{{Short description|Infraorder of mammals}} {{Other uses}} {{Automatic taxobox | name = Pecora | fossil_range = {{Fossilrange|45|0}}Eocene - recent | image = Pecora (infraorder).jpg | image_caption = | taxon = Pecora | authority = Linnaeus, 1758 | subdivision_ranks = Subgroups | subdivision = * †Dromomerycidae * Antilocapridae * Bovimorpha ** Cervoidea *** Cervidae ** Bovoidea *** Bovidae *** Moschidae * Giraffomorpha ** †Palaeomerycidae ** Giraffoidea *** Giraffidae *** †Climacoceratidae }}
'''Pecora''' is an infraorder of even-toed hoofed mammals with ruminant digestion. Most members of Pecora have cranial appendages projecting from their frontal bones; only two extant genera lack them, ''Hydropotes'' and ''Moschus''.<ref name=HD>{{cite journal | last1 = Hassanin | first1 = A. | last2 = Douzery | first2 = E. | year = 2003 | title = Molecular and Morphological Phylogenies of Ruminantia and the Alternative Position of the Moschidae | journal = Systematic Biology | volume = 52 | issue = 2| pages = 206–228 | doi = 10.1080/10635150390192726 | pmid=12746147| doi-access = free }}</ref> The name "Pecora" comes from the Latin word {{Lang|la|pecus}}, which means "cattle".<ref name=bubenik>Bubenik, A. Epigenetical, Morphological, Physiological, and Behavioral Aspects of Evolution of Horns, Pronghorns, and Antlers. in ''Horns, Pronghorns, and Antlers''. G. Bubenik and A. Bubenik eds. Springer-Verlag. New York. 1990</ref> Although most pecorans have cranial appendages, only some of these are properly called "horns", and many scientists agree that these appendages did not arise from a common ancestor, but instead evolved independently on at least two occasions.<ref name=HD /><ref name=bubenik /><ref name = JS>Janis, C., K. Scott. The Interrelationships of Higher Ruminant Families with Special Emphasis on the Members of the Cervoidea. ''American Museum Novitates''. 2893: 1-85. 1987. http://digitallibrary.amnh.org/dspace/handle/2246/5180</ref><ref name="Hassanin et al">{{cite journal | last1 = Hassanin | first1 = A. | last2 = Delsuc | first2 = F. | last3 = Ropiquet | first3 = A. | last4 = Hammer | first4 = C. | last5 = Matthee | first5 = C. | last6 = Ruiz-Garcia | first6 = M. | last7 = Catzeflis | first7 = F. | last8 = Areskoug | first8 = V. | last9 = Nguyen | first9 = T. T. | last10 = Couloux | first10 = A. | year = 2012 | title = Pattern and Timing of Diversification of Cetartiodactyla (Mammalia, Laurasiatheria), as Revealed by a Comprehensive Analysis of Mitochondrial Genomes | journal = Comptes Rendus Biologies | volume = 335 | issue = 1| pages = 32–50 | doi = 10.1016/j.crvi.2011.11.002 | pmid=22226162| doi-access = free }}</ref> Likewise, while Pecora as a group is supported by both molecular and morphological studies, morphological support for interrelationships between pecoran families is disputed.<ref name=HD />
== Evolutionary history == The first fossil ruminants appeared in the Early Eocene and were small, likely omnivorous, forest-dwellers.<ref name=DeMiguel>{{cite journal | last1 = DeMiguel | first1 = D. | last2 = Azanza | first2 = B. | last3 = Morales | first3 = J. | year = 2014| title = Key Innovations in Ruminant Evolution: A Paleontological Perspective | journal = Integrative Zoology | volume = 9| issue = 4| pages = 412–433| doi = 10.1111/1749-4877.12080 | pmid=24148672}}</ref> Molecular dating studies estimate that Ruminantia split into the two sister clades Pecora and Tragulina around 45 million years ago, during the Eocene.<ref name=HD /> However, it was not until 15 million years later, at around 30 million years ago during the Oligocene, that the evolutionary radiation of Pecora began and the five families appeared (Bovidae, Cervidae, Moschidae, Giraffidae, and Antilocapridae).<ref name=HD />
The appearance of many Pecoran fossils during the Miocene suggests that its rapid diversification may correspond to the climate change events of that epoch,<ref name=DeMiguel /><ref name=morales>{{cite journal | last1 = Morales | first1 = J. | last2 = Pickford | first2 = M. | last3 = Soria | first3 = D. | last4 = Pachyostosis | year = 1993 | title = ''Lorancameryx pachyostoticus Nov. Gen. Nov. Sp.'' and Its Bearing on the Evolution of Bony Appendages in Artiodactyls | journal = Geobios | volume = 26 | issue = 2| pages = 207–230 | doi=10.1016/S0016-6995(93)80016-K}}</ref> as this time period was marked by much of Earth's forest habitats being replaced by grasslands due to widespread cooling and drying.<ref name=HD />
It is likely that the antelopes, giraffids, and pronghorns evolved in an open environment while the cervids, including the caribou, evolved in a woodland habitat.<ref name=":0">{{Cite thesis |last=Dagg |first=Anne Innis |author-link=Anne Innis Dagg |date=1967 |title=Gaits and Their Development in the Infraorder Pecora |url=https://uwspace.uwaterloo.ca/handle/10012/14529 |via=UWSpace}}</ref> The type of gallop in Pecorian species is shown to be closely related to their environment and anatomy, where light Pecorian species use both flexed and extended suspensions in their fast gallops.<ref name=":0" /> The white-tail and mule-deer have been observed to primarily use the extended suspension, since in this phase of their gallop they leap over bushes and logs that are present in their brush environment.<ref name=":0" /> However, heavy Pecorian species do not use extended suspensions as most have backs that slope downward with shorter hind legs.<ref name=":0" />
== Taxonomy and classification == Pecora is an infraorder within the larger suborder Ruminantia, and is the sister clade to the infraorder Tragulina (of which Tragulidae is the only surviving family).
