Macrobrachium jacobsoni Holthuis 1950

Macrobrachium jacobsoni Holthuis, 1950

Macrobrachium jacobsoni Holthuis, 1950a:227, fig. 47 [type locality: Sinabang, Pulau Simeulue, off northwestern Sumatra].

DIAGNOSIS.—Rostrum reaching nearly or quite as far as level of distal end of antennal scale, dorsal margin nearly straight, faintly convex or sinuous, rostral formula: 5–6 + 7–9/3–4, dorsal teeth subequally spaced; branchiostegal suture not extending posteriorly beyond hepatic spine; telson with posterior apex not overreaching posterolateral spines; antennal scale with lateral margin nearly straight; 1st pereopod with chela about as long as carpus; 2nd pereopods distinctly unequal in length but rather similar in form; major 2nd pereopod with palm somewhat compressed, fingers without dense pubescence, dentate on opposable margins, not gaping, about as long as palm, latter partially covered with dense pubescence, chela 3 times as long as carpus, palm 1 times as long as carpus, carpus more than as long as merus, without longitudinal grooves; 3rd pereopod overreaching antennal scale by length of dactyl or less, propodus not covered with spines or scales; maximum postorbital carapace length less than 25 mm.

RANGE.—Known only from the Sinabang area of Pulau Simeulue off the Indian Ocean coast of northwestern Sumatra, Indonesia, and from Mindanao, Philippines.

*22. Macrobrachium jaroense (Cowles, 1914)

Palaemon jaroensis Cowles, 1914:385, pl. 3: fig. 8 [type locality: Hibucawan River near Jaro, Leyte, Philippines].

Macrobrachium jaroense.—Holthuis, 1950a:205.

DIAGNOSIS.—Rostrum not reaching level of distal end of antennal scale, dorsal margin sinuous but without distinct dorsal crest, rostral formula: 4–6 + 5–7/2(3), dorsal teeth unequally spaced, more widely separated posteriorly; branchiostegal suture not extending posteriorly beyond hepatic spine; telson with posterior apex not overreaching posterolateral spines; antennal scale with lateral margin straight; 1st pereopod with chela more than as long as carpus; 2nd pereopods unequal in length but similar in form; major 2nd pereopod with palm compressed; fingers dentate on opposable margins but teeth concealed by dense pubescence on either side, fingers slightly gaping, –1 times as long as palm, latter without dense pubescence, chela less than twice as long as palm, latter without dense pubescence, less than twice as long as carpus, palm about as long as carpus, carpus longer than merus, with distinct but shallow longitudinal groove on carpus; minor 2nd pereopod with fingers 1 times as long as palm; 3rd pereopod overreaching antennal scale by length of dactyl and of propodus, latter covered with appressed scales; maximum postorbital carapace length less than 20 mm.

MATERIAL.—PHILIPPINES. Mananga River, Cebu; [10°14′, 123°50′E]; 25 Aug 1909: 24 males [8.2–17.8] 24 females [8.3–13.8], 19 ovig [9.4–13.81].

RANGE.—Known previously only from Taiwan and the 23 specimens in the type series from Leyte, Philippines.