Ben Creisler
Some recent non-dino papers:
Free pdf:
Gerald Mayr (2020)
The otic region of the skull of neognathous birds: on the homology and comparative morphology of some neurovascular and muscular foramina and other external skeletal structures.
Vertebrate Zoology 70(1): 69-85
DOI: 10.26049/VZ70-1-2020-05
https://www.senckenberg.de/wp-content/uploads/2019/11/05_vertebrate_zoology_70_1_2020_Mayr.pdfEven though detailed anatomical studies of the otic region exist for some avian species, there are few comparative data for most extant higher-level clades. In the present study, the external osteology of the otic region of birds is studied in a broad taxonomic context and a focus has been put on the homology of neurovascular and muscular foramina in taxa of the Neognathae. It is detailed that this part of the skull offers signifcant structural variation, which is of potential phylogenetic and physiological signifcance. The otic region of many taxa is for the frst time illustrated and some osteological features are highlighted that are not or only rarely commented on in existing accounts of the otic region. These include the foramina and osseous guiding structures for the occipital ramus of arteria ophthalmica externa, as well as the skeletal correlates of ramus palatinus and ramus hyomandibularis of nervus facialis, and the foramen for musculus columellae. In addition, different conformations of the pila otica are described and some structures of unknown signifcance are highlighted, which require further research.Â
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Christine BÃhmer, ÂJocerand Prevoteau, ÂOlivier Duriez & Anick Abourachid (2019)
Gulper, ripper and scrapper: anatomy of the neck in three species of vultures.
Journal of Anatomy (advance online publication)
doi:
https://doi.org/10.1111/joa.13129https://onlinelibrary.wiley.com/doi/10.1111/joa.13129The headâneck system of birds is a highly complex structure that performs a variety of demanding and competing tasks. Morphofunctional adaptations to feeding specializations have previously been identified in the head and neck, but performance is also influenced by other factors such as its phylogenetic history. In order to minimize the effects of this factor, we here analyzed the anatomy of three closely related vultures that distinctly differ in feeding strategy. Vultures, as obligate scavengers, have occupied a special ecological niche by exclusively feeding on carrion. However, competition among sympatric vultures led to ecological differences such as preference of certain types of food from a carcass. Via comparative dissections we systematically described the craniocervical anatomy in the Griffon vulture (Gyps fulvus), the Cinereous vulture (Aegypius monachus) and the Hooded vulture (Necrosyrtes monachus) that exploit the same food resources in different ways. Our results revealed differences in the number of cervical vertebrae, in the morphology of the atlasâaxis complex as well as in the neck musculature despite overall similarities in the musculoskeletal system. Gulpers, rippers and scrappers adopt specific postures while feeding from a carcass, but the cervical vertebral column is indispensable to position the head during all kinds of behavior. The great range of demands may explain the conservation of the overall muscle topography of the neck across the studied taxa.
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Free pdf:
Davit Vasilyan & Maia Bukhsianidze (2020)
The fossil record of the genus Varanus from the Southern Caucasus (Armenia,Georgia).
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The Southern Caucasus, with its special geographic position and complex topography, is a well-known biodiversity hotspot. However, the formation oft his hotspot remains largely unstudied. To reveal this, a thorough study of the fossil record of the region is necessary. In the present paper, we describe for the first time fossil monitor lizards (Varanus sp.) from two late Miocene localities from the Southern Caucasus (Jradzor, Armenia and Tetri Udabno, Georgia). We suggest that both fossils belong to a small-sized monitor lizard,comparable to the present-day species found in Iran and the Middle East (e.g.,Iraq, Saudi Arabian)--the most western part of the extant monitor lizards'Eurasian distribution range. Our finds show that the genus had a broad distribution in the Eastern Paratethyan region during the late Miocene. In addition, we provide the probable temperature ranges for fossil localities.Â
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Facultative bipedality is regarded as an enigmatic middle ground in the evolution of obligate bipedality and is associated with high mechanical demands in extant lepidosaurs. Traits linked with this phenomenon are largely associated with the caudal end of the animal: hindlimbs and tail. The articulation of the pelvis with both of these structures suggests a morphofunctional role in the use of a facultative locomotor mode. Using a three-dimensional geometric morphometric approach, we examine the pelvic osteology and associated functional implications for 34 species of extant lepidosaur. Anatomical trends associated with the use of a bipedal locomotor mode and substrate preferences are correlated and functionally interpreted based on musculoskeletal descriptions. Changes in pelvic osteology associated with a facultatively bipedal locomotor mode are similar to those observed in species preferring arboreal substrates, indicating shared functionality between these ecologies.
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