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[dinosaur] Bird cranium mosaic evolution + titanosuchid osteomyelitis + Uzbekistan therians + Eocene turtles (free pdfs)

Ben Creisler

For Boxing Day (for countries that celebrate), some free pdfs:

Ryan N. Felice and Anjali Goswami (2017)
Developmental origins of mosaic evolution in the avian cranium.
Proceedings of the National Academy of Sciences (advance online publication)
doi: 10.1073/pnas.1716437115

Free pdf:



Studies reconstructing morphological evolution have long relied on simple representations of organismal form or on limited sampling of species, hindering a comprehensive understanding of the factors shaping biological diversity. Here, we combine high-resolution 3D quantification of skull shape with dense taxonomic sampling across a major vertebrate clade, birds, to demonstrate that the avian skull is formed of multiple semi-independent regions that epitomize mosaic evolution, with cranial regions and major lineages evolving with distinct rates and modes. We further show that the evolvability of different cranial regions reflects their disparate embryonic origins. Finally, we present a hypothetical reconstruction of the ancestral bird skull using this high-resolution shape data to generate a detailed estimate of extinct forms in the absence of well-preserved three-dimensional fossils.


Mosaic evolution, which results from multiple influences shaping morphological traits and can lead to the presence of a mixture of ancestral and derived characteristics, has been frequently invoked in describing evolutionary patterns in birds. Mosaicism implies the hierarchical organization of organismal traits into semiautonomous subsets, or modules, which reflect differential genetic and developmental origins. Here, we analyze mosaic evolution in the avian skull using high-dimensional 3D surface morphometric data across a broad phylogenetic sample encompassing nearly all extant families. We find that the avian cranium is highly modular, consisting of seven independently evolving anatomical regions. The face and cranial vault evolve faster than other regions, showing several bursts of rapid evolution. Other modules evolve more slowly following an early burst. Both the evolutionary rate and disparity of skull modules are associated with their developmental origin, with regions derived from the anterior mandibular-stream cranial neural crest or from multiple embryonic cell populations evolving most quickly and into a greater variety of forms. Strong integration of traits is also associated with low evolutionary rate and low disparity. Individual clades are characterized by disparate evolutionary rates among cranial regions. For example, Psittaciformes (parrots) exhibit high evolutionary rates throughout the skull, but their close relatives, Falconiformes, exhibit rapid evolution in only the rostrum. Our dense sampling of cranial shape variation demonstrates that the bird skull has evolved in a mosaic fashion reflecting the developmental origins of cranial regions, with a semi-independent tempo and mode of evolution across phenotypic modules facilitating this hyperdiverse evolutionary radiation.


Free pdf:

Christen D. Shelton, Anusuya Chinsamy & Bruce M. Rothschild (2017)
Osteomyelitis in a 265-million-year-old titanosuchid (Dinocephalia, Therapsida).
Historical Biology (advance online publication)
doi:Â Âhttps://doi.org/10.1080/08912963.2017.1419348Â Â

Analytical palaeohistology techniques have allowed a better understanding of the microstructure of fossil bone, as well as of bone pathologies of extinct animals. Osteomyelitis is one of the oldest identified bone pathologies, occurring in Synapsida dating back as far as the Lower Permian. Here we show the presence of this pathology in the femur of Jonkeria parva, an omnivorous titanosuchid from the Tapinocephalus Assemblage Zone of the Karoo Basin of South Africa. The pathology is characterised by bony radial spicules growing perpendicular to the normal orientation of the unaffected fibrolamellar bone tissue, and shows localised increase in vascular canal size. Puncture marks on the femur suggests that an attack by a predator may have resulted in a bacterial infection that caused contiguous and subjacent osteomyelitis.


A.O. Averianov and J.D. Archibald (2017)Â

Therian postcranial bones from the Upper Cretaceous Bissekty Formation of Uzbekistan.

Proceedings of the Zoological Institute RAS 321(4): 433â484


The Upper Cretaceous (upper Turonian) Bissekty Formation of Uzbekistan produces the most diverse Cretaceous therian fauna including one stem marsupial and eleven stem placental taxa known from cranial and dental elements. Some isolated postcranial elements from the Bissekty Formation can be confidently attributed to some of these taxa based on morphology and size. The humeral fragments, astragalus, and calcanei attributed to the deltatheroidan Sulestes karakshi Nessov, 1985 are similar to these bones in other stem marsupials. Postcranial bones referred to Zhelestidae Nessov, 1985 and Asioryctitheria Novacek et al., 1997 possess plesiomorphic therian morphologies, which are also present in some stem marsupials. All fragments of scapula from the Bissekty Formation show a plesiomorphic morphology with a trough-like infraspinous fossa placed medially to the supraspinous fossa. Bones attributed to the stem placental Paranyctoides quadrans (Nessov, 1982) and to the zalambdalestid Kulbeckia kulbecke Nessov, 1993 indicate arboreal and cursorial specializations, respectively. In particular, Kulbeckia Nessov, 1993 is similar to Zalambdalestes Gregory et Simpson, 1926 in having long and distally fused tibia and fibula and a long calcaneal tuber. Its distal humerus has a deep trochlea, large medial trochlear keel, and large capitular tail separated from a cylindrical capitulum by a shallow groove. The upper ankle joint of Kulbeckia has the complete separation of medial and lateral astragalotibial articulations.


E.A. Zvonok and I.G. Danilov (2017)

A revision of fossil turtles from the Kiev clays (Ukraine, middle Eocene) with comments on the history of the collection of fossil vertebrates of A.S. Rogovich.

Proceedings of the Zoological Institute RAS 321(4): 485â516



The paper revises material of fossil turtles from the Kiev clays (Vyshgorod and Tripolye localities, Kiev Province, Ukraine; Kiev Formation, upper Lutetian â lower Bartonian, middle Eocene) from the 19th century collection of fossil vertebrates of the Russian naturalist A.S. Rogovich. In the course of more than a century this collection was divided into parts several times and stored in different institutions of Moscow, Saint Petersburg, and Kiev. The turtle material from Rogovichâs collection includes a partial skeleton and isolated shell fragments from Vyshgorod locality referred here to a pancheloniid sea turtle Argillochelys antiqua (Konig, 1825), a species formerly known only from the Paleogene of Western Europe, partial dentaries from Vyshgorod locality, belonging to âDollochelysâ rogovichi Averianov, 2002, a pancheloniid with unclear generic attribution, and sculptured shell fragments of Pan-Cheloniidae indet. from Tripolye locality, erroneously assigned to a crocodile by Rogovich. The material of A. antiqua unites some specimens previously described as Puppigerus sp. and Dollochelys rogovichi, as well as newly revealed specimens. According to our interpretation, parts of the skeleton of A. antiqua from Vyshgorod locality were stored in different institutions for a long time, sharing the fate of the whole Rogovichâs collection of fossil vertebrates. The attribution of the Vyshgorod material to A. antiqua is supported by phylogenetic analysis of pancheloniids. This analysis also demonstrates an Argillochelys clade (A. antiqua + A. cuneiceps [Owen, 1849]), and removes âA.â africana Tong et Hirayama, 2008 from this clade. Analysis of the geographic and stratigraphic distribution of the genus Argillochelys shows that it is restricted to the ?Thanetian â Priabonian of the Peri-Tethyan area (Western and Eastern Europe and Kazakhstan) and possibly also to eastern North America. In addition, our study shows that sculptured pancheloniids of unknown affinities are quite common in the middle Eocene of Eastern Europe and Central Asia.


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