With the discovery of more European pliopithecoid fossils in the mid to late 1970s, and subsequent discovery of pliopithecoid fossils in China, the idea that pliopithecoids were ancestral to gibbons fell out of favor. Today, most paleontologists agree that pliopithecoids hold a basal position in the catarrhine family tree. As such, pliopithecoids represent something similar to the common ancestor of Old World monkeys and apes.
A worn tooth found near Haritalyangar in India and dated from around 9 to 8 million years ago has been suggested as possibly a Pliopithecoid species, Krishnapithecus krishnai, but the wear has made this difficult to determine. However, two recently discovered molars in the same area appear to support this, with placement within the superfamily uncertain (but clearly not Crouzeliinae).
The pliopithecoid fossil record mostly consists of teeth with a few mandibular and maxillary fragments. The dental formula (2.1.2.3) and shape of the teeth are the primary factors which include pliopithecoids among the catarrhini. Although some authors have argued that the narrow upper molars and broad upper molars of pliopithecoids demonstrate their affinity with modern catarrhines, others have demonstrated that these traits are variable between species. In fact, pliopithecoids are more similar to New World monkeys in some aspects of their dentition, including narrow lower incisors (mesiodistally waisted towards the base of the crown). Many species have what is often referred to as a 'pliopithecine triangle', a subtle set of ridges defining a small triangular shaped pit between the protocone and hypocone of the lower molars, but even this trait is variable. Instead, the most defining dental trait present in all pliopithecoids is a tall crowned lower third premolar, which is relatively triangular in outline with a comparatively short, vertically oriented mesiobucal face.
Nearly all of what is known about the body proportions and post-cranial morphology of this family are derived from Pliopithecus vindobonensis, as it is the only species for which a complete skeleton has been found. Still, the majority of fossil material indicates that pliopithecoids were medium sized primates, approximately the size of a howler monkey or a gibbon (8 kg). Köhler estimates a slightly higher average weight of 10 kg. Post-cranially, pliopithecoids had an interesting mix of platyrrhine and catarrhine traits. The brachial index of P. vindobonesis (the length of the radius divided by the length of the humerus) is similar to that of a howler monkey, but the crural index (the length of the tibia divided by the length of the femur) is similar to that of a gibbon. Proportionally, however, the forelimbs of P. vindobonesis were shorter than their hindlimbs, making them comparable to a baboon. The hands and feet of P. vindobonesis were long and curved, suggesting that pliopithecoids were adept and agile climbers. The post-crania of P. vindobonesis also shows that Pliopithecoids had an entepicondylar foramen, which is a primitive trait not found in any other catarrhine primates (extant or extinct). The wrist and hands of pliopithecoids were seemingly much more similar to platyrrhines than to catarrhines, as the carpo-metacarpal joint of the thumb is a modified “hinge joint” compared to the "saddle-like" thumb joint found in Old World monkeys and apes. Pliopithecoids also had a tail.
The following classification scheme represents multiple sources.
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Harrison, Terry (2013). Catarrhine Origins. Wiley-Blackwell. https://www.academia.edu/7124992
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Zapfe, Helmuth (1958). "The skeleton of Pliopithecus (Epipliopithecus) vindobonesis Zapfe and Hürzeler". American Journal of Physical Anthropology. 16 (4): 441–457. doi:10.1002/ajpa.1330160405. /wiki/Doi_(identifier)
Ginsburg, Leonard (1975). "Les Pliopithe'ques des faluns helve´tiens de la Touraine et de l'Anjou". Colloques Internationaux du Centre National de la Recherche Scientifique (218): 877–886.
Ginsburg, Leonard; Mein, Pierre (1980). "Crouzelia rhondanica, nouvelle espe'ce de primate catarrhinien, et essai sur la position systématique de Pliopithecidae". Bulletin du Muséum National d'Histoire Naturelle, Paris (4): 57–85.
