Some recent reptile papers with free pdfs that may be of interest:
Gerardo Carbot-Chanona, Gustavo Rivera-VelÃzquez, Eduardo JimÃnez-Hidalgo, and VÃctor Hugo Reynoso (2020)
The fossil record of turtles and tortoises (Testudines) of Mexico, Central America and the Caribbean Islands, with comments on its taxonomy and paleobiogeography: a bibliographic review.
Revista Mexicana de Ciencias GeolÃgicas (in press)
DOI: http://dx.doi.org/10.22201/cgeo.20072902e.2020.3.1581Â
Testudines is the crown-group that includes all living forms of turtles and their closest extinct relatives. This group is known to exist starting in the Middle Jurassic. The fossil record of Testudines in Mexico is scarce but has been previously compiled in several papers. In this paper, we are presenting an update that includes all osteological and ichnological records of Mexico, and we have added fossil records of turtles and tortoises from Central America and the Caribbean Islands. In Mexico, the Testudines fossil record extends from the Late Jurassic to the Pleistocene, and widely abundant during the late Pleistocene. Kinosternon and Gopherus are the best represented taxa, known from the late Miocene to the late Pleistocene. In Mexico, records of fossil turtles show a wide distribution, except in the areas around the states of Campeche and Quintana Roo in the east; Colima, Guerrero, and Sinaloa in the west, and QuerÃtaro, and Mexico City in the center. Ichnological records are known only in Coahuila, Pueblaand Zacatecas. Reports of fossil turtles in Central America include El Salvador, Honduras, Costa Rica, Nicaragua and Panama--the latter being the country with the most records--and in the Caribbean Islands including Cuba, Dominican Republic, Jamaica, the United States islands of Puerto Rico and Navassa, and the British Island of Sombreroin Anguilla. Seven fossil turtles have been described as new species in Mexico (Notoemys tlaxiacoensis, Yelmochelys rosarioae, Mexichelys coahuilaensis, Allaeochelys liliae, Gopherus donlaloi, G. auffenbergi and G. pargensis, of which G. auffenbergi is synonymous with G. berlandieri, and G. pargensis is considered a nomen vanum); two from Panama (Rhinoclemmys panamaensis and Staurotypus moschus); one from Costa Rica (Rhinoclemmys nicoyama); two from Cuba (Notoemys oxfordensis and Chelonoidis cubensis); one from the Dominican Republic (Chelonoidis marcanoi), one from Puerto Rico (Chelonoidis monensis), and one from Sombrero Island, Anguilla (Chelonoidis sombrerensis).
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Philip J. Bergmann, Gen Morinaga, Elyse S. Freitas, Duncan J. Irschick, GÃnter P. Wagner and Cameron D. Siler (2020)
Locomotion and palaeoclimate explain the re-evolution of quadrupedal body form in Brachymeles lizards.
Proceedings of the Royal Society B 287(1938): 20201994
doi: https://doi.org/10.1098/rspb.2020.1994
https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2020.1994
Evolutionary reversals, including re-evolution of lost structures, are commonly found in phylogenetic studies. However, we lack an understanding of how these reversals happen mechanistically. A snake-like body form has evolved many times in vertebrates, and occasionally a quadrupedal form has re-evolved, including in Brachymeles lizards. We use body form and locomotion data for species ranging from snake-like to quadrupedal to address how a quadrupedal form could re-evolve. We show that large, quadrupedal species are faster at burying and surface locomotion than snake-like species, indicating a lack of expected performance trade-off between these modes of locomotion. Species with limbs use them while burying, suggesting that limbs are useful for burying in wet, packed substrates. Palaeoclimatological data suggest that Brachymeles originally evolved a snake-like form under a drier climate probably with looser soil in which it was easier to dig. The quadrupedal clade evolved as the climate became humid, where limbs and large size facilitated fossorial locomotion in packed soils.
Why skinks that lost their legs evolved new ones
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Reptiles are the only amniotes that maintain the capacity to regenerate appendages. This study presents the first anatomical and histological evidence of tail repair with regrowth in an archosaur, the American alligator. The regrown alligator tails constituted approximately 6â18% of the total body length and were morphologically distinct from original tail segments. Gross dissection, radiographs, and magnetic resonance imaging revealed that caudal vertebrae were replaced by a ventrally-positioned, unsegmented endoskeleton. This contrasts with lepidosaurs, where the regenerated tail is radially organized around a central endoskeleton. Furthermore, the regrown alligator tail lacked skeletal muscle and instead consisted of fibrous connective tissue composed of type I and type III collagen fibers. The overproduction of connective tissue shares features with mammalian wound healing or fibrosis. The lack of skeletal muscle contrasts with lizards, but shares similarities with regenerated tails in the tuatara and regenerated limbs in Xenopus adult frogs, which have a cartilaginous endoskeleton surrounded by connective tissue, but lack skeletal muscle. Overall, this study of wild-caught, juvenile American alligator tails identifies a distinct pattern of wound repair in mammals while exhibiting features in common with regeneration in lepidosaurs and amphibia.
