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Serrano OS, Garcês A, Pires I, Calderón Mateus JA, Olivera JM, Dávila JJ. Congenital Anomalies in American Crocodile ( Crocodylus acutus, Cuvier, 1807) Embryos from a Farm Breeder in Colombia. Vet Sci 2024; 11:317. [PMID: 39058001 PMCID: PMC11281568 DOI: 10.3390/vetsci11070317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 06/21/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
The American crocodile (Crocodylus acutus, Cuvier, 1807) (Class Reptilia, Family Crocodylidae) is a crocodile species inhabiting the Neotropics. Congenital defects have been described in almost every vertebrate group. In crocodiles, teratology alterations have been described in captive animals (pets, zoos, farms) such as Crocodylus niloticus or Gavialis gangeticus. The present study aimed to characterize congenital malformations of C. acutus from a farm in Lomas de Matunilla, Ballestas, Bolívar, Colombia. A total of 550 unhatched eggs were examined after embryo death. A total of 61 embryos presented malformations, with 42 different types of anomalies observed. Limb and tail malformations (29%) were the most common malformations observed. Several malformations, such as cephalothoracopagus, thoracopagus, sternopagus, xiphopagus twins, campylorrachis scoliosa, and acrania, were documented in crocodiles for the first time. Research in teratology enhances our understanding of crocodile biology. It plays a role in their conservation and management, thus helping to ensure the long-term viability of these species in their natural habitats.
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Affiliation(s)
| | - Andreia Garcês
- Wildlife Rehabilitation Center and Exotic Service, Teaching Veterinary Hospital University of Trás-os-Montes and Alto Douro, Quinta dos Prados, 5000-801 Vila Real, Portugal
- Centre for Animal Sciences and Veterinary Studies, Associate Laboratory for Animal and Veterinary Science—AL4AnimalS, University of Trás-os-Montes e Alto Douro, Quinta dos Prados, 5000-801 Vila Real, Portugal;
| | - Isabel Pires
- Centre for Animal Sciences and Veterinary Studies, Associate Laboratory for Animal and Veterinary Science—AL4AnimalS, University of Trás-os-Montes e Alto Douro, Quinta dos Prados, 5000-801 Vila Real, Portugal;
| | - John Alexander Calderón Mateus
- Parque Vivarium del Caribe, Via-Pontezuela-Bayunca, Cartagena 130001, Colombia;
- Cocodrilos de Colombia, Cartagena 130001, Colombia
| | - Juan Medina Olivera
- University of Córdoba, Monteria, Poniente Sur, Córdoba 14071, Colombia;
- Instituto de Investigaciones Geográficas de Investigaciones Geográficas y Ambientales del Caribe (GEOCARIBE), Poniente Sur, Córbora 14071, Colombia
| | - Jhesteiner Julio Dávila
- Grupo de Investigación Biología Evolutiva, Programa de Biología, Facultad de Educación y Ciencias, Universidad de Sucre, Sincelejo, 5-267 Barrio Puerta Roja, Sincelejo 700001, Colombia;
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Sönmez B, Sağol Ö. Congenital malformation in green turtle embryos and hatchlings. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024. [PMID: 38953157 DOI: 10.1002/jez.2851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 06/15/2024] [Accepted: 06/19/2024] [Indexed: 07/03/2024]
Abstract
Successful embryonic development depends on the interaction between genetic factors and environmental variables. Congenital malformations in sea turtles can result from extreme conditions during the incubation period, reducing hatching success and potentially impeding population recovery. We aimed to characterize the congenital malformations found in green turtle nests, determine their prevalence and severity, and understand their drivers during the 2022 nesting season on Samandağ beach on northern Mediterranean nesting beaches. A total of 2986 examples of congenital malformations were observed in 362 out of 907 green turtle nests. The prevalence of congenital malformations per nest was 39%, and the severity (the number of malformed individuals per nest) was 3.8%. Nests with congenital malformations exhibited a lower mean distance from the sea, a shorter incubation duration (a proxy for incubation temperature), lower hatching success, a larger clutch size, and higher mortality at late embryonic and hatchling stages than nests without congenital malformations. There was no significant difference in total mortality between these two nest types. A total of 52 different congenital malformations were recorded, 2 of which were observed for the first time in sea turtles and 28 for the first time in green turtles. The results suggest that congenital malformations may be related to nest temperature and clutch size, while overall mortality may be independent of malformations. Pigmentation disorders and craniofacial malformations typically coexist in cases of multiple malformations. Long-term monitoring of congenital malformations is crucial, as it can provide clues about the health status of the nesting beach and nesting colony.
