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Axolotl (Ambystoma mexicanum) The salamanders belong to the family of the ambistomátidos coming from Mexico. Formerly they called them Siredom mexicanum, but at present its classification is in the genus Ambystoma. Also at first he was confused as larvae specimens of tiger salamander (Ambystoma tigrinum) who had not experienced the metamorphosis. However, they are now recognized as distinct species.

currently distinguish two sub-species both known as axolotls, and Ambystoma Ambystoma mexicanum bombypellum, they differ only by their habitat; the first live near Mexico City and the second in San Martin Texmelucan.

The axolotl is endemic to Mexico. You can find Ambystoma mexicanum south of Mexico City. Its unique natural habitat are the next to Mexico City lakes, canals and rivers some caves, especially in Xochimilco. They were also in the now vanished lakes Texcoco and Chalco.

They can also be found near Chignahuapan, in the state of Puebla.

The introduction by humans of non-native species such as koi and carassius cyprinids, the canals of Xochimilco, has caused a decline in the population of salamanders, whose spawning and young hatchlings are eaten by these species.

The regenerative capacity of axolotl has led him to be endangered by its excessive exploitation for medicinal purposes. For this reason it is essential that aquarists who have a pair of these animals, breed in captivity. They are beautiful and graceful, so buy them and hunt without thinking that they can extinguish.

The IUCN includes in its red list of endangered species axolotls two species, Ambystoma bombypellum and Ambystoma mexicanum. His status is Critically Endangered, extermadamente considered a high risk of extinction in the wild.

Ambystoma bombypellum is just near the town of San Martin, in the state of Mexico.

Spadefoot (Pelobates cultripes)

Toad short limbs, robust body, smooth skin, without parotoid glands, eyes large vertical pupil, and horny ram black color at the base of the hind limbs.

They reach a maximum size of 89 mm, the most common between 55 and 65 mm.

Females are reaching larger sizes and are much more robust. Males have no mouth sacks or nuptial calluses, but a long and yellowish gland on top of the forearms.

Zeal can start by the end of October, being able to produce the first pinned for November. Spawning takes the form of thick cord and may consist of a number of eggs varies between 1380 and 6882. After three to four months metamorphosis concludes with a size ranging between 19 and 41 mm, leaving the water still with tail reabsorb unfinished.

It is a terrestrial toad custom and crepuscular and nocturnal habits except in the rutting season that he can see active during the day, especially if this is rain or fog. Spend the day underground in vertical holes up to 58 cm deep and even more in the summer. In sandy soils quickly it disappears from sight, digging in the ground with spurs that has at the base of the hind limbs.

It feeds on all kinds of insects, especially Coleoptera, Hemiptera and Orthoptera, while the larvae do both plant matter and animal, coming to devour their own kind when the density of individuals in the same pond is excessive.

He prefers to live loose, sandy soil with a certain degree of humidity, either on land or coastal sand, or on the banks or near streams, ponds, marshes or ponds, being very common in fields, sandbanks and coastal dunes, and in general about any wet area.

It is distributed by most of the Iberian Peninsula, missing only in the most arid areas of Southeast Peninsular, Cantabrian coast and Pyrenees.

Spadefoot (Pelobates cultripes)

Toad short limbs, robust body, smooth skin, without parotoid glands, eyes large vertical pupil, and horny ram black color at the base of the hind limbs.

They reach a maximum size of 89 mm, the most common between 55 and 65 mm.

Females are reaching larger sizes and are much more robust. Males have no mouth sacks or nuptial calluses, but a long and yellowish gland on top of the forearms.

Zeal can start by the end of October, being able to produce the first pinned for November. Spawning takes the form of thick cord and may consist of a number of eggs varies between 1380 and 6882. After three to four months metamorphosis concludes with a size ranging between 19 and 41 mm, leaving the water still with tail reabsorb unfinished.

It is a terrestrial toad custom and crepuscular and nocturnal habits except in the rutting season that he can see active during the day, especially if this is rain or fog. Spend the day underground in vertical holes up to 58 cm deep and even more in the summer. In sandy soils quickly it disappears from sight, digging in the ground with spurs that has at the base of the hind limbs.

It feeds on all kinds of insects, especially Coleoptera, Hemiptera and Orthoptera, while the larvae do both plant matter and animal, coming to devour their own kind when the density of individuals in the same pond is excessive.

He prefers to live loose, sandy soil with a certain degree of humidity, either on land or coastal sand, or on the banks or near streams, ponds, marshes or ponds, being very common in fields, sandbanks and coastal dunes, and in general about any wet area.

It is distributed by most of the Iberian Peninsula, missing only in the most arid areas of Southeast Peninsular, Cantabrian coast and Pyrenees.

