Poecilia formosa
Amazon molly
THIS ACCOUNT IS IN PROCESS.
PLEASE CHECK BACK LATER FOR ADDITIONAL INFORMATION.
Type Locality
Palo Alto, México; Girard
1860. (Martin 1978).
Etymology/Derivation of Scientific Name
Poecilia, from Greek
poikilos (Latinized stem poecil), meaning “variegated,
speckled” (Boschung and Mayden 2004).
Synonymy
Characters
Maximum size: 9.6 cm
(Page an Burr 1991).
Coloration: Rows of
brown spots on side (may have rows of dusky black spots) (Page and Burr
1991).
Counts: 10 or more
dorsal fin rays (Hubbs et al 1991).
Body shape:
Mouth position:
External morphology:
Dorsal fin rays 10 to 12; dorsal fin base more than one-half predorsal
length, dark spots on scales do not obscure diamond-shaped color pattern;
exists only as females. Origin of dorsal fin anterior to origin of anal fin
(Hubbs et al 1991).
Additional info from Hubbs
key: Intestinal canal long with many convulsions; teeth not moveable.
Additional info from Page and
Burr 1991: The Amazon Molly is an all-female species thought to have
originated as a result of hybridization between Sailfin and Shortfin
mollies, and is intermediate between these two species in its
characteristics. Eggs develop in Amazon Mollies following stimulation by
sperm of males from either parental species.
Distribution (Native and Introduced)
U.S. distribution:
Native to north Mexico and south Texas, current geographic distribution
reflects a rapid northward expansion via efficient colonizing ability
(Turner, 1982).
Texas distribution:
Native to lower Rio Grande Valley and coastal streams and possibly native to
coastal portions of Nueces River. Introduced populations found in San Marcos
River and San Antonio River. (Martin 1978). Found in conjunctions with P.
latipinna in coastal waters and P. mexicana in inland rivers
(Dawes 1991).
Abundance/Conservation status (Federal, State, NGO)
Habitat Associations
Macrohabitat: prefers
sluggish streams and ditches with fresh or brackish water. . (Martin 1978)
Has to remain near populations of P. mexicana and P. latipinna
in order to be able to reproduce (Avise et al., 1991). Water clear to muddy;
currents none to moderate, sometimes rapid; substrates mud, silt, clay sand,
gravel, rock, boulder, vegetation, and oyster shells; vegetation none to
abundant (Rauchenberger 2005).
Mesohabitat:
Biology
Spawning season:
Spawning habitat:
Spawning Behavior: All
female species that reproduces by gynogenesis (Hubbs et al 1991). Reproduces
by mating with one of the males of P. mexicana or P. latipinna
(Balsano et all 1972). The first recognized vertebrate with unisexual
reproduction (Hubbs and Hubbs, 1932). This all-female species produces
diploid apomictic eggs (Rasch et al., 1982; Monaco et al., 1984).
Embryogenesis is subsequently activated by sperm from a related bisexual
species, normally either P. mexicana or P. latipinna. (Turner
et al., 1980a, 1980b). The process apparently takes place without syngamy,
such that genetic transmission is exclusively clonal (Balsano et al 1989).
There is extensive literature on the reproduction of this fish. This molly
is maintained by mating with males of either parental species, the sperm
activatin the egg but taking no part in inheritance. Thus the offspring are
invariably daughters and each is a genetic copy of its mother (Miller et
al., 2005).
Fecundity: Broods of
about 30 fry are produced sporadically (Dawes 1991).
Age at maturation:
Migration:
Growth and Population
structure:
Longevity:
Food habits:
Phylogeny and morphologically similar fishes
Species from the genus
Poecilia inhabiting eastern Mexico fall naturally into two groups which
differ in respect to numerous morphological characters but which may simply
by referred to here as those with long dorsal fins and those with short
dorsals. In respect to its morphological characters, P. formosa is
intermediate between these two groups (Darnell and Abramoff 1968). It occurs
as a hybrid between P. latipinna and P. mexicana (Hubbs and
Hubbs 1932; Turner 1982).