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Affiliation(s)
- Bektaş Sönmez
- Suşehri Timur Karabal Vocational School, Sivas Cumhuriyet University, Suşehri, Sivas, Türkiye
| | - Özlem Sağol
- Muğla Sıtkı Koçman University, Milas Veterinary Faculty, Undergraduate Student, Muğla, Türkiye
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Mau A, Sotomayor Rodríguez P, Picknell A, Tepedino A, Capaldo D, Fenton H, Pemberton L, Stewart KM, Dennis MM. In-nest mortality and pathology of hawksbill sea turtle (Eretmochelys imbricata) embryos and hatchlings in St. Kitts and Nevis. J Comp Pathol 2024; 209:13-21. [PMID: 38335915 DOI: 10.1016/j.jcpa.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/21/2023] [Accepted: 01/11/2024] [Indexed: 02/12/2024]
Abstract
Strategies to improve the hatch success and survival of critically endangered hawksbill turtles (Eretmochelys imbricata) require knowledge of threats to them including pathological conditions. The objective of this study was to describe the mortality and pathology of embryos and dead-in-nest hatchlings on St. Kitts and Nevis. Over the 2019/20 and 2020/21 nesting seasons, the combined mean (SD) hatch success for the two islands was 81.9% (13.2%) and deceased individuals within excavated nests were early-stage embryos (70.7%), late-stage embryos (17.7%), pipped-hatchlings (8.2%) or dead-in-nest hatchlings (3.4%). From 2017 to 2021, a post-mortem examination was performed on 183 turtles, including histology for 116. Anatomical malformations affected 77 (42.1%) examined turtles and included abnormal scute shape or number (22.4%), dysmelia (8.7%), schistosomus reflexus (7.7%) and compressed carapace (7.7%). Microscopic lesions were found in 49.1% of turtles and included tissue mineralization (26.7%, including renal, fetal membrane, liver, heart or muscle), chorioallantoitis (16.2%) and skeletal muscle degeneration and necrosis (10%). Inflammatory lesions associated with fungal or bacterial infections were in the skin (n = 3), chorioallantois (n = 4), lung (n = 3) or yolk sac (n = 1). These lesions may reflect non-specific terminal conditions but their presence in-nest helps explain some of the mortality and pathology documented in hatchlings that die during rehabilitative care. All of the gonads adequately represented for histological determination of sex were female (n = 62), supporting concern for feminization of Caribbean hawksbill turtle nests. The study identifies lesions that could affect hatch and emergence success. The high frequency of skeletal malformations indicates the need for investigations addressing regional impact and pathogenesis, especially genetic and environmental aetiologies including nest temperature. Immediate examination of live hatchlings on nest emergence is warranted to better determine the prevalence of non-fatal malformations that could impact fitness and population genetics.
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Affiliation(s)
- Alex Mau
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies; Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, 944 Garrod Drive, California 95616, USA
| | - Paula Sotomayor Rodríguez
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies
| | - Angela Picknell
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies; St. Kitts Sea Turtle Monitoring Network, Basseterre, St. Kitts, West Indies
| | - Alissa Tepedino
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies
| | - Dominique Capaldo
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies
| | - Heather Fenton
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies; Australian Registry of Wildlife Health, Taronga Zoo, Bradley's Head Road, Mosman 2088, New South Wales, Australia
| | - Lemuel Pemberton
- The Nevis Turtle Group, Webbes Ground, Gingerland, Nevis, West Indies
| | - Kimberly M Stewart
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies; St. Kitts Sea Turtle Monitoring Network, Basseterre, St. Kitts, West Indies
| | - Michelle M Dennis
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies; Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, 2407 River Drive, Knoxville, Tennessee 37996, USA.
