The evolution of the old world proboscieeans during the late Neogene.

• Project/Area Number: 17540445
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: University of Hyogo
• Principal Investigator: SAEGUSA Haruo University of Hyogo, Institute of natural and environmental sciences, Assistant professor (70254456)
• Project Period (FY): 2005 – 2007
• Project Status: Completed (Fiscal Year 2007)
• Budget Amount: ¥3,710,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥210,000); Fiscal Year 2007: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
• Keywords: Late Miocene / Proboscidea / phylogeny / masticaiton / elephantidae / Anancus / Steeodon / Sinomastodon / 中新世 / 分類学 / テトラフォドン類 / ゴンフォテリウム類 / 骨格 / タイ / 咬耗面 / 機能形態 / テトラロフォドン類 / ケニア:エチオピア:タイ

Research Abstract

In order to illuminate the impact of the late Neogene climatic change on the proboscidean evolution in the realm of the Old World 1) the phylogenetic relationship among the late Neogene probosideans, mainly early elephants, stegdons and sinomasotodons and 2) the grazer /browser habit in those proboscideans are investigated. The new finding of the early proboscideans from the Nakali, Kenya, Middle Awash Ethiopia, Nakhon. Ratchasima, and Myanmar, confirmed the monophyly of the Stegodontidae negating previously supposed sister group relationship between stegodons and early elephants. In the Irrawaddy Group, nearly continuous evolutionary transition from the Stegolophodon to early stegodon is recognized. On the other hand, the earliest example of the elephantids are found from Nakali, which suggest close kinship with tetralophoodons.
The function of the late Neogene gomphotheres, Anancus and Sinomastodon, suggest some of them accomplished the grazing function of their molars by means of the complication of the crown structure, and some of them dominate the early elephants and stegodonts in the grazer guild at the begging of the Pliocene. Later those grazing gomphotheres are declined, presumably defeated by the later elephants which has rapidly increased the efficiency of the horizontal shearing blade of the molar by means of the increase of the lophid number. Propalinal jaw movements appears to have facilitated such rapid evolution. On the other hand, stegodon remains extreme brachiodonty thorough out their history with the minor exception seen in the island dwarf forms.

Research Products

• [Journal Article] New late Miocene elephantoid(Mammalia:Proboscidea) fossils from Lemudong'o, Kenya (2007)
  • Author(s): Saegusa H and Hlusko LJ.
  • Journal Title: Kirtlandia 56 Pages: 140-147
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] New late Miocene elephantoid(Mamnialia:Proboscidea)fossils from Lemudong'o,Kenya (2007)
  • Author(s): Saegusa, H. and Hlusko L.J.
  • Journal Title: Kirtlandia 56 Pages: 140-147
  • Peer Reviewed
• [Journal Article] A new Late Miocene great ape from Kenya and its implications for the origins of African great apes and humans (2007)
  • Author(s): Kunimatsu, Y., et. al.
  • Journal Title: Proceedings of the National Academy of Sciences 104 Pages: 19220-19225
  • Peer Reviewed
• [Journal Article] The paleoecology an paleogeographic conteXt of Lemudong'o,Locality 1,a late Miocene terrestrial fossil site in southern Kenya (2007)
  • Author(s): Ambrose, H.S., et. al.
  • Journal Title: Kirtlandia 56 Pages: 38-52
  • Peer Reviewed
• [Journal Article] Relationships within the Elephantinae using hyoid characters. (2007)
  • Author(s): Shoshani, J.
  • Journal Title: Quaternary International 169-170 Pages: 174-185
  • Peer Reviewed
• [Journal Article] Asa Issie,Aramis and the origin of Australopithecus (2006)
  • Author(s): White, T.D., WoldeGabriel, G., Asfaw, B., Ambrose, S., Beyene, Y., Bernor, R.L., Boisserie, J.-R., Currie, B., Gilbert, H., Haile-Selassie, Y., Hart, W.K., Hlusko, L.J., Howell, F.C., Kono, R.T., Lehmann, T., Louchart, A., Lovejoy, C.W., Renne, P.R., Saegusa, H., Vrba, E.S., Wesselman, H., &Suwa, G.
  • Journal Title: Nature 440 Pages: 883-889
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] Asa Issie, Aramis and the origin of Australopithecus (2006)
  • Author(s): White, T. D., WoldeGabriel, G., Asfaw, B., Ambrose, S., Beyene, Y., Bernor, R. L., Boisserie, J.-R., Currie, B., Gilbert, H., Haile-Selassie, Y., Hart, W. K., Hlusko, L. J., Howell, F. C., Kono, R. T., Lehmann, T., Louchart, A., Lovejoy, C. W., Renne, P. R., Saegusa, H., Vrba, E. S., Wesselman, H., Suwa, G
  • Journal Title: Nature 440 Pages: 883-889
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] New late Miocene elephantoid(Mammalia : Proboscidea) fossils from Lemudong'o, Kenya (2006)
  • Author(s): Saegusam H, Hluskom, LJ
  • Journal Title: Kirtlandia 56 Pages: 140-147
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Neogene mammalian fauna in Myanmar. (2006)
  • Author(s): Takai, M
  • Journal Title: Asian Paleoprimatology 4 Pages: 143-175
• [Journal Article] 日本産化石長鼻類の系統分類の現状と課題 (2005)
  • Author(s): 三枝 春生
  • Journal Title: 化石研究会会誌 38・2 Pages: 78-89
• [Presentation] Preliminary investigations on the Neogene proboscideans from Myanmar (2006)
  • Author(s): Saegusa, H., Thaung-Htike, Zin-Maung-Maung-Thein, Takai, M., Chit Sein
  • Organizer: 日本地質学会第113年学術大会
  • Place of Presentation: 高知大学,高知市
  • Year and Date: 2006-09-17
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] Preliminary investigations on the Neogene proboscideans (2006)
  • Author(s): Saegusa, H., Thaung-Htike, Zin-Maung-Maun-Thein, Takai, M., Chit, Sein
  • Organizer: The 113th Annual Meeting of the Geological Society of Japan
  • Place of Presentation: Kochi
  • Year and Date: 2006-09-17
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] ケニア,ナカリ産の最初期ゾウ科化石(演旨) (2006)
  • Author(s): 三枝 春生、仲谷 英夫、国松 豊、中務 真人、辻川 寛
  • Organizer: 日本古生物学会2006年年会
  • Place of Presentation: 島根大学,島根市
  • Year and Date: 2006-06-24
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] Earliest elephantid remains from Nakali, Kenya (2006)
  • Author(s): Saegusa, H., Nakaya, H., Kunimatsu, Y., Nakatsukasa, M., Tsujikawa, H
  • Organizer: The 2006 Annual Meeting of the Palaeontological Society of Japan
  • Place of Presentation: Matsue
  • Year and Date: 2006-06-24
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Jaw movements and the wear facets of proboscideans (2005)
  • Author(s): Saegusa H.
  • Organizer: 9th International Mammalogical Congress
  • Place of Presentation: Sapporo,Japan
  • Year and Date: 2005-08-04
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] Jaw movement and the wear facets of proboscideans (2005)
  • Author(s): Saegusa, H
  • Organizer: 9th International Mammalogical Congress
  • Place of Presentation: Sapporo
  • Year and Date: 2005-08-04
  • Description: 「研究成果報告書概要(欧文)」より