Miacis

Miacis
Temporal range: 50.0–46.2 Ma
↓
 early to middle Eocene[1]
skull of Miacis parvivorus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Carnivoramorpha
Clade: Carnivoraformes
Genus: †Miacis
Cope, 1872
Type species
†Miacis parvivorus
Cope, 1872
Synonyms
synonyms of species:
  • M. parvivorus:
    • Viverravus parvivorus (Matthew, 1899)[2]
    • Vulpavus parvivorus (Cope, 1873)[3]

Miacis ("small point") is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America from the early to middle Eocene.[4][5][6]

Description

Miacis was five-clawed, about the size of a weasel (~30 cm), and lived on the North American continent. It retained some primitive characteristics such as low skulls, long slender bodies, long tails, and short legs. Miacis retained 44 teeth, although some reductions in this number were apparently in progress and some of the teeth were reduced in size.

Illustration of Miacis

The hind limbs were longer than the forelimbs, the pelvis was dog-like in form and structure, and some specialized traits were present in the vertebrae. It had retractable claws, agile joints for climbing, and binocular vision. Miacis and related forms had brains that were relatively larger than those of the creodonts, and the larger brain size as compared with body size probably reflects an increase in intelligence.[citation needed]

Like many other early carnivoramorphans, it was well suited for an arboreal climbing lifestyle with needle-sharp claws, limbs, and joints resembling modern carnivorans. Miacis was probably a very agile forest dweller that preyed upon smaller animals, such as small mammals, reptiles, and birds, and might also have eaten eggs and fruits.[7]

Classification and phylogeny

Classification

Genus: †Miacis (Cope, 1872)
Species: Distribution of the species and type locality: Age:
†M. parvivorus (Cope, 1872)[8]  USA 50,0 to 46,2 Ma

History of taxonomy

The locations of fossil site where Miacis fossils have been found.

Since Edward Drinker Cope first described the genus Miacis in 1872, at least twenty other species have been assigned to Miacis. However, these species share few synapomorphies other than plesiomorphic characteristics of miacids in general. This reflects the fact that Miacis has been treated as a wastebasket taxon and contains a diverse collection of species that belong to the stemgroup within the Carnivoraformes.[6] Many of the species originally assigned to Miacis have since been assigned to other genera and, apart from the type species, Miacis parvivorus, the remaining species are often referred to with Miacis in quotations (e.g. "Miacis" latidens). The following table lists the former Miacis species in chronological order of their original description and notes the reassignments to other genera.

