Results 11 to 20 of about 1,879 (181)

Evidence of dystocia in an oviparous shark

Journal of Fish Biology
AbstractDystocia, or obstructed labor, is a well‐documented phenomenon in various captive vertebrates, including fish. However, despite the documentation of dystocia in several viviparous (live‐bearing) Chondrichthyan species (i.e., sharks, rays, skates, and chimaeras), there are no reports to date of dystocia in any oviparous (egg‐laying) species ...
Carolyn R. Wheeler, Jodie L. Rummer
openaire   +4 more sources

Correlation of Morphology and Metabolism of Reproductive Traits in the Genus <i>Phrynocephalus</i> Around the Qinghai-Tibetan Plateau. [PDF]

Ecol Evol
We explored the correlation of maternal morphology, metabolism, and reproductive traits in 10 Phrynocephalus lizards around the Qinghai‐Tibetan Plateau. We found that oviparous and viviparous lizards did not differ in their reproductive traits. Phrynocephalus lizards with greater snout‐vent length and higher standard metabolic rates tended to produce ...
Tao X, Xie F, Zhu L, Wu Q.
europepmc   +2 more sources

Two's company: Monozygotic twinning in the small-spotted catshark (Scyliorhinus canicula). [PDF]

J Fish Biol
Abstract Developmental abnormalities in elasmobranchs (sharks and rays) are rarely documented, with reported cases primarily involving fin or cranial deformities. Monozygotic twinning, the formation of identical twins from a single zygote, is particularly rare in these species and has been observed overwhelmingly in viviparous elasmobranchs.
Gajić AA, de Loose E, Martin AG, Neuman E, Karalić E, Beširović H, Gayford JH.   +6 more
europepmc   +2 more sources

Sexual Size Dimorphism in Rays and Skates (Elasmobranchii: Batoidea). [PDF]

Ecol Evol
Interspecific trends in sexual size dimorphism are superficially similar in batoids to sharks, but are underlain by different modes of evolution. Selection for substantial SSD in batoids seems to be weaker than in sharks. This may be due to differences in the strength of fecundity selection.
Gayford JH, Seamone SG, Irschick DJ, Chin A, Rummer JL.   +4 more
europepmc   +2 more sources

Morphology of the unique egg cases of hornsharks (Heterodontiformes: Heterodontidae). [PDF]

J Fish Biol
Abstract Many of the egg cases of oviparous chondrichthyans remain unknown and undescribed in the literature. Egg cases can be a useful taxonomic character for species distinction and can be a valuable indicator of a species distribution in the field.
O'Neill HL, Tokunaga K, White WT.
europepmc   +2 more sources

Artificial Insemination and Parthenogenesis in the Zebra Shark Stegostoma tigrinum

Frontiers in Marine Science, 2022
Maintaining self-sustaining populations of zoo and aquarium collections can be challenged when natural reproduction fails within mixed-sex populations; however, reproductive success can sometimes be restored with the application of reproductive ...
Lance Adams, Kady Lyons, Elizabeth Larkin, Nicole Leier, Janet Monday, Chris Plante, Jean Dubach, Jennifer Wyffels   +7 more
doaj   +1 more source

A Taxonomic Survey of Female Oviducal Glands in Chondrichthyes: A Comparative Overview of Microanatomy in the Two Reproductive Modes

Animals, 2021
Oviducal glands (OGs) are distinct expanded regions of the anterior portion of the oviduct, commonly found in chondrichthyans, which play a key role in the production of the egg in-vestments and in the female sperm storage (FSS).
Martina Francesca Marongiu, Cristina Porcu, Noemi Pascale, Andrea Bellodi, Alessandro Cau, Antonello Mulas, Paola Pesci, Riccardo Porceddu, Maria Cristina Follesa   +8 more
doaj   +1 more source

Mixed-Mode Bacterial Transmission via Eggshells in an Oviparous Reptile Without Parental Care

Frontiers in Microbiology, 2022
Symbiotic microorganisms play important roles in maintaining health and facilitating the adaptation of the host. We know little about the origin and transgenerational transmission of symbiotic bacteria, especially in egg-laying species without parental ...
Teng Li, Yang Yang, Huijun Li, Chunkai Li   +3 more
doaj   +1 more source

To What Extent Can Life History Strategies Inform Reptile Conservation Planning? [PDF]

Ecol Evol
Conservation planners must effectively target interventions to reduce the extinction risk of species. If we can use a species' life history strategies to predict their responses to interventions, this offers a promising approach to better understand species extinction risks and conservation potential.
Stevenson EA, Lucas S, McGowan PJK, Smallegange IM, Mair L.   +4 more
europepmc   +2 more sources

Too Hot to Nest? In a Hot Summer the Tortoise Chersina angulata Can Switch From Nesting to Facultative Viviparity

Frontiers in Ecology and Evolution, 2022
In a captive colony of Chersina angulata in Cape Town, South Africa, we observed in 2015/16 retention of the last egg clutch inside the female until the hatching stage was reached, conforming to the generally accepted definition of viviparity ...
Gerald Kuchling, Margaretha D. Hofmeyr
doaj   +1 more source