Host Records
Environmental factors
influencing male formation and reproductive ecology, including sexual
parasitism on parental species (Hubbs 1964).
Commercial or Environmental Importance
The species is opportunistic
and tolerant of degraded habitat and water quality conditions, has been
collected in stressed aquatic environments by San Antonio river Authority
biologists throughout the lower San Antonio River Basin. (Gonzales and Moran
2005).
References
Abramoff, P., R. M. Darnell and J. S. Balsano. 1968. Electrophoretic
demonstration of the hybrid origin of the gynogenetic teleost Poecilia
formosa. American Naturalist. 102:555-558
Avise, J. C., J. C. Trexler, J. Travis and W. S. Nelson. 1991. Poecilia
mexicana is the Recent Female Parent of the Unisexual Fish P. formosa.
Evolution. 45(6): 1530-1533.
Balsano, J. S., E. M. Rasch and P. J. Monaco. 1989. The evolutionary ecology
of Poecilia formosa and its triploid associate, pp. 277-297. In G. K.
Meffe and F. F. Snelson, Jr (eds.), Ecology and Evolution of Livebearing
Fishes (Poeciliidae). Prentice Hall, Englewood Cliffs, NJ.
Boschung, H. T., Jr., and Richard L. Mayden. 2004. Fishes of Alabama.
Smithsonian Books, Washington, 736 pp.
Dawes, J. A. 1991. Livebearing Fishes. A Guide to Their Aquarium Care,
Biology and Classification. Blandforn, London, England. 240 pp.
Gonzales, M. and E. Moran. 2005. An inventory of fish species within the San
Antonio Missions National Historical Park. San Antonio River Authority,
Final Report.
Hubbs, C. 1964. Interactions between a bisexual fish species and its
gynogenetic sexual parasite. Texas Memorial Museum Bulletin 8: 1-72.
Hubbs, C. L. and L. C. Hubbs. 1932. Apparent parthenogenesis in nature, in a
form of fish hybrid origin. Science 76:628-630.
Hubbs, C., R. J. Edwards and G. P. Garrett. 1991. An annotated checklist of
freshwater fishes of Texas, with key to identification of species. Texas
Journal of Science, Supplement. 43(4):1-56.
Martin, F. D. 1980. Poecilia formosa (Girard) Amazon Molly pp 548 in
D.S. Lee et al. Atlas of North American Freshwater fishes. N.C. State Mus.
Nat. Hist., Raleigh, i-r+854.
Miller, R. R., W. L. Minckley and S. M. Norris. 2005. Freshwater Fishes of
Mexico. The University of Chicago Press. Chicago, IL. pp 234.
Page, L. M., and B. M. Burr. 1991. A Field Guide to Freshwater Fishes of
North America, north of Mexico. Houghton Mifflin Company, Boston, 432 pp.
Rasch, E. M., P. J. Monaco and J. S. Balssano. 1982. Cytophometric and
autoradiographic evidence for funtional apoxomixis in gynogenetic fish,
Poecilia formosa, and its related triploid hybrids. Histochemistry. 73:
515-533.
Rauchenberger, M. 2005 Artificial Key to Mexican Poeciliidae. In Miller, R.
R. et al. 2005. Freshwater Fishes of Mexico. The University of Chicago
Press. Chicago. Illinois.
Turner, B. J. 1982. The evolutionary genetics of a unisexual fish,
Poecilia formosa pp. 265-305. In C. Barigozzi (ed.), Mechanisms of
Speciation. Alan R. Liss, New York.
Turner, B. J. and B. H. Brett, E. M. Rasch and J. S. Balsano. 1980b.
Evolutionary genetics of gynogenetic fish, Poecilia formosa, the
Amazon molly. Evolution. 34:246-258.
Turner, B. J., and B. H. Brett, and R. R. Miller. 1980a. Interspecific
hybridization and the evolutionary origin of gynogenetic fish, Poecilia
formosa. Evolution. 34: 917-922.
|