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Jhonny J. M. Guedes, Henrique C. Costa & Mario R. Moura (2020)
A new tale of lost tails: Correlates of tail breakage in the worm lizard Amphisbaena vermicularis.
Ecology and Evolution (advance online publication)
doi:Âhttps://doi.org/10.1002/ece3.7023
https://onlinelibrary.wiley.com/doi/10.1002/ece3.7023Â
Predator-prey interactions are important evolutionary drivers of defensive behaviors, but they are usually difficult to record. This lack of data on natural history and ecological interactions of species can be overcome through museum specimens, at least for some reptiles. When facing aggressive interactions, reptile species may exhibit the defensive behavior of autotomy by losing the tail, which is also known as "urotomy". The inspection of preserved specimens for scars of tail breakage can reveal possible ecological and biological correlates of urotomy. Herein, we investigated how the probability of urotomy in the worm lizard Amphisbaena vermicularis is affected by sex, body size, temperature, and precipitation. We found higher chances of urotomy for specimens with larger body size and from localities with warmer temperatures or lower precipitation. There was no difference in urotomy frequency between sexes. Older specimens likely faced -- and survived -- more predation attempts through their lifetime than smaller ones. Specimens from warmer regions might be more active both belowâ and aboveground, increasing the odds to encounter predators and hence urotomy. Probability of urotomy decreased with increased precipitation. Possibly, in places with heavier rainfall worm lizards come more frequently to the surface when galleries are filled with rainwater, remaining more exposed to efficient predators, which could result in less survival rates and fewer tailless specimens. This interesting defensive behavior is widespread in squamates, but yet little understood among amphisbaenians. The novel data presented here improve our understanding on the correlates of tail breakage and help us to interpret more tales of lost tails.
====
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Free pdf:
Gerardo Carbot-Chanona, Gustavo Rivera-VelÃzquez, Eduardo JimÃnez-Hidalgo, and VÃctor Hugo Reynoso (2020)
The fossil record of turtles and tortoises (Testudines) of Mexico, Central America and the Caribbean Islands, with comments on its taxonomy and paleobiogeography: a bibliographic review.
Revista Mexicana de Ciencias GeolÃgicas (in press)
DOI: http://dx.doi.org/10.22201/cgeo.20072902e.2020.3.1581Â
Testudines is the crown-group that includes all living forms of turtles and their closest extinct relatives. This group is known to exist starting in the Middle Jurassic. The fossil record of Testudines in Mexico is scarce but has been previously compiled in several papers. In this paper, we are presenting an update that includes all osteological and ichnological records of Mexico, and we have added fossil records of turtles and tortoises from Central America and the Caribbean Islands. In Mexico, the Testudines fossil record extends from the Late Jurassic to the Pleistocene, and widely abundant during the late Pleistocene. Kinosternon and Gopherus are the best represented taxa, known from the late Miocene to the late Pleistocene. In Mexico, records of fossil turtles show a wide distribution, except in the areas around the states of Campeche and Quintana Roo in the east; Colima, Guerrero, and Sinaloa in the west, and QuerÃtaro, and Mexico City in the center. Ichnological records are known only in Coahuila, Pueblaand Zacatecas. Reports of fossil turtles in Central America include El Salvador, Honduras, Costa Rica, Nicaragua and Panama--the latter being the country with the most records--and in the Caribbean Islands including Cuba, Dominican Republic, Jamaica, the United States islands of Puerto Rico and Navassa, and the British Island of Sombreroin Anguilla. Seven fossil turtles have been described as new species in Mexico (Notoemys tlaxiacoensis, Yelmochelys rosarioae, Mexichelys coahuilaensis, Allaeochelys liliae, Gopherus donlaloi, G. auffenbergi and G. pargensis, of which G. auffenbergi is synonymous with G. berlandieri, and G. pargensis is considered a nomen vanum); two from Panama (Rhinoclemmys panamaensis and Staurotypus moschus); one from Costa Rica (Rhinoclemmys nicoyama); two from Cuba (Notoemys oxfordensis and Chelonoidis cubensis); one from the Dominican Republic (Chelonoidis marcanoi), one from Puerto Rico (Chelonoidis monensis), and one from Sombrero Island, Anguilla (Chelonoidis sombrerensis).
======
Free pdf:
Philip J. Bergmann, Gen Morinaga, Elyse S. Freitas, Duncan J. Irschick, GÃnter P. Wagner and Cameron D. Siler (2020)
Locomotion and palaeoclimate explain the re-evolution of quadrupedal body form in Brachymeles lizards.
