title: Djebelemur, a tiny pre-tooth-combed primate from the Eocene of Tunisia: a glimpse into the origin of crown strepsirhines.
abstract: BACKGROUND
  Molecular clock estimates of crown strepsirhine origins generally advocate an ancient antiquity for Malagasy lemuriforms and Afro-Asian lorisiforms, near the onset of the Tertiary but most often extending back to the Late Cretaceous. Despite their inferred early origin, the subsequent evolutionary histories of both groups (except for the Malagasy aye-aye lineage) exhibit a vacuum of lineage diversification during most part of the Eocene, followed by a relative acceleration in diversification from the late Middle Eocene. This early evolutionary stasis was tentatively explained by the possibility of unrecorded lineage extinctions during the early Tertiary. However, this prevailing molecular view regarding the ancient origin and early diversification of crown strepsirhines must be viewed with skepticism due to the new but still scarce paleontological evidence gathered in recent years.
  Here, we describe new fossils attributable to Djebelemur martinezi, a≈50 Ma primate from Tunisia (Djebel Chambi). This taxon was originally interpreted as a cercamoniine adapiform based on limited information from its lower dentition. The new fossils provide anatomical evidence demonstrating that Djebelemur was not an adapiform but clearly a distant relative of lemurs, lorises and galagos. Cranial, dental and postcranial remains indicate that this diminutive primate was likely nocturnal, predatory (primarily insectivorous), and engaged in a form of generalized arboreal quadrupedalism with frequent horizontal leaping. Djebelemur did not have an anterior lower dentition as specialized as that characterizing most crown strepsirhines (i.e., tooth-comb), but it clearly exhibited a transformed antemolar pattern representing an early stage of a crown strepsirhine-like adaptation ("pre-tooth-comb").
  
  
  CONCLUSIONS
  These new fossil data suggest that the differentiation of the tooth-comb must postdate the djebelemurid divergence, a view which hence constrains the timing of crown strepsirhine origins to the Middle Eocene, and then precludes the existence of unrecorded lineage extinctions of tooth-combed primates during the earliest Tertiary.
authors: Laboratoire de Paléontologie, Institut des Sciences de l'Évolution de Montpellier (ISE-M, UMR-CNRS 5554), Université Montpellier 2, Montpellier, France.
authors: Laurent
authors: L
authors: Marivaux
authors: Anusha
authors: A
authors: Ramdarshan
authors: El Mabrouk
authors: el M
authors: Essid
authors: Wissem
authors: W
authors: Marzougui
authors: Hayet
authors: H
authors: Khayati Ammar
authors: Renaud
authors: R
authors: Lebrun
authors: Bernard
authors: B
authors: Marandat
authors: Gilles
authors: G
authors: Merzeraud
authors: Rodolphe
authors: R
authors: Tabuce
authors: Monique
authors: M
authors: Vianey-Liaud
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D053476:Extinction, Biological; D005580:Fossils; D006801:Humans; D007901:Lemuridae / Q000033:anatomy & histology / Q000145:classification* / Q000502:physiology; D008142:Lorisidae / Q000033:anatomy & histology / Q000145:classification* / Q000502:physiology; D010802:Phylogeny; D014070:Tooth / Q000033:anatomy & histology* / Q000502:physiology; D014416:Tunisia