Equus simplicidens, sometimes known as the Hagerman horse or the American Zebra is an extinct species of equine native to North America during the Pliocene and Early Pleistocene. It is one of the oldest and most primitive members of the genus Equus. Abundant remains of it were discovered in 1928 in Hagerman, Idaho. It is the state fossil of Idaho.[3]
The Hagerman horse was given the scientific name of Plesippus shoshonensis in 1930 by a Smithsonianpaleontologist named James W. Gidley[2] who led the initial excavations at Hagerman that same year.
However further study by other paleontologists determined that fossils closely resembled fossils of a primitive horse from Texas named Equus simplicidens, named by paleontologist Edward Drinker Cope in 1892. Because of this similarity, the two forms were interpreted[4] to be the same species, and since the name Equus simplicidens was the older name, it was retained following the taxonomic Principle of Priority. The Hagerman fossils represent some of the oldest widely accepted remains of the genus Equus.
Discoveryedit
A cattle rancher named Elmer Cook discovered some fossil bones on this land in Hagerman, Idaho. In 1928, he showed them to Dr. H. T. Stearns of the U.S. Geological Survey who then passed them on to Dr. James W. Gidley at the Smithsonian Institution. Identified as bones belonging to an extinct horse, the area where the fossils were discovered, called the Hagerman Horse Quarry, was excavated and three tons of specimens were sent back to the Smithsonian in Washington, D.C.
Excavation of the fossils continued into the early 1930s. The Hagerman Horse Quarry floor grew to 5,000 square feet (460 m2) with a backwall 45 feet (14 m) high. Ultimately five nearly complete skeletons, more than 100 skulls, and forty-eight lower jaws as well as numerous isolated bones were found. Some paleontologists believed that such a large amount of fossils found in one location was because of the quarry area being a watering hole at one point. The waterhole could have been where the bones of the Hagerman horses accumulated as injured, old, and ill animals, drawn to water, died there. Other paleontologists think that an entire herd of these animals drowned attempting to ford a flooded river and were swept away in the current and ended up buried in the soft sand at the bottom.
Taxonomyedit
The genus placement of the species is controversial, with some authors choosing to place the species in Plesippus instead.[5] A 2019 phylogenetic analysis found it to be more closely related to living Equus than to Hippidion or Dinohippus, but outside the group containing all living equines.[6] Some authors have argued for a close relationship of Equus simplicidens with living zebras to the exclusion of other living equines, but these claims have been considered equivocal by others, who note that many "stenonine horses" from Eurasia exhibit similarities to zebras.[7]
^Cope, E. D. (1892). "A Contribution to the Vertebrate Paleontology of Texas". Proceedings of the American Philosophical Society. 30 (137): 124–125. JSTOR983215.
^ abJ.W. Gidley (1930) A new Pliocene horse from Idaho. Journal of Mammalogy 11: 300-303 JSTOR 1374150 doi:10.2307/1374150
^D.E. Savage (1951) late Cenozoic vertebrates of the San Francisco Bay region. University of California Bulletin of the Department of Geological Sciences 28: 215-314
^Orlando, Ludovic; Ginolhac, Aurélien; Zhang, Guojie; Froese, Duane; Albrechtsen, Anders; Stiller, Mathias; Schubert, Mikkel; Cappellini, Enrico; Petersen, Bent; Moltke, Ida; Johnson, Philip L. F.; Fumagalli, Matteo; Vilstrup, Julia T.; Raghavan, Maanasa; Korneliussen, Thorfinn (2013-07-04). "Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse". Nature. 499 (7456): 74–78. Bibcode:2013Natur.499...74O. doi:10.1038/nature12323. ISSN 0028-0836. PMID 23803765. S2CID 4318227.
^Cirilli, Omar; Pandolfi, Luca; Rook, Lorenzo; Bernor, Raymond L. (2021-05-12). "Evolution of Old World Equus and origin of the zebra-ass clade". Scientific Reports. 11 (1): 10156. Bibcode:2021NatSR..1110156C. doi:10.1038/s41598-021-89440-9. ISSN 2045-2322. PMC8114910. PMID 33980921.
^O’Brien, Kaedan; Tryon, Christian A.; Blegen, Nick; Kimeu, Boniface; Rowan, John; Faith, J. Tyler (March 2021). "First appearance of Grévy's zebra (Equus grevyi), from the Middle Pleistocene Kapthurin Formation, Kenya, sheds light on the evolution and paleoecology of large zebras". Quaternary Science Reviews. 256: 106835. Bibcode:2021QSRv..25606835O. doi:10.1016/j.quascirev.2021.106835. S2CID 233638447.
, Dr. Greg McDonald
Further readingedit
Boss, N. H. "Explorations for Fossil Horses in Idaho". Explorations and Field Work of the Smithsonian Institution in 1931. 1932.
Gazin, C. L. '" Study of the Fossil Horse Remains from the Upper Pliocene of Idaho. Proceedings from the United States National Museum 83(2,985): 281-320. 1936.
MacFadden, Bruce J. Fossil Horses: Systematics, Paleobiology and Evolution of the Family Equidae. Cambridge Univ. Press, 1992.
McDonald, H. Gregory. "More than Just Horses", Rocks and Minerals, September/October 1993. Vol. 68:322-326.
