Ecology and Status of the Magdalena River Turtle,<i>Podocnemis lewyana</i>, a Colombian Endemic

Gallego‐García, Natalia; Castaño-Mora, Olga Victoria

doi:10.2744/ccb-0643.1

Cited by 18 publications

(12 citation statements)

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“…This is, the pivotal temperature of 33.4 °C produces both sexes in similar proportions, while higher temperatures produce mainly females and lower temperatures produce mainly males . Its reproductive cycle has not been studied in detail, however it is known that there are two nesting seasons: between December and March, and between June and August (Gallego-García and Castaño-Mora, 2008;Ceballos et al, 2014). Its average clutch size varies between 20 to 22 eggs, with an egg weight varying between 18-38 g and an egg size between 31-50 mm long x 21-44 mm width (Páez et al, 2012;Ceballos et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Histological description of the reproductive tract of male and female hatchlings of the Magdalena river turtle (Podocnemis lewyana).

2014

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In this study we described the macroscopic and microscopic histology of the reproductive system of male and female Podocnemis lewyana neonates (3.5 months old). We found macroscopic differences in the morphology of the gonads between the sexes, with ovaries being twice as long as testes, and testes being twice as wide as ovaries. Microscopically, we identified several immature elements, such as the lack of a muscle layer in the oviduct of females, and simple epithelia instead of pseudostratified epithelia in the oviduct and epididymis described in reptile adults. We also found a black pigment observed macroscopically in the mesovarium, and macroscopically and histologically in the epididymis. This pigment is consistent with the center of melano-macrophages described in other vertebrates. Finally we described a supporting mesenchymal structure, the appendage of the oviduct, which was much longer than what has been described in other Podocnemis species.Keywords: epididymis, histology, ovary, oviduct, pigment, testis. RESUMENEn este estudio se realizó una descripción macro y microscópica del sistema reproductivo de tortugas machos y hembras de neonatos de Podocnemis lewyana de 3,5 meses de edad. Se hallaron diferencias macroscópicas en las gónadas, esto es, el ovario fue el doble de largo relativo al testículo, pero el testículo fue el doble de ancho relativo al ovario. Microscópicamente se identificaron varios elementos inmaduros tales como la ausencia de una capa muscular reportada en el oviducto de hembras de reptiles adultas, y epitelios simples en lugar de epitelios pseudoestratificados en oviducto y epidídimo en reptiles adultos. También se describe un pigmento negro observado macroscópicamente en el mesoovario de las hembras, y macroscópica e histológicamente en el epidídimo de los machos. Este pigmento es compatible con los centros de melanomacrófagos reportados en otros vertebrados. Finalmente, se describe también una estructura mesenquimatosa de soporte que identificamos como el apéndice del oviducto, la cual fue mucho más larga que las descritas en otras especies de Podocnemis.

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Section: Introductionmentioning

confidence: 99%

Histological description of the reproductive tract of male and female hatchlings of the Magdalena river turtle (Podocnemis lewyana).

2014

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“…Considering the total area of these four swamps is 17.68 ha (Londoño et al, 2009), the population density counted so far varies between 4.1 and 6.3 juvenile turtles/ha. The fact that these swamps are shallow areas between 1 and 2.7 m deep (Londoño et al, 2009), and that larger turtles are mainly found in deeper areas above 3 m (Gallego-García and Castaño-Mora, 2008), explains the high percentage of small turtles found by this capture-recapture studies. One recommendation to improve the AAFUVER conservation program is to encourage capture using different techniques (e.g., traps, nets, diving) in deeper areas of the river in order to include larger turtles in their capture-recapture program.…”

Section: Reproductive Outputmentioning

confidence: 59%

“…As in the Sinú, Magdalena and Prado Rivers (Vargas-Ramírez et al, 2007;Gallego-García and Castaño-Mora, 2008;Restrepo et al, 2008), P. lewyana has two nesting seasons in the Rio Claro Cocorná Sur River (this study), December to January and June to July approximately. We found a higher number of nests during the June season; however, egg weight was significantly greater in the December season, and egg weight has an important association on hatchling growth.…”

Section: Nesting Seasons and Nesting Beachesmentioning

confidence: 99%

“…In addition to its restricted distribution, this species faces high mortality of eggs and adults due to animal and human predation and habitat alteration associated with artificial manipulations of rivers by hydroelectric dams, river beach mining and forest destruction to grow pasture for cattle (Vargas-Ramírez et al, 2007;Gallego-García and Castaño-Mora, 2008;Páez et al, 2012). These threats have driven this species to be categorized as Endangered at the national and international level (Tortoise and Freshwater Turtle Specialist Group, 1996;Castaño-Mora, 2002).…”

Section: Introductionmentioning

confidence: 99%

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REPRODUCTION AND CONSERVATION OF THE MAGDALENA RIVER TURTLE (Podocnemis lewyana) IN THE CLARO COCORNÁ SUR RIVER, COLOMBIA

Ceballos

Romero²,

Gómez-Saldarriaga

et al. 2014

Acta biol. colomb.

