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Superfetation (also spelled superfoetation – see fetus) is the simultaneous occurrence of more than one stage of developing offspring in the same animal. [1] [2] [3]In mammals, it manifests as the formation of an embryo from a subsequent menstrual cycle, while another embryo or fetus is already present in the uterus.
Like other seahorses, the dwarf seahorse has a head angled at right angles to its body and swims upright using its dorsal fin to propel it and its pectoral fins to steer. It grows to an average length of 2 and 2.5 cm (0.8 and 1.0 in), with a maximum length of 5.0 cm (2.0 in).
Superfecundation is the fertilization of two or more ova from the same cycle by sperm from separate acts of sexual intercourse, which can lead to twin babies from two separate biological fathers. [ 1 ] [ 2 ] The term superfecundation is derived from fecund , meaning able to produce offspring.
A pregnant Southern platyfish. Pregnancy has been traditionally defined as the period of time eggs are incubated in the body after the egg-sperm union. [1] Although the term often refers to placental mammals, it has also been used in the titles of many international, peer-reviewed, scientific articles on fish.
Seahorses should be kept in an aquarium with low flow and placid tank mates. They are slow feeders, so fast, aggressive feeders will leave them without food. [53] Seahorses can coexist with many species of shrimp and other bottom-feeding creatures. Gobies also make good tank-mates.
During intercourse, the female sprays her eggs into the males pouch, which is called a "brood pouch", where they are fertilized and sealed. Females clutch size can be equal to or greater than one thousand and the males' brood size can range from 97 to 1,552 eggs. The number of eggs the female produces varies depending on the size of the seahorse.
Female ghost pipefish incubate their developing embryos inside fused pelvic fins. Evolutionary transitions from female to male care are practically nonexistent in teleosts, so brood pouches were likely not ancestral. [15] Genome sequencing supports this, revealing multiple different origins across and within different brood pouch types. [16]
Short snouted seahorses are considered ovoviviparous meaning that the female deposits eggs into a pouch on the males stomach, called a brood pouch, and the male goes through pregnancy and labour. [9] Sexual maturation occurs during the first reproductive season after birth.