border of genital segment bearing a single seta. 

 Leg 6 absent. 



Acusicola differs from all other known genera 

 of ergasilids except Paraergasilus^ ErgasUoides, 

 and Thersitina by having a 5-segniented first an- 

 tenna. It differs from Ergasiloides by having a 

 3-segmented abdomen {Ergasiloides has only one 

 segment), from Thersitina by the presence of 

 maxillipeds in Thersitina, and from ParaergasiUos 

 by the nature of the second antenna. 



The generic name is Latin, aciis for "needle" and 

 cola for "inhabitant" and refers to the fact that 

 the first two species of the genus are reported from 

 needlefishes. 



Type-species. — Acusicola tenax. 



Acusicola tenax (Roberts) 



Figures 43 to 52 



Speci-Tuens studied. — A single collection contain- 

 ing 203 females removed from the outer tips of the 

 gill filaments (usually the upper filaments) of 17 

 Strongylura marina (UMMZ 143506) caught at 

 Rio de la Pasion, Peten, Guatemala. An additional 

 collection of two females from one 8. marina 

 caught at El Quiche, Guatemala. 



Female.— '^o^y form as in figure 43. Total length 

 800 ft; greatest width 225 jx. Thoracic segments 

 bearing legs 1 to 4 separated from head. Thoracic 

 segments decreasing in width from first to fourth. 

 Genital segment about as wide as long (100 fx. by 

 100 ^) . Abdomen (fig. 44) 3-segmented ; second and 

 third segments only slightly narrower than pre- 

 ceding one. Caudal rami about twice as long as 

 wide (44 \x. by 21 /*) , with three long terminal setae 

 (longest about 175 fx long) and one short median 

 one; patch of spiniforms on ventral surface near 

 distal end of each ramus. 



First antenna (fig. 45) 5-segmented; first seg- 

 ment longest (60 fx) with remaining four each 

 about half as long, armed as in figure. Second 

 antenna (fig. 46) 5-segmented; segments measure 

 103 /x, 325 jii, 60 |n, 60 /x, and 30 /i, respectively, and 

 unarmed. Mandible (fig. 47) armed as in figure. 

 First maxilla a small knob with two setae between 

 mandible and second maxilla. Second maxilla ( fig. 

 48) with brushlike tip. 



Legs 1 to 4 biramose. Leg 1 (fig. 49) exopod 3- 

 segmented, each segment with spinulose outer mar- 

 gins; endopod 2-segmented, each segment with 

 spinulose outer margins and strong clawlike spine 

 on end of terminal segment. Leg 2 (fig. 50) both 



rami 3-segmented ; one spine on outer distal comer 

 of exopod first segment, otherwise armed with 

 setae as in figure. Leg 3 (fig. 51) both rami 3- 

 segmented ; spine on outer distal comer of exopod 

 first segment plus weak spine at terminus of en- 

 dopod, otherwise armed with setae as in figure. Leg 

 4 (fig. 52) exopod 2-segmented, outermost termi- 

 nal seta unusually long and conspicuous ; endopod 

 3-segmented with weak spine on outer corner of 

 terminal segment, otherwise armed with setae as 

 in figure. 



Spine and seta formulas for legs 1 to 4 follow : 



Leg 5 a small papilla bearing one seta near an- 

 terior outer corners of genital segment. Leg 6 

 absent. 



Egg sac about 500 ju, long, bearing 28 to 32 eggs. 



Color in life unknown. 



Male . — Unknown . 



Remarks. — The copepods came from a fresh- 

 water population of Strongylura now referred to 

 S. marina but jx)ssibly representing an undescribed 

 form. Acusicola tenax was previously reported by 

 Roberts (1965) from Texas as a parasite of Po- 

 moxis annularis. 



Acusicola cunula Cressey, New Species 



Figures 53 to 60 



Specimens studied. — Eight females from two 

 collections from the gill filaments of Pseudotylo- 

 surus amgusticeps collected from Brazil. Holo- 

 type female (USNM 125687), two paratype fe- 

 males (USNM 125688) from a single host fish 

 (MCZ 8797) collected at Porto do Moz, near the 

 mouth of the Amazon River, Brazil. Exact locality 

 data for second collection in Brazil (host fish — 

 MCZ 8790) unknown, second collection contains 

 six females. 



Female. — Body form as in figure 53. Total 

 length 652 ix. Greatest width 290 /*. Thoracic seg- 

 ments bearing legs 1 to 4 free. Genital segment 

 (fig. 54) slightly wider than long. Abdomen 3- 

 segmented; ventral posterior border with row of 

 spinules on each segment, last segment row con- 

 fined to outer corners. Caudal rami longer than 

 wide (38 ^ by 24 /t) ; rows of spinules on ventral 



360 



U.S. FISH AND WILDLIFE SERVICE 



