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Back in 1988 a small jaw fragment was unearthed at a construction site near present day San Diego at the southern end of California and promptly filed away in a drawer at the San Diego Natural History Museum as belonging to an unidentified creature. That was until a paleontologist working at the museum realized that it belonged to what might be the earliest mammal with saber-like fangs and sharp scissor-like slicing teeth called carnassials described in the U.S., and the oldest among any cat-like creature anywhere.
The fossil is from the Middle Eocene -- some 42 myo (roughly 40 million years before the most famous sabre-tooth, Smilodon) -- and belonged to an ancient extinct group of mammals referred to as machaeroidines. Remains from this group are so rare that scientists still don't know where to place them in relation to other mammals.
The creature, has been named Diegoaelurus vanvalkenburghae with the first or genus name after the city of San Diego and the second or species name in honor of sabre-tooth expert Dr. Blaire Van Valkenburgh. It is described as being approximately the size of a bobcat and while very cat-like was not closely related to felines. As Poust puts it when describing Diegoaelurus: "I try to start with ‘cat-like’ and walk it back."
For instance, Diegoaelurus' skull was flatter and less dome like than what we see on cats, and it possessed a longer face more like that of a civet or a fossa.
The researchers think that Diegoaelurus likely preyed on both small rhinos and primates, climbing trees in the jungle-like environment that was San Diego back then to get the latter.
The entire paper, Diegoaelurus, a new machaeroidine (Oxyaenidae) from the Santiago Formation (late Uintan) of southern California and the relationships of Machaeroidinae, the oldest group of sabertooth mammals can be read by clicking the provided hyperlink and the Abstract from the paper is below:
A couple more images:
The fossil is from the Middle Eocene -- some 42 myo (roughly 40 million years before the most famous sabre-tooth, Smilodon) -- and belonged to an ancient extinct group of mammals referred to as machaeroidines. Remains from this group are so rare that scientists still don't know where to place them in relation to other mammals.
The creature, has been named Diegoaelurus vanvalkenburghae with the first or genus name after the city of San Diego and the second or species name in honor of sabre-tooth expert Dr. Blaire Van Valkenburgh. It is described as being approximately the size of a bobcat and while very cat-like was not closely related to felines. As Poust puts it when describing Diegoaelurus: "I try to start with ‘cat-like’ and walk it back."
For instance, Diegoaelurus' skull was flatter and less dome like than what we see on cats, and it possessed a longer face more like that of a civet or a fossa.
The researchers think that Diegoaelurus likely preyed on both small rhinos and primates, climbing trees in the jungle-like environment that was San Diego back then to get the latter.
The entire paper, Diegoaelurus, a new machaeroidine (Oxyaenidae) from the Santiago Formation (late Uintan) of southern California and the relationships of Machaeroidinae, the oldest group of sabertooth mammals can be read by clicking the provided hyperlink and the Abstract from the paper is below:
ABSTRACT:
Machaeroidinae is a taxonomically small clade of early and middle Eocene carnivorous mammals that includes the earliest known saber-toothed mammalian carnivores. Machaeroidine diversity is low, with only a handful of species described from North America and Asia. Here we report a new genus and species of machaeroidine, Diegoaelurus vanvalkenburghae, established on the basis of a nearly complete dentary with most of the dentition from the late Uintan (middle Eocene) portion of the Santiago Formation of southern California. The new taxon is the youngest known machaeroidine and provides the first evidence for the presence of multiple machaeroidine lineages, as it differs substantially from Apataelurus kayi, the only near-contemporaneous member of the group. Phylogenetic analysis indicates that Diegoaelurus is the sister taxon of Apataelurus, while older species are recovered as a monophyletic Machaeroides. Both phylogenetic results are relatively weakly supported. The new taxon extends the record of machaeroidines to the end of the Uintan, potentially tying machaeroidine extinction to the faunal turnover spanning the middle to late Eocene transition in North America.
Machaeroidinae is a taxonomically small clade of early and middle Eocene carnivorous mammals that includes the earliest known saber-toothed mammalian carnivores. Machaeroidine diversity is low, with only a handful of species described from North America and Asia. Here we report a new genus and species of machaeroidine, Diegoaelurus vanvalkenburghae, established on the basis of a nearly complete dentary with most of the dentition from the late Uintan (middle Eocene) portion of the Santiago Formation of southern California. The new taxon is the youngest known machaeroidine and provides the first evidence for the presence of multiple machaeroidine lineages, as it differs substantially from Apataelurus kayi, the only near-contemporaneous member of the group. Phylogenetic analysis indicates that Diegoaelurus is the sister taxon of Apataelurus, while older species are recovered as a monophyletic Machaeroides. Both phylogenetic results are relatively weakly supported. The new taxon extends the record of machaeroidines to the end of the Uintan, potentially tying machaeroidine extinction to the faunal turnover spanning the middle to late Eocene transition in North America.
A couple more images:
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