多國(guó)考古學(xué)家日前通過(guò)研究發(fā)現(xiàn)，在中國(guó)東北部生活過(guò)的恐龍?jiān)?jīng)遭遇嚴(yán)寒天氣,，這也解釋了為什么它們身上都長(zhǎng)有羽毛,。
這項(xiàng)研究匯集了法國(guó)、中國(guó),、日本和泰國(guó)多家機(jī)構(gòu)的考古專家,。研究人員在最新一期美國(guó)《國(guó)家科學(xué)院學(xué)報(bào)》上報(bào)告說(shuō)，恐龍大多生活在中生代,，這一時(shí)期全球氣候比較炎熱,，人們由此推測(cè)，恐龍的生存環(huán)境溫度較高,。不過(guò)該研究小組卻提出了相反的意見(jiàn),。他們?cè)谥袊?guó)遼西熱河生物群所在地展開(kāi)工作，這里曾先后發(fā)現(xiàn)中華龍鳥(niǎo),、尾羽龍和小盜龍等多種“帶毛恐龍”,，其生存的年代大約在1.25億到1.1億年前。由于它們并不會(huì)飛,，因此部分科學(xué)家猜測(cè),，羽毛的作用可能是御寒。
為了證實(shí)上述假設(shè),，考古學(xué)家開(kāi)始設(shè)法確定當(dāng)時(shí)的溫度,。最終，他們通過(guò)測(cè)定雨水中的氧同位素含量,，發(fā)現(xiàn)這一時(shí)期與當(dāng)前中國(guó)北方地區(qū)的氣溫十分相近,，到了冬天，各種生物都要經(jīng)歷嚴(yán)寒的考驗(yàn),，烏龜,、蜥蜴等冷血?jiǎng)游镞x擇冬眠，而哺乳動(dòng)物,、鳥(niǎo)類和恐龍只能依靠自身的羽翼和皮毛維持生存,，這也解釋了為什么這一地區(qū)發(fā)現(xiàn)的恐龍化石伴有羽毛。
科學(xué)家們表示,，上述成果能夠幫助人們了解這一地區(qū)恐龍的生活環(huán)境,，從而對(duì)它們的習(xí)性和特點(diǎn)進(jìn)行深入研究,。（生物谷Bioon.com）
生物谷推薦原文出處：
PNAS doi: 10.1073/pnas.1011369108
Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates
Romain Amiota,1,2, Xu Wangb, Zhonghe Zhoua, Xiaolin Wanga, Eric Buffetautc, Christophe Lécuyerd,2, Zhongli Dingb, Frédéric Fluteaue, Tsuyoshi Hibinof, Nao Kusuhashig, Jinyou Moh, Varavudh Suteethorni, Yuanqing Wanga, Xing Xua, and Fusong Zhangb
Abstract
Early Cretaceous vertebrate assemblages from East Asia and particularly the Jehol Biota of northeastern China flourished during a period of highly debated climatic history. While the unique characters of these continental faunas have been the subject of various speculations about their biogeographic history, little attention has been paid to their possible climatic causes. Here we address this question using the oxygen isotope composition of apatite phosphate (δ) from various reptile remains recovered from China, Thailand, and Japan. δ values indicate that cold terrestrial climates prevailed at least in this part of Asia during the Barremian—early Albian interval. Estimated mean air temperatures of about 10 ± 4 °C at midlatitudes (～42 °N) correspond to present day cool temperate climatic conditions. Such low temperatures are in agreement with previous reports of cold marine temperatures during this part of the Early Cretaceous, as well as with the widespread occurrence of the temperate fossil wood genus Xenoxylon and the absence of thermophilic reptiles such as crocodilians in northeastern China. The unique character of the Jehol Biota is thus not only the result of its evolutionary and biogeographical history but is also due to rather cold local climatic conditions linked to the paleolatitudinal position of northeastern China and global icehouse climates that prevailed during this part of the Early Cretaceous.
