Editing Paranthropus (section)

==Description==
===Skull===
''Paranthropus'' had a massively built, tall and flat skull, with a prominent [[gorilla]]-like [[sagittal crest]] along the midline which anchored large [[temporalis muscle]]s used in chewing.<ref name=Wood2004/> Like other australopithecines, ''Paranthropus'' exhibited sexual dimorphism, with males notably larger than females.<ref name=Wood2000/><ref name=McHenry1991a/><ref name=McHenry1991b/> They had large [[molar tooth|molars]] with a relatively thick [[tooth enamel]] coating ([[post-canine megadontia]]),<ref>{{cite journal|first1=A. J.|last1=Olejniczak|first2=T. M.|last2=Smith|first3=M. M.|last3=Skinner|display-authors=et al.|year=2008|title=Three-dimensional molar enamel distribution and thickness in ''Australopithecus'' and ''Paranthropus''|journal=Biology Letters|volume=4|issue=4|pages=406–410|doi=10.1098/rsbl.2008.0223|pmid=18522924|pmc=2610159}}</ref> and comparatively small [[incisor]]s (similar in size to modern [[human]]s),<ref>{{cite journal|first1=P. S.|last1=Ungar|first2=F. E.|last2=Grine|year=1991|title=Incisor size and wear in ''Australopithecus africanus'' and ''Paranthropus robustus''|journal=Journal of Human Evolution|volume=20|issue=4|pages=313–340|doi=10.1016/0047-2484(91)90013-L|bibcode=1991JHumE..20..313U }}</ref> possibly adaptations to processing abrasive foods.<ref name=Williams2015>{{cite journal|first=F. L.|last=Williams|year=2015|title=Dietary proclivities of ''Paranthropus robustus'' from Swartkrans, South Africa|journal=Anthropological Review|volume=78|issue=1|pages=1–19|doi=10.1515/anre-2015-0001|doi-access=free}}</ref><ref name=Wood2012>{{cite journal|first1=B.|last1=Wood|first2=K.|last2=Schroer|year=2012|title=Reconstructing the Diet of an Extinct Hominin Taxon: The Role of Extant Primate Models|journal=International Journal of Primatology|volume=33|issue=3|pages=716–742|doi=10.1007/s10764-012-9602-7|s2cid=15983306}}</ref> The teeth of ''P. aethiopicus'' developed faster than those of ''P. boisei''.<ref>{{cite journal|first=F. V.|last=Ramirez-Rozzi|year=1993|title=Tooth development in East African ''Paranthropus''|journal=Journal of Human Evolution|volume=24|issue=6|pages=429–454|doi=10.1006/jhev.1993.1030|bibcode=1993JHumE..24..429R }}</ref>

''Paranthropus'' had adaptations to the skull to resist large bite loads while feeding, namely the expansive [[squamosal suture]]s.<ref>{{cite journal|first1=C.|last1=Dzialo|first2=S. A.|last2=Wood|first3=M.|last3=Berthaume|display-authors=et al.|year=2013|title=Functional implications of squamosal suture size in ''Paranthropus boisei''|journal=American Journal of Physical Anthropology|volume=153|issue=2|pages=260–268|doi=10.1002/ajpa.22427|pmid=24242913}}</ref> The notably thick [[palate]] was once thought to have been an adaptation to resist a high bite force, but is better explained as a byproduct of facial lengthening and nasal anatomy.<ref>{{cite journal|first=M. A.|last=McCollum|year=1998|title=Palatal thickening and facial form in ''Paranthropus'': Examination of alternative developmental models|journal=American Journal of Physical Anthropology|volume=103|issue=3|pages=375–392|doi=10.1002/(SICI)1096-8644(199707)103:3<375::AID-AJPA7>3.0.CO;2-P|pmid=9261500|doi-access=free}}</ref>

