Ben Creisler
Non-dino papers that may be of interest:
Free pdf:
Matthew J. Vavrek & Donald B. Brinkman
The first record of a trionychid turtle (Testudines: Trionychidae) from the Cretaceous of the Pacific Coast of North America.
Vertebrate Anatomy Morphology Palaeontology 5: 34-37
DOI: 10.18435/vamp29336
Trionychid turtles were widespread throughout much of the Western Interior Basin of North America during the Cretaceous, represented by a wide variety of taxa. Despite their widespread abundance east of the Rocky Mountains, they have not previously been reported from Cretaceous deposits along the Pacific Coast of North America. We report here on an isolated trionychid costal from Vancouver Island, British Columbia. The fossil was recovered from the Late Cretaceous (Turonian to Maastrichtian) Nanaimo Group, on Vancouver Island, British Columbia. While the fossil is generically indeterminate, its presence adds an important datapoint in the biogeographic distribution of Trionychidae.
=====
Evangelos Vlachos (2018)
A Review of the Fossil Record of North American Turtles of the Clade Pan-Testudinoidea.
Bulletin of the Peabody Museum of Natural History 59(1): 3-94
Turtles of the clade Pan-Testudinoidea have a rich fossil record in North America, including the Caribbean, ranging from the late Paleocene to the Holocene. All earlier reports cannot be substantiated herein. The earliest members of this clade probably immigrated in multiple waves from Asia. Current phylogenies of crown Testudinoidea recognize four primary clades: Pan-Emydidae, Pan-Geoemydidae, Pan-Testudinidae, and the lineage leading to Platysternon megacephalum. An updated global phylogeny allows attribution of fossils to these lineages with confidence that allows the discernment of new diversity trends and biogeographic patterns. The diversity of North American Pan-Testudinidae increased consistently throughout the Cenozoic and reached its peak in the early Miocene. The extinction of many testudinids at the end of the Pleistocene, however, decreased tortoise diversity toward its extant levels. The diversity of North American Pan-Emydidae and Pan-Geoemydidae shows opposite patterns. Pan-Emydidae are remarkably diverse today, but their diversity was low in the Eocene and only increased dramatically from the Oligocene and onwards. Pan-Geoemydidae, on the other side, were diverse in the late Paleocene to Eocene, but their diversity decreases to their extremely low present levels starting with the Oligocene. A taxonomic review of 191 named North and Central American pan-testudinoid taxa finds 57 nomina valida, 69 nomina invalida, 64 nomina dubia, and 1 nomen nudum.
===========
Free pdf:
Konstantin Hallmann Â& Eva Maria Griebeler (2018)
An exploration of differences in the scaling of life history traits with body mass within reptiles and between amniotes.
Ecology and Evolution (advance online publication)
Free pdf:
Allometric relationships linking species characteristics to body size or mass (scaling) are important in biology. However, studies on the scaling of life history traits in the reptiles (the nonavian Reptilia) are rather scarce, especially for the clades Crocodilia, Testudines, and Rhynchocephalia (single extant species, the tuatara). Previous studies on the scaling of reptilian life history traits indicated that they differ from those seen in the other amniotes (mammals and birds), but so far most comparative studies used small species samples and also not phylogenetically informed analyses. Here, we analyzed the scaling of nine life history traits with adult body mass for crocodiles (n = 22), squamates (n = 294), turtles (n = 52), and reptiles (n = 369). We used for the first time a phylogenetically informed approach for crocodiles, turtles, and the whole group of reptiles. We explored differences in scaling relationships between the reptilian clades Crocodilia, Squamata, and Testudines as well as differences between reptiles, mammals, and birds. Finally, we applied our scaling relationships, in order to gain new insights into the degree of the exceptionality of the tuatara's life history within reptiles. We observed for none of the life history traits studied any difference in their scaling with body mass between squamates, crocodiles, and turtles, except for clutch size and egg weight showing small differences between these groups. Compared to birds and mammals, scaling relationships of reptiles were similar for timeârelated traits, but they differed for reproductive traits. The tuatara's life history is more similar to that of a similarâsized turtle or crocodile than to a squamate.
========
Ilse Corkery, Ben D.Bell & Nicola J.Nelson (2018)
Thermoregulation of a temperate reptile in a forested habitat.