Proceedings of the Royal Society B 287(1938): 20201994
doi: https://doi.org/10.1098/rspb.2020.1994
https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2020.1994
Evolutionary reversals, including re-evolution of lost structures, are commonly found in phylogenetic studies. However, we lack an understanding of how these reversals happen mechanistically. A snake-like body form has evolved many times in vertebrates, and occasionally a quadrupedal form has re-evolved, including in Brachymeles lizards. We use body form and locomotion data for species ranging from snake-like to quadrupedal to address how a quadrupedal form could re-evolve. We show that large, quadrupedal species are faster at burying and surface locomotion than snake-like species, indicating a lack of expected performance trade-off between these modes of locomotion. Species with limbs use them while burying, suggesting that limbs are useful for burying in wet, packed substrates. Palaeoclimatological data suggest that Brachymeles originally evolved a snake-like form under a drier climate probably with looser soil in which it was easier to dig. The quadrupedal clade evolved as the climate became humid, where limbs and large size facilitated fossorial locomotion in packed soils.
News:
Why skinks that lost their legs evolved new ones
=======
Free pdf:
Cindy Xu, Joanna Palade, Rebecca E. Fisher, Cameron I. Smith, Andrew R. Clark, Samuel Sampson, Russell Bourgeois, Alan Rawls, Ruth M. Elsey, Jeanne Wilson-Rawls & Kenro Kusumi (2020)
Anatomical and histological analyses reveal that tail repair is coupled with regrowth in wild-caught, juvenile American alligators (Alligator mississippiensis).
Scientific Reports 10, Article number: 20122
doi: 10.1038/s41598-020-77052-8.
https://www.nature.com/articles/s41598-020-77052-8Â
Cindy Xu, Joanna Palade, Rebecca E. Fisher, Cameron I. Smith, Andrew R. Clark, Samuel Sampson, Russell Bourgeois, Alan Rawls, Ruth M. Elsey, Jeanne Wilson-Rawls & Kenro Kusumi (2020)
Anatomical and histological analyses reveal that tail repair is coupled with regrowth in wild-caught, juvenile American alligators (Alligator mississippiensis).
Scientific Reports 10, Article number: 20122
doi: 10.1038/s41598-020-77052-8.
https://www.nature.com/articles/s41598-020-77052-8Â
Reptiles are the only amniotes that maintain the capacity to regenerate appendages. This study presents the first anatomical and histological evidence of tail repair with regrowth in an archosaur, the American alligator. The regrown alligator tails constituted approximately 6â18% of the total body length and were morphologically distinct from original tail segments. Gross dissection, radiographs, and magnetic resonance imaging revealed that caudal vertebrae were replaced by a ventrally-positioned, unsegmented endoskeleton. This contrasts with lepidosaurs, where the regenerated tail is radially organized around a central endoskeleton. Furthermore, the regrown alligator tail lacked skeletal muscle and instead consisted of fibrous connective tissue composed of type I and type III collagen fibers. The overproduction of connective tissue shares features with mammalian wound healing or fibrosis. The lack of skeletal muscle contrasts with lizards, but shares similarities with regenerated tails in the tuatara and regenerated limbs in Xenopus adult frogs, which have a cartilaginous endoskeleton surrounded by connective tissue, but lack skeletal muscle. Overall, this study of wild-caught, juvenile American alligator tails identifies a distinct pattern of wound repair in mammals while exhibiting features in common with regeneration in lepidosaurs and amphibia.
News:
Complex tail regeneration has been discovered in alligators
=====Â
Free pdf:
Jhonny J. M. Guedes, Henrique C. Costa & Mario R. Moura (2020)
A new tale of lost tails: Correlates of tail breakage in the worm lizard Amphisbaena vermicularis.
Ecology and Evolution (advance online publication)
doi:Âhttps://doi.org/10.1002/ece3.7023
https://onlinelibrary.wiley.com/doi/10.1002/ece3.7023Â
Predator-prey interactions are important evolutionary drivers of defensive behaviors, but they are usually difficult to record. This lack of data on natural history and ecological interactions of species can be overcome through museum specimens, at least for some reptiles. When facing aggressive interactions, reptile species may exhibit the defensive behavior of autotomy by losing the tail, which is also known as "urotomy". The inspection of preserved specimens for scars of tail breakage can reveal possible ecological and biological correlates of urotomy. Herein, we investigated how the probability of urotomy in the worm lizard Amphisbaena vermicularis is affected by sex, body size, temperature, and precipitation. We found higher chances of urotomy for specimens with larger body size and from localities with warmer temperatures or lower precipitation. There was no difference in urotomy frequency between sexes. Older specimens likely faced -- and survived -- more predation attempts through their lifetime than smaller ones. Specimens from warmer regions might be more active both belowâ and aboveground, increasing the odds to encounter predators and hence urotomy. Probability of urotomy decreased with increased precipitation. Possibly, in places with heavier rainfall worm lizards come more frequently to the surface when galleries are filled with rainwater, remaining more exposed to efficient predators, which could result in less survival rates and fewer tailless specimens. This interesting defensive behavior is widespread in squamates, but yet little understood among amphisbaenians. The novel data presented here improve our understanding on the correlates of tail breakage and help us to interpret more tales of lost tails.
====