A basal phiomorph (Rodentia, Hystricognathi) from the late Eocene of the Fayum Depression, Egypt
The fossil record of phiomorph hystricognathous rodents from the Afro-Arabian Paleogene is important for understanding the origins and dispersal routes of the early crown hystricognaths. Here, we describe a “new” basal phiomorph genus and species, Acritophiomys bowni, based on complete upper and lower dentitions, mandibular fragments, and partial crania from the terminal late Eocene (~34 Ma) Locality 41 (L-41) in the Fayum Depression of northern Egypt. Acritophiomys bowni is the oldest and largest representative of the family “Phiomyidae”, being more or less the same size as contemporaneous gaudeamurids, and is one of the most abundant hystricognaths at L-41. The genus exhibits a mosaic of primitive and derived features, the former shared with primitive hystricognaths, such as Waslamys and Protophiomys from the earliest late Eocene, and the latter shared with Metaphiomys from early Oligocene (~31–29 Ma) sites in the upper sequence of the Jebel Qatrani Formation. Phylogenetic analysis of craniodental features, scored across a number of different hystricognathous groups, consistently places Acritophiomys bowni and members of the genus Phiomys as basal members of the phiomorph stem lineage, implying that the commonly used family “Phiomyidae” is a paraphyletic assemblage. Among other things, this material shows that basal members of the phiomorph clade consistently replaced dP4/4 with permanent P4/4, and suggests an African origin of stem and crown Phiomorpha.
KeywordsAfrica Oligocene Phiomyidae Phiomys Dur at-Talah
Egyptian Geological Museum, Egypt
Duke Lemur Center Division of Fossil Primates
Premolar, followed by superscript and subscript numbers, referring to upper and lower tooth loci (respectively)
Molar, followed by superscript and subscript numbers, referring to upper and lower tooth loci (respectively)
The fourth upper deciduous premolar; the lowercase letter d is used to designate a premolar as deciduous
Recent palaeontological fieldwork in the Fayum area has been funded by U.S. National Science Foundation grants BCS-0416164 to E.L.S. and E.R.S. and BCS-0819186 to E.R.S. Additional funding was provided by Gordon and Ann Getty, The Research Foundation of S.U.N.Y., and by grants from The Leakey Foundation to E.R.S. H.M.S. was funded by a scholarship from the Egyptian Government and a Baldwin Fellowship from The Leakey Foundation. M. Shahin assisted with phylogenetic analyses. J. Groenke and V. Heisey (Stony Brook University) assisted with preparation. We thank the staff of the Egyptian Mineral Resources Authority and the Egyptian Geological Survey for facilitating our work in the Fayum area. Fieldwork in Egypt was managed by P. Chatrath (Duke Lemur Center). We also thank P. Holroyd for her earlier work on Fayum rodents. We thank H. De Bruijn and L. Marivaux for casts. This is Duke Lemur Center publication number 1216.
- Antoine, P., Marivaux, L., Croft, D. A., Billet, G., Ganerød, M., Jaramillo, C., et al. (2011). Middle Eocene rodents from Peruvian Amazonia reveal the pattern and timing of caviomorph origins and biogeography. Proceedings of the Royal Society B. doi: 10.1098/rspb.2011.1732.
- Coster, P., Benammi, M., Lazzari, V., Billet, G., Martin, T., Salem, M., Bilal, A. A., Chaimanee, Y., Schuster, M., Valentin, X., Brunet, M., & Jaeger, J. -J. (2010). Gaudeamus lavocati sp. nov. (Rodentia, Hystricognathi) from the early Oligocene of Zallah, Libya: first African caviomorph? Naturwissenschaften, 97, 697–706.Google Scholar
- Ducrocq, S., Boisserie, J.-R., Tiercelin, J.-J., Delmer, C., Garcia, G., Manthi, F. K., et al. (2010). New Oligocene vertebrate localities from Northern Kenya (Turkana Basin). Journal of Vertebrate Paleontology, 30(1), 293–299.Google Scholar
- Holroyd, P. A. (1994). An examination of dispersal origins for Fayum Mammalia. Ph.D. Durham, North Carolina: Duke University.Google Scholar
- Jaeger, J., Denys, C., & Coiffait, B. (1985). New Phiomorpha and Anomaluridae from the late Eocene of north-west Africa: Phylogenetic implications. In W. P. L. J.-L. Hartenberger (Ed.), Evolutionary Relationships among Rodents—A Multidisciplinary Analysis (pp. 567–588). New York: Plenum Press.Google Scholar
