The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrels
Spermophilus is the most diverse and abundant genus of Eurasian sciurids. Even though many species have been described, the early evolution of the group is poorly understood. Here we present a review of the evolution and taxonomy of early Spermophilus, based on analysis of more than 1500 specimens f...
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| Format: | Article |
| Language: | English |
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Institute of Paleobiology PAS
2019-09-01
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| Series: | Acta Palaeontologica Polonica |
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| Online Access: | http://www.app.pan.pl/archive/published/app64/app006052019.pdf |
| _version_ | 1818337504219103232 |
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| author | Maxim V. Sinitsa Nataliya V. Pogodina |
| author_facet | Maxim V. Sinitsa Nataliya V. Pogodina |
| author_sort | Maxim V. Sinitsa |
| collection | DOAJ |
| description | Spermophilus is the most diverse and abundant genus of Eurasian sciurids. Even though many species have been described, the early evolution of the group is poorly understood. Here we present a review of the evolution and taxonomy of early Spermophilus, based on analysis of more than 1500 specimens from the late Pliocene and Early–Middle Pleistocene of Ukraine and European Russia, representing the most complete and continuous fossil record of the early Old World ground squirrels known to date. In addition to documenting previously unpublished specimens of Spermophilus nogaici, we describe a new species, Spermophilus praecox sp. nov., the oldest member of the genus, from the late Pliocene and Early Pleistocene (middle Villanyian to earliest Biharian) of southern Ukraine. It is intermediate in size between a somewhat smaller Spermophilus nogaici and larger Spermophilus polonicus and Spermophilus primigenius. Morphologically, the new species can be distinguished from all known Spermophilus by the retention of primitive traits including a small P3; rudimentary lingual metaloph; large metaconule and mesostyle; presence of P4–M2 endoloph; and premolariform p4 lacking a lingual metalophid. The patterns of dental evolution in eastern European early Spermophilus throughout 2.15 My indicates the existence of a single gradually evolving S. praecox–S. nogaici lineage characterized by a decrease of molar size but enlargement of premolars; the tendency toward high-crowned teeth with more expanded anterior and reduced posterior lobes; well-developed transverse ridges and anterostyles; reduced endolophs, anteroconules, metaconules, and mesostyles of P4–M2; molariform p4; complete m1–m2 metalophids; and stronger m3 hypoconid, hypoconulid, and entoconulid. Dental character regression suggests that Spermophilus evolved from a relatively largesized sciurid having generalized Otospermophilus-like dentition, probably an unknown North American member of stem Marmotina. |
| first_indexed | 2024-12-13T14:56:16Z |
| format | Article |
| id | doaj.art-6d2726183f0445a294e7df0a06909221 |
| institution | Directory Open Access Journal |
| issn | 0567-7920 1732-2421 |
| language | English |
| last_indexed | 2024-12-13T14:56:16Z |
| publishDate | 2019-09-01 |
| publisher | Institute of Paleobiology PAS |
| record_format | Article |
| series | Acta Palaeontologica Polonica |
| spelling | doaj.art-6d2726183f0445a294e7df0a069092212022-12-21T23:41:14ZengInstitute of Paleobiology PASActa Palaeontologica Polonica0567-79201732-24212019-09-0164364366710.4202/app.00605.2019The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrelsMaxim V. Sinitsa0Nataliya V. Pogodina1Institute of Natural Sciences and Mathematics, Ural Federal University, 19 Mira str., Ekaterinburg, 620002, Russia; and Department of Paleontology, National Museum of Natural History, National Academy of Sciences of Ukraine, 15 Bogdan Khmelnitsky str., Kiev, 01030, UkraineInstitute of Natural Sciences and Mathematics, Ural Federal University, 19 Mira str., Ekaterinburg, 620002, RussiaSpermophilus is the most diverse and abundant genus of Eurasian sciurids. Even though many species have been described, the early evolution of the group is poorly understood. Here we present a review of the evolution and taxonomy of early Spermophilus, based on analysis of more than 1500 specimens from the late Pliocene and Early–Middle Pleistocene of Ukraine and European Russia, representing the most complete and continuous fossil record of the early Old World ground squirrels known to date. In addition to documenting previously unpublished specimens of Spermophilus nogaici, we describe a new species, Spermophilus praecox sp. nov., the oldest member of the genus, from the late Pliocene and Early Pleistocene (middle Villanyian to earliest Biharian) of southern Ukraine. It is intermediate in size between a somewhat smaller Spermophilus nogaici and larger Spermophilus polonicus and Spermophilus primigenius. Morphologically, the new species can be distinguished from all known Spermophilus by the retention of primitive traits including a small P3; rudimentary lingual metaloph; large metaconule and mesostyle; presence of P4–M2 endoloph; and premolariform p4 lacking a lingual metalophid. The patterns of dental evolution in eastern European early Spermophilus throughout 2.15 My indicates the existence of a single gradually evolving S. praecox–S. nogaici lineage characterized by a decrease of molar size but enlargement of premolars; the tendency toward high-crowned teeth with more expanded anterior and reduced posterior lobes; well-developed transverse ridges and anterostyles; reduced endolophs, anteroconules, metaconules, and mesostyles of P4–M2; molariform p4; complete m1–m2 metalophids; and stronger m3 hypoconid, hypoconulid, and entoconulid. Dental character regression suggests that Spermophilus evolved from a relatively largesized sciurid having generalized Otospermophilus-like dentition, probably an unknown North American member of stem Marmotina.http://www.app.pan.pl/archive/published/app64/app006052019.pdfMammaliaRodentiaSciuridaeXerinaeevolutionPliocenePleistoceneeastern Europe |
| spellingShingle | Maxim V. Sinitsa Nataliya V. Pogodina The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrels Acta Palaeontologica Polonica Mammalia Rodentia Sciuridae Xerinae evolution Pliocene Pleistocene eastern Europe |
| title | The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrels |
| title_full | The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrels |
| title_fullStr | The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrels |
| title_full_unstemmed | The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrels |
| title_short | The evolution of early Spermophilus in eastern Europe and the antiquity of the Old World ground squirrels |
| title_sort | evolution of early spermophilus in eastern europe and the antiquity of the old world ground squirrels |
| topic | Mammalia Rodentia Sciuridae Xerinae evolution Pliocene Pleistocene eastern Europe |
| url | http://www.app.pan.pl/archive/published/app64/app006052019.pdf |
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