Willoughby, David P. The Empire of Equus. A.S. Barnes and Co., 1974
February 15, 2024
hagerman, horse, equus, simplicidens, sometimes, known, american, zebra, extinct, species, equine, native, north, america, during, pliocene, early, pleistocene, oldest, most, primitive, members, genus, equus, abundant, remains, were, discovered, 1928, hagerman. Equus simplicidens sometimes known as the Hagerman horse or the American Zebra is an extinct species of equine native to North America during the Pliocene and Early Pleistocene It is one of the oldest and most primitive members of the genus Equus Abundant remains of it were discovered in 1928 in Hagerman Idaho It is the state fossil of Idaho 3 Hagerman horseTemporal range Pliocene Early PleistoceneMounted skeleton of a Hagerman horseScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass MammaliaOrder PerissodactylaFamily EquidaeGenus EquusSubgenus DolichohippusSpecies E simplicidensBinomial name Equus simplicidensCope 1892 1 SynonymsPlesippus shoshonensis Gidley 1930 2 Contents 1 Classification 2 Discovery 3 Taxonomy 4 See also 5 References 6 Further readingClassification edit nbsp Equus simplicidens skullThe Hagerman horse was given the scientific name of Plesippus shoshonensis in 1930 by a Smithsonian paleontologist named James W Gidley 2 who led the initial excavations at Hagerman that same year However further study by other paleontologists determined that fossils closely resembled fossils of a primitive horse from Texas named Equus simplicidens named by paleontologist Edward Drinker Cope in 1892 Because of this similarity the two forms were interpreted 4 to be the same species and since the name Equus simplicidens was the older name it was retained following the taxonomic Principle of Priority The Hagerman fossils represent some of the oldest widely accepted remains of the genus Equus Discovery editA cattle rancher named Elmer Cook discovered some fossil bones on this land in Hagerman Idaho In 1928 he showed them to Dr H T Stearns of the U S Geological Survey who then passed them on to Dr James W Gidley at the Smithsonian Institution Identified as bones belonging to an extinct horse the area where the fossils were discovered called the Hagerman Horse Quarry was excavated and three tons of specimens were sent back to the Smithsonian in Washington D C Excavation of the fossils continued into the early 1930s The Hagerman Horse Quarry floor grew to 5 000 square feet 460 m2 with a backwall 45 feet 14 m high Ultimately five nearly complete skeletons more than 100 skulls and forty eight lower jaws as well as numerous isolated bones were found Some paleontologists believed that such a large amount of fossils found in one location was because of the quarry area being a watering hole at one point The waterhole could have been where the bones of the Hagerman horses accumulated as injured old and ill animals drawn to water died there Other paleontologists think that an entire herd of these animals drowned attempting to ford a flooded river and were swept away in the current and ended up buried in the soft sand at the bottom Taxonomy editThe genus placement of the species is controversial with some authors choosing to place the species in Plesippus instead 5 A 2019 phylogenetic analysis found it to be more closely related to living Equus than to Hippidion or Dinohippus but outside the group containing all living equines 6 Some authors have argued for a close relationship of Equus simplicidens with living zebras to the exclusion of other living equines but these claims have been considered equivocal by others who note that many stenonine horses from Eurasia exhibit similarities to zebras 7 See also editEquus scottiReferences edit Cope E D 1892 A Contribution to the Vertebrate Paleontology of Texas Proceedings of the American Philosophical Society 30 137 124 125 JSTOR 983215 a b J W Gidley 1930 A new Pliocene horse from Idaho Journal of Mammalogy 11 300 303 JSTOR 1374150 doi 10 2307 1374150 Idaho Equus simplicidens state fossil StateFossils com dead link D E Savage 1951 late Cenozoic vertebrates of the San Francisco Bay region University of California Bulletin of the Department of Geological Sciences 28 215 314 Orlando Ludovic Ginolhac Aurelien Zhang Guojie Froese Duane Albrechtsen Anders Stiller Mathias Schubert Mikkel Cappellini Enrico Petersen Bent Moltke Ida Johnson Philip L F Fumagalli Matteo Vilstrup Julia T Raghavan Maanasa Korneliussen Thorfinn 2013 07 04 Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse Nature 499 7456 74 78 Bibcode 2013Natur 499 74O doi 10 1038 nature12323 ISSN 0028 0836 PMID 23803765 S2CID 4318227 Cirilli Omar Pandolfi Luca Rook Lorenzo Bernor Raymond L 2021 05 12 Evolution of Old World Equus and origin of the zebra ass clade Scientific Reports 11 1 10156 Bibcode 2021NatSR 1110156C doi 10 1038 s41598 021 89440 9 ISSN 2045 2322 PMC 8114910 PMID 33980921 O Brien Kaedan Tryon Christian A Blegen Nick Kimeu Boniface Rowan John Faith J Tyler March 2021 First appearance of Grevy s zebra Equus grevyi from the Middle Pleistocene Kapthurin Formation Kenya sheds light on the evolution and paleoecology of large zebras Quaternary Science Reviews 256 106835 Bibcode 2021QSRv 25606835O doi 10 1016 j quascirev 2021 106835 S2CID 233638447 The Hagerman Horse Quarry Hagerman Fossil Beds Critter Corner Hagerman Horse Equus simplicidens Dr Greg McDonaldFurther reading editBoss N H Explorations for Fossil Horses in Idaho Explorations and Field Work of the Smithsonian Institution in 1931 1932 Gazin C L Study of the Fossil Horse Remains from the Upper Pliocene of Idaho Proceedings from the United States National Museum83 2 985 281 320 1936 MacFadden Bruce J Fossil Horses Systematics Paleobiology and Evolution of the Family Equidae Cambridge Univ Press 1992 McDonald H Gregory More than Just Horses Rocks and Minerals September October 1993 Vol 68 322 326 Willoughby David P The Empire of Equus A S Barnes and Co 1974 Castle Rock Ranch Hagerman Horse Quarry Land Exchange Environmental Assessment Retrieved from https en wikipedia org w index php title Hagerman horse amp oldid 1191078157, wikipedia, wiki, book, books, library,
