Urothoe grimaldii   Chevreux,  1895 (Amphipod)
Organism information awaits expert curation
Class: Malacostraca

Size: Length - 6.8 mm

Body robust ; cephalon non-rostrate, longer than first 2 peraeon segments combined ; ocular lobes rounded in front ; eyes large, well separated, nearly dorsal, dark and rounded . Peraeon segments successively increasing in length ; 1st segment of pleon unarmed, 2nd ventrally expanded and with rows of long submarginal plumose setae along ventral and distal margins, posteroinferior angle produced, 3rd pleon segment longer than 2nd, inferior and distal margins convex, lower angles rounded and the distal border carrying I or 2 setules. Segments 4-6 clearly marked out, much shallower than the 3rd, 4th and 5th subequal in length and depth, 6th longer . Telson cleft to base, lobes much longer than broad, narrowing distally, the truncated distal margin broadly crenulate and with 5 setules, outer margin carrying 2 feathered ones a little beyond the middle. 1st Coxa small, nearly oblong and unarmed, 2nd-4th subsimilar, 4th largest, posterior margins concave, postero-inferior corners angular and blunt, a little projecting and armed with 2 or 3 plumose setae, lower borders convex . Coxae 5-7 bilobed, hind lobes larger, rounded and with a row of marginal spine-setae . Antenna 1 short, first 2 segments of peduncle subequal in length, 1st twice as broad as 2nd, upper margins of both with long, slenderplumose setae, distally produced in the former, lower border of 1st with a fringe of marginal setules, 3rd peduncular segment slender, longer than 2nd, almost unarmed, flagellum a little more than half the length of 3rd peduncular segment and 4-segmented . Accessory flagellum two third the length of primary and 2-segmented . 4th and 5th segments of the peduncle of antenna 2 swollen, lower margin of 4th segment with blunt spines alternating with plumose setae, upper border hairy and inner surface with submarginal row of spines. 5th Segment smaller than 4th, with long plumose setae and barrelshaped calceoli . Flagellum much longer than peduncle, 22-segmented, each segment armed with one or two setules and a calceolus . Gnathopod 1 slender, basis proximally narrow, inner margin armed with long plumose setae, ischium very small, merus triangular, carpus almost elliptical, internally expanded and fringed with long, simple setae on the margin and irregularly arranged plumose setae on the inner surface, propodus more than half length of carpus, distally armed with long, simple setae, palm very short, nearly transverse, with 4 or 5 small spines at the rounded defining angle . Dactylus longer than palm, but less than half length of propodus, slender and pointed. 2nd Gnathopod subsimilar to the 1st, basis, ischium and merus with long, pectinate setae, carpus swollen and internally hairy, propodus nearly half length of carpus, narrow and of the same width throughout, palm transverse, serrulate and with a prominent, blunt defining spine, dactylus small and curved, longer than the palm. Peraeopods 1 and 2 slender, subsimilar, 1st larger and more setose, basis as long as the following 3 segments combined, merus a little more than half length of basis, almost oval, outer and inner borders with long, plumose setae, carpus as long as broad, half length of merus, inner margin with flat spines and long setae, outer carrying submarginal plumose setae, propodus club shaped, as long as carpus and armed with flat, blunt spines, dactylus spine-like, almost indistinguishable from the spines on the propodus, shorter than propodus, with a feebly crenulate inner margin . Dactylus of 2nd peraeopod very slender and about half as long as propodus . Basis in the much flattened 3rd peraeopod externally expanded making it nearly equal in length and width, ischium very short, immersed in the adjacent segments, merus partially fused with and sunk into the carpus, carpus much enlarged, with 2 inner and 2 outer transverse rows of apically truncate spines, outer margin with 2 prominent indentations and the outer distal part conically produced . Propodus widening distalwards and produced at the outer distal part, with 4 transverse rows of spines on the inner and outer side, dactylus as long as propodus, strongly curved outwards, inner border with 6 groups of long, well spaced spines, all the segments except dactylus carry long, plumose setae . Peraeopods 4 and 5 subsimilar, 4th slightly larger and less setose, its basis oval and much expanded, shorter than the following 3 segments combined, margins convex, outer with a submarginal row of long, plumose setae and a row of shorter, simple ones marginally, inner border armed with marginal plumose setae, merus oblong-oval, more than half length of basis, outer margin with a long plumose seta in the middle and the inner with 2 fascicles of pectinate spine-setae, carpus shorter than merus, narrowing distally, propodus about half as long as merus, dactylus slender, pointed, shorter than propodus and not much curved . Carpus and propodus strongly spiny. Basis of peraeopod 5 longer than next 3 segments combined, margins nearly parallel, the plumose setae confined to the distal part, merus half as long as basis, distally wider, carpus a little more than half length of merus, propodus and dactylus as in 4th peraeopod . Merus, carpus and propodus more strongly setose than in the 4th . 1st Uropod longer and more spiny than the 2nd, peduncle longer than rami, spiny along margins, rami slender and subequal, inner carrying an inner row of spines . Peduncle of 2nd uropod distally spiny, rami slender, subequal and unarmed . Uropod 3 with a squarish peduncle carring 2 distal groups of spines, rami foliaceous, inner ramus as long as basal segment of outer, outer ramus broader, its apical segment small, both rami with long, plumose setae along margins, outer with 5 additional distal spines on the outer border.

Synonym (s)

Common Name (s)
Economic Importance and Threats



• Kerala, Trivandrum INDIA

Literature Source(s)
  • Rabindranath, P (1971) Haustoriid Amphipods (Crustacea) from India Hydrobiologia Springer 38 521-539 Available at - http://dx.doi.org/10.1007/BF00036557
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at - http://www.marinespecies.org

Page last updated on:2010-12-28

Back to Search