In ''P. boisei'', the [[temporomandibular joint|jaw hinge]] was adapted to grinding food side-to-side (rather than up-and-down in modern humans), which is better at processing the [[starch]]y abrasive foods that likely made up the bulk of its diet. ''P. robustus'' may have chewed in a front-to-back direction instead, and had less exaggerated (less [[synapomorphy and apomorphy|derived]]) anatomical features than ''P. boisei'' as it perhaps did not require them with this kind of chewing strategy. This may have also allowed ''P. robustus'' to better process tougher foods.<ref>{{cite journal|first1=K.|last1=Kupczik|first2=V.|last2=Toro-Ibacache|first3=G. A.|last3=Macho|year=2018|title=On the relationship between maxillary molar root shape and jaw kinematics in ''Australopithecus africanus'' and ''Paranthropus robustus''|journal=Royal Society Open Science|volume=5|issue=8|page=180825|doi=10.1098/rsos.180825|pmc=6124107|pmid=30225074|bibcode=2018RSOS....580825K}}</ref>

The braincase volume averaged about {{cvt|500|cm3}}, comparable to gracile australopithecines, but smaller than ''Homo''.<ref name=Du2018>{{cite journal|first1=A.|last1=Du|first2=A. M.|last2=Zipkin|first3=K. G.|last3=Hatala|display-authors=et al.|year=2018|title=Pattern and process in hominin brain size evolution are scale-dependent|journal=Proceedings of the Royal Society B|volume=285|issue=1873|pages=20172738|doi=10.1098/rspb.2017.2738|pmc=5832710|pmid=29467267}}</ref> Modern human brain volume averages {{cvt|1270|cm3}} for men and {{cvt|1130|cm3}} for women.<ref>{{cite journal|first1=J. S.|last1=Allen|first2=H.|last2=Damasio|first3=T. J.|last3=Grabowski|year=2002|title=Normal neuroanatomical variation in the human brain: an MRI-volumetric study|journal=American Journal of Physical Anthropology|volume=118|issue=4|pages=341–358|doi=10.1002/ajpa.10092|pmid=12124914|s2cid=21705705}}</ref>

===Limbs and locomotion===
Unlike ''P. robustus'', the forearms of ''P. boisei'' were heavily built, which might suggest habitual [[suspensory behaviour]] as in [[orangutan]]s and [[gibbon]]s.<ref name=McHenry2007/><ref name=Dominguez2013/><ref name=Lague2019/> A ''P. boisei'' [[shoulder blade]] indicates long [[infraspinatus muscle]]s, which is also associated with suspensory behavior.<ref>{{cite journal|first1=D. J.|last1=Green|first2=H.|last2=Chirchir|first3=E.|last3=Mbua|year=2018|title=Scapular anatomy of ''Paranthropus boisei'' from Ileret, Kenya|journal=Journal of Human Evolution|volume=125|pages=181–192|doi=10.1016/j.jhevol.2017.06.013|pmid=30502893|doi-access=free|bibcode=2018JHumE.125..181G }}</ref> A ''P. aethiopicus'' ulna, on the other hand, shows more similarities to ''Homo'' than ''P. boisei''.<ref name=Lague2019>{{cite journal|first1=M. R.|last1=Lague|first2=H.|last2=Chirchir|first3=D. J.|last3=Green|first4=E.|last4=Mbua|year=2019|title=Humeral anatomy of the KNM-ER 47000 upper limb skeleton from Ileret, Kenya: Implications for taxonomic identification|journal=Journal of Human Evolution|volume=126|pages=24–38|doi=10.1016/j.jhevol.2018.06.011|pmid=30583842|s2cid=58607106|url=https://www.researchgate.net/publication/329486548|doi-access=free|bibcode=2019JHumE.126...24L }}</ref>