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Evaluation of Putative Hybrid Hatchlings between Hawksbill Sea Turtle (Eretmochelys imbricata) and Green Sea Turtle (Chelonia mydas) in Tortuguero, Costa Rica. J HERPETOL 2022. [DOI: 10.1670/21-017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Sosa-Cornejo I, Martín-Del-Campo R, González-Flores JA, González-Camacho ZB, Cabrera-Cuellar BA, Bielli A, Valdes-Flores JE, Olimón-Andalón V. Leucism: the prevalent congenital malformation in the olive ridley sea turtle of northwestern Mexico. DISEASES OF AQUATIC ORGANISMS 2022; 152:61-71. [PMID: 36394141 DOI: 10.3354/dao03705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Despite being the most abundant sea turtle in the world, the olive ridley turtle Lepidochelys olivacea is classified as Vulnerable by the IUCN. There is evidence of congenital malformations in hatchlings, and the associated causes are multifactorial, with both genetic and environmental sources. Santuario Playa Ceuta (SPC) is a sanctuary for the olive ridley, located at the northernmost region of its nesting range in the Mexican Pacific. The objective of this study was to identify and quantify the prevalence and severity of congenital malformations in olive ridley embryos/hatchlings in SPC during the 2017 nesting season. We collected 62907 eggs from 643 relocated nests that were moved to a hatchery, of which 4242 eggs with obvious development did not hatch and were analyzed for this study. Hatching success was 53.9%, with 22.5% of nests (n = 145) and 0.54% of eggs (n = 344) showing embryos or hatchlings with malformations. The nest severity index was 2.4 (range: 1-10) malformed embryos or hatchlings per nest, and the organism severity index was 1.4 (range: 1-7) malformations per malformed embryo or hatchling. Leucism was the most prevalent malformation (34.4%; 170/494 total observed), with the craniofacial region showing the greatest diversity of malformations (17/35 types). Given the geographical position of SPC, extreme environmental conditions (e.g. cold, heat, and dryness) could be one of the main causes of teratogenesis in this species. However, more studies are needed regarding the presence of contaminants, genetic factors, health assessments of nesting females, and malformation rates of nests that remain in situ versus those that are relocated.
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Affiliation(s)
- Ingmar Sosa-Cornejo
- Doctorado en Ciencias Biológicas, Facultad de Biología, Universidad Autónoma de Sinaloa, Culiacán, Sinaloa 80040, Mexico
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Morphologic and physiologic characteristics of green sea turtle (Chelonia mydas) hatchlings in southeastern Florida, USA. J Comp Physiol B 2022; 192:751-764. [DOI: 10.1007/s00360-022-01450-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/07/2022] [Accepted: 07/19/2022] [Indexed: 11/27/2022]
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NONPIGMENTED VERSUS PIGMENTED: HEALTH VARIABLES AND GENETICS OF ALBINO FLORIDA GREEN TURTLE (CHELONIA MYDAS) HATCHLINGS COMPARED WITH NORMALLY PIGMENTED HATCHLINGS FROM THE SAME CLUTCH. J Wildl Dis 2021; 58:15-29. [PMID: 34699596 DOI: 10.7589/jwd-d-21-00031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/15/2021] [Indexed: 11/20/2022]
Abstract
At the time of hatchling emergence from a nest laid on Juno Beach, Florida, USA, by a normally pigmented green turtle (Chelonia mydas), 23 albino hatchlings and 75 normally pigmented hatchlings were observed. This condition is rarely seen in sea turtles, and little is known about blood analytes and genetics of albino wildlife to date. Therefore, the objective of our study was to assess and compare morphometric measurements (mass, minimum straight carapace length, body condition index), carapacial scute anomalies, a suite of hematologic and plasma biochemical analytes, and two glucose analysis methodologies (glucometer and dry chemistry analysis) in albino (n=20) versus normally pigmented (n=24) hatchlings from this nest. Genetic analyses were completed to identify paternal contributions of hatchlings and to test Mendelian inheritance assumptions. Although morphometric measurements, scute anomalies, and leukocyte morphology were similar between albino and normally pigmented hatchlings, several differences were observed in blood analyte data: immature erythrocytes, packed cell volume, heterophil:lymphocyte ratio, and glucose concentrations (by both methodologies) were significantly higher, whereas absolute immature heterophils, absolute lymphocytes, number of erythrocyte micronuclei, sodium, and chloride were significantly lower in albino hatchlings compared with normally pigmented hatchlings. Considerations for these differences include a stress response from sampling (e.g., timing of procedures or possibly from photosensitivity or reduced visual acuity in albinos) and different osmoregulation, which may reflect physiologic variations or stress. There was a small positive bias (0.10 mmol/L) with glucose by glucometer, similar to reports in other sea turtle species and confirming its suitability for use in hatchlings. All albino hatchlings analyzed (n=10) were from the same father, but the normally pigmented hatchlings (n=24) were from two other fathers. These findings provide insight into the physiology and genetics of albinism in sea turtles.