Zoology 127: 63-69
Highlights
Tuatara are known to be capable of precise thermoregulation in a laboratory setting.
However, in the wild there is a large amount of variation among individuals in their accuracy and amount of time spent thermoregulating.
Variation in body temperature and effectiveness of thermoregulation could not be attributed to sex or body size.
Variation among individuals in timing of burrow use did affect body temperature.
The accuracy of thermoregulation was more effective when sharing a burrow with a seabird.
Abstract
A major focus in zoology is to understand the phenotypic responses of animals to environmental variation. This is particularly important when dealing with ectotherms in a thermally heterogenous environment. We measured body temperatures of a free-ranging, medium sized temperate reptile, the tuatara, Sphenodon punctatus, to investigate its thermal opportunities and the degree to which the animal actively regulates its body temperature. We found high variation in body temperature between individuals, but this variation could not be attributed to sex or body size. However, variation among individuals in timing of burrow use did affect body temperature and in one of the years studied tuatara were found to be more effective in their thermoregulation when sharing a burrow with a seabird (Pachyptila turtur). The strength of this study is that it includes both biotic and behavioural components of the thermal environment of a temperate reptile, areas which are often missing from thermal studies that focus on the abiotic aspects.
====
Free pdf (for now):
Agata Staniewicz, Uthen Youngprapakorn, and Gareth Jones (2018)
First Report of Physiological Color Change in a Crocodilian.
Copeia 106(2): 264-267
Free pdf (temporary):
Physiological color change in animals is a rapid process involving the redistribution of pigments within chromatophores, and may have roles in camouflage, communication, or thermoregulation. Although observed in other ectotherms, it has not previously been documented in crocodilians. Using wild and captive Sunda gharials (Tomistoma schlegelii), we confirm rapid ventral color change in juveniles, as evidenced by significantly darker ventral scales in illuminated vs. dark environments. We also found that color varied significantly with body size, with larger individuals losing the ability to change color, and by testing environmental factors potentially triggering color changeâtemperature, ambient light, background color, or stressâwe report that illumination was the only factor observed to explain the change. Our results reveal an unusual trait not corresponding to established countershading patterns, which provides a basis for further research not only into crocodilian behavioral ecology and physiology, but also into animal camouflage and convergent evolution. These results add further evidence to Tomistoma being an evolutionarily distinct lineage of crocodilian, confined to the threatened peat swamp habitats of Southeast Asia.
====
Edward B. Daeschler & Jason P. Downs (2018)
New description and diagnosis of Hyneria lindae (Sarcopterygii, Tristichopteridae) from the Upper Devonian Catskill Formation in Pennsylvania, U.S.A.Â
Journal of Vertebrate Paleontology Article: e1448834Â
DOI: 10.1080/02724634.2018.1448834.
Thomson (1968 Thomson, K. S. 1968. A new Devonian fish (Crossopterygii: Rhipidistia) considered in relation to the origin of the Amphibia. Postilla 124:1â13, Postilla 124:1â13) described and diagnosed the tristichopterid Hyneria lindae from parts of a disarticulated skull and isolated scales recovered from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A. Since the publication of that description, knowledge of the tristichopterid clade has grown significantly, with numerous new descriptions of Famennian taxa from around the world. Additionally, a concerted effort to collect vertebrates from the Catskill Formation in Pennsylvania has produced significant new material of Hyneria lindae from the type locality at Red Hill, Clinton County, Pennsylvania. The new material serves as the basis for a rediagnosis and redescription of Hyneria lindae. The species is uniquely diagnosed by features including scales with a fringed free margin, a wide and blunt snout, and short intertemporals. The redescription of H. lindae gives occasion to review all of the Catskill Formation tristichopterid material that requires further diagnosis. This includes a near-complete cranial specimen collected near Red Hill that was originally diagnosed as Eusthenodon wÃngsjÃi by Thomson (1976 Thomson, K. S. 1976. The faunal relationships of rhipidistian fishes (Crossopterygii) from the Catskill (Upper Devonian) of Pennsylvania. Journal of Paleontology 50:1203â1208; Journal of Paleontology 50:1203â1208) and is here revised as Hyneria cf. lindae and figured for the first time. The emerging sample of tristichopterids from the Catskill Formation informs the diversity and paleobiogeography of these large predators in the fluvial ecosystems of the Red Hill site and within the Catskill Delta complex.