The Foundation for Sea Turtle Geoarchaeology and Zooarchaeology: Morphology of Recent and Ancient Sea Turtle Nests , St . Catherines Island, Georgia, and Cretaceous Fox Hills Sandstone, Elbert County, Colorado (original) (raw)
Related papers
MODERN AND ANCIENT SEA TURTLE DEPREDATION; AND THE FIRST PROTOSTEGID NEST
Copyrighted Preprint @2023, 2023
Sea turtles preserve clues to their identity in gait symmetry, nest size, position, and morphology. The sequence of nesting activities (nesting ethogram) leaves a sequence of traces on and in the beach. Depredation in a modern rookery (St. Catherines Island, Georgia) drives hatching production. Study of 3,613 nests (1990-2016) documented processes of depredation of loggerhead sea turtles (Caretta caretta Linneaus 1758); initiated by Ghost Crabs (Ocypode quadrata (Fabricius, 1787)) and/or Raccoons (Procyon lotor Linneaus, 1758) upon egg deposition; then transferred to feral hogs (Sus scrofa Linneaus, 1758). Depredation of loggerhead nests presents as traces; leading to deductions about interactions amongst Cretaceous species. Importance of depredation is indicated by great numbers of eggs and multiple nesting events, and by defensive measures thwarting depredation; i.e. covering. The sea turtle nesting ethogram, involves a sequence of 11 steps; preserved as traces or trace fossils. Two instances of sea turtle trace fossils within ethograms are described; a 74 Ma Colorado Fox Hills Nest; and 41+ nests (110 Ma) at Pula, Croatia; interspersed with robust dinosaur bioturbations are nests stepped upon by dinosaurs, tracks of dinosaurs, crocodiles, pterosaurs, sea turtles, birds, and fish. Both of these ancient sites include covering pits, indicating active contemporaneous depredation. At Pula, we describe a float block on the modern beach that represents an ancient analog to modern “hog craters,” representing an Early Cretaceous Dinosaur Depredation Crater containing large round eggs; probably the first described nest of a Protostegid sea turtle. These deductions are substantiated by a Scientific Uncertainty/Certainty Analysis.
PROCEEDINGS OF THE NINETEENTH ANNUAL SYMPOSIUM ON SEA TURTLE CONSERVATION AND BIOLOGY
TM 443:101-103, 1999
NOAA NMFS - 443 PP. 101-103 "The first described fossilized sea turtle nests occur as sedimentary structures preserved in the Fox Hills Sandstone, Elbert County, Colorado. They are Cretaceous analogs to Recent loggerhead sea turtle nests studied on St. Catherines Island, GA (Marsh and Bishop, 1993). Although sea turtles have an extensive geological record extending at least into the Jurassic and Early Cretaceous (Nicholls, 1997; Hirayama, 1997), traces of their terrestrial nesting activities (Caldwell, Carr, and Ogren, 1959; Witherington [and Witherington, 2016]; Hailman and Elowson, 1992) have not been well documented in the literature and fossil traces have only recently been described (Bishop et al., 1997, [ 2011])." N.B. Abstract slightly modified to new literature.
Throwback Thursday: SEA TURTLE NEST STRUCTURES OF THE FOX HILLS FORMATION
Rough Draft (x3)
This short draft "paper" was written as we began to describe a purported fossilized sea turtle nesting sequence in Elbert County, Colorado near the small city of Limon, 80 miles SE of Denver on the western shoreline of the Western Interior Seaway. Until this time no definitive fossilized sea turtle nests had been described in the literature. The opportunity presented itself during a consult for a major mining company. The story is cobbled together from two old draft documents and a new addition.
Ancient Sea Turtle Nests!…from around the World!