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Köhnk S, Brown R, Liddell A. Finding of a two-headed green turtle embryo during nest monitoring in Baa Atoll, Maldives. Onderstepoort J Vet Res 2021; 88:e1-e8. [PMID: 34476952 PMCID: PMC8424721 DOI: 10.4102/ojvr.v88i1.1940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/23/2021] [Accepted: 06/25/2021] [Indexed: 11/01/2022] Open
Abstract
Green sea turtles are one of the two species of marine turtles known to nest in the Maldives. The prevalent time of nesting seems to be inconsistent throughout the island nation. In this study, sea turtle nesting activity was monitored on the island of Coco Palm Dhuni Kolhu in Baa Atoll over a period of 12 months. A total of 13 nests were confirmed with a median hatching success rate of 89.58% as ascertained by nest excavation. In one of the nests, a severely deformed hatchling with polycephaly, an opening in the neck area and a lordotic spine was found, and we investigated in detail with radiographic images and a necropsy. Our findings support the importance of consistent nesting activity and nest monitoring efforts in the country as a basis for conservation efforts.
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Affiliation(s)
- Stephanie Köhnk
- Olive Ridley Project, Bramhall, Stockport, Cheshire, United Kingdom; and, Morphology Lab, Center of Natural History, University of Hamburg, Hamburg.
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Ingle DN, Meredith TL, Perrault JR, Wyneken J. Two heads are not always better than one: Craniofacial and axial bifurcation in cheloniid embryos and hatchlings (Chelonia mydas and Caretta caretta). J Morphol 2021; 282:1233-1244. [PMID: 33982303 DOI: 10.1002/jmor.21366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/05/2021] [Accepted: 05/09/2021] [Indexed: 11/08/2022]
Abstract
Morphological data on craniofacial and axial bifurcation in sea turtles is not well documented in the literature. Here, we use micro-computed tomography (μ-CT) imaging to describe the body, skull, and vertebral morphology in axially-bifurcated cheloniid sea turtle embryos and hatchlings (Chelonia mydas and Caretta caretta) from south Florida beaches. We describe three types of craniofacial and axial bifurcations: bifacial, bicephalic, and bicephalic with biaxial duplication ranging from facial bones to the sacrum. We predicted smaller body dimensions in bifacial and bicephalic embryos and hatchlings compared with their normal counterparts. In addition, we hypothesized that bicephalic individuals would have greater rostral deviation angles than bifacial animals, and that vertebral dimensions would vary between the control and anomalous embryos and hatchlings. Among hatchlings (developmental Stage 31), we found that maximum curved carapace length and curved carapace width were greatest in the control specimens when compared with the anomalous specimens. Overall, we found that rostral deviations were smaller in bifacial animals compared with their bicephalic counterparts. Right and left rostral deviations were symmetrical or nearly symmetrical in all bifacial and bicephalic specimens. Among C. caretta, we found that bicephalic animals had greater standardized vertebral measurements than their bifacial conspecifics. In bifacial animals, bifurcation extended to either the frontal or parietal skull bones, while duplication extended to C5 vertebrae and T8 vertebrae in bicephalic animals. This study provides an in-depth description of anatomical alterations associated with these abnormalities. Prognosis of these organisms is poor; however, understanding the prevalence of these malformations can allow for better assessments of population health, as numerous environmental factors are known to lead to these changes.
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Affiliation(s)
- Danielle N Ingle
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, USA.,Florida Atlantic University High School, Boca Raton, Florida, USA.,College of Education, Florida Atlantic University, Boca Raton, Florida, USA
| | - Tricia L Meredith
- Florida Atlantic University High School, Boca Raton, Florida, USA.,College of Education, Florida Atlantic University, Boca Raton, Florida, USA
| | | | - Jeanette Wyneken
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, USA
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Shaver DJ, Gredzens C, Walker JS, Godard-Codding CAJ, Yacabucci JE, Frey A, Dutton PH, Schmitt CJ. Embryo deformities and nesting trends in Kemp’s ridley sea turtles Lepidochelys kempii before and after the Deepwater Horizon oil spill. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Kemp’s ridley sea turtles Lepidochelys kempii were disproportionately affected by the Deepwater Horizon (DWH) oil spill, which began on 20 April 2010. Embryo deformities were documented in inviable L. kempii eggs before (2008-2010) and after (2011-2013) the DWH spill in 2 Texas (USA) nesting areas (Upper Texas Coast and Padre Island National Seashore). Additional nesting trends, including clutch size and hatching success, were also investigated. Total and late-stage embryo deformity prevalence were 1.5 times greater after 2010 than before, but low in all nesting seasons (mean ± SD: 0.7 ± 8.5% total; 0.6 ± 8.0% late-stage) and did not differ between locations. Craniofacial and carapace deformities were the most frequently observed deformity types. Documented nests in both areas declined in 2010 relative to previous years, ending an exponential increase observed beginning in 1995. Clutch size remained consistent before and after the spill. Hatching success averaged 87.0 ± 33.3% in all years, but no effects from DWH were determined. Collectively, these data represent useful benchmarks against which to judge impacts of future crude oil spills and other catastrophic events.
