Brookesia micra
| Brookesia micra | ||||||||||||
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Brookesia micra ♂ in resting color |
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| Scientific name | ||||||||||||
| Brookesia micra | ||||||||||||
| Glaw , Köhler , Townsend & Vences , 2012 |
Brookesia micra is a species of the stubby-tailed chameleon (Brookesiinae). The 23–29 mm long representative of the genus Brookesia is the smallest known reptile in the world. Brookesia micra occurs exclusively on the island of Nosy Hara in the north of Madagascar . There, the species inhabits the soil area of dry forests.
Brookesia micra was discovered in 2007 during an expedition on Nosy Hara and described in 2012 by a research group from the Zoological State Collection in Munich under the direction of the zoologist Frank Glaw . It belongs to a group of very small Brookesia species from the far north of Madagascar.
features
Brookesia micra is an extremely small and delicate chameleon . The females of the species have a head-to-trunk length of 18.7–19.9 mm, and a total of 26.9–28.8 mm long. The smaller males are 15.3–15.9 mm long from head to body and have a total length of 22.5–23.6 mm. The tail is proportionally very short with 7.2–8.9 (females) and 7.2–7.8 mm (males), even for a Brookesia species. The head is longer than it is wide. B. micra has pronounced bulges, the eyes measure 2.0–2.2 mm in horizontal diameter in females and 1.7–2.2 mm in males. The back ridge starts at the level of the rear eye rims and ends at the base of the tail. B. micra has eleven, more rarely twelve, small spines on each side of the back. A helmet is only indicated by a small crest on the neck. The base of the tail is slightly thicker in males than in females.
The body of B. micra is dark brown when at rest, only on the part of the snout in front of the eyes is a beige spot. The tail becomes more and more yellow towards the end and takes on an orange color at the tip. The stress color differs significantly from this: the brown upper side of the body is interspersed with dark, gray-brown dots. The top of the head, the crest of the back and the base of the tail turn light gray-brown under stress and stand out from the rest of the back.
The hemipenis of the male, which was prepared as a holotype of this genus, is elongated (2.4 mm), relatively wide (maximum width 0.9 mm) and transparent. It has no ornaments. The tip consists of a comb-like structure with six papillae, which are largest in the middle and smallest on the edge. Only one hemipenis is everted, the second hemipenis is only partially everted. If the hemipenissus is not fully everted, the crest is not visible at the tip.
distribution and habitat
Brookesia micra is only known from two places on the north Madagascan island of Nosy Hara . Two deposits were discovered there along a small stream. It is unclear whether B. micra also occurs in other places on the island. The species has also been overlooked by extensive herpetological expeditions in the past, suggesting that it is difficult to spot. The animal habitat consists of the forest floor of a dry forest that grows on eroded limestone chunks.
Way of life
Little is known about the way of life of the species. During the day they move on the limestone blocks and between fallen leaves in their habitat. At night, the animals retreat to branches at a low height (5–10 cm above the ground).
Systematics
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| Phylogenetic tree of the Brookesia minima group. The closest relatives of Brookesia micra occur only in the far north of Madagascar. |
The first individuals of Brookesia micra were discovered in March 2007 during a zoological expedition in northern Madagascar. One male was killed for research purposes and preserved as a holotype for later species description. In 2008, more animals were measured and photographed during a second expedition in February. In February 2012, the first description was finally published in the journal PLoS ONE , together with that of the related species B. tristis , B. confidens and B. desperata . The authors of the first description are the German zoologists Frank Glaw , Jörn Köhler and Miguel Vences as well as their American colleague Ted M. Townsend . At the time of its discovery, Brookesia micra was the smallest known reptile in the world, to which the specific epithet micra (Old Gr. Μικρός mikros , tiny, small) refers.
Within the Brookesia genus , B. micra belongs to the B. minima group, which brings together a number of very small species from northern Madagascar. The species is the sister taxon of a clade formed from B. desperata and B. tristis ; both species are native to the northern tip of Madagascar. The ND2 gene of the two clades differs by 23-26%. Probably the precursors of the two clades were separated from each other by a rise in sea level that made Nosy Hara an island. The dwarfing of B. micra does not result solely from the already very small body size of B. - minima group, but is also the result of insular dwarfism and therefore the result of two processes. However, the authors of the first description emphasize that the interpretation as an island dwarfing is uncertain.
Sources and References
literature
- Frank Glaw, Jörn Köhler, Ted M. Townsend, Miguel Vences: Rivaling the World's Smallest Reptiles: Discovery of Miniaturized and Microendemic New Species of Leaf Chameleons (Brookesia) from Northern Madagascar. In: PLoS ONE . Vol. 7, No. 2, 2012, e31314, doi : 10.1371 / journal.pone.0031314 .
Web links
Individual evidence
- ↑ Glaw et al. 2012 , pp. 7–8.
- ↑ a b c d e Glaw et al. 2012 , pp. 16-17.
- ↑ Glaw et al. 2012 , p. 17.
- ↑ Glaw et al. 2012 , pp. 4–6.
- ↑ Glaw et al. 2012 , pp. 20–22.
Footnotes directly after a statement confirm this individual statement, footnotes directly after a punctuation mark the entire preceding sentence. Footnotes after a space refer to the entire preceding text.