Helohyidae: Difference between revisions
Citation bot (talk | contribs) Add: bibcode, jstor. Removed URL that duplicated unique identifier. Removed parameters. | You can use this bot yourself. Report bugs here. | Suggested by AManWithNoPlan | All pages linked from cached copy of User:AManWithNoPlan/sandbox2 | via #UCB_webform_linked |
mNo edit summary |
||
| Line 1: | Line 1: | ||
{{copy edit|date=August 2020}} |
{{copy edit|date=August 2020}} |
||
{{short description|A group of extinct artiodactyl mammals}} |
{{short description|This is real look it up on Google! A group of extinct artiodactyl mammals}} |
||
{{Automatic taxobox |
{{Automatic taxobox |
||
|fossil_range={{Fossil range|Middle Eocene|Late Oligocene}} |
|fossil_range={{Fossil range|Middle Eocene|Late Oligocene}} |
||
Revision as of 02:16, 5 September 2020
 | This article may require copy editing for grammar, style, cohesion, tone, or spelling. (August 2020) |
| Helohyidae Temporal range:
| |
|---|---|
| |
| Reconstruction of the skull of Achaenodon | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Family: | †Helohyidae |
Helohyidae are a group of extinct artiodactyl mammals.[1][2] They lived mainly in the mid-to-upper Eocene (about 50 to 39 million years ago), although some fossils were found on land in the upper Oligocene (about 28 million years ago).[3]
Description
Helohyidae share vague similarities to present-day pigs, though they were much slimmer. They possessed prominent canines and molars with bunodont cusps; their dental wreaths were bulging and the enamel was wrinkled. Their upper molars were usually squared, due to the enlargement and displacement of the metaconule, but there was also a small hypocone and hypoconsque. The paracholo was reduced and there was no mesostil. Their lower molars increased in size as they proceeded to the bottom of the jaw, and the paraconid was small or absent. Some forms (e.g. Gobiohyus) possessed small diathemes that separated the premolars from each other. The snout was usually elongated (e.g. in Helohyus), but in some forms ascribed to this family (Achaenodon) it was very short. Compared to other primitive artiodactyls such as dichobunids, they possessed higher sagittal ridges; the genus Achaenodon, in particular, possessed a large sagittal crest and its size was much larger than those of other eloiids.
Classification
The Helohyidae family was established by Marshall in 1877 to accommodate some forms of early artiodactyl mammals of the American Eocene. In addition to the genus Helohyus, the North Americans Dyscritochoerus, Parahyus and Achaenodon were later ascribed to this family. Other forms come from the Upper-Middle-East Eocene of Asia (Gobiohyus[4] of Inner Mongolia, Pakkokuhyus of Burma and Progenitohyus[5] of Thailand. The latter form may be close to the origin of the family of hippos-like anthrax. The last known eloiid is Simojovelhyus of The Upper Oligocene of Mexico: the discovery of this form implies the existence of a ghost lineage of eloids of about 10 million years.[6]
Eloiids have been variously classified as relatives of archaic dichobunids or as close to the origin of anthrachotheds. The current opinion is to classify them as relatives of the dichobunids.[7]
References
- ^ Ducrocq, Stéphane; Chaimanee, Yaowalak; Suteethorn, Varavudh; Jaeger, Jean-Jacques (September 1, 1997). "First discovery of Helohyidae (Artiodactyla, Mammalia) in the Late Eocene of Thailand: a possible transitional form for Anthracotheriidae". Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science. 325 (5): 367–372. doi:10.1016/S1251-8050(97)81385-7 – via ScienceDirect.
- ^ "Fossilworks: Helohyidae". fossilworks.org.
- ^ "Helohyidae". www.gbif.org.
- ^ Coombs, Margery C.; Coombs, Walter P. (20 August 1977). "Dentition of Gobiohyus and a Reevaluation of the Helohyidae (Artiodactyla)". Journal of Mammalogy. 58 (3): 291–308. doi:10.2307/1379328. ISSN 0022-2372. JSTOR 1379328.
- ^ Ducrocq, Stéphane; Chaimanee, Yaowalak; Suteethorn, Varavudh; Jaeger, Jean-Jacques (September 13, 1997). "First discovery of Helohyidae (Artiodactyla, Mammalia) in the Late Eocene of Thailand: a possible transitional form for Anthracotheriidae". CRASE. 325 (5): 367–372. Bibcode:1997CRASE.325..367D. doi:10.1016/S1251-8050(97)81385-7.
- ^ Ferrusquea-Villafranca, 2006[full citation needed]
- ^ McKenna and Bell, 1997; Stucky, 1998; Rose, 2006[full citation needed]