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Citation / Citar este artículo como: Ceballos CP, RomeRo i, Gómez-saldaRRiaGa C, miRanda K. Reproduction and conservation of the magdalena River turtle (Podocnemis lewyana) in the Claro Cocorná sur River, Colombia. acta biol. Colomb. 2014;19(3):393-400. ABSTRACTThe Magdalena River Turtle, Podocnemis lewyana, is an endangered and endemic turtle from Colombia. Among the most important information needed to conserve endangered species is to identify, monitor, and protect the sites used by the species to reproduce and grow. In this study we report, for the first time, the reproductive output and the nesting beaches of P. lewyana in the Claro Cocorná Sur River, a tributary of the Magdalena River drainage. We systematically examined a river transect of 8 km with 14 sandy beaches during two nesting seasons in one year. We recorded a yearly production of 47 clutches, 957 eggs, and two preferred nesting beaches: Alto Bonito with 51 %, and Bélgica with 28.3 % of this reproductive output. AAFUVER, a community-based organization, has led a headstarting program since 2010 to decrease in-situ egg mortality due to predation on nesting beaches. AAFUVER collects and incubates the eggs ex-situ, raises the hatchlings for one to five months and then releases them into the same river. To understand potential effects of such egg manipulation, we monitored and compared in-situ and ex-situ incubation temperatures. We found exsitu temperatures below the pivotal temperature known for P. lewyana and below the temperatures in nesting beaches. Finally, we monitored hatchlings growth under AAFUVER captive conditions, and found that hatchlings duplicated their body mass during the first three months of age. Egg weight was strongly associated to body weight at hatching, however this association is lost by the third month of age. We strongly encourage supporting this community-based conservation program, and the protection of the Claro Cocorná Sur River as an important nesting and growth habitat for the conservation of P. lewyana.

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“…Threats to Survival. -Several factors that affect populations of P. lewyana have been identified throughout its distributional range: 1) habitat destruction and pollution; 2) traditional utilization and consumption; 3) commercial exploitation; and 4) hydrological changes due to dams (Gallego-Garcia 2004;Vargas-Ramirez et al 2006, 2007b. Pastures and plantations have replaced original forest throughout a large portion of its territory.…”

Section: 4mentioning

confidence: 99%

Podocnemis lewyana Duméril 1852 – Magdalena River Turtle

Páez¹,

Restrepo²,

Vargas‐Ramírez³

2009

Conservation Biology of Freshwater Turtles and Tortoises

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Podocnemis lewyana, the Magdalena River turtle (Family Podocnemididae), is a medium to large-sized river turtle confined to the Sinú, San Jorge, Cauca, and Magdalena river drainages in Colombia, making it a biogeographic anomaly, being the only South American podocnemid turtle to occur northwest of the Andes Mountains instead of inhabiting the Orinoco, Essequibo, or Amazon drainages. The species is currently classified as Endangered on the IUCN Red List due to the combined effects of habitat modification and the heavy exploitation of adults and eggs for consumption as well as some exploitation of hatchlings for the illegal pet trade. Recent analysis suggests it should be uplisted to Critically Endangered. Information on the species' natural history has been fragmentary, but recent field and laboratory studies have generated more detailed information on P. lewyana systematics, ecology, distribution, trends in abundances, and levels of genetic diversity within and among populations. Podocnemis lewyana is primarily herbivorous as adults and nests in the dry season, preferentially but not exclusively on sandy beaches. Nests suffer heavy human and natural predation and also experience infestations by invertebrates and fungi. Sex ratios in the field covary with nest temperatures, and laboratory studies have confirmed the existence of temperaturedependent sex determination in this species and a high pivotal temperature (33.4°C). These studies have also demonstrated incubation temperature and maternal effects on hatchling size, mass, and growth rates. In most regions, P. lewyana population densities are low, with low levels of genetic diversity and no evidence of phylogeographic differences among sites. Existing legislation meant to protect the species is largely unenforced. However, recent attempts to support community-based conservation initiatives and educational activities make it more likely that well-founded management projects may be possible in the near future. distriBution. -Colombia. Restricted to the Sinú, San Jorge, Cauca, and Magdalena river drainages in northwestern Colombia. synonyMy. -Podocnemis lewyana Duméril 1852. suBsPeCies. -None recognized. Genetic analyses demonstrate no significant phylogeography. status. -IUCN 2008 Red List: Endangered (EN A1bd) (assessed 1996, needs updating); CITES: Appendix II; Colombian Red Book: Endangered.Figure 6. Podocnemis lewyana, hatchling from the Chicagua River, Colombia. Photo by Lina Hinestroza.

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Ecology and Status of the Magdalena River Turtle,Podocnemis lewyana, a Colombian Endemic

Cited by 18 publications

References 3 publications

Histological description of the reproductive tract of male and female hatchlings of the Magdalena river turtle (Podocnemis lewyana).

Histological description of the reproductive tract of male and female hatchlings of the Magdalena river turtle (Podocnemis lewyana).

REPRODUCTION AND CONSERVATION OF THE MAGDALENA RIVER TURTLE (Podocnemis lewyana) IN THE CLARO COCORNÁ SUR RIVER, COLOMBIA

Podocnemis lewyana Duméril 1852 – Magdalena River Turtle

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