A rare species of the Spanner crab Ranina ranina (Linnaeus, 1758) is reported from Gulf of Mannar, in India.

The description of the morphological features of the species is give

Boominathan, N

Gandhi, A

Kasinathan, C

Rajamani, M

Sukumaran, Sandhya

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89Journal of the Marine Biological Association of India (2007)On a rare species of Spanner Crab Ranina ranina from Gulf of Mannar, IndiaJ. Mar. Biol. Ass. India, 49 (1) : 89 - 90, January - June 2007Spanner crabs inhabit coastal waters of several coun-tries in the Indian and Pacific oceans, from the east coastsof southern Africa to Hawaii and the  Great Barrier Reef.They prefer bare sandy areas and inhabit intertidal watersto depths more than 100m. They aggregate to spawnduring the warmer months and mate at any stage in themoult cycle (Brown, 1986) and females store the spermuntil the eggs are extruded.During spawning the femalesoften bury themselves to incubate and protect the eggs.Large females produce at least 2 batches of eggs, eachseason with an average number of 1,20,000 per batch.The eggs remain attached to the female for 4 – 5 weeksbefore hatching (Brown, 1986). They pass through 8larval stages during the following 5 to 8 (longest in higherlatitudes) weeks of their life, and then they settle beforemetamorphosis to the recognizable spanner crab form(Brown, 1986). They may live for 7 to 9 years with malesreaching a size of 150mm carapace length and 900g,while females are smaller, reaching a maximum size of120mm carapace length and 400g in weight (Brown,1986). These  crabs remain completely buried in the sandfor most of the day and emerge rapidly when food ap-pears (Skinner and Hill, 1986).They are opportunisticfeeders. Adults feed on sea urchins (echinoderms) and avariety of small bivalve molluscs, crustaceans, polychaeteworms and fishes. Spanner crabs are often found in areaswhere there is an intensive night time prawn trawl fishery,suggesting that discards from the trawl catch may forma significant part of their diet (Brown, 1986). The spannercrabs constitute a major fishery in Queensland and NewSouth Wales in Australia and  also  support a recreationalfishery.MaterialA female Spanner crab (Red frog crab) Ranina ranina(Linnaeus, 1758) was landed at Pamban North landingcentre on 2nd April 2006. It measured 8.5cm carapacewidth   and 350g weight. It was caught in bottom set gillnet operated at a depth of 20 m, 30 km, away fromNoteOn a rare species of Spanner crab Ranina ranina (Crustacea: Brachyura:Raninidae) from Gulf of Mannar, IndiaC.Kasinathan, Sandhya Sukumaran, A.Gandhi, N.Boominathan and M.RajamaniRegional Centre of Central Marine Fisheries Research Institute, Marine Fisheries P.O., Mandapam Camp - 623 520,Tamil Nadu, IndiaAbstractA rare species of the Spanner crab Ranina ranina (Linnaeus, 1758) is reported from Gulf of Mannar, in India.The description of the morphological features of  the species is given.Table 1. Morphometric measurements of Ranina raninaCharacters Measurement (mm)Carapace width 85Carapace length 101Abdomen length 56Abdomen width 36Chelate leg spines(Right side)Anterior portion 10Posterior portion 5Chelate leg spines(Left side)Anterior portion 14Posterior portion 8Abdominal segments 6Carapace spines 21White spots on the  anterior side of  carapace 10Weight 350 g.Sex Female (egg bearing)Colour of specimen Reddish brownColour of egg OrangeFig. 1. Ranina ranina landed at Pamban90Journal of the Marine Biological Association of India (2007)C. Kasinathan and othersDhanushkodi in the  Gulf of Mannar. The specimen isdeposited in CMFRI museum at Mandapam (Fig .1).Taxonomy: Kingdom: Animalia, Phylum: Arthropoda,Subphylum: Crustacea, Class: Malacostraca,  Subclass :Eumalacostraca, Superorder: Eucarida, Order : Decapoda,Suborder: Pleocyemata, Infraorder: Brachyura, Superfam-ily: Raninoidea, Family: Raninidae, Genus: Ranina,Species : Ranina ranina (Linnaeus, 1758)Description: Carapace width 8.5cm, weight 350g.This red crab is the largest representative species of thegenus Ranina in tropic and subtropic regions. Carapacecompletely covered by low rounded scale like spines inlarge or small numbers, are broader anteriorly. Eye stalksset vertical and longer. Strong cheliped  bears seven oreight teeth. Paddle-shaped walking legs, anterior andposterior borders hairy. Body  reddish brown in colourwith some 10 white spots on anterior part of carapace.Morphometric measurements are given in Table 1.Distribution: The species is widely distributed in theIndo – Pacific region, from Hawaii, Japan, Formosa,Philippines, Australia through the Indonesian Archipelagoto East Africa (Motoh, 1980).Remarks : This crab is very palatable and is eatenwherever it is caught in gillnet or crab trap. Zamboangais well noted for this very tasty crab.AcknowledgementsThe authors wish to acknowledge Dr. Mohan JosephModayil, Director, CMFRI, for providing facilities andDr. N.Kaliaperumal, SIC, CMFRI, Mandapam for theencouragements and support.References:Skinner, D.G. and B.J.Hill.1986. Mar. Biol., 91:  461 -465.Brown, I.W. 1986. Aust. Fish., 45 (10): 3-7.Brown, I.W. 1986. FIRTA project No. 81/71 Final Report,106pp.Motoh, H. 1980. Field guide of the edible crustacea of thePhilippines. SEAFDEC, Philippines, 96pp.Received: 25 October 2006Accepted: 29 May 2007

Rare species of Spanner crab Ranina ranina (Crustacea: Brachyura: Raninidae) from Gulf of Mannar, India

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Rare species of Spanner crab Ranina ranina (Crustacea: Brachyura: Raninidae) from Gulf of Mannar, India

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