Temperature-Controlled Sex Determination in the Sea Turtle Lepidochelys olivacea

The sex of sea turtles is determined by temperature during egg incubation. Thus, climate change affects the sex ratio, exacerbating their vulnerability to extinction. Understanding spatiotemporal effects of temperature on sex determination at the gonadal level may facilitate the design of strategies to mitigate the effects of global warming. Here, we used qRT-PCR and immunofluorescence to analyze the spatiotemporal expression of Dmrt1 and Foxl2 in developing gonads of Lepidochelys olivacea incubated at male-producing temperature (MPT, 26°C) or female-producing temperature (FPT, 33°C). Although both transcription factors are expressed in bipotential gonads up to stage 25, the timing of their sexually dimorphic regulation differs. Whereas the dimorphic expression of Dmrt1 protein initiates at stage 24, Foxl2 protein was expressed specifically in females at stage 25. Interestingly, whereas Dmrt1 colocalizes with Sox9 in cell nuclei of primary medullary cords to form the testis cords, Foxl2 protein is first detected in Sox9-negative cells of primary medullary cords, prior to its substantial expression in the ovarian cortex. Thus, results suggest that the temperature-dependent regulation of sexual pathways is stochastic among the cells of primary medullary cords in undifferentiated bipotential gonads of the olive ridley.

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Dimorphic DNA methylation during temperature-dependent sex determination in the sea turtle Lepidochelys olivacea

General and Comparative Endocrinology ◽

10.1016/j.ygcen.2016.06.026 ◽

2016 ◽

Vol 236 ◽

pp. 35-41 ◽

Cited By ~ 15

Author(s):

Daniela Venegas ◽

Alejandro Marmolejo-Valencia ◽

Christian Valdes-Quezada ◽

Tzipe Govenzensky ◽

Félix Recillas-Targa ◽

...

Keyword(s):

Dna Methylation ◽

Sex Determination ◽

Sea Turtle ◽

Temperature Dependent ◽

Lepidochelys Olivacea

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Exogenous estradiol alters gonadal growth and timing of temperature sex determination in gonads of sea turtle

Developmental Biology ◽

10.1016/j.ydbio.2015.05.022 ◽

2015 ◽

Vol 408 (1) ◽

pp. 79-89 ◽

Cited By ~ 8

Author(s):

Verónica Díaz-Hernández ◽

Alejandro Marmolejo-Valencia ◽

Horacio Merchant-Larios

Keyword(s):

Sex Determination ◽

Sea Turtle ◽

Gonadal Growth

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Chelonicola and Poulinea, two new gomphonemoid diatom genera (Bacillariophyta) living on marine turtles from Costa Rica

Phytotaxa ◽

10.11646/phytotaxa.233.3.2 ◽

2015 ◽

Vol 233 (3) ◽

pp. 236 ◽

Cited By ~ 21

Author(s):

Roksana Majewska ◽

J. P. Kociolek ◽

Evan W. Thomas ◽

Mario De Stefano ◽

Mario Santoro ◽

...

Keyword(s):

