Hyaenodonta Explained

Hyaenodonta ("hyena teeth") is an extinct order of hypercarnivorous placental mammals of clade Pan-Carnivora from mirorder Ferae.[1] [2] Hyaenodonts were important mammalian predators that arose during the early Paleocene in Europe[3] and persisted well into the late Miocene.[4]

Characteristics

Hyaenodonts are characterized by long, often disproportionately large skulls, slender jaws, and slim bodies. They generally ranged in size from 30 to 140 cm at the shoulder. While Simbakubwa kutokaafrika may have been up to (surpassing the modern polar bear in size[5]), this estimate is suspect due to being based on skull-body size ratios derived from felids, which have much smaller skulls for their body size. Other large hyaenodonts include two close and later-surviving relatives of Simbakubwa, Hyainailouros and Megistotherium (the latter likely being the largest in the group), and the much earlier-living Hyaenodon gigas (the largest species from genus Hyaenodon), which may have been as large as 1.4 m high at the shoulder, 3.0 m long and weighed about 330 kg. Most hyaenodonts, however, were in the 5–15 kg range, equivalent to a mid-sized dog.[6] The anatomy of their skulls show that they had a particularly acute sense of smell, while their teeth were adapted for shearing, rather than crushing.

Hyaenodonts were ancestrally plantigrade, but the later, larger forms were generally digitigrade or semidigitigrade. Because of their size range, it is probable that different species hunted in different ways, which allowed them to fill many different predatory niches, with small or medium-sized forms filling roles similar to mustelids or smaller felids of today while the larger forms functioned as apex predators focusing on larger prey, wielding their mighty jaws as their principal weapon as they lacked grasping forelimbs. The carnassials in a hyaenodonts are generally the second upper and third lower molars. However, some hyaenodonts possessed as many as three sequential pairs of carnassials or carnassial-like molar teeth in their jaws. Hyaenodonts, like all creodonts, lacked post-carnassial crushing molar teeth, such as those found in many carnivoran families, especially the Canidae and Ursidae, and thus lacked dental versatility for processing any foods other than meat.[7]

Hyaenodonts differed from Carnivora in that they replaced their deciduous dentition slower in development than carnivorans.[8] Studies on Hyaenodon show that juveniles took 3 to 4 years in the last stage of tooth eruption, implying a very long adolescent phase. In North American forms, the first upper premolar erupts before the first upper molar, while European forms show an earlier eruption of the first upper molar.[9]

At least one hyaenodont lineage, subfamily Apterodontinae, was specialised for aquatic, otter-like habits.[10]

Range

Having evolved in Europe during the Paleocene,[3] hyaenodonts soon after spread into Africa and India, implying close biogeographical connections between these areas.[10] [11] Afterwards, they dispersed into Asia from either Europe or India, and finally, North America from either Europe or Asia.[12] [13]

They were important hypercarnivores in Eurasia, Africa, and North America during the Oligocene, but declined towards the end of the epoch, with almost the entire order becoming extinct by the close of the Oligocene. Several representatives of this order, including hyainailourids Megistotherium, Simbakubwa, Hyainailouros, Sectisodon, Exiguodon, Sivapterodon, Metapterodon, and Isohyaenodon, the prionogalid Prionogale, the teratodontid Dissopsalis and the youngest species of genus Hyaenodon, H. weilini, survived into or evolved during the Miocene, of which, only Dissopsalis survived long enough to go extinct at the close of the Miocene.[4] Traditionally, this has been attributed to competition with carnivorans, but no formal examination of the correlation between the decline of hyaenodonts and the expansion of carnivorans has been recorded, and the latter may simply have moved into vacant niches after the extinction of hyaenodont species.[14]

Classification and phylogeny

Relations

Hyaenodonts were considerably more widespread and successful than the oxyaenids, the other clade of mammals originally classified along with the hyaenodonts as part of Creodonta.[15] In 2015 phylogenetic analysis of Paleogene mammals, by Halliday et al., monophyly of Creodonta was supported and was placed in the clade Ferae, closer to Pholidota than to Carnivora.[16] However, order Creodonta is now considered to be a polyphyletic wastebasket taxon containing two unrelated clades assumed to be closely related (or ancestral) to Carnivora.[3] [8] [9] [10] [11] [17] [18] [19] [20] [21] [22]