Li, Chuan-kuei (1978). "A Miocene gibbon-like primate from Shihhung, Kiangsu Province". Vertebrata PalAsiatica (16): 187–192.
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Harrison, Terry (2013). Catarrhine Origins. Wiley-Blackwell. https://www.academia.edu/7124992
Alba, David; Moyà-Solà, Salvador (2012). "A New Pliopithecid Genus (Primates: Pliopithecoidea) From Castel de Barberà (Vallès-Penedès Basin, Catalonia, Spain)". American Journal of Physical Anthropology. 147 (1): 88–112. doi:10.1002/ajpa.21630. PMID 22101732. /wiki/Doi_(identifier)
Köhler, M; Alba, DM; Solà, SM; MacLatchy, L (December 2002). "Taxonomic affinities of the Eppelsheim femur". American Journal of Physical Anthropology. 119 (4): 297–304. doi:10.1002/ajpa.10140. PMID 12448015. /wiki/Doi_(identifier)
Harrison, Terry (2018). "Catarrhine Origins". In Trevathan, Wenda (ed.). The International Encyclopedia of Biological Anthropology. Vol. 1. John Wiley & Sons. pp. 306–311. doi:10.1002/9781118584538.ieba0087. ISBN 978-1-118-58442-2. 978-1-118-58442-2
Sankhyan, Anek; Kelley, Jay; Harrison, Terry (April 2017). "A highly derived pliopithecoid from the Late Miocene of Haritalyangar, India". Journal of Human Evolution. 105: 1–12. Bibcode:2017JHumE.105....1S. doi:10.1016/j.jhevol.2017.01.010. PMID 28366196. /wiki/Bibcode_(identifier)
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Harrison, Terry (2013). Catarrhine Origins. Wiley-Blackwell. https://www.academia.edu/7124992
Harrison, Terry; Gu, Yumin (1999). "Taxonomy and phylogenetic relationships of early Miocene catarrhines from Sihong, China". Journal of Human Evolution. 37 (2): 225–277. Bibcode:1999JHumE..37..225H. doi:10.1006/jhev.1999.0310. PMID 10444352. https://doi.org/10.1006%2Fjhev.1999.0310
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Alba, David; Moyà-Solà, Salvador; Malgosa, Assumpció; Casanovas-Vilar, Isaac; Robles, Josep; Almécija, Sergio; Galindo, Jordi; Rotgers, Cheyenn; Bertó Mengual, Juan Vicente (2010). "A new species of Pliopithecus Gervais, 1849 (Primates: Pliopithecoidea) from the Middle Miocene (MN8) of Abocador de Can Mata (els Hostalets de Pierola, Catalonia, Spain)". American Journal of Physical Anthropology. 141 (1): 52–75. doi:10.1002/ajpa.21114. PMID 19544577. /wiki/Doi_(identifier)
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Harrison, Terry (1987). "The phylogenetic relationships of the early catarrhine primates: a review of the current evidence". Journal of Human Evolution. 16 (1): 41–80. Bibcode:1987JHumE..16...41H. doi:10.1016/0047-2484(87)90060-1. /wiki/Bibcode_(identifier)
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Andrews, Peter; Harrison, Terry; Delson, Eric; Bernor, Raymond; Martin, L (1996). Distribution and Biochronology of European and Southwest Asian Miocene Catarrhines. Columbia University Press. ISBN 0-231-08246-0. 0-231-08246-0
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Harrison, Terry (2013). Catarrhine Origins. Wiley-Blackwell. https://www.academia.edu/7124992
Andrews, Peter; Harrison, Terry; Delson, Eric; Bernor, Raymond; Martin, L (1996). Distribution and Biochronology of European and Southwest Asian Miocene Catarrhines. Columbia University Press. ISBN 0-231-08246-0. 0-231-08246-0