Costa Rica ◽

Marine Mammals ◽

Sea Turtles ◽

Sea Turtle ◽

New Genera ◽

Olive Ridley ◽

Lepidochelys Olivacea ◽

Marine Turtles ◽

The Family ◽

Long Time

Marine mammals such as whales and dolphins have been known for a long time to host a very specific epizoic community on their skin. Less known however is the presence of a similar community on the carapaces of sea turtles. The present study is the first describing new taxa inhabiting sea turtle carapaces. Samples, collected from nesting olive ridley sea turtles (Lepidochelys olivacea) on Ostional Beach (Costa Rica), were studied using light and scanning electron microscopy. Two unknown small-celled gomphonemoid taxa were analysed in more detail and are described as two new genera, closely related to other gomphonemoid genera with septate girdle bands, such as Tripterion, Cuneolus and Gomphoseptatum. Chelonicola Majewska, De Stefano & Van de Vijver gen. nov. has a flat valve face, uniseriate striae composed of more than three areolae, simple external raphe endings, internally a siliceous flap over the proximal raphe endings and lives on mucilaginous stalks. Poulinea Majewska, De Stefano & Van de Vijver gen. nov. has at least one concave valve, uniseriate striae composed of only two elongated areolae, external distal raphe endings covered by thickened siliceous flaps and lives attached to the substrate by a mucilaginous pad. Chelonicola costaricensis Majewska, De Stefano & Van de Vijver sp. nov. and Poulinea lepidochelicola Majewska, De Stefano & Van de Vijver sp. nov. can be separated based on stria structure, girdle structure composed of more than 10 copulae, raphe structure and general valve outline. A cladistics analysis of putative members of the Rhoicospheniaceae indicates that the family is polyphyletic. Chelonicola and Poulinea are sister taxa, and form a monophyletic group with Cuneolus and Tripterion, but are not closely related to Rhoicosphenia, or other genera previously assigned to this family. Features used to help diagnose the family such as symmetry and presence of septa and pseudosepta are homoplastic across the raphid diatom tree of life.

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Loggerhead sea turtle environmental sex determination: Implications of moisture and temperature for climate change based predictions for species survival

Journal of Experimental Zoology Part B Molecular and Developmental Evolution ◽

10.1002/jez.b.22620 ◽

2015 ◽

Vol 324 (3) ◽

pp. 295-314 ◽

Cited By ~ 42

Author(s):

Jeanette Wyneken ◽

Alexandra Lolavar

Keyword(s):

Climate Change ◽

Sex Determination ◽

Sea Turtle ◽

Environmental Sex Determination ◽

Loggerhead Sea Turtle ◽

Species Survival

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RNAi-Mediated Gene Silencing in a Gonad Organ Culture to Study Sex Determination Mechanisms in Sea Turtle

Genes ◽

10.3390/genes4020293 ◽

2013 ◽

Vol 4 (2) ◽

pp. 293-305 ◽

Cited By ~ 11

Author(s):

Itzel Sifuentes-Romero ◽

Horacio Merchant-Larios ◽

Sarah Milton ◽

Norma Moreno-Mendoza ◽

Verónica Díaz-Hernández ◽

...

Keyword(s):

Organ Culture ◽

Gene Silencing ◽

Sex Determination ◽

Sea Turtle ◽

Sex Determination Mechanisms

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Successful rehabilitation of an oiled sea turtle (Lepidochelys olivacea) affected by the biggest oil spill disaster in Brazil

Veterinární Medicína ◽

10.17221/81/2020-vetmed ◽

2021 ◽

Author(s):

REM Oliveira ◽

FLN Attademo ◽

JS Galvincio ◽

ACB Freire ◽

AS Silva ◽

...

Keyword(s):

Oil Spills ◽

Sea Turtle ◽

Entire Body ◽

Normal Range ◽

Olive Ridley ◽

Lepidochelys Olivacea ◽

Second Stage ◽

Therapeutic Protocol ◽

Mucous Membranes ◽

Therapeutic Procedures

The standardisation of protocols and discussion of therapeutic procedures in the rehabilitation of turtles affected by oil spills are necessary to optimise the recovery time and increase the chances of survival of these animals. This study aimed at reporting the processes adopted for the stabilisation, decontamination, rehabilitation and release of an oiled olive ridley sea turtle (Lepidochelys olivacea), rescued alive on September 23, 2019, at Santa Rita Beach, Extremoz municipality, Rio Grande do Norte, Brazil. Its entire body was covered by oil. At first, the animal was mechanically dry cleaned using a gauze soaked in mineral oil in the keratinised regions (carapace and plastron) and a gauze soaked in vegetable oil was used on the oral, nasal, ocular, and cloacal mucous membranes. The second stage of the oil removal consisted of washing the animal with heated pressurised water (39 °C) and a neutral detergent using a soft foam sponge. The animal received treatment with antitoxins, antibiotics, analgesics, gastrointestinal protectors, and fluid therapy. After 7 days of treatment, the blood count showed that all the parameters were within the normal range. The oil cleaning process and the therapeutic protocol used in the rehabilitation of the olive ridley sea turtle were efficient.

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