title: Gaudeamus lavocati sp. nov. (Rodentia, Hystricognathi) from the early Oligocene of Zallah, Libya: first African caviomorph?
abstract: A new African species of hystricognathous rodent, Gaudeamus lavocati sp. nov., is described herein from the early Oligocene deposits of Zallah locality (Sirt basin, Central Libya). The dental morphology of this species is very close to that of some earliest South American caviomorphs. It allows a reinterpretation of molar crest homologies among earliest caviomorphs, pentalophodonty being confirmed as the plesiomorphic molar condition in Caviomorpha. This morphological resemblance argues for close affinities between Gaudeamus and earliest South American hystricognaths. Cladistic analysis supports Gaudeamus lavocati sp. nov. as the first known African representative of Caviomorpha, implying that its ancestors were part of the African phiomyid group that crossed the South Atlantic by a direct immigration route. Alternatively, the series of derived dental features of Gaudeamus could also be interpreted as evolutionary synchronous convergences of an African hystricognath lineage towards the specialized pattern of some caviomorphs. However, the high level of similarities concerning teeth morphology and enamel microstructure and the similar age of fossiliferous strata on both continents make this interpretation less probable. The phylogenetic position of this taxon is of considerable importance because it represents an enigmatic component of the phiomorph-caviomorph radiation in Africa and appears as a new clue toward the understanding of caviomorph origins.
authors.affiliation: Institut International de Paléoprimatologie, Paléontologie Humaine: Evolution et Paléoenvironnements (iPHEP), UMR-CNRS 6046, Université de Poitiers UFR SFA, 40 avenue du Recteur Pineau, 86022, Poitiers Cedex, France. pauline.coster@univ-poitiers.fr
authors.forename: Pauline
authors.initials: P
authors.lastname: Coster
authors.forename: Mouloud
authors.initials: M
authors.lastname: Benammi
authors.forename: Vincent
authors.initials: V
authors.lastname: Lazzari
authors.forename: Guillaume
authors.initials: G
authors.lastname: Billet
authors.forename: Thomas
authors.initials: T
authors.lastname: Martin
authors.forename: Mustafa
authors.initials: M
authors.lastname: Salem
authors.forename: Awad Abolhassan
authors.initials: AA
authors.lastname: Bilal
authors.forename: Yaowalak
authors.initials: Y
authors.lastname: Chaimanee
authors.forename: Mathieu
authors.initials: M
authors.lastname: Schuster
authors.forename: Xavier
authors.initials: X
authors.lastname: Valentin
authors.forename: Michel
authors.initials: M
authors.lastname: Brunet
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Jaeger
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D003817:Dentition; D017753:Ecosystem; D004641:Emigration and Immigration; D008002:Libya; D012377:Rodentia / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics; D013020:South America