| Poeciliopsis monacha | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cyprinodontiformes |
| Family: | Poeciliidae |
| Genus: | Poeciliopsis |
| Species: | P. monacha |
| Binomial name | |
| Poeciliopsis monacha R. R. Miller, 1960 | |
Poeciliopsis monacha, or the headwater livebearer, is a species of freshwater fish in the family Poeciliidae. It is endemic to Mexico. [1] [2]
Poeciliopsis monacha is endemic to northwestern Mexico where it is present in the upper reaches of streams and arroyos on the western side of the Sierra Madre Occidental mountain range. Some of these watercourses dry up during the summer and the fish may have to survive in springs and pools. Conditions are harsh in winter in the headwaters of the streams at altitudes of around 1,000 m (3,300 ft); there may be frosts and snow may fall. The fish become torpid at temperatures below about 12 °C (54 °F), but there are some hot springs, and water exposed to the sun may warm up during the day. In the summer, no precipitation occurs, much of the water evaporates, and fish may have to survive in dwindling pools where temperatures above about 40 °C (104 °F) will be lethal. [3]
In addition to the stress factors induced by trying to survive in summer in decreasing and warming waters, some pools have very low oxygen levels, exacerbated at night by the lack of the photosynthetic oxygen produced by plants, and often lower at the pool base where the fish feed, or under the mats of algae that tend to accumulate. Under these circumstances, the fish may resort to "surface skimming", a behaviour that allows them to obtain enough oxygen at the interface of water and air. [3]
P monacha is a viviparous species of fish with the young developing in an outgrowth of the female's pericardial sac. [4] After mating, sperm is stored in folds in the ovary lining, and several clutches of young can develop simultaneously at different stages of development. [5]
P. monacha hybridises with Poeciliopsis lucida and Poeciliopsis occidentalis . When a female of P. monacha mates with a male of either of these two species, the offspring are invariably female. [4] In fact this all-female breeding line can be maintained indefinitely in the laboratory by repeatedly back-crossing the offspring to males of P. lucida and P. occidentalis. [4] In the headwaters of the Fuerte River in northwestern Mexico, it is found that only the bisexual form of P. monacha is present in the highest waters, and the proportion of unisexual individuals increases progressively downstream from here. [6]
P. monacha are highly cannibalistic and the juvenile fishes tend to hide from their mother close to the substrate. P. lucida is the reverse, and the young swim beside their mother. Hybrids between the two species are intermediate between these two behaviours. [7]
Poeciliopsis monacha sometimes exhibits black spot disease, caused by parasitic trematode larvae. The parasites burrow into the body wall of the fish and forms tiny cysts. Some authorities consider that infection reduces reproductive success while other authorities believe that fecundity is unaffected. [5]
The unisexual (all female) hybridogenetic fish Poeciliopsis monacha—occidentalis is an ancient clonal lineage that appears to be more than 100,000 generations old. [8] P. monacha was the maternal ancestor of this lineage and P. occidentalis was the paternal ancestor. In these hybridogenetic fish only the haploid maternal P. monacha genome (M), but not the paternal genome, is transmitted to ova (hemiclonal reproduction). The paternal P. occidentalis genome (O) is excluded during a pre-meiotic cell division, thus avoiding synapsis and crossing-over. Fertilization of haploid (M) eggs by O sperm occurs during mating with P. occidentalis males. This fertilization restores diploidy and results in expression of maternal and paternal traits in somatic tissue. These findings indicate that clonal reproduction in a vertebrate lineage is not necessarily transient, but can achieve a substantial evolutionary age. [8]
The Poeciliidae are a family of freshwater 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, and Africa, including Madagascar. Due to release of aquarium specimens and the widespread use of species of the genera Poecilia and Gambusia for mosquito control, though, 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.
Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes, graylings, taimens and lenoks, which are collectively known as the salmonids. The Atlantic salmon, whose Latin name became that of its genus Salmo, is also the eponym of the family and order names.
The mole salamanders are a group of advanced salamanders endemic to North America. The group has become famous due to the presence of the axolotl, widely used in research due to its paedomorphosis, and the tiger salamander which is the official amphibian of many US states, and often sold as a pet.
Haplodiploidy is a sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid. Haplodiploidy is sometimes called arrhenotoky.
The Amazon molly is a freshwater fish native to warm, fresh waters between Tuxpan River in northeastern Mexico and the Rio Grande and the Nueces River in the southern parts of the U.S. state of Texas. It reproduces through gynogenesis, and essentially all individuals are females. The common name acknowledges this trait as a reference to the Amazon warriors, a female-run society in Greek mythology.
Parthenogenesis is a natural form of asexual reproduction in which growth and development of embryos occur in a gamete without combining with another gamete. In animals, parthenogenesis means development of an embryo from an unfertilized egg cell. In plants, parthenogenesis is a component process of apomixis. In algae, parthenogenesis can mean the development of an embryo from either an individual sperm or an individual egg.
