Some recent non-dino tetrapod and reptile papers:
David MarjanoviÄ (2020)
The making of calibration sausage exemplified by recalibrating the transcriptomic timetree of jawed vertebrates.
bioRxiv 2019.12.19.882829 (preprint)
doi: https://doi.org/10.1101/2019.12.19.882829
https://www.biorxiv.org/content/10.1101/2019.12.19.882829v2
Molecular divergence dating has the potential to overcome the incompleteness of the fossil record in inferring when cladogenetic events (splits, divergences) happened, but needs to be calibrated by the fossil record. Ideally but unrealistically, this would require practitioners to be specialists in molecular evolution, in the phylogeny and the fossil record of all sampled taxa, and in the chronostratigraphy of the sites the fossils were found in. Paleontologists have therefore tried to help by publishing compendia of recommended calibrations, and molecular biologists unfamiliar with the fossil record have made heavy use of such works (in addition to using scattered primary sources and copying from each other). Using a recent example of a large node-dated timetree inferred from molecular data, I reevaluate all thirty calibrations in detail, present the current state of knowledge on them with its various uncertainties, rerun the dating analysis, and conclude that calibration dates cannot be taken from published compendia or other secondary or tertiary sources without risking strong distortions to the results, because all such sources become outdated faster than they are published: 50 of the sources I cite to constrain calibrations were published in 2019, half of the total after mid-2016, and 90% after mid-2005. It follows that the present work cannot serve as such a compendium either; in the slightly longer term, it can only highlight known and overlooked problems. Future authors will need to solve each of these problems anew through a thorough search of the primary paleobiological and chronostratigraphic literature on each calibration date every time they infer a new timetree; and that literature is not optimized for that task, but largely has other objectives.
Marcos MartÃn-JimÃneza, Vlad Codrea & AdÃn PÃrez-GarcÃa (2020)
Neuroanatomy of the European uppermost Cretaceous stem turtle Kallokibotion bajazidi
Cretaceous Research 104720 (advance online publication)
doi: https://doi.org/10.1016/j.cretres.2020.104720
https://www.sciencedirect.com/science/article/abs/pii/S0195667120304079
Highlights
The three-dimensional reconstruction of the skull of Kallokibotion bajazidi is done.
It is based on the best-preserved skull and on an unpublished basicranium.
New characters support its atribution to the sister taxon of the crown Testudines.
Its neuronanatomy is analyzed and compared with those of basal and derived forms.
Its sensory capabilities allow to support that it corresponded to a terrestrial form.
ABSTRACT
Kallokibotion bajazidi is one of the few stem turtles identified in the Upper Cretaceous of Europe. This form, exclusive to Maastrichtian outcrops of the HaÈeg Basin (Romania), was described almost a century ago by the famous paleontologist Franz Nopcsa. However, it was identified as an enigmatic taxon until the end of the 20th century due to the limited available information. Recent studies have significantly improved knowledge about this taxon, confirming its attribution to a stem turtle, and being proposed as the sister taxon of the crown Testudines. The first three-dimensional reconstruction of the skull of this bizarre turtle is presented here. It has been made from the best-preserved skull so far known, the information provided by this specimen being complemented by that of an unpublished basicranium, which is analyzed in detail. This study allows to improve knowledge about the cranial osseous anatomy of the species, its phylogenetical identification as form closely related with the crown Testudines being supported. Furthermore, its neuronanatomical study is carried out. Detailed neuroanatomical analyzes on a very limited number of stem turtles have so far been performed. Considering the phylogenetic position of Kallokibotion bajazidi, the comparison of characters linked to the endocast, cranial nerves, nasal cavities, inner ears and circulatory system with those of these forms, as well as with those of members of the stem group, is carried out. Implications relative to the sensory capabilities interpreted for Kallokibotion bajazidi are discussed, the hitherto poorly supported hypothesis regarding its identification as a terrestrial turtle being supported.
Jozef KLEMBARA & Andrej ÄERÅANSKÃ (2020)
Revision of the cranial anatomy of Ophisaurus acuminatus JÃrg, 1965 (Anguimorpha, Anguidae) from the late Miocene of Germany.
in STEYER J.-S., AUGÃ M. L. & MÃTAIS G. (eds), Memorial Jean-Claude Rage: A life of paleo-herpetologist.