Taxonomy

Order: †Hyaenodonta ----
  • (unranked): †Afro-Arabian clade
----
  • ichnotaxa of Hyaenodonta:
    • Ichnogenus: †Creodontipus
    • Ichnogenus: †Dischidodacylus
    • Ichnogenus: †Sarcotherichnus
    • Ichnogenus: †Zanclonychopus
    • Ichnofamily: †Sarjeantipodidae
      • Ichnogenus: †Hyaenodontipus
      • Ichnogenus: †Quiritipes
      • Ichnogenus: †Sarjeantipes

See also

Notes and References

  1. Solé . F. . Lhuillier . J. . Adaci . M. . Bensalah . M. . Mahboubi . M. . Tabuce . R. . The hyaenodontidans from the Gour Lazib area (?Early Eocene, Algeria): implications concerning the systematics and the origin of the Hyainailourinae and Teratodontinae . Journal of Systematic Palaeontology . 12 . 3 . 2013-07-16 . 303–322 . 10.1080/14772019.2013.795196. 84475034 .
  2. Solé . F. . Amson . E. . Borths . M. . Vidalenc . D. . Morlo . M. . Bastl . K. . A New Large Hyainailourine from the Bartonian of Europe and Its Bearings on the Evolution and Ecology of Massive Hyaenodonts (Mammalia) . PLOS ONE . 10 . 9 . 2015-09-23 . e0135698 . 10.1371/journal.pone.0135698 . 26398622 . 4580617. 2015PLoSO..1035698S . free .
  3. Borths . Matthew R. . Stevens . Nancy J. . 2019 . Simbakubwa kutokaafrika, gen. et sp. nov. (Hyainailourinae, Hyaenodonta, 'Creodonta,' Mammalia), a gigantic carnivore from the earliest Miocene of Kenya . Journal of Vertebrate Paleontology . 39 . 1 . e1570222 . 2019JVPal..39E0222B . 10.1080/02724634.2019.1570222 . 145972918.
  4. Barry . J. C. . 1988 . Dissopsalis, a middle and late Miocene proviverrine creodont (Mammalia) from Pakistan and Kenya . Journal of Vertebrate Paleontology . 48 . 1 . 25–45 . 10.1080/02724634.1988.10011682.
  5. Borths . M. R. . Stevens . N. J. . Simbakubwa kutokaafrika, gen. et sp. nov. (Hyainailourinae, Hyaenodonta, 'Creodonta,' Mammalia), a gigantic carnivore from the earliest Miocene of Kenya. Journal of Vertebrate Paleontology . 39 . 2019 . e1570222 . 10.1080/02724634.2019.1570222. 2019JVPal..39E0222B . 145972918 .
  6. Egi . Naoko . 2001 . Body Mass Estimates in Extinct Mammals from Limb Bone Dimensions: the Case of North American Hyaenodontids . Palaeontology . 44 . 3 . 497–528 . 10.1111/1475-4983.00189 . free.
  7. Wang, Xiaoming; and Tedford, Richard H. (2008). "Dogs: Their Fossil Relatives and Evolutionary History." New York: Columbia University Press
  8. Borths . Matthew R. . Stevens . Nancy J. . 2017 . Deciduous dentition and dental eruption of Hyainailouroidea (Hyaenodonta, "Creodonta," Placentalia, Mammalia) . Palaeontologia Electronica . 20 . 3 . 55A . 10.26879/776 . free.
  9. Bastl . Katharina Anna . 2013 . First evidence of the tooth eruption sequence of the upper jaw in Hyaenodon (Hyaenodontidae, Mammalia) and new information on the ontogenetic development of its dentition . Paläontologische Zeitschrift . 88 . 4 . 481–494 . 10.1007/s12542-013-0207-z . 85304920.