Academia Letters, 2021
Trace fossils are traces made in the sediment by ancient animals when they were alive, such as footprints and crawlways. Here we report on the recognition of sea turtle nesting structures in the Recent at St. Catherine's Island (GA), the 74 Ma BP Cretaceous Fox Hills Sandstone on the western shoreline of the Western Interior Seaway, and a newly recognized sea turtle rookery in the in 110 Ma BP late Albian limestone of the proto-Adriatic Sea at Pula, Istria, Croatia. In Croatia, the traces of nesting include 38 covering pits, several open body pits, two egg chambers, and one crawlway entrained in the Late Albian limestones of the Proto-Adriatic Sea. The sea turtle nests are associated with a contemporaneous trample bed made by dinosaurs, with turtle nests deposited on top of the trample bed and exhibit several dinosaur tracks made on top of the nests. The presence of covering pits proves that sea turtles were camouflaging their nests on beaches 110 Ma BP to protect them from depredation. This research is ongoing and will be illuminated by further research publication in the near future. It demonstrates the power of collaborative, international research done from different perspectives of the researchers.
A Review of the Fossil Record of Turtle Reproduction: Eggs, Embryos, Nests and Copulating Pairs
Bulletin of the Peabody Museum of Natural History, 2014
The fossil record of turtle reproduction (e.g., eggs, embryos, nests and copulating pairs) is relatively poor compared with that of dinosaurs. This record extends from the Middle Jurassic to the Pleistocene, and specimens are known from every continent except Antarctica. Fossil turtle eggs are recognized as body fossils, and confident taxonomic identification at the genus or species level is dependent on embryos preserved within fossil eggs or by eggs found within a gravid female. Cladistic analysis of egg and eggshell characters demonstrates a high degree of homoplasy, and only a few characters provide a strong phylogenetic signal. Taphonomic studies of fossil turtle eggs are rare but can elucidate size and number of eggs produced by extinct taxa. Pathological fossil turtle eggs are known from a few localities and provide information about physiological or environmental stresses experienced by the gravid female. Fossil turtle eggs are relatively abundant in Asia, Europe and North America but are poorly represented in Gondwana. An ootaxonomic review of fossil turtle eggs shows that of 15 named ootaxa, 8 are nomina valida, 5 are nomen nudum and 2 are junior synonyms of other ootaxa.
Palaeoecology of Triassic stem turtles sheds new light on turtle origins
Proceedings of the Royal Society of London B Biological Sciences, 2004
Competing hypotheses of early turtle evolution contrast sharply in implying very different ecological settings-aquatic versus terrestrial-for the origin of turtles. We investigate the palaeoecology of extinct turtles by first demonstrating that the forelimbs of extant turtles faithfully reflect habitat preferences, with short-handed turtles being terrestrial and long-handed turtles being aquatic. We apply this metric to the two successive outgroups to all living turtles with forelimbs preserved, Proganochelys quenstedti and Palaeochersis talampayensis, to discover that these earliest turtle outgroups were decidedly terrestrial. We then plot the observed distribution of aquatic versus terrestrial habits among living turtles onto their hypothesized phylogenies. Both lines of evidence indicate that although the common ancestor of all living turtles was aquatic, the earliest turtles clearly lived in a terrestrial environment. Additional anatomical and sedimentological evidence favours these conclusions. The freshwater aquatic habitat preference so characteristic of living turtles cannot, consequently, be taken as positive evidence for an aquatic origin of turtles, but must rather be considered a convergence relative to other aquatic amniotes, including the marine sauropterygians to which turtles have sometimes been allied.
