Japan Geoscience Union Meeting 2016

Presentation information


Symbol B (Biogeosciences) » B-PT Paleontology

[B-PT06] Phanerozoic biodiversity change: Extinction and diversification

Thu. May 26, 2016 10:45 AM - 12:15 PM 301A (3F)

Convener:*Yukio Isozaki(Department of Earth Science and Astronomy, Multi-disciplinary Sciences - General Systems Studies, Graduate School of Arts and Sciences, The University of Tokyo), Yusuke Sawaki(Tokyo Institute of Technology), Chair:Yusuke Sawaki(Tokyo Institute of Technology)

10:45 AM - 11:00 AM

[BPT06-01] Do we have any evidence of the existence of bilaterian animals in the Ediacaran? New trace fossil data from the Ediacaran of western Mongolia

*Tatsuo Oji1, Stephen Dornbos2, Keigo Yada3, Hitoshi Hasegawa1, Sersmaa Gonchigdorj5,4, Takafumi Mochizuki5 (1.Nagoya University Museum, Nagoya University, 2.University of Wisconsin-Milwaukee, 3.Graduate School of Environmental Sciences, Nagoya University, 4.Mongolian University of Science and Technology, 5.Iwate Prefectural Museum)

Keywords:Ediacaran, bilaterians, Mongolia

Although a lot of arguments exist as to the existance or absence of bilaterians in the Ediacaran, no conclusive evidence has so far been obtained. There are a variety of trace fossils from the Ediacaran, but no deeply penetrative, or U-shape burrows have been discovered. Therefore, these Ediacaran traces should be made by protozoans or cnidarians. We found vertically penetrative burrows, presumably assigned to Arenicolites, from multiple horizons of the upper Ediacaran of western Mongoliia. These presumably have U-shape form, and the animal that lived in the burrow should have longitudinally elongate form, probably assignable to bilaterian animals. Mongolia was located in low-lattitudinal area in the late Ediacaran, and animal evolution is thus thought to have proceeded earlier than other areas.