Miohippus sp.
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publication ID |
https://doi.org/ 10.5252/geodiversitas2024v46a9 |
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publication LSID |
urn:lsid:zoobank.org:pub:FF29E123-8A23-4ACF-9D54-FA2191BAF6DA |
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DOI |
https://doi.org/10.5281/zenodo.12531033 |
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persistent identifier |
https://treatment.plazi.org/id/2236042D-FFA1-4070-6903-FBDEFE53FA30 |
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treatment provided by |
Plazi |
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scientific name |
Miohippus sp. |
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( Fig. 5 View FIG )
MATERIAL EXAMINED. — From USNM locality 24FH01670 : GLAC 26987 , partial left dentary with p2-m2 and partial right dentary with p4-m3 from the same individual.
STRATIGRAPHIC AND GEOGRAPHIC RANGE. — Upper member of the Kishenehn Formation, western Montana, United States of America.
DESCRIPTION
GLAC 26987 is composed of two partial lower dentaries (left and right) and includes the left p2-m2 and the right p4-m3 ( Fig. 5 View FIG ). The left dentary includes a small amount of the dentary mesial of the p2 ( Fig. 5A View FIG ). There is some of the dentary present distal of the m2 with no exposed roots, but the alveolus for the m3 is present with only the mesial portion remaining. A small portion of the mesial end of the right dentary is attached with matrix ( Fig. 5B View FIG ). This portion of the right dentary includes part of the diastema and the p2. The right p2 is broken at the root and what is present is mostly the empty alveolus. The remainder of the right dentary fragment is broken just mesial of the p4 and at the posterior root of the m3, exposing the distal root. All other teeth are in good condition with no missing cusps ( Fig. 5C, F View FIG ). The teeth are in a middle stage of wear.
REMARKS
Measurements of the dentition of GLAC 26987 are within the size range of Miohippus annectens ( Marsh 1874) specimens found in the John Day Formation of Oregon affirming this specimen is from the same genus ( Tables 4 View TABLE ; 5 View TABLE ; Famoso 2017). There are no morphological characters in the lower jaw or dentition that can be used to distinguish between Miohippus and Mesohippus Marsh, 1875 , let alone species of either genus ( Famoso 2017). Stirton (1940) noted that Miohippus and Mesohippus are difficult to differentiate, and other recent workers have suggested Mesohippus is a junior synonym of Miohippus ( Masciale 2010; Kocken 2022; Kocken & Pagnac 2022).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.