Lemaitre and Rodngues: A new species of ghost shrimp Lepidophthalmus smuensis 



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endopod narrow, more than 2.5 times as long as broad, 

 distal half slightly bent ventrally; upper exopodal plate 

 shorter and smaller than lower exopodal plate, with 

 rows of long, slender corneous spines on posterolateral 

 margin; lateral margin of exopodal plates with dense 

 setation. 



Coloration (Fig. 4a) 



In life, carapace transparent except for white frontal 

 region. Chelipeds and pereopods 2-5 white, with dense- 

 ly setose areas brownish or dark orange. Abdomen with 

 somites 1,2 transparent; dorsal surface of somites 3-6 

 with olive patterns as follows: somite 3, 4 with stripes 

 on each side of midline, and one stripe on each side 

 forming a "V"; somite 5 with 3 patches on anterior 2/3 

 (each patch located on ends of inverted triangle), and 

 band on posterior margin forming a triangle on each 

 side of midline; somite 6 with two stripes on each side 

 of midline. Telson with three olive stripes (one medial, 

 one on each side adjacent to lateral margin). Uropod 

 olive, with darker areas on central part of exopodal 

 plates and endopod. 



Distribution 



Caribbean coast of Colombia: so far known only from 

 Agrosoledad S.A. shrimp farm, near the mouth of the 

 Sinu River, on the southern coast of the Golfo de Mor- 

 rosquillo, and south of the farm at a beach near the 

 town of San Bernardo del Viento. Intertidal, and in 

 shrimp ponds at about 1.5m depth. 



Etymology 



The specific name is given in honor of the Sinti indians, 

 original inhabitants of the area where the new species 

 was found. 



Remarks 



The traditional division of the family Callianassidae 

 (Borradaile 1903, de Man 1928a, b) has been under con- 

 stant criticism by recent authors (de Saint Laurent 

 1973 and 1979, Manning and Felder 1986, Manning 

 1987, Sakai 1987). For example, some of the American 

 species that in the past were in the genus Callianassa 

 Leach, 1814, are now being reassigned to other genera 

 previously considered junior synonyms of Callianassa. 

 This new species is placed in Lepidophthalmus Holmes, 

 1904, a genus recently resurrected by Manning and 

 Felder (In press). 



Lepidophthalmus sinuensis can be easily distin- 

 guished from the other species in the genus— L. bo- 

 courti (Milne Edwards 1870) from the eastern Pacific, 



and L. louisianensis (Schmitt 1935) and L. jamaicense 

 (Schmitt 1935) from the western Atlantic— by the 

 presence in the new species of large subrectangular 

 projections of the frontal region of the carapace. Other 

 differentiating characters observed in L. sinuensis 

 are: the sexual dimorphism shown in the minor cheli- 

 ped with brush-like setae on the fixed finger of males 

 (lacking in females); the distal segment of the male first 

 pleopod that is weakly divided distally; and the endopod 

 of the uropod that is very slender and bent distally. 



Ecological observations 



Specimens of Lepidophthalmus sinuensis were ob- 

 tained in penaeid shrimp ponds of about 10 ha each, 

 and in a natural habitat on a beach site west of the 

 shrimp farm. Individuals were easily collected by 

 digging with a shovel or using a yabby pump, a suc- 

 tion device of the type described by Reaka and Man- 

 ning (1989). Salinities in the ponds ranged from 15 

 to 25°/oo . The type of sediment where the new species 

 was found is a very fine grey sand. In one pond with 

 both fine sand and clayish bottom sections, L. sinuen- 

 sis was absent in the clayish section whereas it was 

 abundant in the fine-sand section. Therefore, L. sinu- 

 ensis does not appear to survive in clayish sediment. 



The number of burrow openings in the ponds most 

 heavily populated with this callianassid ranged from 

 1894 to 2093 burrow openings/m 2 . Resin casts of the 

 burrows indicate that many have double openings and 

 are Y-shaped. A conservative estimate of the popula- 

 tion density in these ponds probably is about half the 

 burrow density (947-1046 individuals/m 2 ). These den- 

 sities are among the highest recorded for adult thalas- 

 sinids. Dworschak (1987) has reported a density of 

 2420 burrow openings/m 2 of juvenile Upogebia pusilla 

 (Petagna), quoting this number as the highest ever 

 reported, and Griff is (1990) found a maximum density 

 of slightly less than 1400/m 2 of juveniles of Callia- 

 nassa gigas Dana. 



The great proliferation of Lepidophthalmus sinuen- 

 sis in penaeid shrimp ponds can be attributed, possibly, 

 to one or a combination of the following factors: (1) 

 abundant supply of food due to the high productivity 

 that is artificially produced during the penaeid grow- 

 out cycle (e.g., by addition of fertilizers such as chicken 

 manure, urea, and pelleted food); (2) availability of a 

 large area of undisturbed, stable sand, ideal for the con- 

 struction of burrows; (3) concentration and increased 

 survival of callianassid larvae in an enclosed area at 

 the time of transition from the planktonic to the benthic 

 stage; and (4) the ability to survive the drying stages 

 of the ponds between grow-out cycles (one pond left 

 dry for 45 days still had a population of live L. sinuen- 

 sis). Callianassids are known to influence sediment 



