Vertebrate Zoology 70(4): 679-697, doi: 10.26049/VZ70-4-2020-09
Ontogeny and morphofunctional implications of the ethmoidal region in the semiaquatic Potamogale velox (Afrotheria, Mammalia)
expand article infoIrina Ruf, Hendrik Behrens, Ulrich Zeller
‡ Senckenberg, Frankfurt, Germany
Open Access
Afrotheria is a diverse clade in terms of morphofunction and ecology. Although its phylogeny is well supported by molecular data, morphological and ontogenetic analyses are still demanded. This holds especially true for cranial structures that can also provide a deeper insight into sensory and ecological adaptations e.g., the ethmoidal region that houses the sense of smell as well as structures involved in thermoregulation. Here we provide a comparative description of the ethmoidal region of the semiaquatic tenrecoid Potamogale velox based on histological serial sections of the fetal chondrocranium and µCT data of the adult skull. The chondrocranium of Potamogale velox generally resembles the placental morphotype showing a prominent and well-developed cupula nasi anterior with a large processus alaris superior. The nasoturbinal is developing later in ontogeny. The number of olfactory turbinals is already determined before birth and shows a common pattern among small placental mammals: two frontoturbinals, three ethmoturbinals, one interturbinal between ethmoturbinal I and II. Apomorphic characters of Potamogale velox that are related to its semiaquatic mode of life are as follows: proportionally small olfactory turbinal skeleton and a reduced lamina cribrosa, loss of ductus nasolacrimalis, and an enlarged foramen epiphaniale due to the enhanced sensory innervation of the snout. Although the maxilloturbinal, that is involved in thermoregulation, is proportionally larger than in the terrestrial Tenrecoidea its morphological complexity is not significantly increasing from the fetus to the adult. Our results prove once again the importance of a deeper understanding of the cranial ontogeny for morphological studies of the mammalian skull.
Chondrocranium; ethmoid bone; nasal capsule; nasal cavity; ossification; turbinals