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Affiliation(s)
- DJ Shaver
- National Park Service, Padre Island National Seashore, Corpus Christi, TX 78480, USA
| | - C Gredzens
- National Park Service, Padre Island National Seashore, Corpus Christi, TX 78480, USA
| | - JS Walker
- National Park Service, Padre Island National Seashore, Corpus Christi, TX 78480, USA
| | - CAJ Godard-Codding
- The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409, USA
| | - JE Yacabucci
- The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409, USA
| | - A Frey
- NOAA Fisheries, Southwest Fisheries Science Center, La Jolla, CA 92037, USA
| | - PH Dutton
- NOAA Fisheries, Southwest Fisheries Science Center, La Jolla, CA 92037, USA
| | - CJ Schmitt
- US Geological Survey, Columbia Environmental Research Center, Columbia, MO 65201, USA
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Congenital Malformations in Sea Turtles: Puzzling Interplay between Genes and Environment. Animals (Basel) 2021; 11:ani11020444. [PMID: 33567785 PMCID: PMC7915190 DOI: 10.3390/ani11020444] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/28/2022] Open
Abstract
Simple Summary Congenital malformations can lead to embryonic mortality in many species, and sea turtles are no exception. Genetic and/or environmental alterations occur during early development in the embryo, and may produce aberrant phenotypes, many of which are incompatible with life. Causes of malformations are multifactorial; genetic factors may include mutations, chromosomal aberrations, and inbreeding effects, whereas non-genetic factors may include nutrition, hyperthermia, low moisture, radiation, and contamination. It is possible to monitor and control some of these factors (such as temperature and humidity) in nesting beaches, and toxic compounds in feeding areas, which can be transferred to the embryo through their lipophilic properties. In this review, we describe possible causes of different types of malformations observed in sea turtle embryos, as well as some actions that may help reduce embryonic mortality. Abstract The completion of embryonic development depends, in part, on the interplay between genetic factors and environmental conditions, and any alteration during development may affect embryonic genetic and epigenetic regulatory pathways leading to congenital malformations, which are mostly incompatible with life. Oviparous reptiles, such as sea turtles, that produce numerous eggs in a clutch that is buried on the beach provide an opportunity to study embryonic mortality associated with malformations that occur at different times during development, or that prevent the hatchling from emerging from the nest. In sea turtles, the presence of congenital malformations frequently leads to mortality. A few years ago, a detailed study was performed on external congenital malformations in three species of sea turtles from the Mexican Pacific and Caribbean coasts, the hawksbill turtle, Eretmochelys imbricata (n = 23,559 eggs), the green turtle, Chelonia mydas (n = 17,690 eggs), and the olive ridley, Lepidochelys olivacea (n = 20,257 eggs), finding 63 types of congenital malformations, of which 38 were new reports. Of the three species, the olive ridley showed a higher incidence of severe anomalies in the craniofacial region (49%), indicating alterations of early developmental pathways; however, several malformations were also observed in the body, including defects in the carapace (45%) and limbs (33%), as well as pigmentation disorders (20%), indicating that deviations occurred during the middle and later stages of development. Although intrinsic factors (i.e., genetic mutations or epigenetic modifications) are difficult to monitor in the field, some environmental factors (such as the incubation temperature, humidity, and probably the status of feeding areas) are, to some extent, less difficult to monitor and/or control. In this review, we describe the aetiology of different malformations observed in sea turtle embryos, and provide some actions that can reduce embryonic mortality.
