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Evolutionary anatomy

Michelle Jooste, Léanne L Dreyer, Kenneth C Oberlander
BACKGROUND: The southern African Oxalis radiation is extremely morphologically variable. Despite recent progress in the phylogenetics of the genus, there are few morphological synapomorphies supporting DNA-based clades. Leaflet anatomy can provide an understudied and potentially valuable source of information on the evolutionary history and systematics of this lineage. Fifty-nine leaflet anatomical traits of 109 southern African Oxalis species were assessed in search of phylogenetically significant characters that delineate clades...
October 22, 2016: BMC Evolutionary Biology
Karl J Niklas, Ulrich Kutschera
In 1790, the German poet Johann W. v. Goethe (1749-1832) proposed the concept of a hypothetical sessile organism known as the 'Plant Archetype,' which was subsequently reconstructed and depicted by 19th-century botanists, such as Franz Unger (1800-1870) and Julius Sachs (1832-1897), and can be considered one of the first expressions of Evo-Devo thinking. Here, we present the history of this concept in the context of Ernst Haeckel's (1834-1919) biogenetic law espoused in his Generelle Morphologie der Organismen of 1866...
October 18, 2016: Theory in Biosciences, Theorie in Den Biowissenschaften
W Pérez, N Vazquez, R Ungerfeld
The aims of this study were to describe the anatomy of the mouth and pharynx of the pampas deer, and to consider its evolutionary feeding niche according to those characteristics. Gross dissections of the mouth and pharynx were performed in 15 animals, 10 adult females and five young animals under 1 year (three males and two females), all dead by causes unrelated to this anatomical region. The upper lip entered in the constitution of a pigmented nasolabial plane. The masseter muscles weighed 43.8 ± 3.5 g and represented 0...
October 17, 2016: Anatomia, Histologia, Embryologia
Benjamin Fabian, Katharina Schneeberg, Rolf Georg Beutel
Genetically modified organisms are crucial for our understanding of gene regulatory networks, physiological processes and ontogeny. With modern molecular genetic techniques allowing the rapid generation of different Drosophila melanogaster mutants, efficient in-depth morphological investigations become an important issue. Anatomical studies can elucidate the role of certain genes in developmental processes and point out which parts of gene regulatory networks are involved in evolutionary changes of morphological structures...
October 6, 2016: Arthropod Structure & Development
Frank Rühli, Katherine van Schaik, Maciej Henneberg
The field of evolutionary medicine uses evolutionary principles to understand changes in human anatomy and physiology that have occurred over time in response to environmental changes. Through this evolutionary-based approach, we can understand disease as a consequence of anatomical and physiological "trade-offs" that develop to facilitate survival and reproduction. We demonstrate how diachronic study of human anatomy and physiology is fundamental for an increased understanding of human health and disease.
November 1, 2016: Physiology
Henry C Astley
Anuran jumping is a model system for linking muscle physiology to organismal performance. However, anuran species display substantial diversity in their locomotion, with some species performing powerful leaps from riverbanks or tree branches, while other species move predominantly via swimming, short hops or even diagonal-sequence gaits. Furthermore, many anurans with similar locomotion and morphology are actually convergent (e.g. multiple independent evolutions of 'tree frogs'), while closely related species may differ drastically, as with the walking toad (Melanophryniscus stelzneri) and bullfrog-like river toad (Phrynoides aspera) compared with other Bufonid toads...
October 1, 2016: Journal of Experimental Biology
William Ruger Porter, Jayc C Sedlmayr, Lawrence M Witmer
Extant crocodilians are a highly apomorphic archosaur clade that is ectothermic, yet often achieve large body sizes that can be subject to higher heat loads. Therefore, the anatomical and physiological roles that blood vessels play in crocodilian thermoregulation need further investigation to better understand how crocodilians establish and maintain cephalic temperatures and regulate neurosensory tissue temperatures during basking and normal activities. The cephalic vascular anatomy of extant crocodilians, particularly American alligator (Alligator mississippiensis) was investigated using a differential-contrast, dual-vascular injection technique and high resolution X-ray micro-computed tomography (μCT)...
