''Parasesarma leptosoma'', also known as the arboreal crab, is an arboreal, leaf-eating mangrove crab, from East and South Africa where it is found on ''

Rhizophora mucronata ''Rhizophora mucronata'' (loop-root mangrove, red mangrove or Asiatic mangrove) is a species of mangrove found on coasts and river banks in East Africa and the Indo-Pacific region. Description ''Rhizophora mucronata'' is a small to medium si ...

'' and ''

Bruguiera gymnorhiza ''Bruguiera gymnorhiza'', the large-leafed orange mangrove or oriental mangrove,) is a mangrove tree that grows usually to 7-20m high, but sometimes up to 35m, that belongs to the family Rhizophoraceae. It is found on the seaward side of mangrov ...

'', but not on '' Avicennia marina''. It occupies an ecological niche similar to that of another sesarmid, ''

Aratus pisonii ''Aratus pisonii'', commonly known as the mangrove tree crab, is a species of crab which lives in mangrove trees in tropical and subtropical parts of the Americas, from Florida to Brazil on the Atlantic coast, and from Nicaragua to Peru on the Pa ...

'', from the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

. Crabs of the family Sesarmidae are some of the most diverse and important components of mangrove estuary communities in the tropics and are not found in Europe. Two genera common in African, Asian and Australian mangroves are ''Parasesarma'' (26 species) and ''Perisesarma'' (23 species). Often colourful, they have a squarish appearance and have two transverse pectinated crests on the upper edge of the male chelar carpus. The two genera are separated by the absence in ''Parasesarma'' or presence in ''Perisesarma'' of an anterolateral tooth. Crustaceanleg

''Parasesarma leptosoma'' was formerly considered widespread in mangrove along the coast of the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region. A

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

review found that this included several similar species and that the true ''P. leptosoma'' is restricted to coastal parts of South and East Africa, as far north as Tanzania. In order to escape low tide predators, this species twice daily climbs mangrove stems to the canopy and feeds on fresh leaves, and is commonly found on ''Rhizophora mucronata'', but studies suggest that it prefers the foliage of ''Bruguiera gymnorhiza''. Its diet also includes algae, mollusks, insects and annelids. Its aversion to ''Avicennia marina'' may be due to its secreting salt from its leaves, while both ''R. mucronata'' and ''B. gymnorhiza'' are salt excluders. Distinguishing characters are its propodus being three times the length of its dactylus, and the carapace width only some 2 cm. Females carry the eggs, which remain attached to the swimming legs or

pleopod The decapod ( crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various ...

s until hatching. Important physiological adaptations enable these crabs to feed on leaves, with no evidence of fermentation in the gut, a solution common in other animals.

External links

Gallery of images

Bibliography

*''Walking Sideways: The Remarkable World of Crabs'' - Judith S. Weis (Cornell University Press, 23 Oct 2012)

References

{{Taxonbar, from=Q14029708 Mangrove fauna Crabs Taxa named by Franz Martin Hilgendorf