Around 39 million years ago (late middle Eocene, ~Bartonian stage), much of what is now the Sahara Desert in North Africa, including parts of modern Libya, supported a significantly greener, more humid environment than today—not a hyper-arid desert.

While there are no ultra-high-resolution global climate model simulations focused exclusively on the exact Sahara region at ~39 Ma, multiple lines of paleoclimate and paleoenvironmental evidence from sedimentology, fossils, and broader Eocene climate studies confirm a much greener, more humid North African landscape.

The Eocene-Oligocene Transition (EOT), also known as the Eocene-Oligocene extinction event or “Grande Coupure” in Europe, occurred around 34 million years ago (roughly 33.9–33.4 Ma). It marked one of the most significant climatic shifts of the Cenozoic era: the transition from a warm “greenhouse” world to a cooler “icehouse” world.

At ~39 Ma (late middle Eocene, as in Dur At-Talah), North Africa was warmer and wetter, with fluvial-deltaic systems, wetlands, and vegetation supporting diverse mammals and early anthropoid primates.

Fossil sites like Dur At-Talah (or Dur At-Talah escarpment) in central Libya provide direct insights. This locality dates to approximately 39–38 million years ago and preserves a diverse fauna including early primates (anthropoids), rodents, fish, and other vertebrates.

The sediments and fossils indicate fluvial (river-related) and deltaic environments, with freshwater fish (e.g., bichirs, catfishes, lungfish, and early representatives of modern African groups like cichlids and tigerfish). This points to rivers, lakes, or wetlands rather than barren desert.

The presence of primates and other mammals suggests forested or woodland habitats capable of supporting a rich ecosystem. North Africa at this time was warmer and wetter overall during the Eocene’s greenhouse climate.

During the Eocene (especially the early to middle part), global temperatures were much higher, with elevated CO₂ levels. Tropical and subtropical forests extended to higher latitudes, and North Africa had more vegetation and moisture. The region wasn’t uniformly “rainforest” everywhere but featured humid, vegetated landscapes with woodlands, savanna-like areas, rivers, and lakes—far greener than the modern Sahara.

This predates the major global cooling and drying around the Eocene-Oligocene transition (~34 Ma), when Antarctica glaciated and arid conditions intensified in many subtropical regions. The Sahara as a persistent desert is a more recent phenomenon (geologically speaking), with the hyper-arid conditions solidifying later in the Miocene and fluctuating since then.

The Sahara has experienced many humid periods since then, including over 230 precession-driven “Green Sahara” or African Humid Periods recurring roughly every ~21,000 years over the past 8+ million years. The most famous is the Holocene one (~11,000–5,000 years ago), when the region had lakes, rivers, grasslands, and human populations.

The user’s figure of 39 million years ago aligns well with paleontological finds from Libyan sites in the Sahara region. These discoveries help show how dynamic North Africa’s climate and landscapes have been over deep time.

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New late middle Eocene anthropoids from Dur At-Talah, Libya: Implications for early primate dispersal into Afro-Arabia

“New late middle Eocene anthropoids from Dur At-Talah, Libya: Implications for early primate dispersal into Afro-Arabia” refers to a brand-new 2026 paper in the Journal of Human Evolution by Jean-Jacques Jaeger and colleagues.

This paper builds directly on the team’s earlier 2010 Nature discovery at the same site, which first revealed a surprisingly diverse early anthropoid community in Africa at ~39–38 Ma (Bartonian, late middle Eocene). The new work refines and expands that picture with additional tiny dental fossils.

Updated Faunal Diversity at Dur At-Talah

Previously known anthropoids from the site:

• Biretia piveteaui — basal parapithecid.
• Talahpithecus parvus — early oligopithecid.
• Afrotarsius libycus — stem eosimiiform (basal anthropoid with Asian affinities).

New contributions:

• Saharopithecus salemi gen. et sp. nov. — Known from two isolated upper molars (holotype: DT2-25, left M²). This is a small primate (~161–270 g estimated body mass) with a distinctive mosaic of dental features.
• Additional material referred to Talahpithecus sp. (larger than T. parvus) and Afrotarsius sp.

This raises the minimum anthropoid diversity at the site to at least four taxa, making Dur At-Talah the most taxonomically diverse Bartonian anthropoid locality known in Afro-Arabia. All were tiny (roughly 120–500+ g), consistent with an early radiation of small-bodied forms.

Phylogenetic and Morphological Insights on Saharopithecus

Saharopithecus occupies an uncertain position but shares molar traits with both proteopithecids (e.g., Proteopithecus from the later Fayum) and propliopithecids (early catarrhines/ape relatives). Its mosaic of primitive (retained from more basal anthropoids) and derived characters (more advanced crown-ward features) is key.

