Comprehensive Description

provided by Smithsonian Contributions to Zoology
Macrobrachium placidum (De Man, 1892)

Palaemon (Macrobrachium) placidus De Man, 1892:483, pl. 28: fig. 46 [type locality: Kajutanam, north of Padang, western Sumatra].

Macrobrachium placidum.—Holthuis, 1950a:251, fig. 51b.

DIAGNOSIS.—Rostrum not reaching level of distal end of antennal scale, dorsal margin slightly convex, rostral formula: 5–7 + 4–6/2–4, dorsal teeth rather subequally spaced; branchiostegal suture not extending posteriorly beyond hepatic spine; telson with posterior apex not overreaching posterolateral spines; 1st pereopod with chela more than as long as carpus; 2nd pereopods unequal in length and dissimilar in form; major 2nd pereopod with palm compressed, fingers not clothed in dense pubescence, dentate on opposable margins, fingers slightly gaping proximally, longer or shorter than palm, palm without any dense pubescence, chela twice as long as carpus, palm longer or shorter than carpus, carpus 1–1 as long as merus, without longitudinal grooves; minor 2nd pereopod with fingers longer or shorter than palm; 3rd pereopod overreaching antennal scale by length of dactyl, propodus bearing numerous small spines; maximum postorbital carapace length about 25 mm.

RANGE.—Ryukyu Islands and western Sumatra and Java, Indonesia.
bibliographic citation
Chace, Fenner Albert, Jr. and Bruce, A. J. 1993. "The caridean shrimps (Crustacea: Decapoda) of the Albatross Philippine Expedition 1907-1910, Part 6: Superfamily Palaemonoidea." Smithsonian Contributions to Zoology. 1-152. https://doi.org/10.5479/si.00810282.543