Mallorca Midwifery Toad
| Mallorca Midwifery Toad | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Mallorca midwife toad ( Alytes muletensis ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Alytes muletensis | ||||||||||||
| ( Sanchíz & Adrover , 1979) |
The Mallorca midwife toad ( Alytes muletensis ) is a species of amphibian from the genus of midwife toads ( Alytes ) that is endemic to the Mediterranean island of Mallorca . She is called Ferreret in Spanish and Catalan . It was described in 1979 on the basis of subfossil finds from the middle and upper Pleistocene . Initially, it was believed that the species had been extinct for over 2000 years before living specimens were discovered.
features
The Mallorca midwife toad is a very small frog . Females have a head-torso length of up to 38 millimeters, males up to 34.7 millimeters. The head is relatively large, the muzzle is rounded. The large eyes protrude strongly, the pupils are vertically slit-shaped. The parotid glands (ear glands) are only very slightly developed, the eardrum is more or less clearly visible. The palm has three bumps. Hind limbs, fingers and toes are relatively long compared to other species in the genus Alytes . The relatively smooth and shiny skin has warts along the back that are more or less clearly arranged in a longitudinal row. The coloring and drawing of the top are quite variable. The basic color is golden-green, mostly there are olive-green to black spots that are of different sizes and shapes. It is not uncommon for there to be a triangular, dark spot behind the eye. The ventral side is whitish in color.
The tadpoles of the Mallorca midwife toad are relatively slim, quite dark and reach a total length of up to 76 millimeters. Their mouth is wider, the snout longer and the tail shorter than those of other midwife toad species. Your nostrils are closer to your eyes than to the top of your head. The seams of their fins are low and barely protruding above the height of the trunk. The trunk is widest at the level of the spiraculum (breathing hole) on the abdomen . Below the mouth area there are four so-called lingual papillae .
The number of chromosomes is 2n = 38.
distribution and habitat
The distribution area of the Mallorca midwife toad is limited to the Serra de Tramuntana in Mallorca . It inhabits canyon-like erosion gorges in the karst landscape . In these gorges, torrents flow (Catalan "torrents" ), which dry out during the summer except for basin-like accumulations of water. The annual amount of precipitation here is at least 1000 to 2000 millimeters. The water temperatures are in the range of 9 to 22 ° C. Mallorca midwife toads use the crevices in the rock as a hiding place. They can sometimes be found in small groups of up to five animals. The tadpoles are mainly found in the water basins in the bottom region. The species occurs at altitudes of 10 to 850 meters. A few populations also colonize artificial water points such as cattle troughs. Alytes muletensis is the only representative of the midwife toad found in Mallorca.
Way of life
The Mallorca midwife toad is adapted to harsh, dry environmental conditions. Because of its flattened body, it can hide in narrow crevices. The diet of adults consists mainly of little bristles , such as earthworms , as well as woodlice and various types of ground beetles . There is no hibernation. Two periods of higher activity were identified for daily activity, from 8 p.m. to 11 p.m. and from 1 a.m. to 5 a.m.
Both males and females call. These sound formations take place not only during the mating season, but throughout the year. The calling is therefore not only used to find a partner during reproduction, but also obviously to form groups - in an area in which suitable hiding places are scarce and Mallorca midwife toads live widely. Individuals sitting close together may create a more humid microclimate in the shelter. It is also sometimes speculated that it is a “herding” strategy so that the individuals in a group are better protected from predators. It has also been observed that after metamorphosis , young toads follow the calls of other animals when they leave their ponds and seek crevices in the rock.
Reproduction
The mating calls of the males are described as high, melodic "pi..pi..pi". They usually sound in the first hours of the night, but can sometimes also be heard during the day. The calling period lasts from February to August, with the peak between April and July. It is possible that the mating calls of the Mallorca midwife toad could be confused with the calls of the scops owl . The mating and the transfer of the eggs to the male take place on land. Observations of egg-bearing males are mainly from May to July. A male usually carries 7 to 20 eggs that are wrapped around the hind legs and are 5.4 to 7 millimeters in diameter. The eggs of the Mallorca midwife toad are larger than those of other Alytes species, but their number per male is lower. They are carried around by the males for a month or more.
With increasing movements, the tadpoles in the eggs stimulate the male to seek out a watering hole. Contact with the water causes the tadpoles to hatch. This process takes place from the beginning of May. The larvae have a total length of about 18 millimeters when they hatch. Within a few weeks they can reach lengths of up to 76 millimeters. The metamorphosis takes place between June and September, the climax is in June. Some tadpoles can overwinter and only develop into adults in the following summer, after almost a year in the larval stage. Most of the time, the tadpoles hang tail down on the surface of the water; if there is a disturbance, they dive. The reproductive success increases with increasing altitude, because with this the number of predators decreases.
Discovery and systematics
The Mallorca midwife toad was first described as Baleaphryne muletensis in 1979 by Borja Sanchiz and Rafel Adrover on the basis of subfossil finds from the Pleistocene . Initially, it was assumed that this species had become extinct over 2000 years earlier.
As early as the 19th century, tadpoles were found by midwife toads on Mallorca, initially thought to be specimens of Alytes obstetricans var. Boscai , which is most similar to the Mallorca midwife toad . Following the discovery of the fossils, the suspicion was raised that the tadpoles might have been Baleaphryne muletensis . An adult midwife toad preserved in alcohol, caught in Mallorca in 1978 and initially mistaken for a specimen of the common midwife toad ( Alytes obstetricans ), was then examined again. Since the morphology of her humerus resembled that of the fossil species exactly, she was reclassified as Baleaphryne muletensis .
Today the Mallorca midwife toad is placed in the genus Alytes as Alytes muletensis due to its reproductive behavior and biochemical and genetic studies . According to molecular genetic studies, its sister species is the South Iberian midwife toad , Alytes dickhilleni .
