CAJ | 학술논문

2007年,中国地质调查局成都地质调查中心云南1∶5万区域地质调查项目组在距罗平县城东南15 km的罗雄镇大洼子村附近中三叠统关岭组二段地层中发现了罗平生物群。罗平生物群目前已经发现有海生爬行类、鱼类、节肢动物、棘皮动物、菊石、双壳、腹足类、腕足类、植物等十多个大类的化石,完好地体现了当时海洋生物的多样性,是目前已知化石分异度最高的三叠纪海生化石库之一。根据含化石地层中发现的微体化石牙形石Nicoraella Kockeli带,确认罗平生物群时代为中三叠世安尼期Pelsonian亚期。罗平生物群目前发现的海生爬行类种类丰富,基本涵盖了三叠纪时期主要的海生爬行类别,包括鱼龙类、鳍龙类、原龙类以及初龙类。中生代是对海生爬行类至关重要的时期。由于一直没有发现它们留下的遗迹化石,它们的运动模式还一直存在争议。云南罗平生物群海生爬行类研究中发现数百枚保存完好的幻龙类足迹——罗平双桨迹Dikoposichnus luopingensis,为研究其运动模式提供了直接的证据。另外罗平生物群中巨型捕食者张氏幻龙Nothosaurus zhangi的发现也支持了罗平双桨迹造迹者的存在。张氏幻龙拥有三叠纪世界上最大的头骨,这些处于食物链顶层的海生爬行类的繁盛说明当时生态系统已经很完善,代表了二叠纪末生物大灭绝之后海洋生态系统的全面复苏。
2007년,중국지질조사국성도지질조사중심운남1∶5만구역지질조사항목조재거라평현성동남15 km적라웅진대와자촌부근중삼첩통관령조이단지층중발현료라평생물군。라평생물군목전이경발현유해생파행류、어류、절지동물、극피동물、국석、쌍각、복족류、완족류、식물등십다개대류적화석,완호지체현료당시해양생물적다양성,시목전이지화석분이도최고적삼첩기해생화석고지일。근거함화석지층중발현적미체화석아형석Nicoraella Kockeli대,학인라평생물군시대위중삼첩세안니기Pelsonian아기。라평생물군목전발현적해생파행류충류봉부,기본함개료삼첩기시기주요적해생파행유별,포괄어룡류、기룡류、원룡류이급초룡류。중생대시대해생파행류지관중요적시기。유우일직몰유발현타문류하적유적화석,타문적운동모식환일직존재쟁의。운남라평생물군해생파행류연구중발현수백매보존완호적환룡류족적——라평쌍장적Dikoposichnus luopingensis,위연구기운동모식제공료직접적증거。령외라평생물군중거형포식자장씨환룡Nothosaurus zhangi적발현야지지료라평쌍장적조적자적존재。장씨환룡옹유삼첩기세계상최대적두골,저사처우식물련정층적해생파행류적번성설명당시생태계통이경흔완선,대표료이첩기말생물대멸절지후해양생태계통적전면복소。
The Luoping Biota was discovered in 2007 by the Chengdu Center of China Geological Survey during 1:50000 regional mapping works at Dawazi Village, Luoxiong Town, 15 km southeast of Luoping City, Yunnan Province. The interval containing the Luoping biota is the middle to upper part of Member II of the Guanling Formation. The fossil assemblage of the Luoping biota is a mixture of marine animals, terrestrial plants and a few terrestrial animals. To date, more than ten fossil groups have been recovered, which include marine reptiles, fishes, arthropods, echinoderms, ammonites, bivalves, gastropods, lingulid brachiopods, foraminifers, and plants. The Luoping Biota is one of the most diverse Triassic marine fossil Lagerst?tten records in the world. The age of the Luoping biota is assigned to the Pelsonian Substage of the Middle Triassic Anisian Stage based on the index conodontNicoraella Kockeli. Well-preserved, diverse marine reptiles are one of the highlights of the Luoping biota, including ichthyosaurs, sauropterygians, protorosaurs and archosauromorphs. Mesozoic is remarkable for marine reptiles, whose swimming modes, however, remain a topic of much controversy because of the absence of their tracks. Hundreds of seabed tracks found in Luoping Biota, which were assigned toDikoposichnus luopingensis, provide new materials for the study of their locomotive mode. Besides, the macropredator Nothosaurus zhangireported from Luoping Biota also supports the existence of the makers ofDikoposichnus luopingensis. The skull ofNothosaurus zhangi is the largest sauropterygian ever reported in Triassic. The occurrence of a different assemblage of marine reptiles as top predators in the food web indicates a well developed marine ecosystem, showing full rebuilding of the marine ecosystem after the mass extinction that happened about 250 million years ago.