September 28, 2016: Journal of Anatomy
Yuanyuan Li, David Heckmann, Martin J Lercher, Veronica G Maurino
To feed a world population projected to reach 9 billion people by 2050, the productivity of major crops must be increased by at least 50%. One potential route to boost the productivity of cereals is to equip them genetically with the 'supercharged' C4 type of photosynthesis; however, the necessary genetic modifications are not sufficiently understood for the corresponding genetic engineering programme. In this opinion paper, we discuss a strategy to solve this problem by developing a new paradigm for plant breeding...
September 22, 2016: Journal of Experimental Botany
Stephan Lautenschlager, Florian Witzmann, Ingmar Werneburg
Temnospondyls were the morphologically and taxonomically most diverse group of early tetrapods with a near-global distribution during the Palaeozoic and Mesozoic. Members of this group occupied a range of different habitats (aquatic, amphibious, terrestrial), reflected by large morphological disparity of the cranium throughout their evolutionary history. A diagnostic feature of temnospondyls is the presence of an open palate with large interpterygoid vacuities, in contrast to the closed palate of most other early tetrapods and their fish-like relatives...
October 2016: Die Naturwissenschaften
Tomokazu Kawashima, Richard W Thorington, Paula W Bohaska, Fumi Sato
A long-standing issue in squirrel evolution and development is the origin of the styliform cartilage of flying squirrels, which extends laterally from the carpus to support the gliding membrane (patagium). Because the styliform cartilage is one of the uniquely specialized structures permitting gliding locomotion, the knowledge of its origin and surrounding transformation is key for understanding their aerodynamic evolution. The developmental study that would definitely answer this question would be difficult due to the rarity of embryological material...
September 9, 2016: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Nicola S Heckeberg, Dirk Erpenbeck, Gert Wörheide, Gertrud E Rössner
Cervid phylogenetics has been puzzling researchers for over 150 years. In recent decades, molecular systematics has provided new input for both the support and revision of the previous results from comparative anatomy but has led to only partial consensus. Despite all of the efforts to reach taxon-wide species sampling over the last two decades, a number of cervid species still lack molecular data because they are difficult to access in the wild. By extracting ancient DNA from museum specimens, in this study, we obtained partial mitochondrial cytochrome b gene sequences for Mazama bricenii, Mazama chunyi, Muntiacus atherodes, Pudu mephistophiles, and Rusa marianna, including three holotypes...
2016: PeerJ
Robert S Sansom
The exceptionally preserved Cambrian fossil record provides unique insight into the early evolutionary history of animals. Understanding of the mechanisms of exceptional soft tissue preservation frames all interpretations of the fauna and its evolutionary significance. This is especially true for recent interpretations of preserved nervous tissues in fossil ecdysozoans. However, models of soft tissue preservation lack empirical support from actualistic studies. Here experimental decay of the priapulid Priapulus reveal consistent bias towards rapid loss of internal non-cuticular anatomy compared with recalcitrant cuticular anatomy...
2016: Scientific Reports
Kelly G Sullivan, Maya Emmons-Bell, Michael Levin
A key problem in evolutionary developmental biology is identifying the sources of instructive information that determine species-specific anatomical pattern. Understanding the inputs to large-scale morphology is also crucial for efforts to manipulate pattern formation in regenerative medicine and synthetic bioengineering. Recent studies have revealed a physiological system of communication among cells that regulates pattern during embryogenesis and regeneration in vertebrate and invertebrate models. Somatic tissues form networks using the same ion channels, electrical synapses, and neurotransmitter mechanisms exploited by the brain for information-processing...
July 2016: Communicative & Integrative Biology
David Fleck, Nadine Mundt, Felicitas Bruentgens, Petra Geilenkirchen, Patricia A Machado, Thomas Veitinger, Sophie Veitinger, Susanne M Lipartowski, Corinna H Engelhardt, Marco Oldiges, Jennifer Spehr, Marc Spehr
Spermatogenesis ranks among the most complex, yet least understood, developmental processes. The physiological principles that control male germ cell development in mammals are notoriously difficult to unravel, given the intricate anatomy and complex endo- and paracrinology of the testis. Accordingly, we lack a conceptual understanding of the basic signaling mechanisms within the testis, which control the seminiferous epithelial cycle and thus govern spermatogenesis. Here, we address paracrine signal transduction in undifferentiated male germ cells from an electrophysiological perspective...
