Poeciliidae |
![Sailfin molly (Poecilia latipinna)](./modules/Fish-MM/images/200px-Molly.jpg)
Sailfin molly (Poecilia latipinna)
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Scientific classification |
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Genera |
Alfaro
Aplocheilichthys
Belonesox
Brachyrhaphis
Carlhubbsia
Cnesterodon
Fluviphylax
Gambusia (mosquitofishes)
Girardinus
Heterandria
Heterophallus
Hylopanchax
Hypsopanchax
Lacustricola
Lamprichthys
Limia
Micropanchax
Micropoecilia
Neoheterandria
Pamphorichthys
Pantanodon
Phallichthys
Phalloceros
Phalloptychus
Phallotorynus
Plataplochilus
Poecilia (mollies)
Poeciliopsis
Poropanchax
Priapella
Priapichthys
Procatopus
Pseudopoecilia
Quintana
Scolichthys
Tomeurus
Xenodexia
Xenophallus
Xiphophorus (swordtails, platys) |
Poeciliidae is a family of fresh-water
fishes which are
live-bearing aquarium fish (they give birth to live
young). They belong to the order
Cyprinodontiformes and include well-known aquarium fish
like the guppy, molly, platy, and swordtail.
Live-bearing
Rather than describing the whole family Poeciliidae as
"ovoviviparous", it is probably more accurate to say that
the family consists of species which are all live-bearers,
but that these vary in their reproductive life history:
closely allied species within the same clade may show
variable maternal provisioning. It is true that many members
of the family Poeciliidae are considered to be lecitrophic
(meaning that the mother provisions the oocyte with all the
resources it needs prior to fertilization, so that the egg
is independent of the mother), but others are matrotrophic (literally means "mother feeding": the
mother provides the majority of resources to the developing
offspring after fertilization).
1 Week Fry of Poecilia reticulata (Guppy)
Members of the genus Poeciliopsis, for example, show
variable reproductive life history adaptations. Poeciliopsis
monacha, P. lucida, and P. prolifica form part of the same clade within the
genus Poeciliopsis. However, their modes of maternal
provisioning vary greatly. P. monacha can be
considered to be lecitrophic due to the fact that it does
not really provide any resources for its offspring after
fertilization - the pregnant female is basically a swimming
egg sac. P. lucida shows an intermediate level of
matrotrophy (this literally means "mother feeding" and
involves allocation of the majority of resources to the
offspring after fertilization), meaning that to a
certain extent the offspring's metabolism can actually
affect the mother's metabolism, allowing for increased
nutrient exchange. Poeciliopsis prolifica is
considered to be highly matrotrophic, and almost all of the
nutrients and materials needed for fetal development are
supplied to the oocyte after it has been fertilized.
Poeciliopsis elongata, P. turneri, and P. presidionis form another clade which could be
considered an outgroup to the P. monacha/P.lucida/P.prolifica
clade. These three species are very highly matrotrophic - so
much so that in 1947 C. L. Turner described the follicular
cells of P. turneri as "pseudo-placenta, pseudo-chorion,
and pseudo-allantois".
References
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"Poeciliidae".
FishBase. Ed. Ranier Froese and Daniel Pauly.
October 2004 version. N.p.: FishBase, 2004.
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Poeciliidae (TSN 165876).
Integrated Taxonomic Information System. Accessed on 4
June 2004.