NEW RECORD OF PARASESARMA RAOULI RAHAYU AND NG , 2009 ( CRUSTASEA : BRACHYURA : SESARMIDAE ) FROM THE RIAU ARCHIPELAGO , INDONESIA

A specimen of Parasesarma raouli (Crustacea: Brachyura: Sesarmidae) was collected from the mangrove area of Pulau Berang, Lingga, Riau Archipelago, Indonesia in Oktober 2014. This species previously was known only from Johor strait, Peninsular Malaysia. Its color in life is recorded for the first time.


INTRODUCTION
Parasesarma De Man, 1895 is one of the largest genera in the family Sesarmidae and currently contains 34 species (Ng et al., 2008;Rahayu and Ng, 2009;Davie and Pabriks, 2010;Koller et al., 2010;Rahayu and Li, 2013).All its members possess an entire lateral carapace margin without teeth or lobes, a male palm that has two or three distinct pectinate crests, and the tubercles on the dorsal margin of the dactylus of the male chela are distinct and differentiated (Rahayu and Ng, 2005).Parasesarma species can be separated into two groups; one with relatively short ambulatory legs and the second which has relatively long ambulatory legs (Rahayu and Ng, 2009).

MATERIAL AND METHODS
The specimen was collected from Pulau Berang, Lingga, Riau Archipelago, Indonesia, in mangrove environment (Figure 1) and is deposited in the Reference Collection of Research Center of Oceanography (RCO) -Indonesian Institute of Sciences (LIPI), Jakarta, Indonesia.Measurements provided, in millimeters, are for the carapace breadth at the widest point followed by the length.The abbreviation G1 is used for the male first gonopod.
Diagnosis: carapace broader than long, greatest width between prominent epibranchial angles; lateral margins slightly convergent posteriorly; surface relatively smooth; regions well defined; short setae on lateral margin (Figure 2A); front deflexed downward (Figure 2B).Chelipeds (Figure 2D) with upper surface of palm bearing 3 transverse, crests; primary (distalmost) crest composed of 16 tall, broad pectinate teeth; secondary crest with 13 broader, widely spaced, pectinate teeth; third crest much shorter than preceding crests, with 6 lower, more widely spaced, pectinate teeth; cutting edge of fixed finger 0.3 times length of chela; dorsal surface of dactyl with 24 symmetrical, rounded, tubercles, small and closely spaced proximally, becoming larger, more clearly separated distally (Figure 2D).Ambulatory legs long, slender, third pair longest, merus 2.6 times as long as wide (Figure 2A).Male abdomen moderately broad (Figure 2C); somite 6 with slightly convex lateral margin, almost twice as long as wide, telson semicircular, evenly rounded.G1 (Figure 3) relatively slender, straight; apical process bent to form an angle of 45%, corneous part long, tapering, ending in truncated tip (Figure 3C); setae long, simple, originating at the base of the apical process.
Color in life: Carapace dark brown with some yellow specks on the protogastric region.Chelipeds light brown with orangish brown dactylus and fixed finger.Meri of ambulatory   legs dark brown, light brown on carpi, propodi and dactyls.

REMARKS
The specimen from Pulau Berang agrees well with the description and figure of the holotype of P. raouli from Johor Strait, Peninsular Malaysia.There are small differences in the number of pectinate crest and the relative proportion of the merus of the third ambulatory legs.In the holotype of P. raouli, the number of pectinate teeth on the first, second, and third crests are 15-17, 12-15, and 6 respectively, and the merus of the third ambulatory leg is 2.8 as long as wide; while in the present specimen from Pulau Berang, the number of pectinate teeth on the crests are 16, 13 and 6 respectively, and the merus of the third leg is 2.6 times as long as wide.These differences are probably related to the size as the specimen from Berang being smaller than the holotype.
The specimen was found crawling on the base of a mangrove tree in an environment dominated by Sonneratia alba on a sand substrate.Apparently, P. raouli is a rare species, the type series contain 22 specimens and never been recorded again until this one specimen from Riau.