Demography of Acanthochelys spixii (Testudines, Chelidae) in the Brazilian Cerrado

Neto, Habib Jorge Fraxe; Brasil, Marcela Ayub; Horta, Gabriel de Freitas; Barros, Thiago Oliveira; Falcon, Guth Berger; Colli, Guarino R.

doi:10.2744/ccb-0876.1

Cited by 9 publications

(2 citation statements)

References 23 publications

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“…Several studies are available for the other three species of the genus Acanthochelys, focusing on behavior, locomotion, feeding, and other aspects on ecology (Rhodin et al 2009;Brasil et al 2011;Neto et al 2011;Vinke et al 2011). However, biological data on A. radiolata is still scarce (Souza 2004), with the exception of the studies of Molina (1998) and Mocelin et al (2008) that dealt with the reproduction of this turtle in captivity (Mocelin et al 2008 also mentioned one nest found in nature).…”

Section: Introductionmentioning

confidence: 99%

Morphological variation in the Brazilian Radiated Swamp Turtle Acanthochelys radiolata (Mikan, 1820) (Testudines: Chelidae)

Garbin

Karlguth

Fernandes

et al. 2016

Zootaxa

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The freshwater turtle Acanthochelys radiolata (Mikan, 1820) is endemic to the Atlantic Forest domain in Brazil and few studies have been done on the morphology, geographic variation and taxonomy of this species. In this paper we record the morphological variation, as well as sexual dimorphism and ontogenetic changes in A. radiolata throughout its distribution range. We analyzed 118 morphological characters from 41 specimens, both quantitative and qualitative, and performed statistical analyses to evaluate size and shape variation within our sample. Morphological analysis revealed that A. radiolata is a polymorphic species, especially regarding color and shape. Two color patterns were recognized for the carapace and three for the plastron. Diagnostic characteristics of the species, such as the rounded tubercles on the neck and the shallow dorsal sulcus between the 2^nd and 4^th vertebral scutes, varied considerably. Acanthochelys radiolata also showed a high level of ontogenetic variation characterized by a change on the color pattern of plastron and limbs starting from the 4^th month of life. Sexual size dimorphism was observed for the first time on nine morphometric variables and females showed larger sizes than males. Based on these results we conclude that A. radiolata represents one single polymorphic species distributed in the lowlands of the Brazilian Atlantic Forest from the state of Alagoas to the state of Rio de Janeiro and the south of Minas Gerais state.

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Section: Introductionmentioning

confidence: 99%

Morphological variation in the Brazilian Radiated Swamp Turtle Acanthochelys radiolata (Mikan, 1820) (Testudines: Chelidae)

Garbin

Karlguth

Fernandes

et al. 2016

Zootaxa

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“…In addition to climatic factors, it has been amply demonstrated that freshwater turtles exhibit a preference for particular habitats [54][55][56] and that variation in survival probability can be produced by differences in predation levels [57,58]. The differences found at the level of survival in this population in streams with different substrates may be associated with the fact that the muddy substrates afford a reduction in predation risk because it is easier to escape or hide in mud, a pattern that has been reported in other species of freshwater turtles [59,60].…”

Section: Discussionmentioning

confidence: 99%

Long-Term Variation in Survival of A Neotropical Freshwater Turtle: Habitat and Climatic Influences

2019

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Few long-term demographic studies have been conducted on freshwater turtles of South America, despite the need for this type of inquiry to investigate natural variation and strengthen conservation efforts for these species. In this study, we examined the variation in demography of the Chocoan River Turtle (Rhinoclemmys nasuta) based on a population from an island locality in the Colombian Pacific region between 2005 and 2017. We calculated survival, recapture, and transition probabilities, and the effects of stream substrate and El Niño-Southern Oscillation (ENSO) phases (El Niño, Neutral, La Niña) on these variables using a multi-state model. We found differences in survival probabilities between ENSO phases, likely as a consequence of an increase in flood events. In addition, we found support for survival being greater in muddy streams than rocky streams, possibly because it is easier to escape or hide in mud substrates. Recapture probabilities varied by life stages; differences in the probability of recapture between size classes were associated with the high fidelity to territories by adults. The present increases in frequency and severity of El Niño and La Niña may exacerbate the consequences of climatic regimes on natural populations of turtles by increasing the mortality caused by drastic phenomena such as floods.Diversity 2019, 11, 97 2 of 12 scenarios [18][19][20]. The slow life history of turtles makes it necessary for long-term demographic research to generate information relevant to their conservation [21][22][23]. Long-term studies have been relatively common in the north temperate zone, including data of up to three decades' duration on threatened species [24][25][26]. For South America, this kind of long-term research is rare; only the research of Martins and Souza on Hydromedusa maximiliani has included data collected for longer than a decade [27].With 27 species of terrestrial and freshwater turtles, Colombia is considered the seventh most species-rich country in the world, and third at the level of South America behind Brazil and Ecuador [28]. Despite this great diversity, turtles are far from being one of the best-studied animal groups in Colombia; many aspects of their basic biology remain unknown, and long-term research is almost nonexistent or just beginning to be published [29,30]. Among the freshwater turtles recorded in Colombia, the Chocoan River Turtle, Rhinoclemmys nasuta (Geoemydidae), is found only in Colombia and Ecuador [31], and its conservation status is categorized as near-threatened (NT) globally [3], NT in Colombia [32], and endangered (E) in Ecuador [33]. As a consequence of the threatened status of this species, we began studying an island population of R. nasuta in 2005 on Isla Palma, Bahía Málaga, in the central Pacific coastal region of the Department of Valle del Cauca in Colombia [31,34].Using information recorded on R. nasuta during the sampling efforts conducted between 2005 and 2017 on Isla Palma, this research has the goal of evaluating the long-term variation in su...

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Morphology and sexual dimorphism ofAcanthochelys spixii(Testudines, Chelidae) in Brazil

et al. 2016

View full text Add to dashboard Cite

Demography of Acanthochelys spixii (Testudines, Chelidae) in the Brazilian Cerrado

Cited by 9 publications

References 23 publications

Morphological variation in the Brazilian Radiated Swamp Turtle Acanthochelys radiolata (Mikan, 1820) (Testudines: Chelidae)

Morphological variation in the Brazilian Radiated Swamp Turtle Acanthochelys radiolata (Mikan, 1820) (Testudines: Chelidae)

Long-Term Variation in Survival of A Neotropical Freshwater Turtle: Habitat and Climatic Influences

Morphology and sexual dimorphism ofAcanthochelys spixii(Testudines, Chelidae) in Brazil

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