DISSERTATION RESEARCH: The Evolution of Breathing Mechanisms in the Archosauria

论文研究：呼吸机制的进化在初龙类Farish Jenkins Leon Claessens博士脊椎动物呼吸系统的起源-非常不同的肺结构和呼吸机制如何进化-一直受到化石记录中软组织保存的稀有性的限制。 这个问题可以通过采取一种综合的方法来规避，这种方法既采用对活动物的观察，又采用对灭绝形式中保存的硬组织结构的调查。 该项目将重点关注原始龙类（包括恐龙、鳄鱼和鸟类在内的一组动物）肺通气的演变。 现存的两个主龙类类群，鸟类和鳄鱼，表现出截然不同的，似乎是独特的呼吸机制。 鸟类的肺与非呼吸气囊相互连接，空气通过固定大小的肺单向“循环”;鳄鱼有双向流动和辅助肌肉移动肺部。 鸟类和鳄鱼的呼吸周期（吸气和呼气）的骨骼运动尚未得到详细研究。 这项工作将首次尝试将呼吸力学与骨骼特征的详细分析相关联，特别是那些作为特定运动指标和限制运动的指标。 这种结合的方法代表了最有希望的基础上，以跟踪不同的呼吸系统的演变，是代表与初龙类。具体而言，本次调查将：1。通过放射性电影摄影（活体动物的x射线记录）分析鸟类和鳄鱼躯干骨骼的呼吸运动学; 2.识别和追踪骨骼学特征及其在主龙类化石记录中的功能意义; 3.评估系统发育背景下的功能和结构数据（即从其他证据推断的进化关系），以了解进化模式。

Dissertation Research: Evolutions of Breathing Mechanisms in the Archosauria Dr. Farish Jenkins & Leon ClaessensAn understanding of the origin of vertebrate respiratory systems- how very different lung structures and breathing mechanisms evolved- has been constrained by the rarity of soft-tissue preservation in the fossil record. The problem may be circumvented by taking an integrative approach that employs both observations on living animals and a survey of hard tissue structures preserved in extinct forms. The project will focus on the evolution of lung ventilation in the Archosauria, a group of animals that includes dinosaurs, crocodilians and birds. The two living archosaurian groups, birds and crocodilians, exhibit distinct and seemingly unique respiratory mechanisms. Bird lungs are interconnected with non-respiratory air sacs, and air 'circulates' unidirectionally through lungs of fixed size; crocodilians have two-way flow and an accessory muscle that moves the lungs. The skeletal movements of the respiratory cycle (inhalation and exhalation) in birds and crocodilians have not been studied in detail. This work will represent the first attempt to correlate the mechanics of respiration with a detailed analysis of bony features, especially those that are indicators of specific movements and those that constrain movement. This combined approach represents the most promising basis on which to trace the evolution of diverse respiratory systems that is represented with the Archosauria. Specifically, this investigation will: 1. Analyze the respiratory kinematics of the trunk skeleton of birds and crocodilians through cineradiography (x-ray recording of living animals); 2. Identify and trace osteological (bony) characters and their functional implications within the archosaurian fossil record; 3. Assess the functional and structural data in a phylogenetic context (that is, in terms of evolutionary relationships inferred from other evidence) to understand evolutionary patterns.