Species: Type locality: Status and notes:
M. sylvestris (Marsh, 1872)[12] Bridger Formation (Wyoming, USA) now assigned to genus Harpalodon as Harpalodon sylvestris[13][14]
M. vulpinus (Scott & Osborn, 1887)[15] Uinta Basin (Utah, USA) Described as Amphicyon vulpinum; later assigned to Prodaphaenus and Miacis;[16] now recognised as synonym of Miocyon scotti
M. uintensis (Osborn, 1895)[17] Uinta Basin (Utah, USA) now assigned to genus Prodaphaenus as Prodaphaenus uintensis[10]
M. hargeri (Wortman, 1901)[13] Bridger Formation (Wyoming, USA) recognised as close relative to genus Lycarion
M. washakius (Wortman, 1901)[13] Bridger Formation (Wyoming, USA) now assigned to genus Neovulpavus as Neovulpavus washakius[14]
M. medius (Matthew, 1909)[16] Bridger Formation (Wyoming, USA) now assigned to genus Lycarion as Lycarion medius[14]
M. exiguus (Matthew & Granger, 1915)[18] Clark's Fork Basin (Wyoming, USA) recognised as close relative to genus Dormaalocyon
M. latidens (Matthew & Granger, 1915)[18] Clark's Fork Basin (Wyoming, USA) classified as a species of carnivoraform mammals outside of genus Miacis
M. invictus (Matthew & Granger, 1925)[19] Irdin Manha Formation (Inner Mongolia, China) classified as a species of carnivoraform mammals outside of genus Miacis
M. hookwayi (Stock, 1934)[20] Tapo Canyon (California, USA) classified as a species of carnivoraform mammals outside of genus Miacis
M. gracilis (Clark, 1939)[21] Uinta Basin (Utah, USA) classified as a species of carnivoraform mammals outside of genus Miacis
M. latouri (Quinet, 1966)[22] Dormaal (Flemish Brabant, Belgium) now assigned to genus Dormaalocyon as Dormaalocyon latouri[23]
M. lushiensis (Chow, 1975)[24] Shanghuang Quarry (Jiangsu, China) classified as a species of carnivoraform mammals outside of genus Miacis
M. deutschi (Gingerich, 1983)[25] Clark's Fork Basin (Wyoming, USA) classified as a species of carnivoraform mammals outside of genus Miacis
M. petilus (Gingerich, 1983)[25] Clark's Fork Basin (Wyoming, USA) classified as a species of carnivoraform mammals outside of genus Miacis
M. winkleri (Gingerich, 1983)[25] Clark's Fork Basin (Wyoming, USA) now assigned to genus Gracilocyon as type species Gracilocyon winkleri[26]
M. australis (Gustafson, 1986)[27] Rifle Range Hollow or Blue Cliff Horizon (Texas, USA) now assigned to genus Angelarctocyon as Angelarctocyon australis in family Amphicyonidae[28]
M. cognitus Gustafson, 1986[27] Reeves Bonebed (Texas, USA) now assigned to genus Gustafsonia as Gustafsonia cognita in family Amphicyonidae[28]
M. thailandicus (Ducrocq et al., 1992)[29] Krabi (South Thailand) now assigned to genus Xinyuictis as Xinyuictis thailandicus
M. boqinghensis (Huang et al., 1999)[30] Huoshipo, Guojiazhuang Village, Hedi Formation (China) classified as a species of carnivoraform mammals outside of genus Miacis
M. rosei (Heinrich et al., 2008)[1] Wyoming, USA now assigned to genus Gracilocyon as Gracilocyon rosei[26]
M. rundlei (Hooker, 2010)[31] Abbey Wood, England, UK now assigned to genus Gracilocyon as Gracilocyon rundlei[23]
M. solei (Smith & Smith, 2010)[26] Dormaal (Flemish Brabant, Belgium) now assigned to genus Gracilocyon as Gracilocyon solei[26]

Phylogeny

The phylogenetic relationships of genus Miacis are shown in the following cladogram:[32][23][33][14]

 Carnivoramorpha 
 †Viverravidae 
 sensu lato 
 ? 

†Carnivoramorpha sp. (UALVP 31176)

 ? 

†Carnivoramorpha sp. (USNM 538395)

 ? 

†"Sinopa" insectivorus

 Carnivoraformes 
 Clade "B" 
 Clade "C" 

†Africtis

 ? 

†Carnivoraformes undet. Genus B

†Dawsonicyon

†"Miacis" boqinghensis

†"Miacis" hookwayi

†"Miacis" latidens

†"Miacis" petilus

 ? 

†Carnivoraformes undet. Genus A

 †Miacis 

†Miacis parvivorous

 Clade "D" 
†Gracilocyon/Oodectes clade
†Vulpavus clade
 (Carnivora [sensu lato]) 

