Sea Turtles Research Articles

Baseline Skin Microbiota of the Leatherback Sea Turtle

The integumentary system of the leatherback sea turtle (Dermochelys coriacea) is the most visible and defining difference of the species, with its smooth and waxy carapace and finely scaled skin, distinguishing it from the other six sea turtle species. The skin is the body’s largest organ and serves as a primary defense against the outside world and is thus essential to health. To date, we have begun to understand that the microorganisms located on the skin aid in these functions. However, many host–microbial interactions are not yet fully defined or understood. Prior to uncovering these crucial host–microbial interactions, we must first understand the communities of microorganisms present and how they differ through life-stage classes and across the body. Here, we present a comprehensive bacterial microbial profile on the skin of leatherbacks. Using next-generation sequencing (NGS), we identified the major groups of bacteria on the skin of neonates at emergence, neonates at 3–4 weeks of age (i.e., post-hatchlings), and nesting females. These data show that the predominant bacteria on the skin of the leatherback are different at each life-stage class sampled. This suggests that there is a shift in the microbial communities of the skin associated with life-stage class or even possibly age. We also found that different sample locations on the nesting female (i.e., carapace and front appendages = flipper) have significantly different communities of bacteria present. This is likely due to differences in the microhabitats of these anatomic locations and future studies should explore if this variation also holds true for neonates. These data define baseline skin microbiota on the leatherback and can serve as a foundation for additional work to broaden our understanding of the leatherbacks’ host–microbial interactions, the impacts of environmental changes or stressors over time, and even the pathogenicity of disease processes.

Herpesvirus (CHHV-5) associated with fibropapillomatosis in sea turtles in Brazil: an integrative review

A presente pesquisa teve como objetivo compreender como o herpesvírus associado a fibropapilomatose afeta as tartarugas marinhas no litoral brasileiro. Para isso, realizou-se um estudo de revisão integrativa, guiado pela seguinte pergunta norteadora: Quais as evidências científicas sobre como o herpesvírus (ChHV-5) associado a fibropapilomatose afetam as tartarugas marinhas no litoral brasileiro?. Para o levantamento dos artigos na literatura, realizou-se uma busca nas seguintes bases de dados: 1. Portal de periódicos da Capes (CAPES) e 2. Science Direct. Foram utilizados, para busca dos artigos, os seguintes descritores e suas combinações na língua portuguesa e inglesa: fibropapilomatose e tartarugas verdes; herpesvírus e fibropapilomatose; fibropapilomatose e tartarugas marinhas; fibropapilomatose e Chelonia mydas; fibropapilomatose e costa brasileira. Tratando-se dos critérios de inclusão definidos para a seleção dos artigos estes foram: publicações disponibilizadas em portugues, inglês e espanhol; disponibilidade dos textos na versão integral; periódicos revisados por pares; período de publicação entre janeiro de 2017 e abril de 2022; busca por artigos científicos, excluindo-se outros tipos de trabalhos (teses, dissertações, livros e resenhas). Quanto aos critérios de exclusão foram as publicações em duplicidade e aquelas em que o objeto de estudo não estabelecia relação com o tema abordado. A partir das definições, critérios e combinações de palavras-chaves definidas para o estudo foram localizadas 161 publicações. A amostra final foi composta por cinco artigos. De acordo com os resultados foi possível constatar que todas as diferentes avaliações encontradas na presente revisão integrativa, demonstraram a presença do agente e da doença em tartarugas verdes no Brasil. Devido à história de vida complexa das tartarugas-verdes (Chelonia mydas), é difícil quantificar o impacto que a fibropapilomatose ocasiona na população destes indivíduos. No entanto, a presença em alta frequência de indivíduos portadores, o caráter multifatorial da fibropapilomatose, as ações antrópicas e as atividades econômicas desenvolvidas na região contribuem tanto para a manutenção do ChHV-5 como para o desenvolvimento da forma clínica da doença. Sendo assim, mesmo perante a dificuldade de quantificar o impacto do ChHV-5, a ocorrência agente infeccioso interfere negativamente na população Chelonia mydas. Dessa forma, estudos futuros são necessários para elucidar os efeitos intra e interpopulacionais da fibropapilomatose entre Chelonia mydas e as correlações com os fatores ambientais e atividades antrópicas.

