SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 543 ...

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FIGURE 6.—Macrobrachium idae, male from Naujan River, Mindoro,
Philippines, carapace length 16.7 mm: a, anterior carapace and appendages,
lateral aspect; b, right 3rd pereopod, dactyl, and propodus; c, same, dactyl,
denuded.
posterior apex not overreaching posterolateral spines; antennal
scale with lateral margin slightly convex; 1st pereopod with
chela less than 3 times as long as carpus; 2nd pereopods similar
in form but not usually equal in length, palm subcylindrical,
fingers pubescent, especially either side of proximal part of
opposable margins, latter dentate proximally, fingers not
noticeably gaping, '/2 as long as palm, latter naked, chela
shorter than carpus, palm more than x li as long as carpus,
carpus more than twice as long as merus, without longitudinal
grooves; 3rd pereopod overreaching antennal scale by more
than length of dactyl, propodus not covered with spines or
scales; maximum postorbital carapace length about 20 mm.
MATERIAL.—PHILIPPINES. Naujan River, Mindoro;
[13°16'Nf 121°19^];5 Jun 1908: 1 male [16.9].
RANGE.—Madagascar to southern India, Philippines, Indonesia,
and eastward as far as the Admiralty Islands.
REMARKS.—The identity of the specimen assigned to this
species (Figure 6) is somewhat tentative, but it agrees almost
exactly with the illustrations by De Man (1902) of M. robustus,
which Holthuis (1950a: 145) noted "undoubtedly belongs to M.
idae."
Macrobrachium palawanense may be a valid species, but we
have been unable to distinguish it from M. idae on the basis of
the descriptions and illustrations published by Johnson (1962a,
1973). That author convincingly separated the species from M.
weberi but mentioned no characters that do not apply as well to
our concept of Af. idae.
21. 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
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
posterior apex not overreaching posterolateral spines; antennal
scale with lateral margin nearly straight; 1st pereopod with
chela about '/2 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'/2 times as long as carpus, palm 1 3 A times
as long as carpus, carpus more than 4 /5 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)
FIGURE 7
Palaemon jaroensis Cowles, 1914:385, pi. 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 2 h 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
FIGURE 7.—Macrobrachium jaroense from Mananga River, Cebu, Philippines:
a. anterior carapace and appendages, lateral aspect, of male with carapace
length of 16.0 mm; b, right 3rd pereopod, dactyl, and propodus, of male with
carapace length of 16.5 mm; c, same, dactyl, denuded.