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Poeciliidae

{{Short description|Family of ray-finned fishes}}

{{Automatic taxobox

| image = Xiphophorus helleri 03.jpg

| image_caption = Green swordtail, Xiphophorus hellerii

| taxon = Poeciliidae

| authority = Bonaparte, 1831{{cite journal | author1 = Richard van der Laan | author2 = William N. Eschmeyer | author3 = Ronald Fricke | name-list-style = amp |year=2014 | title = Family-group names of Recent fishes | url = https://biotaxa.org/Zootaxa/article/view/zootaxa.3882.1.1/10480 | journal = Zootaxa | volume = 3882 | issue =2 | pages = 001–230| doi = 10.11646/zootaxa.3882.1.1 | pmid = 25543675 | doi-access = free }}

| subdivision_ranks = Subfamilies & Genera

| subdivision = See text

}}

Poeciliidae are a family of freshwater ray-finned fishes of the order Cyprinodontiformes, the tooth-carps, and include well-known live-bearing aquarium fish, such as the guppy, molly, platy, and swordtail. The original distribution of the family was the Southeastern United States to north of Río de la Plata, Argentina. Due to release of aquarium specimens and the widespread use of species of the genera Poecilia and Gambusia for mosquito control, though, introduced poeciliids can today be found in all tropical and subtropical areas of the world. In addition, Poecilia and Gambusia specimens have been identified in hot springs pools as far north as Banff, Alberta.{{cite web |url=http://srd.alberta.ca/FishWildlife/FisheriesManagement/documents/CostsAndThreatsOfInvasiveSpeciesInAlberta-Mar-04.pdf |title=Archived copy |access-date=2013-07-26 |url-status=dead |archive-url=https://web.archive.org/web/20130509063453/http://srd.alberta.ca/FishWildlife/FisheriesManagement/documents/CostsAndThreatsOfInvasiveSpeciesInAlberta-Mar-04.pdf |archive-date=2013-05-09 }}

Live-bearing

All species in the Poecilidae are live-bearers. Differences are seen in the mode and degree of support the female gives the developing larvae. Many members of the family Poeciliidae are considered to be lecithotrophic (the mother provisions the oocyte with all the resources it needs prior to fertilization, so the egg is independent of the mother), but others are matrotrophic (literally "mother feeding": the mother provides the majority of resources to the developing offspring after fertilization). Lecithotrophy and matrotrophy are not discrete traits. Most scientific studies quantify matrotrophy using a matrotrophy index (MI), which is the dry mass of fully developed offspring divided by the dry mass of a fertilized egg.{{Cite journal|last1=Kwan|first1=Lucia|last2=Fris|first2=Megan|last3=Rodd|first3=F. Helen|last4=Rowe|first4=Locke|last5=Tuhela|first5=Laura|last6=Panhuis|first6=Tami M.|date=2015-03-12|title=An examination of the variation in maternal placentae across the genusPoeciliopsis(Poeciliidae)|url=http://dx.doi.org/10.1002/jmor.20381|journal=Journal of Morphology|volume=276|issue=6|pages=707–720|doi=10.1002/jmor.20381|pmid=25765517|s2cid=10946526|issn=0362-2525}}

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 that genus. However, their modes of maternal provisioning vary greatly. P. monacha can be considered to be lecithotrophic because 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, meaning that to a certain extent the offspring's metabolism can actually affect the mother's metabolism, allowing for increased nutrient exchange. P. 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. This level of matrotrophy allows Poeciliopsis to carry several broods at different stages of development, a phenomenon known as superfetation. Because the space for developing embryos is limited, viviparity reduces brood size. Superfetation can compensate for this loss by keeping embryos at various stages and sizes during development.Thibault, R. E., and R. J. Schultz. 1978. Reproductive adaptations among viviparous fishes (Cyprinodontiformes Poeciliidae). Evolution 32:320-333.

P. elongata, P. turneri, and P. presidionis form another clade that could be considered an outgroup to the P. monacha, P.lucida, and 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".{{citation needed|date=April 2014}} The greater degree of matrotrophy in a species is linked with a higher degree of placentation, including "a thicker maternal follicle, higher degree of vascularization, and greater number of villi in the placenta".