Comparison of Bacterial Contamination in Sea Turtle Natural and Semi-natural Hatching Nest at Boom Beach Banyuwangi

Comparison of Bacterial Contamination in Sea Turtle Natural and Semi-natural Hatching Nest at Boom Beach Banyuwangi

High Loggerhead (Caretta caretta) Bycatch Rate along with Several Endangered Target Species: Two Reasons to Look for Alternative to Traditional Large-Mesh Bottom-Set Gillnets (Garrasia) for More Sustainable Fisheries in the Gulf of Gabès (Tunisia)

Fishery bycatch poses a significant threat to sea turtles. This study provides an updated assessment of Loggerhead turtle (Caretta caretta) bycatch in the Gulf of Gabès, focusing on the impact of the Garrasia gillnets. Through 61 onboard observations conducted alongside fishermen in Zarzis deploying a bottom-set gillnet, called “Garrasia”, and targeting elasmobranch species, comprehensive data were collected, including the number of sea turtles captured, soak time, length of gillnets, location, and biometric data of sea turtles. Analysis revealed a catch per unit effort (CPUE) for sea turtles of 0.63 (95% CI [0.355–0.893]) turtles per kilometer per 24 h with a notably high mortality rate of 92.06% (95% CI [87.3–96.8]). In the Gulf of Gabès, 23 vessels are reported to use Garrasia, resulting in an estimated annual total capture of 3756.53 turtles with a 95% CI [1907.81–5902.30]. These findings underscore the significant impact of Garrasia on sea turtle populations in the Gulf of Gabès. The study calls for immediate collaborative efforts among researchers, local stakeholders, authorities and fishermen to elaborate balanced conservation strategies that consider both ecological sustainability and socio-economic factors, aiming to achieve a sustainable marine ecosystem.

Global mercury concentrations in biota: their use as a basis for a global biomonitoring framework.

An important provision of the Minamata Convention on Mercury is to monitor and evaluate the effectiveness of the adopted measures and its implementation. Here, we describe for the first time currently available biotic mercury (Hg) data on a global scale to improve the understanding of global efforts to reduce the impact of Hg pollution on people and the environment. Data from the peer-reviewed literature were compiled in the Global Biotic Mercury Synthesis (GBMS) database (>550,000 data points). These data provide a foundation for establishing a biomonitoring framework needed to track Hg concentrations in biota globally. We describe Hg exposure in the taxa identified by the Minamata Convention: fish, sea turtles, birds, and marine mammals. Based on the GBMS database, Hg concentrations are presented at relevant geographic scales for continents and oceanic basins. We identify some effective regional templates for monitoring methylmercury (MeHg) availability in the environment, but overall illustrate that there is a general lack of regional biomonitoring initiatives around the world, especially in Africa, Australia, Indo-Pacific, Middle East, and South Atlantic and Pacific Oceans. Temporal trend data for Hg in biota are generally limited. Ecologically sensitive sites (where biota have above average MeHg tissue concentrations) have been identified throughout the world. Efforts to model and quantify ecosystem sensitivity locally, regionally, and globally could help establish effective and efficient biomonitoring programs. We present a framework for a global Hg biomonitoring network that includes a three-step continental and oceanic approach to integrate existing biomonitoring efforts and prioritize filling regional data gaps linked with key Hg sources. We describe a standardized approach that builds on an evidence-based evaluation to assess the Minamata Convention's progress to reduce the impact of global Hg pollution on people and the environment.