GEODIVERSITAS 42(28): 539-557
DOI: https://doi.org/10.5252/geodiversitas2020v42a28
http://sciencepress.mnhn.fr/en/periodiques/geodiversitas/42/28
The anguine species Ophisaurus acuminatus JÃrg, 1965 is known on the basis of only one specimen consisting of skull bones and osteoderms from the late Miocene (MN 9) HÃwenegg/Hegau locality in Germany. Since its first description, several other new species of Ophisaurus Daudin, 1803 have been described from various Miocene localities in Europe. The diagnoses of these new species are based mostly on characters on the parietal and partially frontal bones. Although most of the cranial elements of O. acuminatus are well preserved, its parietal is absent. The knowledge of the detailed anatomy of this anguine species is crucial for the understanding of its interrelationship within the genus Ophisaurus. For our re-study of this specimen we used a high-resolution X-ray microcomputed tomography. The application of this method enabled: 1) to reveal the anatomy of not visible portions of the previously described bones; 2) to discover the bones completely or almost completely embedded in the sediment; and 3) to identify previously not determined skull bones. Our study enabled to identify three distinguished features for this species and confirmed the validity of the species O. acuminatus.
===============
Borealoilysia nov. gen.Â
Jason J. Head (2020)
A South American snake lineage from the Eocene Greenhouse of North America and a reappraisal of the fossil record of "anilioid" snakes.
Geobios (advance online publication)
doi: https://doi.org/10.1016/j.geobios.2020.09.005
https://www.sciencedirect.com/science/article/abs/pii/S0016699520300978
"Anilioidea" is a likely paraphyletic assemblage of pipe snakes that includes extant Aniliidae from equatorial South America, Uropeltoidea from South and Southeast Asia, and a fossil record that consists primarily of isolated precloacal vertebrae ranging from the earliest Late Cretaceous and includes geographic distributions in North America, South America, Europe, and Africa. Articulated precloacal vertebrae from the middle Eocene Bridger Formation of Wyoming, attributed to Borealoilysia nov. gen., represent an unambiguous North American aniliid record and prompts a reconsideration of described pipe snakes and their resultant biogeographic histories. On the basis of vertebral apomorphies, the vast majority of reported fossils cannot be assigned to "Anilioidea". Instead, most records represent stem taxa and macrostomatans erroneously assigned to anilioids on the basis of generalized features associated with fossoriality. A revised fossil record demonstrates that the only extralimital distributions of fossil "anilioids" consist of the North American aniliid record, and there is no unambiguous fossil record of Old World taxa. The occurrence of aniliids in the mid-high latitudes of the late early Eocene of North America is consistent with histories of northward shifts in equatorial ecosystems during the early Paleogene Greenhouse.
====
Free pdf:
David MarjanoviÄ (2020)
The making of calibration sausage exemplified by recalibrating the transcriptomic timetree of jawed vertebrates.
bioRxiv 2019.12.19.882829 (preprint)
doi: https://doi.org/10.1101/2019.12.19.882829
https://www.biorxiv.org/content/10.1101/2019.12.19.882829v2
Molecular divergence dating has the potential to overcome the incompleteness of the fossil record in inferring when cladogenetic events (splits, divergences) happened, but needs to be calibrated by the fossil record. Ideally but unrealistically, this would require practitioners to be specialists in molecular evolution, in the phylogeny and the fossil record of all sampled taxa, and in the chronostratigraphy of the sites the fossils were found in. Paleontologists have therefore tried to help by publishing compendia of recommended calibrations, and molecular biologists unfamiliar with the fossil record have made heavy use of such works (in addition to using scattered primary sources and copying from each other). Using a recent example of a large node-dated timetree inferred from molecular data, I reevaluate all thirty calibrations in detail, present the current state of knowledge on them with its various uncertainties, rerun the dating analysis, and conclude that calibration dates cannot be taken from published compendia or other secondary or tertiary sources without risking strong distortions to the results, because all such sources become outdated faster than they are published: 50 of the sources I cite to constrain calibrations were published in 2019, half of the total after mid-2016, and 90% after mid-2005. It follows that the present work cannot serve as such a compendium either; in the slightly longer term, it can only highlight known and overlooked problems. Future authors will need to solve each of these problems anew through a thorough search of the primary paleobiological and chronostratigraphic literature on each calibration date every time they infer a new timetree; and that literature is not optimized for that task, but largely has other objectives.
===============
Marcos MartÃn-JimÃneza, Vlad Codrea & AdÃn PÃrez-GarcÃa (2020)
Neuroanatomy of the European uppermost Cretaceous stem turtle Kallokibotion bajazidi
Cretaceous Research 104720 (advance online publication)
doi: https://doi.org/10.1016/j.cretres.2020.104720
https://www.sciencedirect.com/science/article/abs/pii/S0195667120304079
Highlights
The three-dimensional reconstruction of the skull of Kallokibotion bajazidi is done.
It is based on the best-preserved skull and on an unpublished basicranium.
New characters support its atribution to the sister taxon of the crown Testudines.