Zapfe, Helmuth (1958). "The skeleton of Pliopithecus (Epipliopithecus) vindobonesis Zapfe and Hürzeler". American Journal of Physical Anthropology. 16 (4): 441–457. doi:10.1002/ajpa.1330160405. /wiki/Doi_(identifier)
Alba, David; Moyà-Solà, Salvador; Robles, Josep M.; Galindo, Jordi (2012). "Brief Communication: The Oldest Pliopithecid Record in the Iberia Peninsula Based on New Material From the Vallès-Penedès Basin". American Journal of Physical Anthropology. 147 (1): 135–140. doi:10.1002/ajpa.21631. PMID 22170401. /wiki/Doi_(identifier)
Köhler, M; Alba, DM; Solà, SM; MacLatchy, L (December 2002). "Taxonomic affinities of the Eppelsheim femur". American Journal of Physical Anthropology. 119 (4): 297–304. doi:10.1002/ajpa.10140. PMID 12448015. /wiki/Doi_(identifier)
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Zapfe, Helmuth (1958). "The skeleton of Pliopithecus (Epipliopithecus) vindobonesis Zapfe and Hürzeler". American Journal of Physical Anthropology. 16 (4): 441–457. doi:10.1002/ajpa.1330160405. /wiki/Doi_(identifier)
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Harrison, Terry (2013). Catarrhine Origins. Wiley-Blackwell. https://www.academia.edu/7124992
Andrews, Peter; Harrison, Terry; Delson, Eric; Bernor, Raymond; Martin, L (1996). Distribution and Biochronology of European and Southwest Asian Miocene Catarrhines. Columbia University Press. ISBN 0-231-08246-0. 0-231-08246-0
Harrison, Terry (1987). "The phylogenetic relationships of the early catarrhine primates: a review of the current evidence". Journal of Human Evolution. 16 (1): 41–80. Bibcode:1987JHumE..16...41H. doi:10.1016/0047-2484(87)90060-1. /wiki/Bibcode_(identifier)
Begun, David (2002). The Pliopithecoidea (PDF). Cambridge University Press. ISBN 0-521-66315-6. Archived from the original (PDF) on 2011-09-25. Retrieved 2016-02-09. 0-521-66315-6
Andrews, Peter; Harrison, Terry; Delson, Eric; Bernor, Raymond; Martin, L (1996). Distribution and Biochronology of European and Southwest Asian Miocene Catarrhines. Columbia University Press. ISBN 0-231-08246-0. 0-231-08246-0
P. piveteaui is considered a junior synonym of P. antiquus (Bergounioux and Crouzel, 1965; Harrison, 1991; Andrews et al., 1996), and as a distinct species by Begun (2002).
Ginsburg (1975) and Moyá-Solá et al. (2001) recognize P. auscitanensis and P. rhodancia as a distinct genus, Crouzelia.
Ginsburg (1975) and Moyá-Solá et al. (2001) recognize P. auscitanensis and P. rhodancia as a distinct genus, Crouzelia.
P. priensis is placed into Pliopithecus by Andrews et al. (1996) and Moyá-Solá et al. (2001), but it has since been moved into Pleisopliopithecus by Begun (2002) and Harrison (2013)
Ji, Xueping; Harrison, Terry; Zhang, Yingqi; Wu, Yun; Zhang, Chunxia; Hu, Jinming; Wu, Dongdong; Hou, Yemao; Li, Song; Wang, Guofu; Wang, Zhenzhen (2022). "The earliest hylobatid from the Late Miocene of China". Journal of Human Evolution. 171: 103251. Bibcode:2022JHumE.17103251J. doi:10.1016/j.jhevol.2022.103251. ISSN 0047-2484. PMID 36113226. https://doi.org/10.1016%2Fj.jhevol.2022.103251
Harrison, Terry (2018). "Catarrhine Origins". In Trevathan, Wenda (ed.). The International Encyclopedia of Biological Anthropology. Vol. 1. John Wiley & Sons. pp. 306–311. doi:10.1002/9781118584538.ieba0087. ISBN 978-1-118-58442-2. 978-1-118-58442-2