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Anatomic Interactive Atlas of the Loggerhead Sea Turtle ( Caretta caretta) Head. Animals (Basel) 2021; 11:ani11010198. [PMID: 33467620 PMCID: PMC7830008 DOI: 10.3390/ani11010198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 11/29/2022] Open
Abstract
Simple Summary Because several diseases have been reported affecting the head of sea turtles, accurate anatomic knowledge of this body part is necessary. We provide an open access, anatomic, interactive atlas of the head of the loggerhead sea turtle (Caretta caretta), to facilitate anatomic learning using osteology, gross dissection, and computed tomography (CT) images. Using segmentation and visualization software, relevant anatomic structures were identified and colored in all images, and a computer atlas was developed. This atlas, composed of 55 images, provides an interactive anatomic resource for veterinarians, biologists, researchers, and students involved in loggerhead sea turtle conservation. Abstract The head of the sea turtle is susceptible to congenital, developmental, traumatic, and infectious disorders. An accurate interpretation and thorough understanding of the anatomy of this region could be useful for veterinary practice on sea turtles. The purpose of this study was to develop an interactive two-dimensional (2D) atlas viewing software of the head of the loggerhead sea turtle (Caretta caretta) using images obtained via osteology, gross dissections, and computed tomography (CT). The atlas is composed of 10 osteology, 13 gross dissection, 10 sagittal multiplanar reconstructed CT (bone and soft tissue kernels), and 22 transverse CT (bone and soft tissue windows) images. All images were segmented and colored using ITK-SNAP software. The visualization and image assessment were performed using the Unity 3D platform to facilitate the development of interactive content in 2D. This atlas can be useful as an interactive anatomic resource for assessment of the head of loggerhead sea turtles.
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Wyneken J, Salmon M. Linking Ecology, Morphology, and Behavior to Conservation: Lessons Learned from Studies of Sea Turtles. Integr Comp Biol 2020; 60:440-455. [PMID: 32617553 DOI: 10.1093/icb/icaa044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Here we describe examples of studies that have contributed both to a basic understanding of the biology of imperiled marine turtles, and to their management and conservation. Key elements include, first and foremost, correctly identifying species that differ strikingly in their morphology at different life stages because with growth, they change size by several orders of magnitude and have accompanying shape changes. We also review comprehensive field studies documenting the need for management actions to correct abnormal shifts in sex ratios caused by climate change. We highlight the need to describe those perturbations in terms that are clear to regulators and personnel responsible for management and conservation policies. Finally, we review several basic studies that enhance our understanding of how selection has shaped morphological, functional, and performance attributes, and describe how that knowledge can be applied to the tasks required for enhancing species recovery.
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Affiliation(s)
- Jeanette Wyneken
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, USA
| | - Michael Salmon
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, USA
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Choi E, Charles KE, Charles KL, Stewart KM, Morrall CE, Dennis MM. Leatherback Sea Turtle (Dermochelys coriacea) Embryo and Hatchling Pathology in Grenada, with Comparison to St. Kitts. CHELONIAN CONSERVATION AND BIOLOGY 2020. [DOI: 10.2744/ccb-1395.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Esther Choi
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies [; ; ]
| | | | | | - Kimberly M. Stewart
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies [; ; ]
| | | | - Michelle M. Dennis
- Center for Conservation Medicine and Ecosystem Health, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies [; ; ]
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15
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Martín-Del-Campo R, Bárcenas-Ibarra A, Lund G, Rodríguez-Ríos D, Yong-Villalobos L, García-Hernández J, García-Gasca A. Mercury Concentration, DNA Methylation, and Mitochondrial DNA Damage in Olive Ridley Sea Turtle Embryos With Schistosomus Reflexus Syndrome. Vet Pathol 2019; 56:940-949. [PMID: 31434549 DOI: 10.1177/0300985819868649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Schistosomus reflexus syndrome (SR) is a rare and lethal congenital malformation that has been reported in the olive ridley sea turtle (Lepidochelys olivacea) in Mexico. Although the etiology remains unclear, it is presumed to be genetic. Since embryonic development in sea turtles largely depends on environmental conditions, we investigated whether sea turtle total mercury content participates in the etiology of SR. Given that several toxins are known to affect both DNA methylation and/or mitochondrial DNA (mtDNA) copy number, we also probed for associations of these parameters to SR and mercury exposure. We measured the levels of each variable in malformed olive ridley sea turtle embryos (either with SR or other non-SR malformations) and embryos without malformations. Malformed embryos (with or without SR) showed higher mercury concentrations compared to normal embryos, while only embryos with SR showed higher levels of methylation compared to embryos without malformations and those with other malformations. Furthermore, we uncovered a positive correlation between mercury concentrations and DNA methylation in SR embryos. With respect to mtDNA copy number, no differences were detected across experimental groups. Because of sample size limitations, this study is an initial attempt to understand the association of environmental toxins (such as mercury) and epigenetic alterations (DNA methylation) in the etiology of SR in sea turtles.