Poeciliopsis is a genus of poeciliid fishes that primarily are native to Mexico and Central America. The only exceptions are P. turrubarensis where the range extends into Colombia, and P. occidentalis where the range extends into Arizona and New Mexico.
The Gila topminnow or charalito is a species of fish in the family Poeciliidae. It is found in Mexico and the United States.
The Yaqui topminnow is a species of fish in the family Poeciliidae. Its scientific name is Poeciliopsis sonoriensis; it is also sometimes considered a subspecies of Poeciliopsis occidentalis as P. o. sonoriensis. This fish is native to Mexico and the United States, with a few native and introduced populations persisting in Arizona in the United States, and a number of populations still extant in northern Sonora, Mexico.
Pseudo-arrhenotoky or paternal genome elimination is the phenomenon where males develop from fertilized eggs but the paternal genome is heterochromatinized or lost in the somatic cells and not passed on to their offspring.
In biology, a klepton and synklepton is a species that requires input from another biological taxon to complete its reproductive cycle. Specific types of kleptons are zygokleptons, which reproduce by zygogenesis; gynokleptons which reproduce by gynogenesis, and tychokleptons, which reproduce by a combination of both systems.
Parthenogenesis is a mode of asexual reproduction in which offspring are produced by females without the genetic contribution of a male. Among all the sexual vertebrates, the only examples of true parthenogenesis, in which all-female populations reproduce without the involvement of males, are found in squamate reptiles. There are about 50 species of lizard and 1 species of snake that reproduce solely through parthenogenesis. It is unknown how many sexually reproducing species are also capable of parthenogenesis in the absence of males, but recent research has revealed that this ability is widespread among squamates.
Parthenogenesis is a form of reproduction where eggs develop without fertilization, resulting in unisexual species. This phenomenon is closely related with reproductive modes such as hybridogenesis, where fertilization occurs, but the paternal DNA is not passed on. Among amphibians, it is seen in numerous frog and salamander species, but has not been recorded in caecilians.
Pregnancy has been traditionally defined as the period of time eggs are incubated in the body after the egg-sperm union. 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, e.g. Consistent with this definition, there are several modes of reproduction in fish, providing different amounts of parental care. In ovoviviparity, there is internal fertilization and the young are born live but there is no placental connection or significant trophic (feeding) interaction; the mother's body maintains gas exchange but the unborn young are nourished by egg yolk. There are two types of viviparity in fish. In histotrophic viviparity, the zygotes develop in the female's oviducts, but she provides no direct nutrition; the embryos survive by eating her eggs or their unborn siblings. In hemotrophic viviparity, the zygotes are retained within the female and are provided with nutrients by her, often through some form of placenta.
The fertile hybrids of European water frogs reproduce by hybridogenesis (hemiclonally). This means that during gametogenesis, they discard the genome of one of the parental species and produce gametes of the other parental species. The first parental genome is restored by fertilization of these gametes with gametes from the first species. In all-hybrid populations of the edible frog Pelophylax kl. esculentus, however, triploid hybrids provide this missing genome.
Poeciliopsis prolifica, or the blackstripe livebearer, is a species of small freshwater fish in the family Poeciliidae. It is endemic to Mexico. It is a viviparous species and the female can have several clutches of young developing internally at the same time, hence the specific name prolifica, from the Latin proles, "offspring" and ferax, "rich, fruitful" in reference to the great number of young produced.
Poeciliopsis lucida, the clearfin livebearer, is a species of small freshwater fish in the family Poeciliidae. Reproduction is viviparous, and the female can have several clutches of young developing internally at the same time. It is one of several species of small livebearing fish endemic to Mexico that were described in 1960 by the American ichthyologist Robert Rush Miller.
Leszek Berger was a Polish herpetologist and malacologist.
Gynogenesis, a form of parthenogenesis, is a system of asexual reproduction that requires the presence of sperm without the actual contribution of its DNA for completion. The paternal DNA dissolves or is destroyed before it can fuse with the egg. The egg cell of the organism is able to develop, unfertilized, into an adult using only maternal genetic material. Gynogenesis is often termed "sperm parasitism" in reference to the somewhat pointless role of male gametes. Gynogenetic species, "gynogens" for short, are unisexual, meaning they must mate with males from a closely related bisexual species that normally reproduces sexually.
Androgenesis occurs when a zygote is produced with only paternal nuclear genes. During standard sexual reproduction, one female and one male parent each produce haploid gametes, which recombine to create offspring with genetic material from both parents. However, in androgenesis, there is no recombination of maternal and paternal chromosomes, and only the paternal chromosomes are passed down to the offspring. The offspring produced in androgenesis will still have maternally inherited mitochondria, as is the case with most sexually reproducing species.