September 2016: Journal of General Physiology
Marissa L Gredler
An intromittent phallus is used for sperm transfer in most amniote taxa; however, there is extensive variation in external genital morphology within and among the major amniote clades. Amniote phalluses vary in number (paired, single, or rudimentary), spermatic canal morphology (closed tube or open sulcus), and mode of transition between resting and tumescent states (inflation, rotation, eversion, or muscle relaxation). In a phylogenetic context, these varying adult anatomies preclude a clear interpretation for the evolutionary history of amniote external genitalia; as such, multiple hypotheses have been presented for the origin(s) of the amniote phallus...
October 2016: Integrative and Comparative Biology
Bruno F Simões, Filipa L Sampaio, Ronald H Douglas, Ullasa Kodandaramaiah, Nicholas R Casewell, Robert A Harrison, Nathan S Hart, Julian C Partridge, David M Hunt, David J Gower
Much of what is known about the molecular evolution of vertebrate vision comes from studies of mammals, birds and fish. Reptiles (especially snakes) have barely been sampled in previous studies despite their exceptional diversity of retinal photoreceptor complements. Here, we analyze opsin gene sequences and ocular media transmission for up to 69 species to investigate snake visual evolution. Most snakes express three visual opsin genes (rh1, sws1, and lws). These opsin genes (especially rh1 and sws1) have undergone much evolutionary change, including modifications of amino acid residues at sites of known importance for spectral tuning, with several tuning site combinations unknown elsewhere among vertebrates...
October 2016: Molecular Biology and Evolution
Stephen L Brusatte, Amy Muir, Mark T Young, Stig Walsh, Lorna Steel, Lawrence M Witmer
Modern crocodylians are a morphologically conservative group, but extinct relatives (crocodylomorphs) experimented with a wide range of diets, behaviors, and body sizes. Among the most unusual of these fossil groups is the thalattosuchians, an assemblage of marine-dwellers that transitioned from semi-aquatic species (teleosaurids and kin) into purely open-ocean forms (metriorhynchids) during the Jurassic and Cretaceous Periods (ca. 191-125 million years ago). Thalattosuchians can give insight into the origin of modern crocodylian morphologies and how anatomy and behavior change during a major evolutionary transition into a new habitat...
August 17, 2016: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Thomas Wynn, Frederick L Coolidge
How did the human mind evolve? How and when did we come to think in the ways we do? The last thirty years have seen an explosion in research related to the brain and cognition. This research has encompassed a range of biological and social sciences, from epigenetics and cognitive neuroscience to social and developmental psychology. Following naturally on this efflorescence has been a heightened interest in the evolution of the brain and cognition. Evolutionary scholars, including paleoanthropologists, have deployed the standard array of evolutionary methods...
July 2016: Evolutionary Anthropology
Cathrin Pfaff, Roberto Zorzin, Jürgen Kriwet
BACKGROUND: Living anguilliform eels represent a distinct clade of elongated teleostean fishes inhabiting a wide range of habitats. Locomotion of these fishes is highly influenced by the elongated body shape, the anatomy of the vertebral column, and the corresponding soft tissues represented by the musculotendinous system. Up to now, the evolution of axial elongation in eels has been inferred from living taxa only, whereas the reconstruction of evolutionary patterns and functional ecology in extinct eels still is scarce...
2016: BMC Evolutionary Biology
Sarah E Gabbott, Philip C J Donoghue, Robert S Sansom, Jakob Vinther, Andrei Dolocan, Mark A Purnell
The success of vertebrates is linked to the evolution of a camera-style eye and sophisticated visual system. In the absence of useful data from fossils, scenarios for evolutionary assembly of the vertebrate eye have been based necessarily on evidence from development, molecular genetics and comparative anatomy in living vertebrates. Unfortunately, steps in the transition from a light-sensitive 'eye spot' in invertebrate chordates to an image-forming camera-style eye in jawed vertebrates are constrained only by hagfish and lampreys (cyclostomes), which are interpreted to reflect either an intermediate or degenerate condition...
August 17, 2016: Proceedings. Biological Sciences
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