See also

References

Wikimedia Commons has media related to Miacis.
Wikispecies has information related to Miacis.
  1. ^ a b Heinrich, R. E.; Strait, S. G.; Houde, P. (2008). "Earliest Eocene Miacidae (Mammalia: Carnivora) from northwestern Wyoming". Journal of Paleontology. 82 (1): 154–162. Bibcode:2008JPal...82..154H. doi:10.1666/05-118.1. S2CID 35030667.
  2. ^ J. L. Wortman and W. D. Matthew (1899.) "The ancestry of certain members of the Canidae, the Viverridae, and Procyonidae." Bulletin of the American Museum of Natural History 12(6):109-138
  3. ^ E. D. Cope (1873) "On some Eocene mammals, obtained by Hayden's Geological Survey of 1872." Paleontological Bulletin 12:1-6
  4. ^ McKenna, Malcolm C.; Bell, Susan K. (1997). Classification of Mammals Above the Species Level. New York: Columbia University Press. ISBN 978-0-231-11012-9. Retrieved 16 March 2015.
  5. ^ J. J. Flynn (1998.) "Early Cenozoic Carnivora ("Miacoidea")." In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.) "Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals." Cambridge University Press, Cambridge. ISBN 0-521-35519-2
  6. ^ a b Welsey-Hunt, G. D.; Flynn, J. J. (2005). "Phylogeny of the Carnivora: basal relationships among the Carnivoramorphans, and assessment of the position of 'Miacoidea' relative to Carnivora". Journal of Systematic Palaeontology. 3 (1): 1–28. Bibcode:2005JSPal...3....1W. doi:10.1017/S1477201904001518. S2CID 86755875.
  7. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 214. ISBN 1-84028-152-9.
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  9. ^ M. R. Thorpe (1923) "New species of Uinta Carnivora from White River, Utah." Archived 2023-01-09 at the Wayback Machine American Journal of Science 5(27):218-224
  10. ^ a b Anthony R. Friscia and D. Tab Rassmussen (2010) „Middle Eocene Carnivoramorpha of the Uinta Basin, Utah”. Annals of Carnegie Museum, vol. 79 (1), pp. 51-63
  11. ^ K. D. Rose, A. E. Chew, R. H. Dunn, M. J. Kraus, H. C. Fricke and S. P. Zack (2012) "Earliest Eocene mammalian fauna from the Paleocene-Eocene Thermal Maximum at Sand Creek Divide, southern Bighorn Basin, Wyoming." University of Michigan Papers on Paleontology 36:1-122
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  15. ^ W. B. Scott and H. F. Osborn (1887.) "Preliminary Report on the Vertebrate Fossils of the Uinta Formation, Collected by the Princeton Expedition of 1886." Proceedings of the American Philosophical Society 24(126):255-264
  16. ^ a b W. D. Matthew (1909) "The Carnivora and Insectivora of the Bridger Basin, middle Eocene." Memoirs of the American Museum of Natural History 9:289-567
  17. ^ H. F. Osborn (1895) "Fossil mammals of the Uinta Basin. Expedition of 1894." Bulletin of the American Museum of Natural History 7(2):71-105
  18. ^ a b W. D. Matthew and W. Granger (1915.) "A revision of the Lower Eocene Wasatch and Wind River faunas." Bulletin of the American Museum of Natural History 34(1):1-103
  19. ^ Matthew W. D. & Granger W. (1925.) "New mammals from the Irdin Manha Eocene of Mongolia." American Museum Novitates 198:1–10.
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  22. ^ G. E. Quinet (1966) "Les mammifères du Landénien continental belge, second tome. Etude de la morphologie dentaire comparée des carnivores de Dormaal." Mémoires de l'Institut Royal des Sciences Naturelles Belges, 158:1-64.
  23. ^ a b c Solé, Floréal; Smith, Richard; Coillot, Tiphaine; de Bast, Eric; Smith, Thierry (2014). "Dental and tarsal anatomy of Miacis latouri and a phylogenetic analysis of the earliest carnivoraforms (Mammalia, Carnivoramorpha)". Journal of Vertebrate Paleontology. 34 (1): 1–21. Bibcode:2014JVPal..34....1S. doi:10.1080/02724634.2013.793195. ISSN 0272-4634. S2CID 86207013.
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  29. ^ Ducrocq S., Buffetaut E., Buffetaut-Tong H., Helmcke-Ingavat R., Jaeger J.-J., Jongkanchanasoontorn Y. and Suteethorn V. (1992) "A lower Tertiary vertebrate fauna from Krabi (South Thailand)." Neues Jahrbuch fuer Geologie und Palaeontologie Abhandlungen 184(1): 101–122.
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