General Information

COMMON NAMES: a fiddler-crab TRADITIONAL NAMES: Kō‘iti Raukura (RR), Koro‘iti (AK), Kohitihiti Kula (TS), Kohitihiti Kura (TW), Fetike (MH RK), Kalama ?ID (PK) GLOBAL DISTRIBUTION: NATIVE e.Africa - Indonesia - Cooks - Tuamotu; n. to Taiwan COOK ISLANDS STATUS: Native; S.Group - common; N.Group - common; Marine, near-shore; mud-flats, intertidal SIGNIFICANCE LIST: oil production; KEY FEATURES: Carapace 21x34mm (LxW); fiddle to 55mmL. CARAPACE very narrow between the eyes (a "narrow-fronted fiddler-crab"). COLOUR contrasting morphs - blue-black with pale lattice or blotches, and yellow with cream blotches and dark spots. MALE "fiddle" (=chela or cheliped) red to pink base with dark band over base of fixed-finger (=pollex); an indistinct long-triangular depression extending about 25% along the fixed-finger (pollex); a granular surface on the base of the fiddle; and a dorsal spine on the wrist segment (=merus). FEMALE has patch of hairs on each posterior corner of carapace. SIMILAR SPECIES: Uca crassipes has a broad projection between the eyes (vs. narrow projection); sharp-edged short-triangular pit at the base of the fixed-finger (vs. indistinct long-triangular depression); without dark-bar on base of fixed-finger (vs. usually with dark bar).

Cook Islands Distribution

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Southern Group: Present    Makatea:
RR	MG	AT	MK	MT	AK	PL	TK	MN
+++		-	-		P			P

Northern Group: Present
TN	MH	RK	PK	NS	SW
+++	P	P?	+++		++

Uca tetragonon (Herbst, 1790)
SYNONYMS: Uca tetragonum; Gelasimus tetragonon; Uca duperreyi

TAXONOMY: ANIMALIA; ARTHROPODA; CRUSTACEA; MALACOSTRACA; EUMALACOSTRACA; Eucarida; Decapoda; Reptantia; Brachyura; Brachygnatha; Brachyrhyncha; OCYPODIDAE

SIGNIFICANCE NOTES -
POSITIVE SIGNIFICANCE: oil production;. Comments: Used in production of scented coconut oil (Rakahanga-Sims84)

GENERAL NOTE: The common and large fiddler on Rarotonga and Aitutaki is the narrow-front Uca tetragonon which has a typically minimal vertical wave in which it barely raises its body and simply moves the fiddle up and down. They court on the surface and mate on the surface or in their burrows. Females sometimes build chimneys.

Vouchers:
Tongareva:TCrocker39 as Uca duperryi; fieldspecimen+photo, both morphs, c.2002, G.McCormack with ID as Uca tetragonon. Manihiki: BPBM-AccNo.1971.201 with ID as Uca tetragonon; probably includes Uca annulipes of Bullivant74, 2006/02 G.McCormack Pukapuka: fieldspecimen+photo, 2/2004, G.McCormack with ID as Uca tetragonon. Suwarrow: fieldspecimen+photo, dark morph female, 1985, G.McCormack with ID as Uca tetragonon 2006/02.

References:
None recorded.

Data Update History (information):
zTX, zB02, zM02, zupM06a, zD02, zupD06a

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