The specific epithet refers to the location of the type specimen , the Cova de Muleta ("Muleta Cave") on the coast southwest of Port de Sóller in the municipality of Sóller .
Hazard and protection
The IUCN lists the Mallorca midwife toad as "vulnerable" (endangered). The main cause of the endangerment of the species and the current limitation of the range to erosion gorges of the Serra de Tramuntana are predators introduced by humans on the island such as the viper snake ( Natrix maura ) and the Iberian water frog ( Rana perezi ). Both species were not originally native to Mallorca. They eat tadpoles and adult specimens of the Mallorca midwife toad. It is also possible that the tadpoles of the Iberian water frog are competing with those of the Mallorca midwife toad for food and habitat. The Mallorca midwife toad is therefore almost only found in erosion canyons today, in which neither of these two species has been found so far.
In 2002 there was an unknown non-fungal disease in an isolated resettlement population that killed some tadpoles but did not recur in 2003 and 2004.
A specimen of Alytes muletensis found dead in 2004 was found to be infected with the fungus Batrachochytrium dendrobatidis , the cause of chytridiomycosis . In a subsequent study of 21 populations, Batrachochytrium dendrobatidis was found in four of the populations, of which almost 100% of the animals examined were infected in two of the populations. In one of the two particularly badly affected populations, animals from the offspring were released into the wild in captivity. The fungus was also found in Mallorca midwife toads, which died in captivity in 1991, 1992, 1994 and 1995. Batrachochytrium dendrobatidis probably came to Mallorca through animals from the reintroduction program. The captive population was probably infected in 1991 by specimens of the South African clawed frog Xenopus gilli kept in the same breeding facility .
The total population is estimated to be 500 to 1500 pairs, spread across approximately 25 mostly isolated populations. The number of animals increased slightly due to the release of animals from the breeding program at Jersey Zoo from 1988 onwards . The increase remained constant even during drought years such as 1999 and 2000. The population trend is recorded on the basis of annual counts of the tadpoles, most of them so far - over 30,000 specimens - were counted in 2004. The increase in pre-existing populations is not dependent on releases, but it is unlikely that new populations would have established without the releases. It is estimated that a quarter of the midwife toads living in Mallorca today are descended from captive animals. The area of the species in the Sierra de Tramuntana has possibly doubled thanks to the offspring.
In 2002 the release program with animals from Jersey was stopped, but should be continued with animals from a new breeding facility on Mallorca. Since 2004 the release into the wild has been completely stopped due to the discovered diseases. To protect the Mallorca midwife toad, the establishment of a reserve has been proposed. Due to the small number of possible areas for future reintroduction, conservation efforts are currently focused on creating new water basins for the tadpoles. Efforts are also being made to remove the viper snake from areas where the Mallorca midwife toad is found. A new resettlement program is being developed.
The Majorca midwife toad is listed as a priority species by the European Union in Annexes II and IV of the Habitats Directive and is therefore a species of community interest that must be strictly protected, for whose preservation special protected areas must be designated by the member states.
supporting documents
- Andreas Nöllert, Christel Nöllert: The amphibians of Europe. Franckh Kosmos Verlag, Stuttgart 1992, ISBN 3-440-06340-2 .
- Mallorca Midwife Toad at www.edgeofexistence.org , accessed August 26, 2008
Individual evidence
- ↑ Gaetano Odierna, Franco Andreone, Gennaro Aprea, Oscar Arribas, Teresa Capriglione, Miguel Vences: Cytological and molecular analysis in the rare discoglossid species, Alytes muletensis (Sanchiz & Adrover 1977) and its bearing on archaeobatrachian phylogeny . Chromosome Research 8: 435–442, 2000 ( online ; PDF; 254 kB)
- ↑ www.edgeofexistence.org, accessed August 26, 2008
- ^ Josep Antoni Alcover , Joan Mayol : Survival of Baleaphryne Sanchiz and Adrover, 1979 (Amphibia: Anura: Discoglossidae) on Mallorca . In: Amphibia-Reptilia . No. 3/4, 1981, pp. 343-345.
- ^ I. Martinez-Solano, HA Goncalves, JW Arntzen, M. Garcia-Paris: Phylogenetic relationships and biogeography of midwife toads (Discoglossidae: Alytes) . In: Journal of Biogeography . No. 31, 2004, pp. 603-618.
- ↑ Alytes muletensis in the endangered Red List species the IUCN 2008 Posted by: Joan Mayol Serra, Richard Griffiths, Jaime Bosch, Trevor Beebee, Benedikt Schmidt, Miguel Tejedo, Miguel Lizana, Iñigo Martínez-Solano, Alfredo Salvador, Mario García-París , Ernesto Recuero Gil, Jan Willem Arntzen, 2006. Retrieved November 22, 2008.
- ↑ Susan F. Walker, Jaime Bosch, Timothy Y. James, Anastasia P. Litvintseva, Juan Antonio Oliver Valls, Samuel Pina, Gerardo Garcia, Ghislaine Abadie Rosa, Andrew A. Cunningham, Sarah Hole, Richard Griffiths, Matthew C. Fisher: Invasive pathogens threaten species recovery programs . In: Current Biology . Volume 18, Issue 18, 2008, doi : 10.1016 / j.cub.2008.07.033 , pp. R853 – R854.
Web links
- The Ferreret , an authentic island inhabitant (Spanish, English, German from p. 87 and with the explanations of the pictures, PDF, 8.14 MB)
- Photos of the Mallorca midwife toad on www.herp.it
- IUCN Redlist: Distribution map of Alytes muletensis
- Mallorca Midwife Toad at amphibiaweb.org
