Abstract Patterns of genetic structure in highly mobile marine vertebrates may be accompanied by phenotypic variation. Most studies in marine turtles focused on population genetic structure have been performed at rookeries. We studied whether genetic and morphological variation of the endangered green turtle (Chelonia mydas) is consistent geographically, focusing on foraging grounds. An association between population genetic structure and body shape variation at broad (inter-lineage) and fine (foraging grounds) scales was predicted and analysed using mitochondrial DNA and geometric morphometrics. Although genetic and phenotypic differentiation patterns were congruent between lineages, no fine-scale association was found, suggesting adaptive divergence. Connectivity among Pacific foraging grounds found here suggests that temperatures of ocean surface currents may influence the genetic structure of C. mydas on a broad scale. Our results suggest that vicariance, dispersal, life-history traits and ecological conditions operating in foraging grounds have shaped the intraspecific morphology and genetic diversity of this species. Considering a range of geographic and temporal scales is useful when management strategies are required for cosmopolitan species. Integrating morphological and genetic tools at different spatial scales, conservation management is proposed based on protection of neutral and adaptive diversity. This approach opens new questions and challenges, especially regarding conservation genetics in cosmopolitan species.

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Fibropapillomatosis (FP) is characterized by multiple fibroepithelial tumors in all parts of the skin and has been reported in sea turtles worldwide. Clinically infected individuals are often emaciated and anemic. In Mexico, however, there are few records of this disease. In this study of green turtles Chelonia mydas in Laguna San Ignacio in Baja California Sur (BCS), we noted one juvenile with multifocal fibropapilloma lesions on the external upper surface of its eyes and hind flippers. Light microscopy revealed hyperkeratosis, epidermal hyperplasia, dermal papillary projections, and fibroblast proliferation. Electron microscopy revealed viral particles. Biopsies of normal skin were done to determine the origin of the turtle through genetic analysis. Its mitochondrial DNA matched that of a haplotype (CMP2) from a Hawaiian green turtle population. Finding FP in a turtle captured in BCS elucidates the need for further monitoring along the west coast of Mexico. Further investigation should include testing tumors to detect and characterize any chelonid herpesviruses and explore any association with FP and other diseases that pose a health risk to other sea turtle species. Received March 26, 2016; accepted August 3, 2016.

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During routine monitoring in Ojo de Liebre Lagoon, Mexico, a juvenile black turtle (Chelonia mydas) was captured, physically examined, measured, weighed, sampled, and tagged. The turtle showed no clinical signs suggestive of disease. Eleven months later, this turtle was recaptured in the same area, during which one lesion suggestive of fibropapilloma on the neck was identified and sampled for histopathology and molecular analysis. Histopathology revealed hyperkeratosis, epidermal hyperplasia, acanthosis, papillary differentiation and ballooning degeneration of epidermal cells, increased fibroblasts in the dermis, and angiogenesis, among other things. Hematological values were similar to those reported for clinically healthy black turtles and did not show notable changes between the first capture and the recapture; likewise, clinicopathological evaluation did not show structural or functional damage in the turtle’s systems. The chelonid alphaherpesvirus 5 (ChHV5) UL30 gene was amplified and sequenced for phylogeny; Bayesian reconstruction showed a high alignment with the genus Scutavirus of the Eastern Pacific group. This is one of the first reports of ChHV5 in a cutaneous fibropapilloma of a black turtle in the Baja California peninsula.

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Marine species may exhibit genetic structure accompanied by phenotypic differentiation related to adaptation despite their high mobility. Two shape-based morphotypes have been identified for the green turtle ( Chelonia mydas ) in the Pacific Ocean: the south-central/western or yellow turtle and north-central/eastern or black turtle. The genetic differentiation between these morphotypes and the adaptation of the black turtle to environmentally contrasting conditions of the eastern Pacific region has remained a mystery for decades. Here we addressed both questions using a reduced-representation genome approach (Dartseq; 9473 neutral SNPs) and identifying candidate outlier loci (67 outlier SNPs) of biological relevance between shape-based morphotypes from eight Pacific foraging grounds ( n = 158). Our results support genetic divergence between morphotypes, probably arising from strong natal homing behaviour. Genes and enriched biological functions linked to thermoregulation, hypoxia, melanism, morphogenesis, osmoregulation, diet and reproduction were found to be outliers for differentiation, providing evidence for adaptation of C. mydas to the eastern Pacific region and suggesting independent evolutionary trajectories of the shape-based morphotypes. Our findings support the evolutionary distinctness of the enigmatic black turtle and contribute to the adaptive research and conservation genomics of a long-lived and highly mobile vertebrate.

Background: Fibropapillomatosis (FP) is an infectious disease considered to be one of the primary causes of mortality for many green turtles stokes around the world, commonly associated with a herpesvirus identified as Chelonid herpesvirus type 5 (ChHV-5). To detect the viral particles associated with the specific lesions of FP, Histopathology, Transmission Electron Microscopy and PCR studies have been used; in this manuscript we described by gross Pathology and Histopathology cutaneous FPs in an eastern Pacific Green Turtle (EPGT) C. mydas from Ojo de Liebre lagoon (LOL) and in an olive ridley turtle L. olivacea from the Gulf of Ulloa (GU) in the Baja California Peninsula. Methods: During September and December 2016, olive ridley turtles were caught at GU and EPGTs were caught at LOL. A physical examination adapted for sea turtles was carried out and morphometric data was taken. Two tissue samples (2 and 3 cm aprox. respectively) from two turtles that presented neoplasms were recollected; the lesions were completely resected, fixed in formalin and sent to the Marine Botany Laboratory at the Autonomous University of Baja California Sur to be processed with the Histopathology routine technique and were reviewed using a microscope with ×10 and ×40 lenses. Results: One olive ridley turtle (adult female) caught at GU, presented a FP-like lesion at the right eye, in addition to two FP-like lesions at the ventral part of the right anterior flipper; in LOL, an EPGT (sub adult female), presented a FP-like lesion at the ventral base of the right anterior flipper. The examination of the nodules by light microscopy revealed orthokeratotic hyperkeratosis, epidermal hyperplasia with areas of edema, dermal papillary differentiation, increased fibroblasts in the dermis and mild infiltration of lymphocytes arranged at the perivascular level and at the dermo-epidermal junction. Conclusions: It is important and necessary to complement this kind of studies with the use of PCR to determine the role of the disease causative agent in the development of the neoplasms. Monitoring along the west coast of Mexico is essential to determine the presence, prevalence and incidence of FP and other diseases.