar canal, which they refer to as the “coronoid canal,” in afrotherian placentals). If these structures are indeed homologous, then they would represent a striking potential synapomorphy uniting paucituberculatans and argyrolagids.…”

On the development of the chondrocranium and the histological anatomy of the head in perinatal stages of marsupial mammals

“…Studies based on CT scanning involve the documentation of sections, analogous to histological work. In this regard, CT scanning is a very helpful guide, permitting quick identification of structures and the reconstruction of soft-tissues without the effort needed to produce well-procesed and stained serial sections [ 5 ]. High-resolution CT scanning, together with new methods of staining, have been used to generate three-dimensional images of organs and soft tissues, which could potentially have a significant impact on studies of organogenesis and anatomy [ 6 , 7 ].…”