White, 1861
Diagnosis:
Rostrum very distinct and reaching beyond the cornea of the eyes; in adult specimens the rostrum ends in three or five large teeth of equal size. In juveniles the rostrum is a simple elongate narrowly triangular tooth which reaches beyond the middle of the eyes.
The antennal angles are bluntly rounded and unarmed. The antennular peduncle reaches with about half of the third segment beyond the antennal peduncle.
The third maxilliped has the merus and ischium widely expanded to form an operculum. Also the carpus (which is only slightly longer than wide) and especially the propodus (which is much wider than long) are distinctly widened. The dactylus is very slender.
The large first pereiopod of the female shows on the outer surface of the palm near the base of the fixed finger, a deep crescent-shaped depression with tubercles and spinules; this depression is not present in the males, where the anterior margin of the palm shows a rather wide not too deep concavity. In both sexes the carpus of the larger leg is shorter than the palm.
The merus has a short process in the basal part of the lower margin, which ends in a few small sharp teeth. The telson is slightly broader than long and is distinctly shorter than the elongate, roughly diamond-shaped endopod of the uropod.
The lateral margins of the telson are convex. In adult specimens the posterior margin of the telson consists of three bluntly rounded lobes; in the young the posterior margin of the telson is about straight but for a median concavity. No spines are found on the telson.
Type:
Type locality of C. turnerana: "Africa occ. (Cameroons)"; holotype in BM, no 58.36, in alcohol, condition fair.
Type locality of C. krukenbergi: "Central-Amerika" (this evidently is an incorrect statement of the type locality, as the species, before or since, has never been found outside West Africa); type material in SMF(not located in 1989), where it should be on permanent loan from the Zoological Museum Heidelberg University, Germany.
Type locality of C. diademata: "Afrika. Vielleicht aus Westafrika"; holotype male in MZS, preserved in alcohol, condition fair.
Geographical Distribution:
West Africa from the Ivory Coast to Congo.
Habitat and Biology:
Like most, if not all Callianassa species, C. turnerana lives in burrows in the mud It is found in estuarine areas, sometimes in practically fresh water Every few (3 to 5) years the species swarms in enormous numbers in the slightly brackish or almost fresh waters of the estuaries.
Size:
Total body length 5.5 to 14.5 cm.
Interest to Fisheries:
The swarming of C. turnerana is the sign for the native population for large scale fishing activities. With baskets and with their bare hands the people from Cameroon catch enormous quantities while wading out into the river. Monod (1927: 595-601; 1928: 117-121) gave a vivid account of the fishery for these Callianassids in the Cameroon River near Douala. The female shrimps are eaten whole; the males are said to contain a substance that irritates the throat. The male abdomina are pressed and produce a kind of oil. The females are eaten and are highly esteemed as food. Part of the catch is eaten fresh, part is dried for later use in sauces and soups. A little known account of the fishery is given by Mary H. Kingsley (1897:402): "This swarming of the crayfish occurs about every five years, and for days the river-water is crowded with them, so that you can bale them out by basketfuls. This the native does, accompanying his operations with songs and tom-toms, and he then eats any quantity of them; another quantity he smokes and preserves, in what he pleases to regard as a dried state, for sauce making; and the greatest quantity of all he chucks in heaps to fester round his dwellings".
Remarks:
This species is probably the only crustacean (and certainly the only Thalassinid) for which a country is named. As reported by Vanhöffen (1911) and Monod (1927, 1928), when the Portuguese in the 15th century discovered the Cameroon River, they arrived at a time that C. turnerana was swarming; greatly impressed by this phenomenon they named the river Rio dos Camarãos (shrimp river) and a nearby cape Cabo dos Camarãos. The English transliterated this to Cameroons River, and the name Cameroons was used for the country and also adopted in other languages (Cameroun in French, Kamerun in German, Kameroen in Dutch, etc.).