Tracking shifts in Society Islands marine subsistence through time: Intra‐site analysis of faunal remains and fishing gear

AbstractWe discuss new data from Colonization Phase and Early Expansion/Development Phase assemblages in the pre‐contact Society Islands. We focus on analysis of marine faunal remains and fishing gear to infer diachronic shifts in subsistence practices at two well‐dated coastal sites. Both Colonization Phase (AD 950–1200) and Early Expansion Phase (AD 1200–1450) faunal assemblages are dominated by fish and mollusks as opposed to animal domesticates. Colonization Phase assemblages see higher capture of Scombrids and higher capture of marine mammals and turtle. Early Expansion fishhook assemblages and faunal remains document a movement towards increased capture of reef fish as well as the adoption of local styles and locally specific fishing practices. Overall, the diachronic trend in the Society Island diets is towards a decrease in turtle, marine mammal, and wild bird remains and an increase in terrestrial domesticated species roughly two hundred years after colonization, similar to patterns seen elsewhere in Eastern Polynesia.

Osteolytic Lesions in a Sub-Adult Loggerhead Sea Turtle (Caretta caretta): A Case Report

Osteolytic lesions in loggerhead sea turtles (Caretta caretta) during rehabilitation are attributed to multiple causes, including gas embolism, hypothermia, and osteomyelitis due to bacterial or fungal infection. This study reports the appearance of osteolytic lesions in a sub-adult loggerhead sea turtle with involvement of the right fore and hind flippers, visible swelling of the elbow and knee joints, and accompanied by lameness after 45 days of rehabilitation. Radiographs and computed tomography revealed multiple lytic bone lesions. This was the fourth rehabilitation admission of the turtle after being accidentally captured by trawler ships (bycatch) in 2019, 2020, 2022, and 2023. Potential causes were dysbaric osteonecrosis due to a past decompression sickness event and hypothermia with osteomyelitis from bacterial infection. Blood cultures and antibiotic susceptibility testing led to the isolation of Ewingella americana responsive to enrofloxacin. This study investigates extensive fore and hind flipper involvement in a sub-adult loggerhead turtle, aiming to determine causes and risk factors. The pathogenesis and significance of these lesions is discussed.

Fine-scale foraging ecology and habitat use of sympatric green and hawksbill turtles in the Western Indian ocean

Using stable isotope analysis of carbon and nitrogen of turtle tissues and putative prey items, we investigated the diet of immature green turtles and hawksbill turtles foraging in the lagoon of Aldabra Atoll, a relatively undisturbed atoll in the southern Seychelles. Aldabra offers a unique environment for understanding sea turtle ecology. Green turtles mostly consumed seagrass and brown algae while hawksbill turtles mainly consumed mangroves and invertebrates. Green turtles showed a dietary shift with size (a proxy for age). There was minimal niche overlap between species and evidence of small-scale foraging site fidelity with turtle tissue reflecting site-specific prey. This highlights the ecological importance of seagrass and mangrove habitats and suggests that turtles play a role in controlling algal biomass at Aldabra. This study is the first to closely examine the foraging ecology of these sympatric turtle species in the Western Indian Ocean, a globally important region for both species.

Biophysical characteristics of coastal habitat at Geleang island Karimunjawa National Park as a nesting area hawksbill turtle (Eretmochelys imbricata, Linnaeus 1766)

The hawksbill turtle (E. imbricata) are internationally Critically Endangered as determined by the IUCN. For this reason, action is needed to preserve the sea turtle in the future. The purpose of this study was to determine the bio-physical characteristics of the beach (beach width and slope; pH, temperature, grain size and sand moisture; nest size; nest distance from high tide; beach vegetation and predators) where hawksbill turtles (E. imbricata) lay their eggs on Geleang Island, Karimunjawa National Park. Concerning conservation, the number, condition, egg removal techniques and egg maintenance found on Geleang Island from January to February 2022 were also described. The research was conducted from January to April 2022 using the observation method which includes field observation and primary data collection. The results showed that Geleang Island has a narrow beach width with a gentle slope. The pH of the sand ranges from 6.5 - 7, the average sand temperature variable is around 28˚C. Sand humidity has a value range of 82% - 90%. Sand grain analysis on Geleang Island, the results of the most retained sediment were found to be on test sieves with a diameter of 250 µm so that it was classified as a type of medium sand. The dominant vegetations are sea pine (Casuarina equisetifolia) and gabusan (Scaevola taccada). No predators of hatchlings were found on Geleang Island. The amount of hawksbill turtle eggs found on Geleang Island from January to February 2022 amounted to 1.981 eggs.Keywords: Characteristic of coastal habitat; hawksbill hatchlings