''Paranthropus'' were [[biped]]s, and their hips, legs and feet resemble ''A. afarensis'' and modern humans.<ref>{{cite journal |vauthors=Wood B, Richmond BG |title=Human evolution: taxonomy and paleobiology |journal=Journal of Anatomy |volume=197 |issue=1 |pages=19–60 |date=July 2000 |pmid=10999270 |pmc=1468107 |doi=10.1046/j.1469-7580.2000.19710019.x}}</ref><ref>{{cite journal|first1=T. M.|last1=Ryan|first2=K. J.|last2=Carlson|first3=A. D.|last3=Gordon|display-authors=et al.|year=2018|title=Human-like hip joint loading in ''Australopithecus africanus'' and ''Paranthropus robustus''|journal=Journal of Human Anthropology|volume=121|pages=12–24|doi=10.1016/j.jhevol.2018.03.008|pmid=29706230|s2cid=14060188|url=https://www.repository.cam.ac.uk/handle/1810/277557|doi-access=free|bibcode=2018JHumE.121...12R }}</ref> The pelvis is similar to ''A. afarensis'', but the hip joints are smaller in ''P. robustus''. The physical similarity implies a similar walking gait.<ref>{{cite journal |vauthors=Macchiarelli R, Bondioli L, Galichon V, Tobias PV |title=Hip bone trabecular architecture shows uniquely distinctive locomotor behaviour in South African australopithecines |journal=Journal of Human Evolution |volume=36 |issue=2 |pages=211–32 |date=February 1999 |pmid=10068067 |doi=10.1006/jhev.1998.0267|bibcode=1999JHumE..36..211M }}</ref> Their modern-humanlike big toe indicates a modern-humanlike foot posture and range of motion, but the more distal ankle joint would have inhibited the modern human toe-off [[bipedal gait cycle|gait cycle]]. By 1.8 mya, ''Paranthropus'' and ''[[H. habilis]]'' may have achieved about the same grade of bipedality.<ref>{{cite journal|first1=R. L.|last1=Susman|first2=T. M.|last2=Brain|year=1988|title=New first metatarsal (SKX 5017) from Swartkrans and the gait of ''Paranthropus robustus''|journal=American Journal of Physical Anthropology|volume=77|issue=1|pages=7–15|doi=10.1002/ajpa.1330770103|pmid=3189526}}</ref>

===Height and weight===
In comparison to the large, robust head, the body was rather small. Average weight for ''P. robustus'' may have been {{cvt|40|kg}} for males and {{cvt|32|kg}} for females;<ref name=Wood2000/> and for ''P. boisei'' {{cvt|50|kg}} for males and {{cvt|34|kg}} for females.<ref name=Wood2000/> At Swartkrans Cave Members 1 and 2, about 35% of the ''P. robustus'' individuals are estimated to have weighed {{cvt|28|kg}}, 22% about {{cvt|43|kg}}, and the remaining 43% bigger than the former but less than {{cvt|54|kg}}. At Member 3, all individuals were about {{cvt|45|kg}}.<ref name=McHenry1991a/> Female weight was about the same in contemporaneous ''H. erectus'', but male ''H. erectus'' were on average {{cvt|13|kg|1}} heavier than ''P. robustus'' males.<ref name=Susman2001>{{cite journal|first1=R. L.|last1=Susman|first2=D.|last2=de Ruiter|first3=C. K.|last3=Brain|year=2001|title=Recently identified postcranial remains of ''Paranthropus'' and Early ''Homo'' from Swartkrans Cave, South Africa|journal=Journal of Human Evolution|volume=41|issue=6|pages=607–629|doi=10.1006/jhev.2001.0510|pmid=11782111|bibcode=2001JHumE..41..607S |s2cid=26326715}}</ref> ''P. robustus'' sites are oddly dominated by small adults, which could be explained as heightened predation or mortality of the larger males of a group.<ref name=Braga2017>{{cite journal|first1=J.|last1=Braga|first2=J. F.|last2=Thackeray|first3=L.|last3=Bruxelles|first4=J.|last4=Dumoncel|first5=J.-P.|last5=Fourvel|year=2017|title=Stretching the time span of hominin evolution at Kromdraai (Gauteng, South Africa): Recent discoveries|journal=Comptes Rendus Palevol|volume=16|issue=1|pages=58–70|doi=10.1016/j.crpv.2016.03.003|bibcode=2017CRPal..16...58B |doi-access=free}}</ref> The largest-known ''Paranthropus'' individual was estimated at {{cvt|54|kg}}.<ref name=McHenry1991a>{{cite journal|first=H. M.|last=McHenry|author-link=Henry McHenry (anthropologist)|year=1991|title=Petite bodies of the "robust" australopithecines|journal=American Journal of Physical Anthropology|volume=86|issue=4|pages=445–454|doi=10.1002/ajpa.1330860402}}</ref>

