Macrophthalmus convexus Stimpson

Convex Sentinel Crab (Macrophthalmus convexus)

The Convex Sentinel Crabs are very small crabs having an average carapace diameter of about 1 x 1,5 cm to 1,5 x 3 cm and exceedingly long eyestalks.

They live in the intertidal zone, where they can be found abundantly on muddy places near the outlets of small streams, and are therefore absent from islands without such freshwater streams, e.g. the Tuamotus. The crabs feed on smallest food particles, which they sift out from the sand.

These crabs dig their burrows in muddy sand, in which they flee at the slightest disturbance.

On Aitutaki the crabs are called papaka.

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Photo: J. Poupin; by courtesy of J. Poupin

http://decapoda.ecole-navale.fr/index.php
http://decapoda.free.fr

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Ocypode pallidula Hombron & Jacquinot

Common Ghost-Crab (Ocypode pallidula)

Distribution:

Austral Islands: Raivavae, Rurutu
Cook Islands: ‘Atiu, Aitutaki, Ma’uke, Mangaia, Manuae, Miti’aro, Nassau, Palmerston, Pukapuka, Rakahanga, Rarotonga, Tongareva
Gambier Islands: Aukena, Mangareva
Hawai’i Islands: Laysan, Midway, O’ahu
Norfolk Islands: Norfolk Island
Tuamotu Archipelago: Manihiki, Marutea (Sud), Moruroa, Raraka
Wallis & Futuna: Alofi

local names:

‘atike – Aitutaki / Cook Islands
kalami – Pukapuka / Cook Islands
kohiti – Rakahanga / Cook Islands
kohitihiti – Tongareva / Cook Islands
ko’iti – Rarotonga / Cook Islands
tike – Ma’uke / Cook Islands
tiketike – ‘Atiu, Miti’aro / Cook Islands
titorotai – Mangaia / Cook Islands

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The Common Ghost-Crab is indigenous in the Indo-Pacific region, where it can be found running about the beaches in search for food, and digging burrows in the sand.

It is a rather small species, reaching a carapace size of about 2,5 cm in diameter.

On the Cook Islands, where the species seems to be very common, it is known by several names, including ‘atike, kalami, kohiti, kohitihiti, ko’iti, tike, tiketike and titorotai.

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References:

[1] Katsushi Sakai; Michael Türkay: Revision of the genus Ocypode with the description of a new genus, Hoplocypode (Crustacea: Decapoda: Brachyura). Memoirs of the Queensland Museum 56(2): 665-793. 2013

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Photo: J. Poupin; by courtesy of J. Poupin

http://decpoda.ecole-navale.fr/index.php
http://decapoda.free.fr

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edited: 17.12.2018

Ocypode ceratophthalma (Pallas)

Horn-eyed Ghost-Crab (Ocypode ceratophthalma)

Distribution:

Cook Islands: Aitutaki, Pukapuka, Rakahanga, Rarotonga
Fiji: Kadavu, Makaluva, Viti Levu
Gambier Islands: Mangareva
Hawai’i Islands: O’ahu
Kiribati: Abariringa, Kiritimati, Palmyra, Tabuaeran
Marquesas: Eiao, Nuku Hiva
Norfolk Islands
Samoa: Tutuila, ‘Upolu
Society Islands: Bora Bora, Manuae, Mo’orea, Ra’iatea, Tahiti
Wallis & Futuna: Alofi, ‘Uvea
Tuamotu Archipelago: Fakarava, Makatea, Makemo, Marutea (Sud), Mataiva, Rangiroa, Raraka, Raroia, Taiaro, Takapoto, Tikehau

local names:

avi’ivi’i – Samoa
kalami wolomatua – Pukapuka / Cook Islands
kohite – Rakahanga / Cook Islands
pa’a – Samoa

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The Horn-eyed Ghost-Crab is indigenous to the Indo-Pacific, where it occurs from the coasts of East Africa far into Polynesia, where the animals run about the beaches in search for edible things, including washed up dead fish, or dead sea birds, but also newly hatched sea turtles.

It is a quite large species with a carapace size of up to 8 cm in diameter. It can be distinguished from other related crabs by the eyestalks extending beyond the eyes into long points, those stalks are longer in males, and shorter or almost absent in females.

In Samoa, the species is called avi’ivi’i resp. pa’a.

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References:

[1] Katsushi Sakai; Michael Türkay: Revision of the genus Ocypode with the description of a new genus, Hoplocypode (Crustacea: Decapoda: Brachyura). Memoirs of the Queensland Museum 56(2): 665-793. 2013

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Photo: J. Poupin; by courtesy of J. Poupin

http://decpoda.ecole-navale.fr/index.php
http://decapoda.free.fr

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edited: 19.12.2018