A large platypterygiine ichthyosaur from the Late Cretaceous of Poland and its macropredatory adaptations

Data from a comprehensive study into the lithological composition and lateral distribution of Albian and Cenomanian deposits in the Middle Dnister region (Ukraine), in the watersheds of the Smotrych–Tarnava–Studenytsia–Ushytsia–Kalyus–Zhvan–Lyadova–Nemiya–Murafa–Rusava–Markovka rivers, are presented in the paper. Cretaceous deposits of Volyn-Podillia are part of the terrigenous-carbonate subformation of the Jurassic-Cretaceous carbonate formation (J3–K1) and the glauconite Cretaceous formation (K1al3–K2), which includes gaizeous (K1al3–K2s1), siliceous-chalk (K2s2–K2k) and marl-gaizeous (K2sn–K2m) subformations. Cretaceous deposits of the Middle Dnister region are represented by the lower (Albian stage) and upper parts (Cenomanian stage).The study is focused on the distribution of micro- and macrofauna (e.g. molluscs, calcareous nannoplankton) in the Albian and Cenomanian deposits and their facies affiliation, as well as on the quantitative analysis of organic remains and palaeoecological conditions. Differences in homogeneous conditions of sedimentation within the epicontinental sea basin of the modern Middle Dnister region at the Early-Late Cretaceous boundary were insignificant. Due to a study of Cretaceous macro- and microfauna, its facies distribution, quantitative analysis, and palaeoecological conditions, it is possible to trace slight differences between close homogeneous conditions of sedimentation within the relatively homogeneous sea basin of the Middle Dnister region on the verge of the Early and Late Cretaceous. This shallow epicontinental sea was characterized by normal salinity and well-aerated warm waters with temporary strong bottom currents within shallow water and with maximum depths up to 150–200 m in some areas and soft muddy bottom of deep-water areas. Phosphatisation of the early-middle Cenomanian fauna is evidence for the important role of the Carpathian upwelling at that time. Geochemically active phosphorus is concentrated on shelf due to changes in salinity, temperature, pH, CO2 content and other parameters of the aquatic environment, which were characteristic for this region of Volyn-Podillia.

A list of 51 localities of fossil sea turtles from the Middle Jurassic, Early and Late Cretaceous, Paleocene, Eocene and Miocene of Russia, Uzbekistan, Kazakhstan, Tajikistan, and Ukraine is provided. For four localities in Tajikistan, Kazakhstan, and Ukraine presence of sea turtles is not confirmed by current data. Two new taxa, Dollochelys rogovichi sp.nov. (Cheloniidae, Eocene, Ukraine) and Turgaiscapha kushmurunica gen. et sp.nov. (Chelonioidea indet., cf. Dermochelyidae, Late Cretaceous, Kazakhstan), are described.

Functional morphology," in its broadest sense, is simply the study of relationships between biological form and its functions."Function" can include many different aspects of an organism's biological adaptations, but in this context, and as most often used in physical anthropology, I will concentrate on mechanical function.There is a very long history of interest in the mechanical significance of anatomical variation (Galilei, 1638).Engineering principles were applied to the human skeleton by anatomists and orthopedic surgeons in the 1800s, most famously by Wolff (1892), whose name became associated with the concept of bone functional adaptation (i.e., "Wolff's Law"), despite many problems with the original formulation of the concept (Ruff, Holt, & Trinkaus, 2006).Comparative anatomists and anthropologists were aware of this work (Keith, 1918;Morton, 1924).However, the actual application of mechanical principles to the interpretation of extant and fossil humans and other primates was relatively rare during the early history of physical anthropology.Today, functional morphological studies make up a significant and expanding component of research in our field, due to many conceptual and technical advances over the past 100 years, particularly during the past 50 years.In this article, I review these developments, focusing in particular on the role of the AJPA as an outlet for encouraging and presenting new research in this area.

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BackgroundMany neritic to nearshore species of marine adapted turtle from the Late Cretaceous of North America are thought to represent the stem lineage of Cheloniidae but due to fragmentary holotypes, low total specimen counts, and resultantly incomplete morphological character suites, are routinely placed either within or outside of crown group Chelonioidea leaving their precise cladistic affinities uncertain. Despite this systematic ambiguity, the referral of these species to either the stem of Cheloniidae or Chelonioidea belies the critical importance of these taxa in any investigation into the origins of extant marine turtles. The adequate incorporation of these species into phylogenetic studies requires the formal description of relatively complete specimens, particularly those possessing associated cranial and post-cranial material.MethodsRemarkably complete fossil specimens of several adult and juvenile marine turtles from the Mooreville Chalk and Eutaw Formations (Alabama, USA) are formally described and assigned to Prionochelys matutina. This material provides new information into the anatomy, ontogeny, and cladistic affinities of the species. A phylogenetic hypothesis for Late Cretaceous marine turtles is then generated through the consilience of stratigraphic, morphological, and molecular data.ResultsPhylogenetic analysis places Prionochelys matutina on the stem of Cheloniidae as a member of a monophyletic clade with other putative pan-cheloniids, including Ctenochelys stenoporus, Ctenochelys acris, Peritresius martini, and Peritresius ornatus. The members of this clade possess incipient secondary palates, pronounced carapacial and plastral fontanelles at all stages of development, and are characterized by the presence of superficial ossifications at the apices of the neural keel elevations along the dorsal midline of the carapace.DiscussionThe epithecal osteoderms dorsal to the neural series (epineurals) found in Ctenochelyidae are unique among turtles. The presence of epineurals in ctenochelyid turtles shows that epithecal ossifications arose independently in both leatherback (Dermochelyidae) and hard-shelled (Cheloniidae) marine turtles. Whether or not the epineurals of Ctenochelyidae are homologous with the dermal ossicles comprising the carapace of Dermochelys coriacea remains untested however, histological thin sectioning of dermochelyid and ctenochelyd epithecal elements may reveal meaningful information in future studies.

