Kolponomosis an extinctgenusofcarnivoranmammal that existed in the Late Arikareean North American Land Mammal Age, earlyMioceneepoch, about 20 million years ago. It was likely a marine mammal.[1]The genus was erected in 1960 byRuben A. Stirton,a paleontologist at the University of California Museum of Paleontology, Berkeley, for the speciesK. clallamensis,on the basis of a partial skull and jaw found on theOlympic Peninsula.At the time, Stirton questionably assigned it toProcyonidae,its systematic position remained problematic until the discovery of more fossils including a nearly complete cranium from the original locality ofK. clallamensiswhich helped identify it as part of the group from whichpinnipedsevolved.[2]
| Kolponomos Temporal range:
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|---|---|
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| Skull | |
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| Mandible | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | †Amphicynodontidae |
| Genus: | †Kolponomos Stirton, 1960 |
| Species | |
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Description
editIn life, species ofKolponomoshad downturned snouts and broad, heavy molars that would have been suited to a diet of hard-shelled marine invertebrates, and their narrow snouts and anteriorly directed eyes indicate that they would have hadstereoscopic vision.[2]Large neck muscle attachments and robust foot bones combine with these features to suggest thatKolponomosfilled a unique niche among marine carnivores, approached today only by the very distantly relatedsea otter.Due to the lack of a complete skeleton, however, it is difficult to make inferences about this genus' other adaptations.
Based on the skull and jaws known,Kolponomosconvergently evolvedmandibular and bite features that had similarities to extant bears, sea otters, and even thesabretoothSmilodon.The anterior portion of the jaw becomes a functional anchoring fulcrum in bothKolponomosandSmilodon.Although dental morphology and heavy occlusal wear patterns are shared with the sea otter.Kolponomos' dentition was less efficient but exhibited higher stiffness than in the sea otter.[1]Riley Black wrote thatKolponomosbit like a sabrecat, crunched like a bear.[3]
Aspects of its feeding morphology were similar to the giant otterSiamogale melilutra,althoughKolponomosis not an otter[4]
Discovery
editKolponomos clallamensisis known from theMioceneofSlip Point Lighthouse,Washington (48°18′N124°12′W/ 48.3°N 124.2°W,paleocoordinates48°00′N116°54′W/ 48.0°N 116.9°W).[5][6][7]The species was originally based on arostrumfound in 1957 at Slip Point inClallam Bay, Washington.A nearly complete cranium was found at the same location in 1988. BothK. clallamensisandK. newportensisare associated with the lateArikareeanNALMA.[8]
Kolponomos newportensiswas described in 1994 byR. Tedford,L. BarnesandClayton E. Ray.It is represented by single specimen: a nearly complete skull, jaw and post-cranial bones found in aconcretionof sediment. The concretion was discovered in two pieces by fossil collectorDouglas EmlongnearNewport, Oregon,the first in 1969 and the second, eight years later, in 1977. Because the concretion had been hardened so much bytectonicstress, the paleontological laboratory at theSmithsonian Institutionconsidered them "the most difficult materials ever encountered by our laboratory.,"[9]and a combination of techniques proved essential to its extraction and preparation, which lasted two decades. Discovery ofK. newportensisdisproved the earlier hypothesis that the genus was related to the ancestors ofraccoons,and instead was a stem-pinniped.[2][10][11]
References
edit- ^abTseng, Z. Jack; Grohé, Camille; Flynn, John J. (2016-03-16)."A unique feeding strategy of the extinct marine mammal Kolponomos: convergence on sabretooths and sea otters".Proceedings of the Royal Society B: Biological Sciences.283(1826): 20160044.doi:10.1098/rspb.2016.0044.PMC4810869.PMID26936242.
- ^abcTedford, R. H.;Barnes, L. G.; Ray, C. E. (1994)."The early Miocene littoral ursoid carnivoranKolponomos:Systematics and mode of life "(PDF).Proceedings of the San Diego Society of Natural History.29:11–32. Archived fromthe original(PDF)on 22 September 2012.Retrieved24 July2010.
- ^"Prehistoric Animal Bit Like a Sabercat, Crunched Like a Bear".Science.2016-03-03. Archived fromthe originalon May 12, 2019.Retrieved2019-12-07.
- ^Tseng, Z. Jack; Su, Denise F.; Wang, Xiaoming; White, Stuart C.; Ji, Xueping (2017-11-09)."Feeding capability in the extinct giant Siamogale melilutra and comparative mandibular biomechanics of living Lutrinae".Scientific Reports.7(1): 15225.Bibcode:2017NatSR...715225T.doi:10.1038/s41598-017-15391-9.ISSN2045-2322.PMC5680181.PMID29123190.
- ^"Kolponomos clallamensis".Fossilsworks.Retrieved17 December2021.
- ^"Slip Point Lighthouse (Miocene of the United States)".Fossilworks.Retrieved17 December2021.
- ^Stirton, R. A. (1960). "A Marine Carnivore from the Clallam Miocene Formation, Washington: Its Correlation with Nonmarine Faunas".University of California Publications in Geological Sciences.36(7).OCLC692426.
- ^Hunt, Robert M. Jr. (1998)."Ursidae, pp. 174–195 (180)".In Janis, C. M.; Scott, K. M.; Jacobs, L. L. (eds.).Evolution of Tertiary Mammals of North America: Terrestrial carnivores, ungulates, and ungulatelike mammals.Evolution of Tertiary Mammals of North America. Vol. 1. Cambridge University Press.ISBN9780521355193.Retrieved30 December2013.
- ^C. E. Ray (1976). "Fossil marine mammals of Oregon".Systematic Zoology.25(4). Society of Systematic Biologists: 420–436.doi:10.2307/2412515.JSTOR2412515.
- ^Rybczynski, N.; Dawson, M.R.; Tedford, R.H. (2009). "A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia".Nature.458(7241): 1021–24.Bibcode:2009Natur.458.1021R.doi:10.1038/nature07985.PMID19396145.S2CID4371413.
- ^Berta, A.; Morgan, C.; Boessenecker, R.W. (2018)."The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses".Annual Review of Earth and Planetary Sciences.46:203–228.Bibcode:2018AREPS..46..203B.doi:10.1146/annurev-earth-082517-010009.S2CID135439365.
