Parapithecus revisited: now a little lemur close to Indri and Dermoptera

A few years ago,
Parapithechus (Fig 1) from the Eocene-Oligocene Fayum of Egypt, nested in the large reptile tree (LRT 2337 taxa) with South American monkeys.

That turns out to have been a mistake on review.
Thank goodness for review. That’s where the real learning takes place.

Today’s revisions
nest Parapithecus with Indri (Fig 1), the lemur closest to the flying lemurs = dermopterans in the LRT. The ‘baby face’ exhibited by Parapithecus appears to be the result of phylogenetic miniaturization as Parapithecus is about half the size of Indri.

None of these taxa (including dermopterans) retain an upper canine.
In Parapithecus the canine alveoli remain, and that would ordinarily score Parapithecus with canines, as it did in 2023. However, considering the other scores and morphologies that link Parapithecus to canine-less taxa, Parapithecus may be showing us the first step toward canine loss in this clade: by losing its canines. Parapithecus also lacks lower incisors (see below). This is rare among primates.

Simons 1995 reported,
“The parapithecids discussed here are a group of anthropoideans that in Africa had reached the “monkey” grade of organization with postorbital closure and metopic and symphyseal fusion.”

Parapithecus grangeri
(Schlosser 1910, Simons 1986, Simons 2001, Eocene-Oligocene 35mya) nesst with Alouatta, the howler monkey, in the LRT. A post-orbital plate and three molars are present. Lower incisors are absent. Note the perforated lateral jugal here and in Indri, convergent with Alouatta from South America.

This removes the earlier tension that linked an Old World primate, Parapithecus, with a New World primate, Alouatta, which arose from Rooneyia and Smilodectes in the LRT. Both are from southern North America.

Athenapub.com reports,
“Comparatively small orbits and size differences in jaws and teeth show that Parapithecus was both diurnal and sexually dimorphic. This is the only specimen of the species that shows (from sockets) that there were four small upper incisors. Several mandibular examples establish that there were no permanent lower incisors and that the symphysis was fused. Like other early anthropoideans this species possessed a smaller cranial capacity and less-developed orbital frontality than later anthropoideans. There is full postorbital closure and fusion of the metopic suture, and the ectotympanic forms a rim to the auditory aperture (Simons 2001).”

“The general cranial anatomy of Parapithecus shows very little similarity to that of Tarsiiformes or to strepsirrhines [lemurs and kin], other than in its comparatively small brain size. Many of the similarities to platyrrhines [New World monkeys] that can be observed are presumably shared primitive features, such as the absence here of a tubular ectotympanic that is known to be absent also in the early catarrhines [Old World monkeys] Catopithecus and Aegyptopithecus. Unlike tarsiers, omomyids and even Aegyptopithecus, the basisphenoid and basioccipital of DPC 18651 are broad, more as in platyrrhines or even Rooneyia.”

“The mosaic nature of the anatomy of this skull, combining as it does a mixture of primitive, platyrrhine and perhaps even catarrhine characteristics would indicate that cited postcranial resemblance to extant catarrhines are also convergent (Simons 2001).”

This appears to be a novel hypothesis of interrelationships.
If not, please provide a citation or cladogram so I can promote it here. Apologies for the earlier errors in which the human filter got in the way.

Housekeeping in the mammal subset of the LRT continues to find and resolve issues like this. Hopefully all the ‘dust’ will be swept out before too long. Freshman naiveté is real. A little more experience is always helpful IMHO.

References
Schlosser M 1911. Beitriige zur Kenntnis der Oligoziinen Landsiiugetiere aus dem Fayum. Beitr. Palaeontol. Geol. Oesterr.-Ung. 24: 51-167.
Seiffert ER, Simons EL, Fleagle JG and Godinot M 2010. Paleogene Anthropoids in (Ed: Werdelin L) Cenozoic Mammals of Africa Chapter 22, 369–392. https://doi.org/10.1525/california/9780520257214.003.0022
Simons EL 1995. Crania of Apidium: Primitive Anthropoidean (Primates, Parapithecidae) from the Egyptian Oligocene. American Museum Novitates 3124:10pp.

wiki/Apidium
wiki/Parapithecus
wiki/Catarrhini
wiki/Platyrrhini
wiki/Aotus
wiki/Alouatta
wiki/Chilecebus

Source: https://pterosaurheresies.wordpress.com/2025/09/12/parapithecus-revisited-now-a-little-lemur-close-to-indri-and-dermoptera/