New remains of a sea turtle from the San Carlos quarry (Upper Cretaceous, Campanian), Austin Formation in the north of Coahuila state, Mexico, are reported. San Carlos quarry is composed of limestones and its Campanian age is based on the presence of the ammonites Scaphites hippocrepis and Delawarella delawarensis. In addition to the presence of turtles, this quarry also contained ammonites, bivalves, crabs, sea urchins, bony fish remains, and shark teeth. The study material is housed at Museo Paleontológico de Múzquiz. The preserved fossil elements correspond to postcranial elements, which present morphological characteristics that allowed them to be identified as belonging to a small-sized turtle related to Protostegidae. These new sea turtle remains expand the knowledge and distribution of Protostegidae along the Western Interior Seaway, where large and medium-sized sea turtles were distributed.

Mortality due to capture in longline fisheries has been implicated as a significant factor contributing to population declines for several species of threatened or endangered sea turtles. Identification of methods to reduce or prevent sea turtle bycatch is a high priority for fisheries managers and a necessary component of conservation efforts. One approach to reducing sea turtle interactions with longline fisheries is to take into account the behavior of sea turtles and the factors that lead them to interact with fishing gear. An understanding of the sensory cues that attract sea turtles to longline gear could help guide efforts to develop gear and bait that is less attractive, non-detectable, or even repellent to sea turtles. This paper presents a review of morphological, physiological, and behavioral studies conducted to assess the auditory, chemosensory, and visual capabilities of sea turtles, as well as the large pelagic fishes that are targeted by longline fisheries. We discuss the potential for exploiting differences in the sensory biology of these evolutionarily distinct groups to refine longline fishing techniques and reduce incidental bycatch of sea turtles without impacting the catch rates of targeted fish species. Based on the current evidence, differences in visual capabilities of sea turtles and pelagic fishes provide a promising avenue for development of a sensory-based deterrent.

Specimens referred to Osteopygis (Late Cretaceous-Paleocene, North America) represent a chimera, a polyphyletic mixture of taxa. The holotype of Osteopygis (AMNH 1485) and more complete referred postcranial specimens resemble non-marine stem cryptodires (“macrobaenids”). Because the skull material historically referred to Osteopygis shares synapomorphies with cheloniid sea turtles, all current workers accept Osteopygis as a stem-cheloniid sea turtle. Multiple lines of evidence combine to support the hypothesis that sea turtle cranial material is not attributable to Osteopygis. These lines of evidence include: phylogenetic hypotheses of character evolution, the tenuous historical attribution of specimens, and the taphonomy of the Hornerstown Formation. The name-bearing Osteopygis material and referred postcrania are best considered Eucryptodira incertae sedis (cf. “Macrobaenidae”). The cranial specimens formerly assigned to the Osteopyginae now are restricted to the clade Euclastes and those referred to Osteopygis emarginatus are here referred to Euclastes wielandi (comb. nov.). The ‘decapitation’ of Osteopygis reconciles morphological trends within stem cheloniids.

India's extensive coastline is a crucial nesting ground for various sea turtle species, including the Olive Ridley, Green, Hawksbill, and Leatherback turtles. Key nesting sites range from Gujarat to Odisha and the Andaman and Nicobar Islands. However, human activities such as coastal development, pollution, and fishing pose significant threats to sea turtle populations. Conservation efforts, including beach protection, hatchery programs, and community involvement, are essential for safeguarding these species. This review examines the nesting patterns, reproductive behaviour, and challenges faced by sea turtles along the Indian coastline. It highlights the importance of specific nesting sites in different states for sea turtle conservation. Also discusses the impacts of climate change, human-induced threats, and the importance of genetic diversity and population dynamics. Comparative analyses with global nesting sites provide insights into enhancing sea turtle conservation efforts worldwide. India's diverse and essential nesting habitats are vital for the survival of sea turtles and the health of marine ecosystems. Protecting these nesting sites is crucial for the conservation of sea turtles and the overall well-being of marine biodiversity.

