Atlantic Parrot

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Atlantic Parrot
Atlantic Parrot (male [left] and female [right])

Atlantic Parrot (male [left] and female [right])

Systematics
Order : Toothpies (Cyprinodontiformes)
Subordination : Cyprinodontoidei
Family : Viviparous toothcarps (Poeciliidae)
Subfamily : Live-bearing toothcarps (Poeciliinae)
Genre : Poecilia
Type : Atlantic Parrot
Scientific name
Poecilia mexicana
( Steindachner , 1863)

The Atlantic carp ( Poecilia mexicana ) belongs to the viviparous toothcarp family .

distribution

The habitat of the Atlantic larva are bodies of water that differ in their chemical composition, such as salinity, as well as in temperature and flow speeds, so that this species can be described as a generalist. They live both in mountain streams and in coastal rivers, but prefer flat areas with weak currents.

The spread extends along the Atlantic coast from northern Mexico to the northern areas of Costa Rica .

There is also a cave population that is already adapted to this habitat.

features

Atlantic larvae have a gray to bluish shimmering basic color. There are three to five rows of dark spots along the flank. A pronounced sexual dimorphism is found between adult males and females , which is particularly evident in the anal fin , the maximum standard length and in the color of the caudal and dorsal fin . The differentiation of the sexes in young animals that are of the same color is only possible on the basis of the shape and size of the anal fin.

Female Atlantic males can grow up to nine centimeters long. Their anal fin is often colored orange. When the females are pregnant, as with all viviparous toothcarps, the so-called gestation mark, a dark area, appears on the belly.

The males are up to 7 inches long. The basic coloration of dominant males can be darker than that of females and submissive males. Their dorsal and caudal fins often show orange and black areas. The biggest difference between the sexes is in the gonopodium , which only males have. It develops in the period of sexual maturity and consists of the 3rd, 4th and 5th fin rays of the anal fin, which are lengthened in the course of development, while the other fin rays recede.

Reproduction

In contrast to most other viviparous toothcarps, there is no courtship display in Atlantic pups, instead the males harass the females. Before copulation, the gonopodium, which normally rests on the abdomen, is splayed forward at an angle. The male adopts a swimming position at a fixed angle and introduces the gonopodium into the sexual opening of the female. During the subsequent insemination , sperm packets are released, which dissolve in the sexual organs of the female and release freely movable sperm threads.

In the female's sexual organs, the mature eggs are fertilized and then develop in the womb. The duration of pregnancy can vary due to the influence of external factors such as temperature, diet and age of the female and is around 28 to 32 days. After the gestation period, 15 to 60 young fish are born, depending on the size of the female. Actually, however, the litter of the young is a special form of egg-laying. The well-developed young animals leave the egg during egg-laying, so that only the impression of a live birth arises, they are ovoviviparous . After the litter, the next eggs ripen and can be fertilized in the womb after 5 to 7 days.

Cave population

In a limestone cave, the Cueva del Azufre in the Mexican state of Tabasco , which is traversed by a stream, lives a cave population of the Atlantic larvae . It is the only known cave population of its kind and is called the cave molly.

The cave molly differs from their conspecifics that live on the surface in several ways. They have reduced but functional visible eyes. In some individuals, the eyes are overgrown with fine skin. Most of the cave molly have a pale pink color and colorless fins, some individuals have a golden basic color. Females often have a pillow-like growth around the genital opening.

In terms of behavior, the animals of the cave population show less sexual and aggressive behavior than the surface populations. They were also observed breathing air more frequently than their aboveground counterparts , presumably because toxic hydrogen sulfide is dissolved in the cave water .

Relationship to the Amazon Parrot

It was through genetic studies are evidence that the exclusively female Amazonenkärpflinge by a single hybridization event between Atlantikkärpflingen and Breitflossenkärpflingen 40,000 and 100,000 years ago, according to other, more recent information is even arisen before about 280,000 years ago. Here, a female Atlantic larva was fertilized by a male broad-finned larva.

attitude

Because of their high tolerance with regard to many factors, such as salt concentration and temperature fluctuations, and because of their rapid reproduction, both the wild type and individual cultivated forms are kept in the aquarium hobby.

Atlantic larva and other closely related species, such as the broad-finned larva and the Amazon larva , were very often used as model species in behavioral biology in the past. Atlantic males, like most poecilids, are well suited as model organisms . They are easy to keep and reproduce well in captivity. Their behavior does not change under laboratory conditions compared to behavior in the natural habitat . Several studies have confirmed that poeciliids pay attention to and react to the behavior of other members of their own population, for example when choosing a partner or avoiding predators. When choosing a partner, it was recognized that individuals have preferences for easily recognizable properties such as body size or ornaments, which is why they can be used well in experiments for partner selection.

Web links

Commons : Atlantic Parrot ( Poecilia mexicana )  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Costa, GC and Schlupp, I. (2010): Biogeography of the Amazon molly: ecological niche and range limits of an asexual hybrid species, Global Ecology and Biogeography, 19, 442–451
  2. ↑ a b c d e f g h Tobler, M. and Plath, M. (2007): When the light goes out: Mollys in extreme habitats. The aquarium and terrarium magazine, 60, 76–79
  3. ↑ a b c Sterba, G. (1978): Handbuch der Aquarienfische, 2nd edition, BLV Verlagsgesellschaft, Munich
  4. ^ A b c Stallknecht, H. (1989): Live-bearing tooth carps and their breeding forms, 1st edition, Verlag J. Neumann-Neudamm, Melsungen
  5. ↑ a b Herald, ES (1961): Knaur's Tierreich in Farben Fisch, Droemersche Verlagsanstalt, Munich
  6. ^ Sterba, G. (1987): Freshwater fish of the world, Verlag Eugen Ulmer, Stuttgart
  7. ↑ Plath, M., Makowicz, AM, Schlupp, I. and Tobler, M. (2007): Sexual harassment in live-bearing fishes (Poeciliidae): comparing courting and noncourting species, Behavioral Ecology, 18, 680–688
  8. ^ BJ Turner: The evolutionary genetics of a unisexual fish Poecilia formosa. In: C. Barigozzi (Ed.): Mechanisms of speciation. Alan R. Liss, New York, 1982. pp. 265-305.
  9. ↑ Druen, M and Dugatkin, LA (2011): Information societies: communication networks and sexual selection, In: Ecology and Evolution of Poeciliid Fishes (editors: Evans, JP, Pilastro, A., and Schlupp, I.), The University of Chicago Press, Chicago, 218-227