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Affiliation(s)
- Rodolfo Martín-Del-Campo
- Laboratorio de Biología Molecular y Celular, Centro de Investigación en Alimentación y Desarrollo, Mazatlán, Sinaloa, Mexico
| | - Annelisse Bárcenas-Ibarra
- Laboratorio de Biología Molecular y Celular, Centro de Investigación en Alimentación y Desarrollo, Mazatlán, Sinaloa, Mexico
| | - Gertrud Lund
- Departamento de Ingeniería Genética, CINVESTAV (GL, DRR), Irapuato, Guanajuato, Mexico
| | - Dalia Rodríguez-Ríos
- Departamento de Ingeniería Genética, CINVESTAV (GL, DRR), Irapuato, Guanajuato, Mexico
| | - Lenin Yong-Villalobos
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio)/Unidad de Genómica Avanzada, CINVESTAV, Irapuato, Guanajuato, Mexico
| | - Jaqueline García-Hernández
- Laboratorio de Ciencias Ambientales, Centro de Investigación en Alimentación y Desarrollo, Guaymas, Sonora, Mexico
| | - Alejandra García-Gasca
- Laboratorio de Biología Molecular y Celular, Centro de Investigación en Alimentación y Desarrollo, Mazatlán, Sinaloa, Mexico
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16
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Martín-Del-Campo R, Bárcenas-Ibarra A, Sifuentes-Romero I, Llera-Herrera R, García-Gasca A. Methylation status of the putative Pax6 promoter in olive ridley sea turtle embryos with eye defects: An initial approach. Mech Dev 2018; 154:287-295. [PMID: 30110613 DOI: 10.1016/j.mod.2018.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/05/2018] [Accepted: 08/10/2018] [Indexed: 12/26/2022]
Abstract
Normal development involves the interplay of genetic and epigenetic regulatory mechanisms. Pax6 is an eye-selector factor responsible for initiating the regulatory cascade for the development of the eyes. For the olive ridley sea turtle (Lepidochelys olivacea), a threatened species, eye malformations have been reported. In order to study the DNA methylation status of the putative promoter of the Pax6 gene in embryos with ocular malformations, an exploratory study was carried out in which DNA was isolated from embryos with anophthalmia, microphthalmia, and cyclopia, as well as from their normal counterparts. The 5'-flanking region from the Pax6 gene was isolated, showing two CpG islands (CGIs). The methylation status of CGIs in malformed embryos was compared with that of normal embryos by bisulfite sequencing. Putative transcription factor binding sites and regulatory features were identified. Methylation patterns were observed in both CpG and non-CpG contexts, and were unique for each malformed embryo; in the CpG context, an embryo with cyclopia showed a methylated cytosine upstream the CGI-1 not present in other embryos, an embryo with left anophthalmia presented two methylated cytosines in the CGI-1, whereas an embryo with left anophthalmia and right microphthalmia showed two methylated cytosines in the CGI-2. Normal embryos did not show methylated cytosines in the CGI-1, but one of them showed one methylcytosine in the CGI-2. Methylated transcription factor-binding sites may affect Pax6 expression associated to the cellular response to environmental compounds and hypoxia, signal transduction, cell cycle, lens physiology and development, as well as the transcription rate. Although preliminary, these results suggest that embryos with ocular malformations present unique DNA methylation patterns in the putative promoter of the Pax6 gene in L. olivacea, and probably those subtle, random changes in the methylation status can cause (at least in part) the aberrant phenotypes observed in these embryos.
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Affiliation(s)
- Rodolfo Martín-Del-Campo
- Laboratory of Molecular Biology, Centro de Investigación en Alimentación y Desarrollo (CIAD), Avenida Sábalo Cerritos s/n, Mazatlán, Sinaloa 82110, Mexico.
| | - Annelisse Bárcenas-Ibarra
- Laboratory of Molecular Biology, Centro de Investigación en Alimentación y Desarrollo (CIAD), Avenida Sábalo Cerritos s/n, Mazatlán, Sinaloa 82110, Mexico
| | - Itzel Sifuentes-Romero
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Raúl Llera-Herrera
- Laboratory of Molecular Biology, Centro de Investigación en Alimentación y Desarrollo (CIAD), Avenida Sábalo Cerritos s/n, Mazatlán, Sinaloa 82110, Mexico; Instituto de Ciencias del Mar y Limnología (Unidad Académica Mazatlán), Universidad Nacional Autónoma de México, Avenida Joel Montes Camarena s/n, PO Box 811, Mazatlán, Sinaloa 82040, Mexico
| | - Alejandra García-Gasca
- Laboratory of Molecular Biology, Centro de Investigación en Alimentación y Desarrollo (CIAD), Avenida Sábalo Cerritos s/n, Mazatlán, Sinaloa 82110, Mexico.