San Antonio frog (Hyla arborea)

The tree frog is long, wide head and fingers ending in adhesive disks.

Along flank carding a black lateral line running edged with white. The skin is smooth and a green grass in the back, while the belly is slightly grainy and pale gray. In the throat the male has a vocal sac swells and takes the form of a vegija when croaks.

It is located in the temperate zones of Europe and Asia as well as in Northeast Africa.

His favorite places are covered by lush vegetation wet places. At the beginning of the spring remains in the vicinity of water, but in summer and autumn prefer to settle in the bushes and trees as it can nimbly climb thanks to the adhesive disks of his fingers.

It is completely invisible among the foliage, it has the ability to rapidly change color from green to gray and even brown. It feeds on small insects and spiders.

The coupling takes place in the spring, and females lay eggs in clusters. After metamorphosis, the little frogs measure 15 to 20 mm in length.

Crayfish (Austropotamobius italicus, Austropotamobius pallipes)

It is a decapod arthropod with a body covered by a (exoskeleton) shell hard consistency by impregnations calcium salts.

The body of the crab has fragmented into two portions an earlier or a later or carapace and abdomen. In the front of the head and thorax separated by the so-called "cervical groove" are included. The front part of the shell extends in an area called "face" on the sides of the eyes are inserted. The mouth is located on the ventral side of the head and is surrounded by legs (maxillipeds) that help the animal in driving and discrimination food to be ingested through the mouth hole.

The native crayfish of our rivers has 5 pairs of legs (pereiopods) inserted laterally into the ventral carapace. The first pair of legs has very developed and used tweezers to capture their food. The next two pairs of legs have pincers but also a considerably smaller size and the last two pairs of legs have a nail. Except for the first couple, the rest of the leg assembly uses it mainly to move. At the end of the face are inserted anteriorly, -more largas- antennas and -more antennules called cortas-. This set of sensory appendages is its organ of balance.

His respiratory system is based on a gill housing into two chambers arranged on both sides of the cavity of the carapace.

The abdomen is composed of six segments, each of which may be found a pair of appendages (pleopods). The last couple of these birrámeos appendages is highly developed and by the end segment of the telson form a powerful caudal fin swimming.

The discreet digestive system Crayfish concludes in a year located in the ventral part of the telson.

Sexual differentiation between males and females due to differences in the sexual holes that open in the basal parts of the last legs locomotives males and in the first two pairs of pleopods amending as copulatory organs is established and, thus, they are greater than others also in males. In females the sexual holes are on the third pair of legs locomotives and pleopods are reduced or absent in the first pair and the second pair no changes are observed.

He habitat Our crayfish is really not very demanding in terms of habitat requirements is you need to live, however appreciates the rich waters calcium salts and amounts of dissolved oxygen in water between 3 and 12 mg / l will suffice, the bearing temperature range (between 8.5 and 22 ° C) and is also quite broad. With all crab can be a good indicator of environmental quality of our rivers.

It is located in areas with low flow velocity of water, with funds of variable nature, but more often prefer the gravel bottoms. It is an animal that runs away from light and therefore hidden among the riparian vegetation, in holes dug into the slopes of the banks and under stones. As a result most activity unfolds at night and remains active from spring to autumn, the rest of the year hibernating in their favorite hiding places.

Reproduction

The reproductive coupling occurs shortly before hibernation and female with a setting between 40 and 80 eggs placed under the abdomen and fixed in their pleopods protects them until the following spring, when the eggs hatch.

mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms - mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms mms

Growth and development is done through silent, where the crab is released from its shell or exuvia increasing its size. This process repeats five or six times during the first year. Subsequently the number of seedlings decreased to conclude with two changes in males and in females during adulthood. the native crayfish live an average period of six or seven years, although there are copies that have come to exceed ten years.

Food and customs

The until recently well Autropatamobius pallipes eats everything: macroinvertebrates, amphibian larvae, small fish, carrion, aquatic plants, algae, etc. But this behavior, say so little "ethical" is censored by predators chasing the crab which, incidentally, are not inconsiderable: insects beetles and dragonflies, fish, birds and mammals such as otters.

However the main cause of the population decaimento crayfish and the source of all the evils that have led him to his status of species "endangered", leading from a fungal disease known as crayfish plague, caused by a fungus the saprolegnias group called Aphanomyces astaci, whose presence in Spain was detected, irrefutably, back in the late seventies.

This singular fact should not obscure the fact that the pipes, construction of dams and flow regulation, water pollution and poaching have also hurt our already battered crab. to make matters worse, the strong tradition of our country cangrejera induced promote repopulation with other crabs substitute purporting to be ours, as is the case of American crayfish: Procambarus clarkii. Or the also from North America: signal crayfish, now widely distributed in many sections of the Douro River.