This morphology does not fit neatly into a single African clade. Instead, it suggests independent dispersal events from Asian anthropoid lineages into Afro-Arabia. Asian eosimiiforms and related forms appear to have contributed multiple times, with different groups arriving and diversifying in Africa.

Broader Implications for Primate Dispersal and Origins

Multiple colonization waves:

The diversity (eosimiiforms, parapithecids, oligopithecids, plus this new form with proteopithecid/propliopithecid-like traits) at one locality and time slice strongly favors several independent arrivals from Asia rather than a single influx followed by in-situ African radiation. This aligns with growing evidence of Asian origins or early diversification for basal anthropoids (eosimiids, amphipithecids, etc.).

Timing:

By ~39 Ma, anthropoids had already achieved notable diversity in Afro-Arabia. This pushes back the window for successful trans-oceanic or island-hopping dispersal (likely across the Tethys Sea) and implies earlier undocumented phases of movement.

Biogeographic context:

Dur At-Talah now stands as the oldest well-documented anthropoid community in Afro-Arabia. It predates the richer but younger Fayum deposits (~34–30 Ma) and shows that the later Oligocene explosion built on an already complex Eocene foundation.

Evolutionary filter:

The small body sizes reinforce that early anthropoid evolution occurred among diminutive insectivore-frugivore forms. Larger sizes appeared later in the Eocene/Oligocene.

Paleoenvironmental Tie-In

These primates lived in a humid, fluvial-deltaic landscape with rivers, wetlands, woodlands, and lush vegetation—very different from today’s Sahara. This green setting would have facilitated survival and diversification after dispersal.

Open Questions and Future Directions

The paper highlights gaps:

The African record remains fragmentary, and phylogenetic placements (especially for Afrotarsius and now Saharopithecus) are still debated. More fossils, especially cranial or postcranial material, are needed. Continued work in Libya and other under-explored North African sites is emphasized.

Overall significance:

This discovery strengthens the “Out of Asia” (or at least multiple Asia-to-Africa) model for early higher primates, complicates a simple African cradle narrative, and shows that primate biogeography in the Eocene was more dynamic and multi-route than previously appreciated. It fits into a broader pattern where greenhouse conditions, sea-level fluctuations, and vegetation corridors enabled faunal exchanges between Asia and Afro-Arabia.

Title: New late middle Eocene anthropoids from Dur At-Talah, Libya: Implications for early primate dispersal into Afro-Arabia

Published: Journal of Human Evolution (2026)

DOI: 10.1016/j.jhevol.2026.103843

Authors: JeanJacques Jaeger ^a, Yaowalak Chaimanee, Mouloud Benammi ^a, Laurent Marivaux ^b, Olivier Chavasseau ^a, K. Christopher Beard ^c, Xavier Valentin ^a, Osama Hlal ^d, Awad Bilal ^e, Pauline Coster ^f, Michel Brunet ^a g

Abstract

Eocene anthropoids from Afro-Arabia are central to understanding the early evolutionary history and paleobiogeography of higher primates.

However, the timing and pattern of their initial dispersal into Africa remain debated.

Fossil evidence from several northern African Eocene localities indicates an unexpectedly early diversification of anthropoids, giving rise to two alternative scenarios: a single dispersal of an Asian stem anthropoid followed by rapid in situ radiation or multiple independent dispersals of distinct Asian clades before the late middle Eocene.

The late middle Eocene (∼39–38 Ma) locality of Dur At-Talah, Libya, provides critical evidence for evaluating these hypotheses.

Previously, three anthropoids were reported from the site: Biretia piveteaui (basal parapithecid), Talahpithecus parvus (early oligopithecid), and Afrotarsius libycus (stem eosimiiform).

Here, we describe additional anthropoid materials that reveal greater taxonomic diversity than previously recognized.

We establish a new taxon, Saharopithecus salemi gen. et sp. nov., a morphologically distinctive form of uncertain phylogenetic position that shares molar characters with both proteopithecids and propliopithecids.

Additional specimens are referred to Talahpithecus sp. and Afrotarsius sp., increasing the documented anthropoid diversity at Dur At-Talah to at least four taxa.

The mosaic of primitive and derived dental characters observed in the new taxon supports the hypothesis that multiple Asian anthropoid lineages independently colonized Afro-Arabia by the late middle Eocene.

These findings establish Dur At-Talah as the most taxonomically diverse Bartonian anthropoid locality currently known in Afro-Arabia and highlight the importance of continued paleontological exploration in the region for resolving early anthropoid biogeographic history.