The reason for placental evolution in Poeciliids is controversial, and involves two major groups of hypotheses, adaptive and conflict hypotheses.{{Cite journal|last1=Furness|first1=Andrew I.|last2=Avise|first2=John C.|last3=Pollux|first3=Bart J.A.|last4=Reynoso|first4=Yuridia|last5=Reznick|first5=David N.|date=May 2021|title=The evolution of the placenta in poeciliid fishes|journal=Current Biology|volume=31|issue=9|pages=2004–2011.e5|doi=10.1016/j.cub.2021.02.008|pmid=33657405|s2cid=232093911|issn=0960-9822|doi-access=free|bibcode=2021CBio...31E2004F }} Adaptive hypotheses, including the locomotor hypothesis,{{Cite journal|last1=Thibault|first1=Roger E.|last2=Schultz|first2=R. Jack|date=June 1978|title=Reproductive Adaptations Among Viviparous Fishes (Cyprinodontiformes: Poeciliidae)|url=http://dx.doi.org/10.2307/2407600|journal=Evolution|volume=32|issue=2|pages=320–333|doi=10.2307/2407600|jstor=2407600|pmid=28563744|issn=0014-3820}} Trexler-DeAngelis Model{{Cite journal|last1=Trexler|first1=Joel C.|last2=DeAngelis|first2=Donald L.|date=November 2003|title=Resource Allocation in Offspring Provisioning: An Evaluation of the Conditions Favoring the Evolution of Matrotrophy|url=http://dx.doi.org/10.1086/378822|journal=The American Naturalist|volume=162|issue=5|pages=574–585|doi=10.1086/378822|pmid=14618536|bibcode=2003ANat..162..574T |s2cid=23879988|issn=0003-0147}} (reproductive allotment), and life-history facilitation,{{Cite journal|last1=Pires|first1=Marcelo N.|last2=Bassar|first2=Ronald D.|last3=McBride|first3=Kevin E.|last4=Regus|first4=John U.|last5=Garland|first5=Theodore|last6=Reznick|first6=David N.|date=2011-03-24|title=Why do placentas evolve? An evaluation of the life-history facilitation hypothesis in the fish genus Poeciliopsis|url=http://dx.doi.org/10.1111/j.1365-2435.2011.01842.x|journal=Functional Ecology|volume=25|issue=4|pages=757–768|doi=10.1111/j.1365-2435.2011.01842.x|bibcode=2011FuEco..25..757P |issn=0269-8463}} broadly suggest that the placenta evolved to facilitate the evolution of another advantageous trait in the fish's environment. The conflict hypothesis suggests the placenta is a nonadaptive byproduct of genetic "tug-o-war" between the mother and the offspring for resources.{{Cite journal|last1=Crespi|first1=Bernard|last2=Semeniuk|first2=Christina|date=May 2004|title=Parent-Offspring Conflict in the Evolution of Vertebrate Reproductive Mode|url=http://dx.doi.org/10.1086/382734|journal=The American Naturalist|volume=163|issue=5|pages=635–653|doi=10.1086/382734|pmid=15122484|bibcode=2004ANat..163..635C |s2cid=13491275|issn=0003-0147}}

Image:Poecilia reticulata Fry DSC04357 nevit.jpg

Taxonomy

Until recently, the egg-laying African killifish (genera now placed in Procatopodidae and Pantanodontidae) were also placed in the Poecilidae. This treatment led to hypotheses that the Poecilidae are an ancient clade that antedate the breakup of Gondwana (the split between Africa and South America) 100 million years ago, and that live-bearing subsequently evolved in South America.Hrbek, T., J. Seekinger, and A. Meyer. 2007. A phylogenetic and biogeographic perspective on the evolution of poeciliid fishes. Molecular Phylogenetics and Evolution 43:986-998. However, more recent studies have found this taxonomic treatment to be paraphyletic, and have placed these families outside the Poecilidae. These new taxonomic treatments support that the Poecilidae are much younger than previously thought, are entirely a live-bearing group, and are only native to the Americas.{{Cite journal |last1=Bragança |first1=Pedro H. N. |last2=Amorim |first2=Pedro F. |last3=Costa |first3=Wilson J. E. M. |date=2018-02-09 |title=Pantanodontidae (Teleostei, Cyprinodontiformes), the sister group to all other cyprinodontoid killifishes as inferred by molecular data |url=https://zse.pensoft.net/articles.php?id=22173 |journal=Zoosystematics and Evolution |language=en |volume=94 |issue=1 |pages=137–145 |doi=10.3897/zse.94.22173 |issn=1860-0743 |doi-access=free}}{{Cite web |title=CAS - Eschmeyer's Catalog of Fishes |url=https://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp |access-date=2025-03-15 |website=researcharchive.calacademy.org |language=en}}

Poeciliids colonized North America through the Antilles, while they were connected 44 million years ago. Poeciliids then moved to Central America by the Aves land bridge on the Caribbean Plate. When South America connected to Central America three million years ago, some further dispersal southward occurred, but South American species did not move into Central America.

= Genera =

The family is divided into subfamilies and tribes as follows:

References

  • {{FishBase_family|family=Poeciliidae|year=2004|month=October}}
  • {{ITIS |id=165876 |taxon=Poeciliidae |access-date=4 June 2004}}

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Category:Percomorpha families

Category:Fishkeeping

Category:Freshwater fish of Central America

Category:Freshwater fish of South America

Category:Freshwater fish of Mexico

Category:Freshwater fish of the United States

Category:Live-bearing fish

Category:Ovoviviparous fish

Category:Viviparous fish

Category:Taxa named by Charles Lucien Bonaparte