Mantella

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Mantella
Golden mantella (Mantella aurantiaca) from the Ramsar Menalamba site, Torotorofotsy Wetlands Reserve.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Mantellidae
Subfamily: Mantellinae
Genus: Mantella
Boulenger, 1882
Type species
Dendrobates betsileo
, 1872
Diversity
16 species

Mantella (also known as golden frogs or Malagasy poison frogs) are a prominent genus of aposematic frogs in the family Mantellidae, endemic to the island of Madagascar.[1] Members of Mantella are diurnal and terrestrial, with bright aposematic coloration or cryptic markings.

Natural history

Mantella are an example of

Malagasy mantella (Mantella madagascariensis) and placed them within the genus Dendrobates
based on their close resemblance.

This placement was heavily debated until 1882, when

synonymized
with M. baroni.

The genus remained within Dendrobatidae until the late 19th century. The Royal Natural History (1893) by Richard Lydekker included the genus Mantella as one of two genera representing Dendrobatidae, saying that they could be "distinguished by the tip of the tongue being notched; while in Dendrobates of Tropical America the tongue is entire."[2]

During the first quarter of the 20th century, another three species of Mantella were described, including the

zoologist and explorer. Mocquard's work describes M. attemsi as follows: "First digit extends as far as the second. [Replilatero-dorsal] present, starting at the rear of the upper eyelid. Skin very porous, slightly rough on the back and the head, stomach side smooth; lower back of the legs very rough. Back a dark red-brown, rest of the body black."[3]
This species was later synonymised with M. betsileo.

Description

Species of this genus are small, varying in length between 18–31 millimetres (0.71–1.22 in).[4] Most Mantella species are sexually dimorphic in size, with females being larger than males. Mantella vary in shape from streamlined to plump/rounded bodies, with skin that is either smooth or granular. They have small, angular heads, with large eyes that are either entirely dark or have lighter coloration around the edge of the iris. Mantella have a very distinct tympanum. The tips or discs of the fingers are slightly enlarged, though those of the climbing mantella (Mantella laevigata) are distinctly larger than in other members of the genus. They have four fingers on each forelimb and five on each hindlimb; some species have webbed digits, while others do not. The tibiotarsal articulation is roughly between the shoulder and the nostrils.

Many species of Mantella are similar to the

ventral region, excluding the golden mantella and black-eared mantella (Mantella milotympanum). The venter is normally uniform black, dark grey, or brown and are often marked with blueish or white spots, flecks, or blotches. There are similar blueish to white markings in the form of either spots or a continuous horseshoe-shaped marking on the vocal sac. These characteristics can be used to distinguish between species, such as Baron's mantella (Mantella baroni) and the Malagasy mantella
(Mantella madagascariensis), when locality data is unavailable.

Mantella show a variety in alkaloid profiles between individual frogs of the Ranomafana region. These same alkaloids have been found to be sequestered by certain insects. It has also been observed that Mantella retain alkaloids in their skin for years in captivity. This, combined with analyses of stomach contents and diet, suggests that members of Mantella obtain at least some of their alkaloids from arthropod prey.[5]

Distribution

Habitat that beautiful mantella (Mantella pulchra) can be found around at Vohimana Experimental Reserve, Madagascar
Bronze variation of yellow mantella (Mantella crocea) at the Bakozetra locality, north of the Torotorofotsy Wetlands Reserve

Mantella are endemic to the island of Madagascar and its smaller coastal islands ("Nosy" in

bamboo forests, semi-arid streambeds, slow moving forest streams, seasonal streams, montane grassland savannah, and wet canyons.[4][6][7]

Some members of the genus such as

Nosy Boraha
(Sainte Marie), M. ebenaui have been found living in garbage dumps, feeding on flies. Similar behavior has been reported in western Madagascar, with M. betsileo inhabiting rubbish piles behind human dwellings.

Locality variations

There are several populations of Mantella species that exhibit unusual coloration, some of which are intermediates between species living in

Ambohitantely Reserve and Savakoanina that have green, red and yellow colourations. This often makes it difficult to distinguish between the two species.[4]

Populations of

aff. baroni.[8]

Malagasy mantella (Mantella madagascariensis), a species similar in appearance to M. baroni, is also notably variable among different localities. Niagarakely is one such locality within the Anosibe An'ala District of the Alaotra-Mangoro Region. Here, M. madagascariensis exhibit highly broken yellow/green and mottled black dorsal coloration.