- Jaeger, J.-J., Marivaux, L., Salem, M., Bilal, A. A., Benammi, M., Chaimanee, Y., et al. (2010). New rodent assemblages from the Eocene Dur At-Talah escarpment (Sahara of central Libya): systematic, biochronological, and palaeobiogeographical implications. Zoological Journal of the Linnean Society, 160, 195–213.Google Scholar
- Lavocat, R. (1973). Les Rongeurs du Miocène d’Afrique Orientale. Montpellier: Mémoires et Travaux de l’Institut de Montpellier de l’École Pratique des Hautes Études.Google Scholar
- Lewis, P. J., & Simons, E. L. (2006). Morphological trends in the molars of fossil rodents from the Fayum Depression, Egypt. Palaeontology Africa, 42, 37–42.Google Scholar
- Marivaux, L., Adaci, M., Bensalah, M., Rodrigues, H. G., Hautier, L., Mahboubi, M. h., Mebrouk, F., Tabuce, R., & Vianey-Liaud, M. (2011). Zegdoumyidae (Rodentia, Mammalia), stem anomaluroid rodents from the Early to Middle Eocene of Algeria (Gour Lazib, Western Sahara): new dental evidence. Journal of Systematic Palaeontology, 9(4), 563–588.Google Scholar
- Osborn, H. F. (1908). New fossil mammals from the Fayûm Oligocene of Egypt. Bulletin of the American Museum of Natural History, 24, 265–272.Google Scholar
- Patterson, B., & Wood, A. E. (1982). Rodents from the Deseadan Oligocene of Bolivia and the relationships of the Caviomorpha. Bulletin of the Museum of Comparative Zoology, 149, 371–543.Google Scholar
- Pickford, M., Sawada, Y., Senut, B. (2011). Geochronology and palaeontology of the Palaeogene deposits in the Sperrgebiet, Namibia. pp. 129–130 in 122nd International Senckenberg Conference: “The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment and the History of Early Primates”, T. Lehmann and S. F. K. Schaal (Eds). Senckenberg Gesellschaft für Naturforschung, Frankfurt.Google Scholar
- Pickford, M., Senut, B., Morales, J., Mein, P., & Sánchez, I. M. (2008). Mammalia from the Lutetian of Namibia. Memoir of the Geological Survey of Namibia, 20, 465–514.Google Scholar
- Rasmussen, D. T., & Gutierrez, M. (2009). A Mammalian Fauna from the Late Oligocene of Northwestern Kenya. Palaeontographica Abteilung A, 288, 52.Google Scholar
- Sallam, H., Seiffert, E. R., Steiper, M. E., Simons, E. L. (2009). Fossil and molecular evidence constrain scenarios for the early evolutionary and biogeographic history of hystricognathous rodents. Proceedings of the National Academy of Sciences, United States of America, 106, 16722–16727.Google Scholar
- Sallam, H. M., Seiffert, E. R., Simons, E. L. (2011). Craniodental morphology and systematics of a new family of Hystricognathous Rodents (Gaudeamuridae) from the Late Eocene and Early Oligocene of Egypt. PLoS ONE 6(2). doi: 10.1371/journal.pone.0016525.
- Schlosser, M. (1910). Uber einige fossile Saugetiere aus dem Oligocan von Agypten. Zoologischer Anzeiger, 35, 500–508.Google Scholar
- Schlosser, M. (1911). Beitrage zur Kenntnis der oligozanen Landsaugetiere aus dem Fayum, Agypten. Beitrage zur Palaeontologie und Geologie Osterreich-Ungarns und des Orients, 24, 51–167.Google Scholar
- Seiffert, E. R. (2010). Chronology of Paleogene mammal localities. In L. Werdelin & W. J. Sanders (Eds.), Cenozoic Mammals of Africa. Berkeley: University of California Press.Google Scholar
- Seiffert, E. R., Bown, T. M., Clyde, W. C., Simons, E. L. (2008). Geology, paleoenvironment, and age of Birket Qarun Locality 2 (BQ-2), Fayum Depression, Egypt. In: J. G. Fleagle, C. C. Gilbert (Eds.), Elwyn L. Simons: A Search for Origins. Springer, New York, pp 71–86.Google Scholar
- Swofford, D. L. (1998). PAUP* Phylogenetic Analysis Using Parsimony (*and Other Methods), Version 4. Sunderland, MA: Sinauer Associates.Google Scholar
- Winkler, A. J., MacLatchy, L., Mafabi, M. (2005). Small rodents and a Lagomorph from the Early Miocene Bukwa Locality, Eastern Uganda. Palaeontologia Electronica 8(1), 24A:12p.Google Scholar
- Wood, A. E. (1955). A revised classification of the rodents. Journal of Mammalogy 36(2), 165–187.Google Scholar
- Wood, A. E. (1968). Early Cenozoic mammalian faunas, Fayum Province, Egypt, Part II: the African Oligocene Rodentia. Peabody Musuem Bulletin, 28, 23–205.Google Scholar