Endocrine data provide further evidence of physiologic derangement in sea turtles affected by the Deepwater Horizon oil spill

This study was conducted to characterize the adrenocortical and thyroid status of Kemp’s ridley sea turtles Lepidochelys kempii that were affected by the Deepwater Horizon oil spill. A plasma aldosterone assay was validated for L. kempii, and it was used along with previously validated assays for corticosterone and free thyroxine to assess hormone concentrations of 30 L. kempii that were hospitalized due to oil exposure, representing 2 severities of oiling (lightly or heavily oiled). Hormone concentrations were also assessed in relation to 8 clinical biochemical analytes. Analysis of paired samples indicated that oiled turtles had significantly higher initial aldosterone and corticosterone concentrations, which declined during convalescence (average 96 and 90% decrease, respectively). Thyroxine concentrations significantly increased between admission and convalescence (average 65% increase). Initial biochemical data indicated significantly higher plasma potassium, ionized magnesium, and lactate concentrations compared to convalescent values. Aldosterone concentrations were positively correlated with corticosterone, negatively correlated with free thyroxine, and variably correlated with several clinical biochemical analytes. Results of this study indicate that L. kempii had robust adrenocortical activity after oiling, capture, and transport to the hospital, regardless of the degree of oiling, resulting in very high plasma concentrations of aldosterone and corticosterone. This study also confirms that aldosterone can be reliably measured in sea turtle plasma samples, providing another diagnostic tool for the physiologic assessment of this Critically Endangered species.

Tracing the origins of sea turtle eggs in the markets of Costa Rica

AbstractUnsustainable wildlife trade is a major contributor to biodiversity loss; however, trade regulations have failed to prevent the decline of high‐profile species. Where wildlife is traded legally, opportunities exist to launder protected species through legal channels. The legal commercialization of olive ridley sea turtle eggs from Ostional, Costa Rica, has been criticized with some suggesting that the legal trade stimulates illegal extraction and sale of eggs. We aimed to identify whether the traceability rules, under which the Ostional project operates, were suitably robust. We surveyed markets across Costa Rica, by purchasing openly available sea turtle eggs and recording qualitative and quantitative data at the point of sale. We found that 378 (80%) of turtle eggs openly sold in the market were from olive ridley sea turtles. Green (n = 5) and leatherback (n = 6) turtle eggs were only on offer on three occasions, but no vendor referred to Ostional. Vendors frequently breached trade regulations, which appeared to be due to these regulations misaligning with consumer demand. Although the Ostional traceability rules are regularly flouted, we found no evidence that Ostional is being used as a cover to sell eggs from other turtle species.

Exceptionally preserved shark fossils from Mexico elucidate the long-standing enigma of the Cretaceous elasmobranch Ptychodus.