Pecora's placement within Artiodactyla can be represented in the following cladogram:<ref>{{cite journal|year=2006|title=A higher-level MRP supertree of placental mammals|journal=BMC Evol Biol|volume=6|doi=10.1186/1471-2148-6-93|pmc=1654192|pmid=17101039|last= Beck|first= N.R.|page=93 |doi-access=free }}</ref><ref name="O'Leary2013">{{cite journal|last1= O'Leary|first1= M.A.|last2= Bloch|first2= J.I.|last3= Flynn|first3= J.J.|last4= Gaudin|first4= T.J.|last5= Giallombardo|first5= A.|last6= Giannini|first6= N.P.|last7= Goldberg|first7= S.L.|last8= Kraatz|first8= B.P.|last9= Luo|first9= Z.-X.|last10= Meng|first10= J.|last11= Ni|first11= X.|last12= Novacek|first12= M.J.|last13= Perini|first13= F.A.|last14= Randall|first14= Z.S.|last15= Rougier|first15= G.W.|last16= Sargis|first16= E.J.|last17= Silcox|first17= M.T.|last18= Simmons|first18= N.B.|last19= Spaulding|first19= M.|last20= Velazco|first20= P.M.|last21= Weksler|first21= M.|last22= Wible|first22= J.R.|last23= Cirranello|first23= A.L.|title= The Placental Mammal Ancestor and the Post-K-Pg Radiation of Placentals|journal= Science|volume= 339|issue= 6120|year= 2013|pages= 662–667|doi= 10.1126/science.1229237|pmid= 23393258|s2cid= 206544776|hdl= 11336/7302|hdl-access= free}}</ref><ref name="Song2012">{{cite journal|last1= Song|first1= S.|last2= Liu|first2= L.|last3= Edwards|first3= S.V.|last4= Wu|first4= S.|title= Resolving conflict in eutherian mammal phylogeny using phylogenomics and the multispecies coalescent model|journal= Proceedings of the National Academy of Sciences|volume= 109|issue= 37|year= 2012|pages= 14942–14947|doi= 10.1073/pnas.1211733109|pmid= 22930817|pmc= 3443116|doi-access= free}}</ref><ref name="dos Reis2012">{{cite journal|last1=dos Reis|first1= M.|last2= Inoue|first2= J.|last3= Hasegawa|first3= M.|last4= Asher|first4= R.J.|last5= Donoghue|first5= P.C.J.|last6= Yang|first6= Z.|title= Phylogenomic datasets provide both precision and accuracy in estimating the timescale of placental mammal phylogeny|journal= Proceedings of the Royal Society B: Biological Sciences|volume= 279|issue= 1742|year= 2012|pages= 3491–3500|doi= 10.1098/rspb.2012.0683|pmid= 22628470|pmc= 3396900|doi-access= free}}</ref><ref name="Upham2019">{{cite journal|last1= Upham|first1= N.S.|last2= Esselstyn|first2= J.A.|last3= Jetz|first3= W.|title= Inferring the mammal tree: Species-level sets of phylogenies for questions in ecology, evolution, and conservation|journal= PLOS Biology|volume= 17|issue= 12|year= 2019|article-number= e3000494|doi= 10.1371/journal.pbio.3000494|pmid= 31800571|pmc= 6892540|doi-access= free}}(see e.g. Fig S10)</ref>
{{Clade|style=font-size:100%;line-height:100% |label1=Artiodactyla |1={{Clade |1=Tylopoda (camels)50 px |label2=Artiofabula |2={{Clade |1=Suina (pigs)50 px |label2=Cetruminantia |2={{Clade |label1=Ruminantia (ruminants) |1={{Clade |1=Tragulidae (mouse deer)50 px |2='''Pecora''' (horn bearers)50 px }} |label2=Cetancodonta/Whippomorpha |2={{Clade |1=Hippopotamidae (hippopotamuses)50 px |2=Cetacea (whales)50 px }} }} }} }} }}
Current attempts to determine the relationships among pecoran families (as well as all artiodactyls) rely on molecular studies, as little consensus exists in morphological studies.<ref name=HD /> Different families within Pecora are recognized as valid by different groups of scientists.<ref name=DeMiguel /><sup>and sources therein, pp. 4–5</sup>