ABSTRACT: Dinosaur reproductive biology is often inferred from the biology of extant taxa; however, taphonomic studies of modern nest sites have focused exclusively on avian, rather than reptilian species. We documented eight Agassiz’s desert tortoise (Gopherus agassizii) nests and ten loggerhead sea turtle (Caretta caretta) nests. Gopherus agassizii excavated burrows up to 70 cm long and laid rigid-shelled eggs 10–12 cm below the burrow floor. The 19 cm 3 12 cm depressions consisted of hard consolidated sand surrounded by a 3–4-cm-high rim and contained 2–5 hatched eggs in a single layer. These hatched egg bottoms represent , 25% of the original egg, and five of 27 contained fully developed dead neonates. Desiccated membrane separated from the egg interior forming pockets that filled with eggshell and sand. Of 106 and 79 eggshell fragments in the hatched egg and surrounding sand, 48% and 23% occurred concave up, respectively. However, the combined numbers of eggshell fragments inside the eggs and in the immediately surrounding sand approximates the 60:40 ratios at in situ avian nests. Therefore, this ratio may provide reliable evidence for hatching sites regardless of the incubation strategy employed by the adult. Caretta caretta nests differed from those of tortoises in their greater depth (, 50 cm) and occurrence in moist, cohesive sand. Clutches contained over 100 pliable-shelled eggs that tore and collapsed upon hatching, without brittle fracture. Failed eggs in two clutches showed five development stages, indicating that the deaths occurred over an extended time period. With the exception of predation, the G. agassizii and C. caretta nests showed no significant eggshell or hatched eggs above the egg chamber.
2018 Frazier et al (Remains of Leatherback turtles, Dermochelys coriacea__RH-6 and HD-6).pdf
PeerJ, 2018
Small, irregular isolated bones identified as remains of leatherback turtles (Dermochelys coriacea) were recovered from Mid to Late Holocene sites at Ra’s al-Hamra and Ra’s al-Hadd, coastal Oman. These provide the third instance of this animal being documented from any prehistoric site anywhere, and the records provide one of the oldest, if not the oldest, dates for this distinctive chelonian—even though they do not refer to fossils. Decades of research in this region has yielded vast amounts of archaeological information, including abundant evidence of intense exploitation and utilization of marine turtles from about 6,500 to 4,000 BP. During part of this period, turtle remains in human burials have been extraordinary; the turtle involved, Chelonia mydas, has been abundant in the region during modern times. Yet despite intense and varied forms of prehistoric marine resource exploitation, and major, long-term archaeological work, no other turtle species has been previously authenticated from these, or other coastal sites. The documentation of remains of the largest and most distinctive of living marine turtles, D. coriacea, at Ra’s al-Hamra and Ra’s al-Hadd, presented herein, provide detailed information that serves as the basis for future interpretations and discussions regarding incomplete, disarticulated remains from the Mid to Late Holocene, particularly in reference to taphonomic questions and diverse environmental conditions.
PeerJ, 2023
Modern sea turtle long bone osteohistology has been surprisingly well-studied, as it is used to understand sea turtle growth and the timing of life history events, thus informing conservation decisions. Previous histologic studies reveal two distinct bone growth patterns in extant sea turtle taxa, with Dermochelys (leatherbacks) growing faster than the cheloniids (all other living sea turtles). Dermochelys also has a unique life history compared to other sea turtles (large size, elevated metabolism, broad biogeographic distribution, etc.) that is likely linked to bone growth strategies. Despite the abundance of data on modern sea turtle bone growth, extinct sea turtle osteohistology is virtually unstudied. Here, long bone microstructure of the large, Cretaceous sea turtle Protostega gigas is examined to better understand its life history. Humeral and femoral analysis reveals bone microstructure patterns similar to Dermochelys with variable but sustained rapid growth through early ontogeny. Similarities between Progostegea and Dermochelys osteohistology suggest similar life history strategies like elevated metabolic rates with rapid growth to large body size and sexual maturity. Comparison to the more basal protostegid Desmatochelys indicates elevated growth rates are not present throughout the entire Protostegidae, but evolved in larger and more derived taxa, possibly in response to Late Cretaceous ecological changes. Given the uncertainties in the phylogenetic placement of the Protostegidae, these results either support convergent evolution towards rapid growth and elevated metabolism in both derived protostegids and dermochelyids, or a close evolutionary relationship between the two taxa. Better understanding the evolution and diversity of sea turtle life history strategies during the Late Cretaceous greenhouse climate can also impact current sea turtle conservation decisions.