The fossil fish Ptychodus Agassiz, 1834, characterized by a highly distinctive grinding dentition and an estimated gigantic body size (up to around 10 m), has remained one of the most enigmatic extinct elasmobranchs (i.e. sharks, skates and rays) for nearly two centuries. This widespread Cretaceous taxon is common in Albian to Campanian deposits from almost all continents. However, specimens mostly consist of isolated teeth or more or less complete dentitions, whereas cranial and post-cranial skeletal elements are very rare. Here we describe newly discovered material from the early Late Cretaceous of Mexico, including complete articulated specimens with preserved body outline, which reveals crucial information on the anatomy and systematic position of Ptychodus. Our phylogenetic and ecomorphological analyses indicate that ptychodontids were high-speed (tachypelagic) durophagous lamniforms (mackerel sharks), which occupied a specialized predatory niche previously unknown in fossil and extant elasmobranchs. Our results support the view that lamniforms were ecomorphologically highly diverse and represented the dominant group of sharks in Cretaceous marine ecosystems. Ptychodus may have fed predominantly on nektonic hard-shelled prey items such as ammonites and sea turtles rather than on benthic invertebrates, and its extinction during the Campanian, well before the end-Cretaceous crisis, might have been related to competition with emerging blunt-toothed globidensine and prognathodontine mosasaurs.

Carapace Scute Variations of the Olive Ridley Sea Turtle (<i>Lepidochelys olivacea</i>): Polymerization as an Evolutionary Trend

The carapace scute pattern is an important morphological feature of turtles that, along with the phylogenetic stability, has a high level of intraspecific variability. The olive ridley sea turtle (Lepidochelys olivacea; Cheloniidae) demonstrates extreme instability of pholidosis, and the aim of our study is to identify the range of the carapace scute variations in this species. We studied 655 L. olivacea hatchlings from nine natural clutches on the Southern coast of Sri Lanka and identified 120 different patterns of carapace scutes. The vertebral and pleural scutes were the most variable, ranging in number from four or five to ten. Five pairs of pleural scutes, a normal condition for some species of sea turtles, were found in only 11.9% of individuals. The hatchlings with six and seven scutes in the vertebral and pleural series were the most numerous. 13 pairs of marginal scutes were the stable norm in 92.7% of individuals. Newborn turtles with symmetrical scute patterns predominated (60.9%). Comparison of the pholidosis variability in hatchlings from different clutches revealed the presence of specific scute patterns. We assume that the clutch differences are more related to the genetic characteristics of the breeding turtles than to the influence of environmental factors. The unique variable pholidosis of L. olivacea demonstrates a trend toward scute polymerization, a rare phenomenon in turtle evolution.

The effects of substrate temperature on the reproductive success of Caretta caretta on a volcanic beach in the Mediterranean Sea

A five-year of monitoring (2018–2022) of the loggerhead sea turtle Caretta caretta nests in “Pozzolana di Ponente” beach on Linosa Island (Pelagie Archipelago, Italy) is here reported. To explore how temperatures affect the hatching success and the possible occurrence of any malformation in hatchlings, incubation temperature values were recorded using data loggers positioned at depths of 5 and 35 cm (for each nest) from the surface, approximately 0.5 m from the nest chamber. The obtained results highlighted important issues related to the success of hatching and the incidence of body anomalies. The temperatures recorded at different depths near the nests (5 and 35 cm) in some periods of incubation of the eggs were above optimal development temperature (i.e., ~33°C), causing high mortality rates, especially during the first two years of the survey (2018–2019). In the next three years (2020–2022), the implementation of shading cover cloths of the nests increased the survival rate and decreased the incidence of malformed individuals. Furthermore, atmospheric temperature data were extrapolated from the “Copernicus Climate Change” web service and included in our analyses to assess any changes over the timeframe analysed. Over five years (2018–2022), the average atmospheric temperature increased slightly by 1.7°C. In light of global warming, the implementation of effective and low-cost mitigation activities, such as the use of shade cloth covers to protect the nests from overheating, should be considered a suitable conservation action.

Genomic Characterization of Listeria monocytogenes and Other Listeria Species Isolated from Sea Turtles.

