Bone Phosphate Isotopic Patterns of Modern and Extinct Terrestrial Vertebrates

现代和灭绝陆生脊椎动物的骨磷酸同位素模式

• 批准号: 9507992
• 负责人: Reese Barrick
• 金额: $ 16.95万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-15 至 1998-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9507992&HistoricalAwards=false
• 关键词: Bone; Phosphate; Isotopic; Patterns; Modern

Barrick 9507992 The question of whether dinosaurs lacked effective temperature control and were heterotherms or were endothermic homeotherms has important implications for their life histories, evolution, rise to dominance in terrestrial ecosystems, and eventual extinction. A great deal of evidence has been amassed regarding dinosaur endothermy which includes brain size, feeding mechanics, paleobiogeography, posture and gait, behaviors, bone histology and predator/prey relationships (Carroll, 1988; Weishample et al., 1990). These studies have changed the general perception of dinosaurs and they are now thought of as active animals, though considered to be ectothermic or mass homeotherms (Ostrom, 1980). During the initial phase of funding (EAR91-06660), we investigated the application of a new high precision 18O isotopic technique for the analysis of bone phosphate. By using the isotopic difference between core body and extremities and the phosphate paleotemperature equation, realtive body temperature differences can be calculated to determine if an fossil animal was a heterotherm or homeotherm. Of the 13 species of dinosaurs analyzed, all appear to be homeotherms with one Jurassic species exhibiting regional heterothermy. These homeothermic bone isotope patterns cannot be ascribed to diagenetic alteration, because none of the specimens have isotopic equilibrium between the co-existing phases of bone phosphate with structural carbonate or calcite cements (co-existing phase test). This proposal seeks funds to expand our modern bone isotope data base by working with the NCSU School of Veterinary Medicine on 5 modern target species. The species will also propose to expand our fossil data base to complete our survey of different dinosaur clades, and also to search for the origins of homeothermy in therapsids and in a Triassic assemblage from Argentina.

Barrick 9507992 恐龙是否缺乏有效的温度控制，是异温动物还是吸温恒温动物，这一问题对于它们的生命史、进化、在陆地生态系统中占据主导地位以及最终灭绝具有重要意义。 关于恐龙的吸热性，已经积累了大量证据，包括大脑大小、进食机制、古生物地理学、姿势和步态、行为、骨骼组织学以及捕食者/猎物关系（Carroll，1988；Weishample 等，1990）。 这些研究改变了对恐龙的普遍看法，它们现在被认为是活跃的动物，尽管被认为是变温动物或群体恒温动物（Ostrom，1980）。 在资助的初始阶段 (EAR91-06660)，我们研究了一种新的高精度 18O 同位素技术在骨磷酸盐分析中的应用。 利用核心体和四肢之间的同位素差异和磷酸盐古温度方程，可以计算出相对体温差异，以确定化石动物是异温动物还是恒温动物。 在分析的 13 种恐龙中，所有恐龙似乎都是恒温动物，其中一种侏罗纪物种表现出区域异温性。 这些恒温骨同位素模式不能归因于成岩蚀变，因为没有一个标本在骨磷酸盐与结构碳酸盐或方解石水泥的共存相之间具有同位素平衡（共存相测试）。 该提案寻求资金通过与北卡罗来纳州立大学兽医学院合作研究 5 个现代目标物种来扩大我们的现代骨同位素数据库。 该物种还将建议扩大我们的化石数据库，以完成我们对不同恐龙分支的调查，并寻找兽孔类和来自阿根廷的三叠纪组合的恒温起源。