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17
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MICROCOMPUTED TOMOGRAPHIC, MORPHOMETRIC, AND HISTOPATHOLOGIC ASSESSMENT OF CONGENITAL BONE MALFORMATIONS IN TWO NEOTROPICAL VIPERIDS. J Wildl Dis 2017; 53:804-815. [DOI: 10.7589/2016-08-181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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18
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Bentley BP, Haas BJ, Tedeschi JN, Berry O. Loggerhead sea turtle embryos (Caretta caretta) regulate expression of stress response and developmental genes when exposed to a biologically realistic heat stress. Mol Ecol 2017; 26:2978-2992. [PMID: 28267875 DOI: 10.1111/mec.14087] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 02/15/2017] [Accepted: 02/21/2017] [Indexed: 12/30/2022]
Abstract
Oviparous reptile embryos are expected to breach their critical thermal maxima if temperatures reach those predicted under current climate change models due to the lack of the maternal buffering processes and parental care. Heat-shock proteins (HSPs) are integral in the molecular response to thermal stress, and their expression is heritable, but the roles of other candidate families such as the heat-shock factors (HSFs) have not been determined in reptiles. Here, we subject embryonic sea turtles (Caretta caretta) to a biologically realistic thermal stress and employ de novo transcriptomic profiling of brain tissue to investigate the underlying molecular response. From a reference transcriptome of 302 293 transcripts, 179 were identified as differentially expressed between treatments. As anticipated, genes enriched in the heat-shock treatment were primarily associated with the Hsp families, or were genes whose products play similar protein editing and chaperone functions (e.g. bag3, MYOC and serpinh1). Unexpectedly, genes encoding the HSFs were not significantly upregulated under thermal stress, indicating their presence in unstressed cells in an inactive state. Genes that were downregulated under thermal stress were less well functionally defined but were associated with stress response, development and cellular organization, suggesting that developmental processes may be compromised at realistically high temperatures. These results confirm that genes from the Hsp families play vital roles in the thermal tolerance of developing reptile embryos and, in addition with a number of other genes, should be targets for evaluating the capacity of oviparous reptiles to respond adaptively to the effects of climate change.
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Affiliation(s)
- Blair P Bentley
- Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, Perth, 6009, Australia.,Oceans and Atmosphere, Commonwealth Scientific and Industrial Research Organization (CSIRO), Floreat, 6014, Australia
| | - Brian J Haas
- Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, MA, USA
| | - Jamie N Tedeschi
- Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, Perth, 6009, Australia
| | - Oliver Berry
- Oceans and Atmosphere, Commonwealth Scientific and Industrial Research Organization (CSIRO), Floreat, 6014, Australia
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19
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Abstract
The olive ridley sea turtle ( Lepidochelys olivacea), considered the most abundant sea turtle species, is listed as vulnerable on the International Union for Conservation of Nature Red List. The most important nesting areas are located in the Eastern Pacific, and congenital malformations have been previously reported in this species. The present study was conducted in a single population at El Verde beach, one of the most important nesting beaches for the species in the northwestern Mexican Pacific. The study was based on embryos that had been incubated in a controlled environment. Schistosomus reflexus syndrome (SRS) was observed in 124 of 20 257 olive ridley embryos (0.6%), comprising 124 of 400 (31%) cases of congenital malformations over a 7-month period. Affected embryos had malformations of the carapace, bridge, or plastron, resulting in exposure of the abdominal or thoracic viscera, as well as spinal malformation and abnormal positioning of limbs adjacent to the head with subsequent ankylosis. SRS phenotypes (although lethal) varied from mild to severe, although most cases were severe. SRS was mostly associated with congenital malformations in the neck (short neck, 80%), tail (anury, 38%), and flippers (different types of dysmelias, 53%). In most cases of severe SRS, ankyloses were present. Documenting these findings could be important to identify the cause of the developmental defects, and identification of the cause of the defects may be of significance to the population and to our efforts to manage this and other populations at risk.
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