Listeria monocytogenes is a ubiquitous pathogen found both in the environment and food. It can cause listeriosis in a wide range of animals as well as in humans. Investigations on presence, spread and virulence are still limited to terrestrial and human environments. Embracing the One Health Approach, investigating the presence and spread of L. monocytogenes in marine ecosystems and among wildlife, would provide us with useful information for human health. This study investigated the presence of L. monocytogenes and Listeria spp. in two species of sea turtles common in the Mediterranean Sea (Caretta caretta and Chelonia mydas). A total of one hundred and sixty-four carcasses of sea turtles (C. caretta n = 161 and C. mydas n = 3) stranded along the Abruzzo, Molise, Campania, and Calabria coasts, were collected. Brain and fecal samples were taken, enriched, and cultured for the detection of Listeria spp. From the specimens collected, strains of L. monocytogenes (brain n = 1, brain and feces n = 1, multiorgan n = 1 and feces n = 1), L. innocua (feces n = 1 and brain n = 1), and L. ivanovii (brain n = 1) were isolated. Typical colonies were isolated for Whole Genome Sequencing (WGS). Virulence genes, disinfectants/metal resistance, and antimicrobial resistance were also investigated. L. monocytogenes, L. innocua, and L. ivanovii were detected in C. caretta, whilst only L. monocytogenes and L. innocua in C. mydas. Notable among the results is the lack of significant differences in gene distribution between human and sea turtle strains. Furthermore, potentially pathogenic strains of L. monocytogenes were found in sea turtles.

The tale of the sea turtle flipper tagging technique, a global environmental impact assessment

AbstractAlthough sea turtle flipper tagging is a tenet field technique generating irreplaceable scientific data worldwide since the inception of sea turtle conservation in 1920s along the Great Barrier Reef, the procedure was reported to trigger outbreaks of sea turtle fibropapillomatosis (FP) in 2018. This global environmental impact assessment performed during 2020–2023 meta‐analyzed three impacts on sea turtles health and conservation of the presence of visible flipper tags: a risk of clinical expression of FP lesions at the tag insertion point, a deterrent effect of the presence of flipper tags on sea turtle fishing, and a risk of entanglement of sea turtles in fishing gears. This essay concluded that the risk of expression of a FP lesion at the flipper tag insertion point is most probably correlated to a direct inoculation of ChHV5 via infected tagging equipment, and that the risk of entanglement in fishing gears can be mitigated by the choice of metallic flipper tags over plastic flipper tags. This essay also strongly recalls the sea turtle flipper tagging technique represents a remedy to knowledge gaps relevant to climate velocity research and can be a deterrent on sea turtle fishing in a frame of strong partnerships with indigenous people, independently of communities' socio‐cultural backgrounds.

Influence of sand grain size on the nest escape of green sea turtle hatchlings

Sea turtle hatchlings rely on their finite energy reserve to sustain embryonic development in underground nests and during the first few days of their post-hatch life, including nest escape, beach crossing, and swimming offshore. This study aimed to investigate if the grain size of the nest substrate has an impact on green sea turtle (Chelonia mydas) hatchlings’ energy usage during nest escape. About-to-hatch green sea turtle eggs were incubated in laboratory chambers filled with either coarse-grain sand (φ = 0.507 phi) or fine-grain sand (φ = 2.028) at a temperature of 28oC. Open-flow respirometry was used to measure the hatchlings’ oxygen consumption rate during nest escape, which was then converted to energy consumption values. Results showed that hatchling morphology, hatching success, emergence success, and synchronous emergence rate were not significantly different between the groups of hatchlings in coarse versus fine sand. Hatchlings that dug through coarse sand emerged significantly faster (168 ± 13.9 h) than those in fine sand (233.21 ± 12.6 h) (t (26) = –3.473, p = 0.002). Additionally, the hatchlings in coarse sand (310.55 ± 28.1 kJ) consumed significantly less energy than hatchlings in fine sand (474.85 ± 64.7 kJ) (t (17.739) = –2.328, p = 0.032). A difference in amount of energy reserve upon emergence was detected between coarse and fine sand groups. To improve hatchery management practices, relocating “doomed” clutches into coarse sand (φ = 0.507) could potentially maximise the hatchlings’ energy reserve.

