Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record

Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernández, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin

Anatomy, ontogeny, and evolution of the archosaurian respiratory system: A case study on Alligator mississippiensis

The avian lung is highly specialized and is both functionally and morphologically distinct 30 from that of their closest extant relatives, the crocodilians. It is highly partitioned, with a 31 unidirectionally ventilated and immobilized gas-exchanging lung, and functionally decoupled, 32 compliant, poorly vascularized ventilatory air-sacs. To understand the evolutionary history of 33 the archosaurian respiratory system, it is essential to determine which anatomical 34 characteristics are shared between birds and crocodilians and the role these shared traits play 35 in their respective respiratory biology. To begin to address this larger question, we examined 36 the anatomy of the lung and bronchial tree of ten American alligators (Alligator 37 mississippiensis) and eleven ostriches (Struthio camelus) across an ontogenetic series using 38 traditional and micro-computed tomography (µCT), three-dimensional (3D) digital models, and 39 morphometry. Intraspecific variation and left to right asymmetry were present in certain 40 aspects of the bronchial tree of both taxa but was particularly evident in the cardiac (medial) 41 region of the lungs of alligators and the caudal aspect of the bronchial tree in both species. The 42 cross-sectional area of the primary bronchus at the level of the major secondary airways and 43 cross-sectional area of ostia scaled either isometrically or negatively allometrically in alligators 44 and isometrically or positively allometrically in ostriches with respect to body mass. Of fifteen 45 lung metrics, five were significantly different between the alligator and ostrich, suggesting that 46 these aspects of the lung are more interspecifically plastic in archosaurs. One metric, the 47 distances between the carina and each of the major secondary airways, had minimal 48 intraspecific or ontogenetic variation in both alligators and ostriches, and thus may be a 49 conserved trait in both taxa. In contrast to previous descriptions, the 3D digital models and CT 50 scan data demonstrate that the pulmonary diverticula pneumatize the axial skeleton of the 51 ostrich directly from the gas-exchanging pulmonary tissues instead of the air sacs. Global and 52 specific comparisons between the bronchial topography of the alligator and ostrich reveal 53 multiple possible homologies, suggesting that certain structural aspects of the bronchial tree 54 are likely conserved across Archosauria, and may have been present in the ancestral 55 archosaurian lung

Airplane Design and the Biomechanics of Flight – A More Completely Multi- Disciplinary Perspective

Aeronautics is usually presumed to have started as a formal engineering discipline somewhere in historical time between the mythological experiments of Daedalus and his ill-fated son, Icarus; and the dreams and schemes of Leonardo da Vinci during the Italian Renaissance. As reviewed in this paper, “aeronautics” has a far longer history, extending over a period of about 300 million years beginning with the evolution of the ability of insects to fly. With the advent of the success of the Wright brothers, technologists quickly turned their attention from the inspirations and lessons provided by natural models of flying machines to a more practical quest for increasingly dramatic improvements in speed, range and altitude performance far beyond the limits of what muscles and flapping wings could provide. Based on recent work done by the first author in support of the NASA/DARPA Morphing Aircraft Structures Program, a purpose of this paper is to demonstrate in broader terms some of the numerous, very rich sources of inspiration such multi-disciplinary explorations continue to offer both the engineering practitioner and educator