  10. Laudet . V. . Grohé . C. . Morlo . M. . Chaimanee . Y. . Blondel . C. . Coster . P. . Valentin . X. . Salem . M. . Bilal . A. A. . Jaeger . J. J. . Brunet . M. . New Apterodontinae (Hyaenodontida) from the Eocene Locality of Dur At-Talah (Libya): Systematic, Paleoecological and Phylogenetical Implications . PLOS ONE . 7 . 11 . 2012-11-21 . e49054 . 10.1371/journal.pone.0049054 . 23185292 . 3504055 . 2012PLoSO...749054G. free .
  11. Solé, Floréal & Smith, Thierry (2013). "Dispersals of placental carnivorous mammals (Carnivoramorpha, Oxyaenodonta & Hyaenodontida) near the Paleocene-Eocene boundary: a climatic and almost worldwide story" Geologica Belgica 16/4: 254–261
  12. Wang, Xiaoming; Qiu, Zhanxiang and Wang, Banyue (2005). "Hyaenodonts and carnivorans from the early Oligocene to early Miocene Xianshuihe Formation, Lanzhou Basin, Gansu Provinnce, China" Palaeontologia Electronica Vol. 8, Issue 1; 6A: 14p.
  13. Web site: "New Remains of Hyaenodontidae (Creodonta, Mammalia) From the Oligocene of Central Mongolia" . 2008-05-04 . dead . https://web.archive.org/web/20100508021919/http://www.oeaw.ac.at/kfq/downloads_Nagel/ANNPAL_2074.pdf . 2010-05-08.
  14. Lang . Andreas Johann . Engler . Thomas . Martin . Thomas . and . November 2021 . Dental topographic and three‐dimensional geometric morphometric analysis of carnassialization in different clades of carnivorous mammals (Dasyuromorphia, Carnivora, Hyaenodonta) . Journal of Morphology . 283 . 5 . 91–108 . 10.1002/jmor.21429 . free . free . 20.500.11811/10981.
  15. (1985): The Field Guide to Prehistoric Life. Facts on File Publications, New York.
  16. Halliday . Thomas J. D. . Upchurch . Paul . Goswami . Anjali . Resolving the relationships of Paleocene placental mammals . Biological Reviews . 92 . 2015 . 1 . 521–550 . 1464-7931 . 10.1111/brv.12242 . 28075073 . 6849585.
  17. Prevosti, F. J., & Forasiepi, A. M. (2018). "Introduction. Evolution of South American Mammalian Predators During the Cenozoic: Paleobiogeographic and Paleoenvironmental Contingencies"
  18. Polly . P. D. . 1994 . What, if anything, is a creodont? . 10.1080/02724634.1994.10011592 . Journal of Vertebrate Paleontology . 14 . Supplement 3 . 42A.
  19. Polly . P. D. . 1996 . The skeleton of Gazinocyon vulpeculus gen. et comb. nov. and the cladisitic relationships of Hyaenodontidae (Eutheria, Mammalia) . Journal of Vertebrate Paleontology . 16 . 2 . 303–319 . 10.1080/02724634.1996.10011318. 84853339 .
  20. Morlo . M. . Gunnell . G. . Polly . P. D. . 2009 . What, if not nothing, is a creodont? Phylogeny and classification of Hyaenodontida and other former creodonts . 10.1080/02724634.2009.10411818 . Journal of Vertebrate Paleontology . 29 . Supplement 3 . 152A.
  21. Solé, F. & Ladevèze, S. (2017). "Evolution of the hypercarnivorous dentition in mammals (Metatheria, Eutheria) and its bearing on the development of tribosphenic molars." Evolution & Development, 19(2), 56–68.
  22. Solé . Floréal . Marandat . Bernard . Lihoreau . Fabrice . 2020 . The hyaenodonts (Mammalia) from the French locality of Aumelas (Hérault), with possible new representatives from the late Ypresian . Geodiversitas . 42 . 13 . 185–214 . 10.5252/geodiversitas2020v42a13 . free.

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