According to a 1991 study, based on [[femur]] length and using the dimensions of modern humans, male and female ''P. robustus'' are estimated to have stood on average {{cvt|132|and|110|cm|ftin|0}}, respectively, and ''P. boisei'' {{cvt|137|and|124|cm|ftin|0}}. However, the latter estimates are problematic as there were no positively identified male ''P. boisei'' femurs at the time.<ref name=McHenry1991b>{{cite journal|first=H. M.|last=McHenry|author-link=Henry McHenry (anthropologist)|year=1991|title=Femoral lengths and stature in Plio-Pleistocene hominids|journal=American Journal of Physical Anthropology|volume=85|issue=2|pages=149–158|doi=10.1002/ajpa.1330850204|pmid=1882979}}</ref> In 2013, a 1.34 Ma male ''P. boisei'' partial skeleton was estimated to be at least {{cvt|156|cm|ftin|0}} and {{cvt|50|kg}}.<ref name=Dominguez2013>{{cite journal|first1=M.|last1=Domínguez-Rodrigo|first2=T. R.|last2=Rayne|first3=E.|last3=Baquedano|display-authors=et al.|year=2013|title=First Partial Skeleton of a 1.34-Million-Year-Old ''Paranthropus boisei'' from Bed II, Olduvai Gorge, Tanzania|journal=PLOS ONE|volume=8|issue=12|page=e80347|pmc=3855051|pmid=24339873|doi=10.1371/journal.pone.0080347|bibcode=2013PLoSO...880347D|doi-access=free}}</ref>

===Pathology===
''Paranthropus'' seems to have had notably high rates of [[pitting enamel hypoplasia]] (PEH), where [[tooth enamel]] formation is spotty instead of mostly uniform. In ''P. robustus'', about 47% of [[baby teeth]] and 14% of adult teeth were affected, in comparison to about 6.7% and 4.3%, respectively, in any other tested hominin species. The condition of these holes covering the entire tooth is consistent with the modern human ailment [[amelogenesis imperfecta]]. However, since circular holes in enamel coverage are uniform in size, only present on the [[molar teeth]], and have the same severity across individuals, the PEH may have been a genetic condition. It is possible that the [[coding region|coding-DNA]] concerned with thickening enamel also left them more vulnerable to PEH.<ref>{{cite journal|first1=I.|last1=Towle|first2=J. D.|last2=Irish|year=2019|title=A probable genetic origin for pitting enamel hypoplasia on the molars of ''Paranthropus robustus''|journal=Journal of Human Evolution|volume=129|pages=54–61|doi=10.1016/j.jhevol.2019.01.002|pmid=30904040|bibcode=2019JHumE.129...54T |s2cid=85502058|url=http://researchonline.ljmu.ac.uk/id/eprint/10289/1/Towle_Irish_JHE%202019.pdf}}</ref>

There have been 10 identified cases of [[tooth decay|cavities]] in ''P. robustus'', indicating a rate similar to modern humans. A molar from [[Drimolen]], South Africa, showed a cavity on the [[tooth root]], a rare occurrence in fossil [[great ape]]s. In order for cavity-creating bacteria to reach this area, the individual would have had to have also presented either [[alveolar process#Alveolar bone loss|alveolar resportion]], which is commonly associated with [[gum disease]]; or super-eruption of teeth which occurs when teeth become worn down and have to erupt a bit more in order to maintain a proper bite, and this exposed the root. The latter is most likely, and the exposed root seems to have caused [[hypercementosis]] to anchor the tooth in place. The cavity seems to have been healing, which may have been caused by a change in diet or [[oral microbiology|mouth microbiome]], or the loss of the adjacent molar.<ref name=Towle2019>{{cite journal|first1=I.|last1=Towle|first2=A.|last2=Riga|first3=J. D.|last3=Irish|display-authors=et al.|year=2019|title=Root caries on a ''Paranthropus robustus'' third molar from Drimolen|journal=American Journal of Physical Anthropology|volume=170|issue=2|pages=319–323|doi=10.1002/ajpa.23891|pmid=31265762|s2cid=195786562|url=https://www.biorxiv.org/content/biorxiv/early/2019/04/11/573964.full.pdf}}</ref>