Until the beginning of the 21st century it was understood that the family Moschidae (musk deer) was sister to Cervidae. However, a 2003 phylogenetic study by Alexandre Hassanin (of National Museum of Natural History, France) and colleagues, based on mitochondrial and nuclear analyses, revealed that Moschidae and Bovidae form a clade sister to Cervidae. According to the study, Cervidae diverged from the Bovidae-Moschidae clade 27 to 28 million years ago.<ref name="Hassanin2003">{{cite journal | last1=Hassanin | first1=A. | last2=Douzery | first2=E. J. P. | title=Molecular and morphological phylogenies of Ruminantia and the alternative position of the Moschidae | journal=Systematic Biology | date=2003 | volume=52 | issue=2 | pages=206–28 | doi=10.1080/10635150390192726 | url=https://www.researchgate.net/publication/10760976 | pmid=12746147| doi-access=free }}</ref> The following cladogram is based on the 2003 study.<ref name="Hassanin2003"/>
{{Clade | style=font-size: 100%; line-height:100% | label1=Ruminantia | 1={{clade | label1=Tragulina | 1=Tragulidae 50 px | label2='''Pecora''' | 2={{clade | 1=Antilocapridae 50 px | 2=Giraffidae 50 px | 3={{clade | 1=Cervidae 50 px | 2={{clade | 1=Bovidae 50px | 2=Moschidae 50 px }} }} }} }} }}
'''Infraorder Pecora''' ("horned ruminants", "higher ruminants") * Incertae sedis ** Family †Dromomerycidae ** Family Antilocapridae (pronghorn) * Parvorder Bovimorpha ** Superfamily Cervoidea *** Family Cervidae (deer) ** Superfamily Bovoidea *** Family Moschidae (musk deer) *** Family Bovidae (cattle, goats, sheep, and antelopes) * Parvorder Giraffomorpha ** Family †Palaeomerycidae ** Superfamily Giraffoidea *** Family Giraffidae (giraffes and okapi) *** Family †Climacoceratidae
== Anatomy == Pecorans share characteristics with other artiodactyls, including a four-chambered stomach, and a paraxonic foot, meaning that it supports weight on the third and fourth digits. Several characteristics distinguish Pecora from its sister taxon, Tragulina: an astragalus with parallel sides, a loss of the trapezium, and differences in parts of the skull such as the petrosal bone.<ref name=JS />
The distinguishing features of most pecoran families are cranial appendages. Most modern pecorans (with the exception of the Moschidae) have one of four types of cranial appendages: horns, antlers, ossicones, or pronghorns.<ref name=DeMiguel />
* '''True horns''' have a bone core that is covered in a permanent sheath of keratin. They are indicative of Bovidae. Horns develop in the periosteum over the frontal bone, and can be curved or straight.<ref name=JS /> Surface features on the keratin sheath (e.g., ridges or twists) are thought to be caused by differential rates of growth around the bone core.<ref name=JS /> * '''Antlers''' are bony structures that are shed and replaced each year in members of the family Cervidae. They grow from a permanent outgrowth of the frontal bone called the pedicle.<ref name=JS /> Antlers can be branched, as in the white-tailed deer (''Odocoileus virginianus''), or palmate, as in the moose (''Alces alces''). * '''Ossicones''' are permanent bone structures that fuse to the frontal or parietal bones during the lifetime of an animal.<ref name=JS /> They are found only in the Giraffidae and closely related extinct clades,<ref name=JS /> represented in modern animals by the giraffe (''Giraffa camelopardalis'') and the okapi (''Okapia johnstoni''). * '''Pronghorns''' are similar to horns in that they have keratinous sheaths covering permanent bone cores; however, these sheaths are deciduous and can be shed like antlers.<ref name=JS /> Very little is known about the development of pronghorns, but they are generally presumed to have evolved independently.<ref name=JS /> The only extant animal with pronghorns is the pronghorn antelope (''Antilocapra americana'').
== References == {{Reflist}}
== External links == * {{Cite EB1911|wstitle=Pecora|short=x}}
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Category:Pecora Category:Ruminants Category:Extant Burdigalian first appearances