Species

There are currently 16 species of Mantella, with five recognized species groups.[1][4] Most species are easily identifiable by their color patterns, although there are a number of locality variations with an uncertain taxonomic status.[4]

Species group Image Binomial (scientific name) Common name IUCN conservation status Distribution
Mantella laevigata group
Mantella laevigata
Methuen & Hewitt, 1913
Climbing mantella Least Concern northeastern Madagascar
Mantella manery
Vences, Glaw & Böhme, 1999
Marojejy mantella Vulnerable northern Madagascar
Mantella betsileo group
Mantella betsileo
Grandidier, 1872
Brown mantella Least Concern western & central Madagascar
Mantella ebenaui Boettger, 1880 Ebenau's mantella Least Concern northeastern Madagascar
Mantella expectata
Busse & Böhme, 1992
Blue-legged mantella Endangered southwestern Madagascar
Mantella viridis
Pintak & Böhme, 1988
Green mantella Endangered northern Madagascar
Mantella bernhardi group
Mantella bernhardi
Vences, Glaw, Peyrieras, Böhme & Busse, 1994
Bernhard's mantella Vulnerable southeastern Madagascar
Mantella cowanii group
Mantella cowanii
Boulenger, 1882
Cowan's or harlequin mantella Endangered central Madagascar
Mantella baroni Boulenger, 1888 Baron's mantella Least Concern central Madagascar
Mantella haraldmeieri
Busse, 1981
Harald Meier's mantella Endangered southern Madagascar
Mantella nigricans
Guibé, 1978
Guibe's mantella Least Concern northeastern Madagascar
Mantella aurantiaca group
Mantella aurantiaca
Mocquard, 1900
Golden mantella Endangered central Madagascar
Mantella crocea
Pintak & Böhme, 1990
Yellow mantella Vulnerable central Madagascar
Mantella madagascariensis
Grandidier, 1872
Malagasy mantella Vulnerable central Madagascar
Mantella milotympanum
Staniszewski, 1996
Black-eared mantella Critically Endangered eastern Madagascar
Mantella pulchra
Parker, 1925
Beautiful mantella Near Threatened eastern Madagascar

Threats

Slash-and-burn farming method (known locally as tavy) being used near the Vohimana Experimental Reserve, Madagascar.

Several species in the genus are threatened because of

IUCN Red List of Threatened Species
.

Species in this genus have tested positive for Batrachochytrium dendrobatidis (Bd). As of yet, there have been no negative effects observed within amphibian populations in Madagascar, suggesting that the Bd strain has a low virulence level but should be closely monitored.[6]

Gallery

  • Mantella aurantiaca
    Mantella aurantiaca
  • Mantella baroni
    Mantella baroni
  • Mantella bernhardi
    Mantella bernhardi
  • Mantella cowanii
    Mantella cowanii
  • Mantella expectata
    Mantella expectata

References

  1. ^ a b Frost, Darrel R. (2017). "Mantella Boulenger, 1882". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 6 January 2018.
  2. ^ Lydekker, Richard (1893). The Royal Natural History Vol. V - Reptiles, Amphibians and Fishes. Frederick Warne & Co. p. 271.
  3. ^ Mocquard, Francois (1909). "Synopsis des familles, genres et espèces des reptiles écailleux et des batraciens de Madagascar (1909)". Masson: 65–67.
  4. ^
    ISBN 978-3-929449-03-7.{{cite book}}: CS1 maint: location missing publisher (link
    )
  5. .
  6. ^ a b c "The IUCN Red List of Threatened Species". The IUCN Red List of Threatened Species. 2017.
  7. .
  8. ^ Vences, Miguel; Glaw, Frank; Mausfeld, Patrick; Böhme, Wolfgang (October 1998). "Comparative osteology of Malagasy poison frogs of the genus Mantella" (PDF). Zoological Bulletin. 48: 206.

External links