Sea turtles are basically creatures that spend their entire lives in marine or estuarine habitats. Their only remaining reptilian ties to terrestrial habitats are for nesting and restricted cases of basking. Consequently, physiological, anatomical, and behavioral adaptations have evolved largely in response to selection in the aquatic environment, and sea turtles share many common elements with larger fishes and cetaceans in their habitat utilization and migrations. A generalized habitat model may be constructed for sea turtles based on ontogenetic stages: early juvenile nursery habitat, later juvenile developmental habitat, adult foraging habitat, and adult inter-nesting and/or breeding habitat. In sea turtles as in fishes, the numbers and diversity of potential predators and resulting mortality rates are inversely proportional to the size of the juvenile. The advantage of pelagic, oceanic nurseries is the low density of predatory fishes and sea birds there dictated by low primary production.

Animal Orientation Strategies for Movement in Flows

The first record of Desmatochelys cf. D. lowii from the Late Cretaceous (Campanian) of Coahuila, Mexico

Turtles creep through the pages of The Anatomical Record.

The role of the North American seaway in creating and maintaining Late Cretaceous global greenhouse conditions has been unclear. An isotopic analysis of marine turtle and fish fossils from western Kansas and the Mississippi embayment reveals that the inflow of Tethyan surface waters to the seaway was limited. During the mid- and Late Cretaceous period, North America was split by the north–south oriented Western Interior Seaway. Its role in creating and maintaining Late Cretaceous global greenhouse conditions remains unclear. Different palaeoceanographic reconstructions portray diverse circulation patterns1,2,3. The southward extent of relatively cool, low-salinity, low-δ18O surface waters critically distinguishes among these models, but past studies of invertebrates could not independently assess water temperature and isotopic compositions. Here we present oxygen isotopes in biophosphate from coeval marine turtle and fish fossils from western Kansas, representing the east central seaway, and from the Mississippi embayment, representing the marginal Tethys Ocean. Our analyses yield precise seawater isotopic values and geographic temperature differences during the main transition from the Coniacian to the early Campanian age (87–82 Myr), and indicate that the seaway oxygen isotope value and salinity were 2‰ and 3‰ lower, respectively, than in the marginal Tethys Ocean. We infer that the influence of northern freshwater probably reached as far south as Kansas. Our revised values imply relatively large temperature differences between the Mississippi embayment and central seaway, explain the documented regional latitudinal palaeobiogeographic zonation4,5 and support models with relatively little inflow of surface waters from the Tethys Ocean to the Western Interior Seaway2,3.

In the last years the microbial communities (microbiota) associated with the digestive tract of animals have been subjected to wide research interest (Ley et al., 2008; Zhu et al., 2010; Huttenhower et al., 2012). The presence of functional relationship between the host and the associated microbiome (the genes and genomes of the microbiota) has been highlighted, and the new term of hologenome has been proposed to refer to the set of functions (genes) of host and microorganisms associated with it (Zilber-Rosenberg and Rosenberg, 2008). The study of model animals has revealed roles for the microbiome in adaptive immunity development and in host physiology, ranging from mate selection to skeletal biology and lipid metabolism (Ley et al., 2008; Kostic et al., 2013; Du Toit, 2016). For vertebrates, most of the studies on gut microbiota and microbiome have been performed in mammals (i.e., mouse, rat and humans) and in fishes (as the model Danio rerio) (Huttenhower et al., 2012; Kostic et al., 2013). Recently, microbiotas and microbiomes of non-model organisms have started to be investigated with the aim to shed light on animal-associated microbial diversity (Keenan et al., 2013; Mengoni et al., 2013; Cahill et al., 2016) and to potentially discover new biotechnologically important microbial strains (Papaleo et al., 2012; Sanchez et al., 2012). Sea turtles (Testudines, Reptilia) occur in oceanic and neritic habitats, from the tropics to subarctic waters, and venture onto terrestrial habitats to nest or bask in tropical and temperate latitudes. Sea turtle populations around the world have dwindled and, in many places, continue to decline (Wallace et al., 2010). Caretta caretta L. (Loggerhead Turtle) is distributed throughout the subtropical and temperate regions of the Mediterranean Sea and Pacific, Indian, and Atlantic Oceans. Loggerhead Turtle is classified as Vulnerable A2b in the IUCN Red List (http://www.iucnredlist.org/details/3897/0). The Loggerhead Turtle plays important roles in maintaining marine ecosystem (Bjorndal and Jackson, 2002; Bolten and Witherington, 2003). These roles range from maintaining productive coral reef ecosystems to transporting essential nutrients from the oceans to beaches and coastal dunes. However, in spite of the considerable importance for the study of vertebrates, few studies only are present on microbial communities associated with sea turtles (Ferronato et al., 2009; Sarmiento-Ramirez et al., 2014; Yuan et al., 2015) and no reports on gut microbial communities. The aim of this work is the characterization, for the first time, of the gut microbiota of the sea turtle C. caretta, to shed a preliminary light on its features with respect to other reptiles and to marine vertebrates. Both feces and intestine samples were taken to have the wider overview of gut microbiota taxonomic composition.