Superfetation in the viviparous fish Heterandria formosa (Poeciliidae)

2019 ◽  
Vol 280 (5) ◽  
pp. 756-770
Author(s):  
María Guadalupe Guzmán‐Bárcenas ◽  
Mari Carmen Uribe
Keyword(s):  
Viviparous Fish ◽  
Heterandria Formosa

Memoirs: Observation on the Breeding and Development of the viviparous fish, Heterandria formosa

1940 ◽  
Vol s2-81 (324) ◽  
pp. 479-520
Author(s):  
ELIZABETH A. FRASER ◽  
RACHEL M. RENTON
Keyword(s):  
Early Stage ◽  
Late Development ◽  
Head Region ◽  
Mature Ovum ◽  
Entire Area ◽  
Short Account ◽  
Viviparous Fish ◽  
Large Size ◽  
Noteworthy Feature ◽  
Heterandria Formosa

1. A short account is given of the breeding habits of Heterandria formosa in an aquarium. 2. The ovary and the mature ovum are briefly described, the noteworthy feature of the ripe ovum being the small quantity of yolk. 3. Degeneration of ova is found to be a common occurrence in unfertilized females, and to a less extent in those full of developing embryos. 4. The method for ensuring the fertilization of the egg within the follicle is portrayed. Over the area where the spermatozoa have entered the cells of the ovarian epithelium and those of the follicle form a solid plug which eventually disrupts to enable the fully developed embryo to escape into the cavity of the ovary. 5. It is characteristic of early development that the egg is encircled by a unilaminar ectoderm before there is any visible differentiation into endoderm and mesoderm. 6. Owing to the scarcity of yolk only a few periblast cells arise and no syncytial layer is formed. 7. The primitive-germ cells are visible at an early stage within the apparently undifferentiated mesendoderm cells. 8. A striking feature is the large size of the pericardium and its growth upwards as a pericardium hood which completely surrounds the head region of the embryo. Over the walls runs a network of blood-vessels from which the maternal capillaries become eventually separated by only an attenuated layer of protoplasm. Both respiration and nutrition are effected through the follicle. 9. A remarkable specialization is the development of a urinary bladder which expands into a thin-walled vesicle of enormous dimensions, finally occupying almost the entire area formerly filled by the pericardium and the yolk-granules. 10. The development of Heterandria is compared with that of other viviparous fishes. 11. The significance of the unusual features in early and late development is discussed and some comparisons are made with the conditions in higher vertebrates.

scholarly journals Differences in offspring size predict the direction of isolation asymmetry between populations of a placental fish

2013 ◽  
Vol 9 (5) ◽  
pp. 20130327 ◽  
Author(s):  
Matthew Schrader ◽  
Rebecca C. Fuller ◽  
Joseph Travis
Keyword(s):  
Reproductive Isolation ◽  
Offspring Size ◽  
Hybrid Inviability ◽  
Haldane’S Rule ◽  
Haldane's Rule ◽  
Asymmetric Pattern ◽  
Heterandria Formosa ◽  
Different Populations ◽  
Selection For

Crosses between populations or species often display an asymmetry in the fitness of reciprocal F 1 hybrids. This pattern, referred to as isolation asymmetry or Darwin's Corollary to Haldane's Rule, has been observed in taxa from plants to vertebrates, yet we still know little about which factors determine its magnitude and direction. Here, we show that differences in offspring size predict the direction of isolation asymmetry observed in crosses between populations of a placental fish, Heterandria formosa . In crosses between populations with differences in offspring size, high rates of hybrid inviability occur only when the mother is from a population characterized by small offspring. Crosses between populations that display similarly sized offspring, whether large or small, do not result in high levels of hybrid inviability in either direction. We suggest this asymmetric pattern of reproductive isolation is due to a disruption of parent–offspring coadaptation that emerges from selection for differently sized offspring in different populations.

Sharply Angled Lateral Curvature Modification in Anal Fin of a Viviparous Fish, Xenotoca variata (Cyprinodontiformes: Goodeidae)

2020 ◽  
Vol 38 (1) ◽  
Author(s):  
Atsuo Iida ◽  
Risako Nakai ◽  
Jumpei Nomura ◽  
Rieko Tanaka ◽  
Nobutoshi Mizuno ◽  
...  
Keyword(s):  
Viviparous Fish ◽  
Lateral Curvature
Sign in / Sign up

Export Citation Format

Share Document