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[dinosaur] Avian respiration evolution + titanosaur tracks + lepidosaur evolution + more

Ben Creisler

Some recent (and one not so recent) dino- and non-dino related articles and material:

John N. Maina (editor) (2017)
The Biology of the Avian Respiratory System: Evolution, Development, Structure and Function.
Springer International Publishing
ISBN: 978-3-319-44152-8 (Print) 978-3-319-44153-5 (Online)
DOI: 10.1007/978-3-319-44153-5


The central focus of this book is the avian respiratory system. The authors explain why the respiratory system of modern birds is built the way it is and works the way that it does. Birds have been and continue to attract particular interest to biologists. The more birds are studied, the more it is appreciated that the existence of human-kind on earth very much depends directly and indirectly on the existence of birds. Regarding the avian respiratory system, published works are scattered in biological journals of fields like physiology, behavior, anatomy/morphology and ecology while others appear in as far afield as paleontology and geology. The contributors to this book are world-renowned experts in their various fields of study. Special attention is given to the evolution, the structure, the function and the development of the lung-air sac system. Readers will not only discover the origin of birds but will also learn how the respiratory system of theropod dinosaurs worked and may have transformed into the avian one. In addition, the work explores such aspects as swallowing mechanism in birds, the adaptations that have evolved for flight at extreme altitude and gas exchange in eggs. It is a highly informative and carefully presented work that provides cutting edge scientific insights for readers with an interest in the respiratory biology and the evolution of birds. 


Notable chapters:

Min Wang & Zhonghe Zhou (2017)
The Evolution of Birds with Implications from New Fossil Evidences.
in The Biology of the Avian Respiratory System  pp.1-26
DOI: 10.1007/978-3-319-44153-5_1

Birds have evolved on the planet for over 150 million years and become the most speciose clade of modern vertebrates. Their biological success has been ascribed to important evolutionary novelties including feathers, powered flight, and respiratory system, some of which have a deep evolutionary history even before the origin of birds. The last two decades have witnessed a wealth of exceptionally preserved feathered non-avian dinosaurs and primitive birds, which provide the most compelling evidence supporting the hypothesis that birds are descended from theropod dinosaurs. A handful of Mesozoic bird fossils have demonstrated how birds achieved their enormous biodiversity after diverging from their theropod relatives. On basis of recent fossil discoveries, we review how these new findings add to our understanding of the early avian evolution.


C. G. Farmer (2017)
Pulmonary Transformations of Vertebrates.
in The Biology of the Avian Respiratory System pp. 99-112
DOI: 10.1007/978-3-319-44153-5_3

The structure of the lung subserves its function, which is primarily gas exchange, and selection for expanded capacities for gas exchange is self-evident in the great diversity of pulmonary morphologies observed in different vertebrate lineages. However, expansion of aerobic capacities does not explain all of this diversity, leaving the functional underpinnings of some of the most fascinating transformations of the vertebrate lung unknown. One of these transformations is the evolution of highly branched conducting airways, particularly those of birds and mammals. Birds have an extraordinarily complex circuit of airways through which air flows in the same direction during both inspiration and expiration, unidirectional flow. Mammals also have an elaborate system of conducting airways; however, the tubes arborize rather than form a circuit, and airflow is tidal along the branches of the bronchial tree. The discovery of unidirectional airflow in crocodilians and lizards indicates that several inveterate hypotheses for the selective drivers of this trait cannot be correct. Neither endothermy nor athleticism drove the evolution of unidirectional flow. These discoveries open an uncharted area for research into selective underpinning of unidirectional airflow.


Lorenzo Alibardi (2017)
Review: cornification, morphogenesis and evolution of feathers.
Protoplasma 254(3): 1259–1281
DOI: 10.1007/s00709-016-1019-2

Feathers are corneous microramifications of variable complexity derived from the morphogenesis of barb ridges. Histological and ultrastructural analyses on developing and regenerating feathers clarify the three-dimensional organization of cells in barb ridges. Feather cells derive from folds of the embryonic epithelium of feather germs from which barb/barbule cells and supportive cells organize in a branching structure. The following degeneration of supportive cells allows the separation of barbule cells which are made of corneous beta-proteins and of lower amounts of intermediate filament (IF)(alpha) keratins, histidine-rich proteins, and corneous proteins of the epidermal differentiation complex. The specific protein association gives rise to a corneous material with specific biomechanic properties in barbules, rami, rachis, or calamus. During the evolution of different feather types, a large expansion of the genome coding for corneous feather beta-proteins occurred and formed 3–4-nm-thick filaments through a different mechanism from that of 8–10 nm IF keratins. In the chick, over 130 genes mainly localized in chromosomes 27 and 25 encode feather corneous beta-proteins of 10–12 kDa containing 97–105 amino acids. About 35 genes localized in chromosome 25 code for scale proteins (14–16 kDa made of 122–146 amino acids), claws and beak proteins (14–17 kDa proteins of 134–164 amino acids). Feather morphogenesis is periodically re-activated to produce replacement feathers, and multiple feather types can result from the interactions of epidermal and dermal tissues. The review shows schematic models explaining the translation of the morphogenesis of barb ridges present in the follicle into the three-dimensional shape of the main types of branched or un-branched feathers such as plumulaceous, pennaceous, filoplumes, and bristles. The temporal pattern of formation of barb ridges in different feather types and the molecular control from the dermal papilla through signaling molecules are poorly known. The evolution and diversification of the process of morphogenesis of barb ridges and patterns of their formation within feathers follicle allowed the origin and diversification of numerous types of feathers, including the asymmetric planar feathers for flight.


