Direct Evidence for Gradual Ontogenetic Dietary Shift in the Green Turtle,<i>Chelonia mydas</i>

Morais, Renato A.; Santos, Robson G.; Longo, Guilherme O.; Yoshida, Eduardo Tadashi Estevam; Stahelin, Gustavo D.; Horta, Paulo Antunes

doi:10.2744/ccb-1058.1

Cited by 21 publications

(8 citation statements)

References 36 publications

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“…Multiyear maturation and the large neonate-to-adult body size disparity of many dinosaurs and other archosauromorphs is predictive of ontogenetic niche partitioning and/or dietary changes. Evidence for these phenomena have been observed directly in Limusaurus (2) and are probably widespread in dinosaurs given ontogenetic social segregation in many dinosaur clades (56) and examples of ontogenetic dietary change in many extant species within Archosauromorpha (61)(62)(63). These lifehistory characteristics may have predisposed terrestrial archosauromorphs transitioning from carnivory to omnivory or herbivory (3,26) toward the evolution of rhamphothecae (Figs.…”

Section: Discussionmentioning

confidence: 94%

Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks

Wang

Stiegler

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Beaks are innovative structures characterizing numerous tetrapod lineages, including birds, but little is known about how developmental processes influenced the macroevolution of these important structures. Here we provide evidence of ontogenetic vestigialization of alveoli in two lineages of theropod dinosaurs and show that these are transitional phenotypes in the evolution of beaks. One of the smallest known caenagnathid oviraptorosaurs and a small specimen of the Early Cretaceous bird both possess shallow, empty vestiges of dentary alveoli. In both individuals, the system of vestiges connects via foramina with a dorsally closed canal homologous to alveoli. Similar morphologies are present in, a beaked theropod that becomes edentulous during ontogeny; and an analysis of neontological and paleontological evidence shows that ontogenetic reduction of the dentition is a relatively common phenomenon in vertebrate evolution. Based on these lines of evidence, we propose that progressively earlier postnatal and embryonic truncation of odontogenesis corresponds with expansion of rostral keratin associated with the caruncle, and these progenesis and peramorphosis heterochronies combine to drive the evolution of edentulous beaks in nonavian theropods and birds. Following initial apomorphic expansion of rostral keratinized epithelia in perinatal toothed theropods, beaks appear to inhibit odontogenesis as they grow postnatally, resulting in a sequence of common morphologies. This sequence is shifted earlier in development through phylogeny until dentition is absent at hatching, and odontogenesis is inhibited by beak formation .

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Section: Discussionmentioning

confidence: 94%

Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks

Wang

Stiegler

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…R: reef; R*: reef in a highly urbanized area; E: estuarine area; U: unconsolidated substrate; −: data not available. Refer to Tables 1 & 2 for details on study areas forcing these animals to feed on animal matter, which may be more energetic and easily digestible source for juvenile green turtles (Bjorndal 1980, Forbes 1996, Morais et al 2014). In addition to the results of this study, studies conducted in Pacific waters that showed a higher animal matter content in neritic green turtle diets were also located in areas with relatively low water temperatures (Lemons et al 2011) or in tropical waters seasonally influenced by cold waters (Amorocho & Reina 2007).…”

Section: Animal Ingestion and Foraging Strategymentioning

confidence: 99%

Regional and local factors determining green turtle Chelonia mydas foraging relationships with the environment

Santos¹,

Martins²,

Batista³

et al. 2015

Mar. Ecol. Prog. Ser.

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Changes in green turtle Chelonia mydas foraging patterns were evaluated within a latitudinal gradient along tropical and subtropical coasts in the southwestern Atlantic and investigated as to how green turtles responded to regional and local changes in their foraging habitats. In addition, we evaluated how changes in feeding ecology caused populations to be more susceptible to various anthropogenic threats. The literature and original diet data of 427 green turtles were analyzed. Turtles from tropical and subtropical reefs exhibited the classic pattern of herbivorous benthic foraging, turtles from estuarine areas exhibited a more generalist diet and pelagic foraging, and turtles from colder reef areas, located between the winter isotherms of 10°C and 20°C, exhibited an omnivorous diet and pelagic foraging strategy. The amount of ingested animal matter was higher in occurrence and abundance in the green turtle diets in the most southern foraging areas. Foraging ecology was influenced by regional (phycogeographical provinces and water temperature) and local (urbanization and rivers) factors. Green turtles exhibited high foraging plasticity, and their importance to the ecosystem was not restricted to their role as herbivores. Green turtles may also have an important role as second-order consumers in certain areas, mainly in the cooler waters at the extremes of their distribution. Foraging plasticity was observed both in the type of diet item and foraging strategy, which implies that there may be variation in the exposure of populations to threats.

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“…To date, most investigations of the green turtle's gut microbiome have typically involved bacterial identification in cloacal or faecal contents. The faecal bacterial communities of green turtle mostly dominated by bacteria with in the phyla Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria while the relative abundance of these bacteria may vary at different health [32] , age [24] , [25] , nutrition [33] , [34] and environmental conditions [25] , [35] . Additionally, bacteria present in faecal contents only represent the overall gut microbiota rather than bacterial communities of specific anatomical regions of the GI tract [36] , [37] .…”

Section: Introductionmentioning

confidence: 99%

Characterisation and comparison of the mucosa-associated bacterial communities across the gastrointestinal tract of stranded green turtles, <em>Chelonia mydas</em>

et al. 2020

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Chelonia mydas are primarily herbivorous long-distance migratory sea turtles that contribute to marine ecosystems. Extensive research has been conducted to restore the populations of green turtles. Little is known about their gut microbiota which plays a vital role in their health. We investigated the mucosa-associated bacterial communities across the gastrointestinal (GI) tract of a total four (3, juvenile and 1, adult) stranded green turtles. Samples taken from four GI regions including oesophagus, stomach, small intestine and large intestine were analysed by high-throughput sequencing targeting hypervariable V1-V3 regions of the bacterial 16S rRNA gene. Bacterial diversity and richness decreased longitudinally along the GI tract from oesophagus to the small intestine of stranded turtles. The large intestine showed a higher bacterial diversity and richness compared to small intestine. The bacterial community of green turtles' GI tract was largely dominated by Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes and Fusobacteria. Aerobic and facultative anaerobic bacteria prevailed primarily in the oesophagus while anaerobes ( Lachnospiraceae , Peptostreptococcaceae and Ruminococcaceae ) constituted the bulk of large intestinal microbiota. Firmicutes dominated the GI tract except within the small intestine where Proteobacteria prevailed. At the OTU level, six percent of the total OTUs (>1% relative abundance) were common in all GI regions. This is a comprehensive characterisation of bacterial microbiota across the GI tract in green turtles which will provide a reference for future studies on turtle gut microbiome and their metabolism to improve their health and nutrition during rehabilitation.

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Direct Evidence for Gradual Ontogenetic Dietary Shift in the Green Turtle,Chelonia mydas

Cited by 21 publications

References 36 publications

Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks

Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks

Regional and local factors determining green turtle Chelonia mydas foraging relationships with the environment

Characterisation and comparison of the mucosa-associated bacterial communities across the gastrointestinal tract of stranded green turtles, <em>Chelonia mydas</em>

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