Morphological variation of the cirri and penis in the hermaphroditic sea-turtle barnacle Chelonibia testudinaria (Linnaeus, 1758) (Cirripedia: Balanomorpha: Chelonibiidae)

Abstract Phenotypic plasticity of the penis and cirri of acorn barnacles is well documented for intertidal species. We investigated whether these phenomena also occur in the epizoic sea-turtle barnacle, Chelonibia testudinaria (Linnaeus, 1758). We compared the morphologies of the penis and cirri, and fertilization rates for adult, hermaphroditic barnacles on different regions of the carapace of sea turtles, and at different levels of crowding on the carapace. Barnacles were more abundant in the posterior position of loggerhead sea turtles, Caretta caretta (Linnaeus, 1758), followed by the central, central costal, and anterior positions. Barnacles in clustered groups were fertilized 68% more often than solitary individuals. Penis size increased with barnacle size and among individual sea turtles. Cirrus length and width also varied with barnacle size, among individual sea turtles, and among positions. Larger barnacles had longer and wider feeding cirri, and cirri were longer and wider in the central and posterior positions of the carapace than in the anterior and central costal positions. The phenotypic plasticity of the morphologies of the penis and cirrus is far less dramatic in Ch. testudinaria than in intertidal species. This may be explained by the epizoic barnacles not being permanently fixed and able to move to preferred positions on the host shell.

Turtles for the ancestors: A zooarchaeological study of ritual deposits on Fakahina, Tuamotu archipelago (French Polynesia)

AbstractRituals and feasting ceremonies at Polynesian marae depict culturally complex relationships between humans and animals that cannot be explained by subsistence alone. In Central‐East Polynesia, this topic still requires the elaboration of a “ritual zooarchaeology” framework. Using sea turtle assemblages from three sacred sites on Fakahina atoll (Tuamotu), this study offers a preliminary approach to faunal deposits from ritual contexts. Following systematic excavations of marae on Fakahina, analysis aimed to determine whether faunal deposits could be linked with intentional feasting and offering behaviours. To detect how ritual actions were organised through space, skeletal and taphonomic variables were examined for both overall sites and “sub‐assemblages” within sites based on the spatial associations of fauna with site features.At certain site features, derived quantitative units such as %MAU and recovery rate could identify potential offering behaviours through the intentional sorting of culturally significant body parts. The taphonomic signatures of site features could also identify open or closed deposition environments, assisting with the identification of disturbed features as either exposed platforms or enclosed cists. In addition to highlighting previously undocumented complexity in the use of site features, an overall comparison of turtle remains from the three sites shows the potential of these methods to explore variation in ritual practices.

New occurrences of the bone-eating worm Osedax from Late Cretaceous marine reptiles and implications for its biogeography and diversification.

The bone-eating worm Osedax is a speciose and globally distributed clade, primarily found on whale carcasses in marine environments. The earliest fossil evidence for Osedax borings was previously described in plesiosaur and sea turtle bones from the mid-Cretaceous of the United Kingdom, representing the only unequivocal pre-Oligocene occurrences. Confirming through CT scanning, we present new evidence of Osedax borings in three plesiosaur specimens and, for the first time, identify borings in two mosasaur specimens. All specimens are from the Late Cretaceous: one from the Cenomanian of the United Kingdom, two from the Campanian of the southeastern United States, and two from the Maastrichtian of Belgium. This extends the geographic range of Osedax in the Cretaceous to both sides of the northern Atlantic Ocean. The bones contain five borehole morphotypes, potentially created by different species of Osedax, with the Cenomanian specimen containing three morphotypes within a single tooth. This combined evidence of heightened species diversity by the Cenomanian and broad geographic range by the Campanian potentially indicates an earlier origin and diversification for this clade than previously hypothesized. Preservational biases indicate that Osedax was probably even more widely distributed and speciose in the Cretaceous than apparent in the fossil record.