A paper (non-English) from last year not yet mentioned:

In Catalan:

Josep Marmi (2016)

Origen i reconstrucció paleoambiental dels jaciments d'icnites de Titanosaure de Fumanya

[Origin and paleoenvironmental reconstruction of  the titanosaur track sites at Fumanya]

Ciències 31: 42-48


Free pdf:



The Fumanya megatrack sites (Berguedà) has been unfortunately in the news due to a landslide occurred on 10th May 2016, which has resulted in a great loss in terms of heritage, science and tourism. These megatrack sites consist of a vast rock surface showing thousands of titanosaur footprints with plant remains assigned to palms and extinct conifers. These sites correspond to the base of the Tremp Formation, which records the evolution of the northeastern Iberia transitional to continental environments throughout the last six millions of years of the Mesozoic era. The study of titanosaur footprints as well as plant fossils re-vealed interesting issues about the environment where these huge dinosaurs inhabited and their paleoecology. Based on these data, we are able to imagine titanosaurs walking on mudflats and concentrated at the margins of freshwater lakes where they probably fed on fern and palm leaves as well as conifer shoots. Several parallel trackways would demonstrate that these animals developed some social behaviour.


Hsi-Yin Shan, Xiao-Chun Wu, Yen-Nien Cheng & Tamaki Sato (2017)

Maomingosuchus petrolica, a restudy of ‘Tomistoma’ petrolica Yeh, 1958.

Palaeoworld (advance online publication)

doi: https://doi.org/10.1016/j.palwor.2017.03.006


Tomistoma petrolica Yeh, 1958 is restudied here based on 18 new specimens from the same horizon of the type and a previously referred specimen (IVPP V 5015) in Maoming, Guangdong Province. Our restudy reveals that ‘T.’ petrolica is morphologically incomparable with the extant species Tomistoma schlegelii and other species referred to Tomistoma in a number of osteological features, such as the penetration by the first dentary tooth in the anterior tip of the rostrum, the premaxilla-maxillary suture on the palate with a strong anterior projection, the jugal-quadratojugal suture starting from the posteroventral corner of the infratemporal fenestra, the sharp anterior process of the palatine relatively long, the palatine-pterygoid suture anteriorly positioned, and the broad tip of the neural spine of the third cervical vertebra. Therefore, a new genus, Maomingosuchus, is erected to include Maomingosuchus petrolica. This study also supports the previous view that a common pattern of the phylogenetic relationships among the Tomistominae cannot be established before collecting more specimens of the fragmentary taxa and sampling a suitable set of characters for the phylogenetic analysis of the group. However, this study suggests that M. petrolica may be grouped in a lineage also including Tomistoma lusitanica (Portugal), Gavialosuchus eggenburgensis (Austria), the living species T. schlegelii, Paratomistoma courti (northern Africa), and Tomistoma coppensi (central Africa). Within the lineage, M. petrolica appears to be more closely related to T. schlegelii than to the P. courti-T. coppensi clade and T. schlegelii is most probably related to the T. lusitanica-G. eggenburgensis clade rather than to M. petrolica. With the addition of M. petrolica, our phylogenetic results indicate that the origin and dispersal history of the extant species were much more complicated than what we previously thought.



Free pdf:

Tomasz Skawiński​ & Bartosz Borczyk (2017)

Evolution of developmental sequences in lepidosaurs. 

PeerJ 5:e3262

doi:  https://doi.org/10.7717/peerj.3262



Lepidosaurs, a group including rhynchocephalians and squamates, are one of the major clades of extant vertebrates. Although there has been extensive phylogenetic work on this clade, its interrelationships are a matter of debate. Morphological and molecular data suggest very different relationships within squamates. Despite this, relatively few studies have assessed the utility of other types of data for inferring squamate phylogeny.


We used developmental sequences of 20 events in 29 species of lepidosaurs. These sequences were analysed using event-pairing and continuous analysis. They were transformed into cladistic characters and analysed in TNT. Ancestral state reconstructions were performed on two main phylogenetic hypotheses of squamates (morphological and molecular).


Cladistic analyses conducted using characters generated by these methods do not resemble any previously published phylogeny. Ancestral state reconstructions are equally consistent with both morphological and molecular hypotheses of squamate phylogeny. Only several inferred heterochronic events are common to all methods and phylogenies.


Results of the cladistic analyses, and the fact that reconstructions of heterochronic events show more similarities between certain methods rather than phylogenetic hypotheses, suggest that phylogenetic signal is at best weak in the studied developmental events. Possibly the developmental sequences analysed here evolve too quickly to recover deep divergences within Squamata.


Humberto G. Ferrón, Carlos Martínez-Pérez & Héctor Botella (2017)
The evolution of gigantism in active marine predators
Historical Biology (advance online publication)
doi:  http://dx.doi.org/10.1080/08912963.2017.1319829   

A novel hypothesis to better understand the evolution of gigantism in active marine predators and the diversity of body sizes, feeding strategies and thermophysiologies of extinct and living aquatic vertebrates is proposed. Recent works suggest that some aspects of animal energetics can act as constraining factors for body size. Given that mass-specific metabolic rate decreases with body mass, the body size of active predators should be limited by the high metabolic demand of this feeding strategy. In this context, we propose that shifts towards higher metabolic levels can enable the same activity and feeding strategy to be maintained at bigger body sizes, offering a satisfactory explanation for the evolution of gigantism in active predators, including a vast quantity of fossil taxa. Therefore, assessing the metabolic ceilings of living aquatic vertebrates and the thermoregulatory strategies of certain key extinct groups is now crucial to define the energetic limits of predation and provide quantitative support for this model.