New Oligocene primate from Saudi Arabia and the divergence of apes and Old World monkeys

Abstract

It is widely understood that Hominoidea (apes and humans) and Cercopithecoidea (Old World monkeys) have a common ancestry as Catarrhini deeply rooted in Afro-Arabia. The oldest stem Catarrhini in the fossil record are Propliopithecoidea, known from the late Eocene to early Oligocene epochs (roughly 35-30 Myr ago) of Egypt, Oman and possibly Angola. Genome-based estimates for divergence of hominoids and cercopithecoids range into the early Oligocene; however, the mid-to-late Oligocene interval from 30 to 23 Myr ago has yielded little fossil evidence documenting the morphology of the last common ancestor of hominoids and cercopithecoids, the timing of their divergence, or the relationship of early stem and crown catarrhines. Here we describe the partial cranium of a new medium-sized (about 15-20 kg) fossil catarrhine, Saadanius hijazensis, dated to 29-28 Myr ago. Comparative anatomy and cladistic analysis shows that Saadanius is an advanced stem catarrhine close to the base of the hominoid-cercopithecoid clade. Saadanius is important for assessing competing hypotheses about the ancestral morphotype for crown catarrhines, early catarrhine phylogeny and the age of hominoid-cercopithecoid divergence. Saadanius has a tubular ectotympanic but lacks synapomorphies of either group of crown Catarrhini, and we infer that the hominoid-cercopithecoid split happened later, between 29-28 and 24 Myr ago.

H3.5 is a novel hominid-specific histone H3 variant that is specifically expressed in the seminiferous tubules of human testes

“…Since we assumed that selective pressure on duplicated H3 variant genes could deviate from their ancestral counterparts, we calculated substitution rates for the coding regions of various H3 variants using the distance matrix calculated for phylogenetic analyses and divergence times for Catarrhines as mentioned in (Zalmout et al 2010). Interestingly, the substitution rate for H3F3B in human, chimpanzee and orangutan is relatively low (0,12-0,20%/ Myr), whereby we calculated slightly elevated rates for H3F3C (0,15-0,29%/Myr).…”

Examining Phylogenetic Relationships Among Gibbon Genera Using Whole Genome Sequence Data Using an Approximate Bayesian Computation Approach

“…These ranges take into account the uncertainty we have with regard ape speciation times and ancestral diversity. Thirty million years sits at the upper end of the range when apes are thought to have diverged from other old world monkeys (ZALMOUT et al 2010). The earliest known "sub-species" split times observed in great apes is ~80kya (western and cross river gorilla), while the earliest known "species" split time (which is what our gibbon data essentially is) is 175kya (western and eastern gorillas), with most being much older (on the order of millions of years) (PRADO-MARTINEZ et al 2013).…”

Hippos stem from the longest sequence of terrestrial cetartiodactyl evolution in Africa

“…Discoveries of such deposits most often provide important evidence for the evolutionary history of mammals, in particular for primates [12][13][14] . And yet, despite several new early to late Oligocene sites found during the last decade 12,[15][16][17][18][19] , the anthracothere diversity of Paleogene AraboAfrica remained as described by Schmidt 20 and revised by Ducrocq 21 for the Fayum depression: four species of Bothriogenys and one of Qatraniodon 22 .…”