Embryonic development of Kinosternon scorpioides (Testudines: Kinosternidae)

Braga, Brenda Stefany dos Santos; Fernandes-Neto, Dário Lisboa; Leal, Relionan Pimentel; Silva, Samantha Ribeiro; Ferreira, María Auxiliadora Pantoja; Oliveira-Bahia, Verônica Regina Lobato de; Marques, J. R. F.; Guimarães, Diva Anélie de Araújo

doi:10.1007/s00435-021-00517-5

Cited by 5 publications

(2 citation statements)

References 43 publications

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“…Paradoxically, hatchling size was positively correlated with the relative duration of the primary period of embryonic growth. Growth data on K. scorpioides incubated at 30°C suggests that the prolongation of incubation does not reflect the continued accretion of embryonic tissue per se (dos Santos Braga et al, 2021), but rather a period of low metabolic activity that precedes hatching (Ewert, 1991). Also, a delay in the offset of incubation might be triggered at 30°C (Ewert, 1991).…”

Section: Discussionmentioning

confidence: 99%

Disentangling the correlated evolution of body size, life history, and ontogeny in miniaturized chelydroid turtles

Cordero

2021

Evolution and Development

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Organismal miniaturization is defined by a reduction in body size relative to a large ancestor. In vertebrate animals, miniaturization is achieved by suppressing the energetics of growth. However, this might interfere with reproductive strategies in egg‐laying species with limited energy budgets for embryo growth and differentiation. In general, the extent to which miniaturization coincides with alterations in animal development remains obscure. To address the interplay among body size, life history, and ontogeny, miniaturization in chelydroid turtles was examined. The analyses corroborated that miniaturization in the Chelydroidea clade is underlain by a dampening of the ancestral growth trajectory. There were no associated shifts in the early sequence of developmental transformations, though the relative duration of organogenesis was shortened in miniaturized embryos. The size of eggs, hatchlings, and adults was positively correlated within Chelydroidea. A phylogenetically broader exploration revealed an alternative miniaturization mode wherein exceptionally large hatchlings grow minimally and thus attain diminutive adult sizes. Lastly, it is shown that miniaturized Chelydroidea turtles undergo accelerated ossification coupled with a ~10% reduction in shell bones. As in other vertebrates, the effects of miniaturization were not systemic, possibly owing to opposing functional demands and tissue geometric constraints. This underscores the integrated and hierarchical nature of developmental systems.

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Section: Discussionmentioning

confidence: 99%

Disentangling the correlated evolution of body size, life history, and ontogeny in miniaturized chelydroid turtles

Cordero

2021

Evolution and Development

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“…However, few describe the embryonic development of pronephros and mesonephros. This is even scarcer concerning South American turtles, for which only publications addressing general embryonic development are found (Braga et al, 2021; Guzman & Bonilla, 1990; Hildebrand et al, 1997; Magalhães et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Pronephros and mesonephros characterization during the embryonic development of the giant South American river turtle, Podocnemis expansa (Podocnemididae: Testudines)

Magalhães

Dias

Oliveira

et al. 2022

The Anatomical Record

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This study aimed to describe pronephros and mesonephros morphology during the embryonic development of Podocnemis expansa. Eggs were collected on an artificial beach at Balbina, Amazonas, Brazil, during the entire incubation period (mean of 59 days). The kidney-gonad complex was processed using light microscopy and the mesonephros using transmission electron microscopy. The pronephros was present for the first time on stage 4, composed of external glomeruli devoid of a capsule, protruding into the coelomic cavity, and internally composed of a capillary network. The pronephros degenerated after development stage 15. The first sign of the appearance of the mesonephros occurred around stage 8, indicated by the early formation of renal corpuscles. The mesonephros comprised an renal corpuscles, neck segment, proximal tubule, intermediate segment, distal tubule, collector tubule, and collector duct. Ultrastructural analysis of the mesonephros brush border was done in the proximal tubule, and the presence of cells with structural characters indicative of secretory activity was detected in the juxtatubular region. Renal corpuscles and proximal tubules were the main components that underwent morphological alterations during mesonephros degeneration. The pronephros is a transient kidney, and the mesonephros became the functional embryonic kidney in P. expansa. Mesonephros degeneration occurs in the cranial-caudal direction, and histologically, the degeneration is identified by changes in the morphology of the renal corpuscle and proximal tubule. However, the mesonephros is still present after hatching.

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A systematic comparative description of extant turtle humeri, with comments on humerus disparity and evolution based on fossil comparisons

Hermanson,

Arnal,

Szczygielski

et al. 2024

The Anatomical Record

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The humerus is central for locomotion in turtles as quadrupedal animals. Osteological variation across testudine clades remains poorly documented. Here, we systematically describe the humerus anatomy for all major extant turtle clades based on 38 species representing the phylogenetic and ecological diversity of crown turtles. Three Late Triassic species of shelled stem turtles (Testudindata) are included to establish the plesiomorphic humerus morphology. Our work is based on 3D models, establishing a publicly available digital database. Previously defined terms for anatomical sides of the humerus (e.g., dorsal, ventral) are often not aligned with the respective body sides in turtles and other quadrupedal animals with sprawling gait. We propose alternative anatomical directional terms to simplify communication: radial and ulnar (the sides articulating with the radius/ulna), capitular (the side bearing the humeral head), and intertubercular (opposite to capitular surface). Turtle humeri show low morphological variation with exceptions concentrated in locomotory specialists. We propose 15 discrete characters to summarize osteological variation for future phylogenetic studies. Disparity analyses comparing non‐shelled and shelled turtles indicate that the presence of the shell constrains humerus variation. Flippered aquatic turtles are released from this constraint and significantly increase overall disparity. Ontogenetic changes of turtle humeri are related to increased ossification and pronunciation of the proximal processes, the distal articulation areas, and the closure of the ectepicondylar groove to a foramen. Some turtle species retain juvenile features into adulthood and provide evidence for paedomorphic evolution. We review major changes of turtle humerus morphology throughout the evolution of its stem group.

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Embryonic development of Kinosternon scorpioides (Testudines: Kinosternidae)

Cited by 5 publications

References 43 publications

Disentangling the correlated evolution of body size, life history, and ontogeny in miniaturized chelydroid turtles

Disentangling the correlated evolution of body size, life history, and ontogeny in miniaturized chelydroid turtles

Pronephros and mesonephros characterization during the embryonic development of the giant South American river turtle, Podocnemis expansa (Podocnemididae: Testudines)

A systematic comparative description of extant turtle humeri, with comments on humerus disparity and evolution based on fossil comparisons

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