Its neuronanatomy is analyzed and compared with those of basal and derived forms.
Its sensory capabilities allow to support that it corresponded to a terrestrial form.
ABSTRACT
Kallokibotion bajazidi is one of the few stem turtles identified in the Upper Cretaceous of Europe. This form, exclusive to Maastrichtian outcrops of the HaÈeg Basin (Romania), was described almost a century ago by the famous paleontologist Franz Nopcsa. However, it was identified as an enigmatic taxon until the end of the 20th century due to the limited available information. Recent studies have significantly improved knowledge about this taxon, confirming its attribution to a stem turtle, and being proposed as the sister taxon of the crown Testudines. The first three-dimensional reconstruction of the skull of this bizarre turtle is presented here. It has been made from the best-preserved skull so far known, the information provided by this specimen being complemented by that of an unpublished basicranium, which is analyzed in detail. This study allows to improve knowledge about the cranial osseous anatomy of the species, its phylogenetical identification as form closely related with the crown Testudines being supported. Furthermore, its neuronanatomical study is carried out. Detailed neuroanatomical analyzes on a very limited number of stem turtles have so far been performed. Considering the phylogenetic position of Kallokibotion bajazidi, the comparison of characters linked to the endocast, cranial nerves, nasal cavities, inner ears and circulatory system with those of these forms, as well as with those of members of the stem group, is carried out. Implications relative to the sensory capabilities interpreted for Kallokibotion bajazidi are discussed, the hitherto poorly supported hypothesis regarding its identification as a terrestrial turtle being supported.
====
Free pdf:
Jozef KLEMBARA & Andrej ÄERÅANSKÃ (2020)
Revision of the cranial anatomy of Ophisaurus acuminatus JÃrg, 1965 (Anguimorpha, Anguidae) from the late Miocene of Germany.
in STEYER J.-S., AUGÃ M. L. & MÃTAIS G. (eds), Memorial Jean-Claude Rage: A life of paleo-herpetologist.
GEODIVERSITAS 42(28): 539-557
DOI: https://doi.org/10.5252/geodiversitas2020v42a28
http://sciencepress.mnhn.fr/en/periodiques/geodiversitas/42/28
The anguine species Ophisaurus acuminatus JÃrg, 1965 is known on the basis of only one specimen consisting of skull bones and osteoderms from the late Miocene (MN 9) HÃwenegg/Hegau locality in Germany. Since its first description, several other new species of Ophisaurus Daudin, 1803 have been described from various Miocene localities in Europe. The diagnoses of these new species are based mostly on characters on the parietal and partially frontal bones. Although most of the cranial elements of O. acuminatus are well preserved, its parietal is absent. The knowledge of the detailed anatomy of this anguine species is crucial for the understanding of its interrelationship within the genus Ophisaurus. For our re-study of this specimen we used a high-resolution X-ray microcomputed tomography. The application of this method enabled: 1) to reveal the anatomy of not visible portions of the previously described bones; 2) to discover the bones completely or almost completely embedded in the sediment; and 3) to identify previously not determined skull bones. Our study enabled to identify three distinguished features for this species and confirmed the validity of the species O. acuminatus.
===============
Borealoilysia nov. gen.Â
Jason J. Head (2020)
A South American snake lineage from the Eocene Greenhouse of North America and a reappraisal of the fossil record of "anilioid" snakes.
Geobios (advance online publication)
doi: https://doi.org/10.1016/j.geobios.2020.09.005
https://www.sciencedirect.com/science/article/abs/pii/S0016699520300978
"Anilioidea" is a likely paraphyletic assemblage of pipe snakes that includes extant Aniliidae from equatorial South America, Uropeltoidea from South and Southeast Asia, and a fossil record that consists primarily of isolated precloacal vertebrae ranging from the earliest Late Cretaceous and includes geographic distributions in North America, South America, Europe, and Africa. Articulated precloacal vertebrae from the middle Eocene Bridger Formation of Wyoming, attributed to Borealoilysia nov. gen., represent an unambiguous North American aniliid record and prompts a reconsideration of described pipe snakes and their resultant biogeographic histories. On the basis of vertebral apomorphies, the vast majority of reported fossils cannot be assigned to "Anilioidea". Instead, most records represent stem taxa and macrostomatans erroneously assigned to anilioids on the basis of generalized features associated with fossoriality. A revised fossil record demonstrates that the only extralimital distributions of fossil "anilioids" consist of the North American aniliid record, and there is no unambiguous fossil record of Old World taxa. The occurrence of aniliids in the mid-high latitudes of the late early Eocene of North America is consistent with histories of northward shifts in equatorial ecosystems during the early Paleogene Greenhouse.
====