Volaticotherini
| Volaticotherini Temporal range:
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| Holotype of Volaticotherium | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | †Eutriconodonta |
| Clade: | †Volaticotherini Meng et al., 2006 |
| Type species | |
| † Volaticotherium antiquum Meng et al., 2006
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| Genera | |
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Volaticotherini is a
Since most remains are primarily teeth, they are foremostly diagnosticated by their highly distinctive
Definition
Volaticotherini is phylogenetically defined as the clade derived from the most recent common ancestor of Argentoconodon, Ichthyoconodon, and Volaticotherium.[2]
History
Subsequent analyses have consistently recovered Argentoconodon as the sister taxon of Volaticotherium, with Ichthyoconodon as the sister taxon of that clade and thus the basalmost volaticotherin.
Characteristics
Since most volaticotherian remains are based on teeth, the diagnostic characteristic of the group is its molar morphology. Though classified as "triconodont" in shape, volaticotherian molars are highly atypical, possessing high, curved, backwards facing cusps aligned anteroposteriorly, lacking a cingulum.[1][2] Canines and incisors tend to be fairly large.
In the two forms that do possess postcranial remains, Argentoconodon and Volaticotherium, we see a highly specialised femur, lacking a femoral neck.[2]
Aerial locomotion
One genus of volaticotherin, Volaticotherium, has clear evidence of being capable of gliding. It was the first gliding Mesozoic mammal discovered and lived at least 70 million years before the appearance of the first flying and gliding
Distribution
Volaticotherini was a relatively widespread and long-lived clade, with occurrences known from the Toarcian of South America, Oxfordian of China, and Berriasian of Morocco. The presence of volaticotherins in Gondwana is unusual, as they are among the few known Gondwanan triconodonts (and, if aligned with triconodontids, the only representatives of the group in Gondwanna), with Argentoconodon occurring as far back as the Early Jurassic in otherwise australosphenidan dominated faunas.[2][6]
Diet
Though highly unusual and possibly indicating atypical occlusion patterns,[1][2] volaticotherian molars are thought to have had a shearing motion as in other eutriconodonts.[7][6] Combined with long canines, this seems to indicate that, like their relatives, they were probably carnivorous. Ichthyoconodon was fairly large by Mesozoic mammal standards, and were probably capable of tackling vertebrate prey.[7] In a study about Mesozoic mammal diets Argentoconodon ranks among carnivorous species, while Volaticotherium ranks among insectivorous taxa.[8] This same result is provided almost identically in a posterior study, albeit with Volaticotherium closer to the carnivore space.[9]
It has been noted that most gliding mammals are predominantly herbivorous,
Paleoecology
Volaticotherins, as is typical for gliding animals, were adapted for an arboreal lifestyle.[1] One volaticotherin, Ichthyoconodon, was recovered from marine facies and consequently initially interpreted as an aquatic animal.[12] However, many terrestrial mammals are preserved in aquatic environments, so it is unclear how strong this evidence is regarding its life habits,[7] though its teeth appear to not have undergone long aquatic transportation.[12]
References
- ^ S2CID 28414039.
- ^ S2CID 85069761.
- S2CID 4317817.
- ^ S2CID 205245235.
- S2CID 10324906.
- ^ doi:10.4202/pp.2016.67_035 (inactive 31 January 2024).)
{{cite journal}}: CS1 maint: DOI inactive as of January 2024 (link - ^ ISBN 0-231-11918-6.
- PMID 24089340.
- PMID 33623117.
- ^ Jackson, Stephen Matthew and Schouten, Peter. Gliding Mammals of the World, Csiro Publishing, 2012
- S2CID 4463476.
- ^ a b Sigogneau-Russell, Denise (1995). "Two possibly aquatic triconodont mammals from the Early Cretaceous of Morocco" (PDF). Acta Palaeontologica Polonica. 40 (2): 149–162.