Diegoaelurus ("San Diego's cat") is an extinct genus of placental mammals from the extinct subfamily Machaeroidinae within extinct family Oxyaenidae. This genus contains only one species Diegoaelurus vanvalkenburghae, which was found in the Santiago Formation in California. This mammal lived during the Uintan stage of the Middle Eocene Epoch around 46.2 to 39.7 million years ago.[1][2]
| Diegoaelurus Temporal range: middle Eocene
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| Holotype of Diegoaelurus vanvalkenburghae, (SDSNH 38343) | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | †Oxyaenodonta |
| Family: | †Oxyaenidae |
| Subfamily: | †Machaeroidinae |
| Genus: | †Diegoaelurus Zack, Poust, & Wagner, 2022 |
| Type species | |
| Diegoaelurus vanvalkenburghae Zack, Poust, & Wagner, 2022
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| A map showing the fossil finds of D. vanvalkenburghae as well as other machaeroidinid genera. | |
Etymology
editThe name of genus Diegoaelurus comes from city San Diego and from Ancient Greek αἴλουρος (aílouros-) 'cat'. Diegoaelurus vanvalkenburghae was named after Dr. Blaire Van Valkenburgh in honor of her research on carnivorous mammals and saber-toothed predator paleoecology.[1]
Discovery
editThe holotype fossils were discovered in Oceanside, San Diego county by paleontologist Brad Riney in 1988.[1] The fossils were housed for over three decades in a museum until 2022 when the fossils were described and recognised as a new genus and species.[1][3] This creature is so far the only North American species of Machaeroidinae known outside of Utah and Wyoming.[1] According to a paper on the creature, ''The present study highlights how poorly documented the machaeroidine fossil record remains''.[1]
Description
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Diegoaelurus vanvalkenburghae was small in stature, with a size comparable to a fossa.[3] The holotype fossils (SDSNH 38343) consists of a mandible and well preserved dentition.[1] Its discovery has made paleontologists question whether this group's extinction was caused due to the large faunal turnover at the end of the Eocene.[1] This creature as well as its subfamily were some of the first predatory saber toothed mammals to have evolved, 30 million years before the Machairodontinae (saber-toothed cats) evolved in the Miocene.[1][4] Due to the lack of remains, there is questioning to these animals ecological niches.[1] However, there are good remains from Machaeroides eothen which support a hypercarnivorous lifestyle for the group.[1] D. vanvalkenburghae is actually the latest surviving member of its subfamily.[1]
Classification
editThe phylogenetic relationships of genus Diegoaelurus are shown in the following cladogram:[1]
| Machaeroidinae |
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Extinction
editDiegoaelurus along with all the members of its subfamily went extinct at the end of the Eocene.[1] A supported theory is that these mammals went extinct during the Eocene-Oligocene extinction event;[1] A large faunal turnover at the end of the epoch[5] was probably caused by climate change, like the freezing of Antarctica disrupting ocean currents and global temperature.[6][7] Many of the primitive mammals like the Palaeotheriidae, Xiphodontidae, Dichobunidae and the Adapidae were replaced by more advanced mammals like the Rhinocerotidae (true rhinos), Castoridae (beavers) Oreodonts, and other more advanced Artiodacytyls as well as the Erinaceids (hedgehogs).[8] It seems once the Oxyaenids went extinct their ecological nice was filled in by the Nimravids, a family of saber-toothed mammals that belonged to the group Feliformia.[1][9][10][11]
References
edit- ^ a b c d e f g h i j k l m n o p Zack, Shawn P.; Poust, Ashley W.; Wagner, Hugh (2022-03-15). "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". PeerJ. 10: e13032. doi:10.7717/peerj.13032. ISSN 2167-8359. PMC 8932314. PMID 35310159.
- ^ Sofia Quaglia (March 15, 2022). "A new saber-toothed mammal was among the first hypercarnivores". Science News.
- ^ a b "Paleontologists discover new San Diego saber-toothed catlike species". Los Angeles Times. 2022.
- ^ "Not all saber-toothed animals were predators, fossils reveal". National Geographic. 2020. Archived from the original on March 3, 2021.
- ^ Ivany, Linda C.; Patterson, William P.; Lohmann, Kyger C. (2000). "Cooler winters as a possible cause of mass extinctions at the Eocene/Oligocene boundary" (PDF). Nature. 407 (6806): 887–890. Bibcode:2000Natur.407..887I. doi:10.1038/35038044. hdl:2027.42/62707. PMID 11057663. S2CID 4408282.
- ^ Zachos, James C.; Quinn, Terrence M.; Salamy, Karen A. (1996-06-01). "High-resolution (104 years) deep-sea foraminiferal stable isotope records of the Eocene-Oligocene climate transition". Paleoceanography. 11 (3): 251–266. Bibcode:1996PalOc..11..251Z. doi:10.1029/96PA00571. ISSN 1944-9186.
- ^ Shackleton, N. J. (1986-10-01). "Boundaries and Events in the Paleogene Paleogene stable isotope events". Palaeogeography, Palaeoclimatology, Palaeoecology. 57 (1): 91–102. Bibcode:1986PPP....57...91S. doi:10.1016/0031-0182(86)90008-8.
- ^ Hooker, J.J.; Collinson, M.E.; Sille, N.P. (2004). "Eocene-Oligocene mammalian faunal turnover in the Hampshire Basin, UK: calibration to the global time scale and the major cooling event" (PDF). Journal of the Geological Society. 161 (2): 161–172. Bibcode:2004JGSoc.161..161H. doi:10.1144/0016-764903-091. S2CID 140576090.
- ^ Diegoaelurus in the Paleobiology Database
- ^ "Meet the Cat Family". Junior Observer. The Sunday Observer. Colombo, Sri Lanka: Associated Newspapers of Ceylon. July 16, 2012. Retrieved January 2, 2013.
- ^ Werdelin, L.; Yamaguchi, N.; Johnson, W. E. & O'Brien, S. J. (2010). "Phylogeny and evolution of cats (Felidae)". In Macdonald, D. W. & Loveridge, A. J. (eds.). Biology and Conservation of Wild Felids. Oxford, UK: Oxford University Press. pp. 59–82. ISBN 978-0-19-923445-5.