PARACYCLOPS REVISION 



129 



(Figure 15A). Genital double-somite, second and third abdominal 

 somites lacking pits on dorsal and ventral surfaces (Figure 15A,B). 

 Seminal receptacle divided into complex anterior and posterior 

 lobes (Figure 15B). Caudal rami slightly divergent and 3.5 times 

 longer than broad (Figure 15A,B). Posterolateral seta (IV) and inner 

 terminal seta (V) with complex spinular ornamentation as figured 

 (Figure 14C); terminal accessory seta (VI) strong and plumose. 



Antennule (Figure 16A) compact and 7-segmented; first (ances- 

 tral segments I-V) and second (ancestral segments VI-XI) segments 

 separated ventrally but incompletely separated dorsally. First and 

 second segments here treated as distinct segments. Segment 3 with 

 partial suture line (indicating boundary between ancestral segments 

 XIII and XIV) and spiniform seta. Segment 5 with partial suture line 

 (indicating boundary between ancestral segments XXI and XXII) 

 and with characteristic short aesthetasc. Short aesthetasc located 

 distally on anteroventral margin of segment 6. Setal formula 8, 12,6, 

 5, 4 + aesthetasc. 2 + aesthetasc, 7 + aesthetasc. Coxobasis of 

 antenna lacking spinular row near base of inner setae caudally 

 (arrowed in Figure 16C); with complex ornamentation on caudal 

 (Figure 16C) and frontal (Figure 16B) surfaces as figured. 



Terminal exopodal segments of legs 2-4 each with two 

 semispinulose setae (arrowed in Figures. 17A; 1 8A,D). Praecoxa of 

 leg 1 (Figure 17D) without spinular row at outer corner; basis with 

 setiform spine on inner margin not extending beyond distal margin 

 of second endopodal segment; intercoxal sclerite without spinular 

 row on posterior surface (Figure 17E); terminal endopodal segment 

 with 3 inner setae. Terminal endopodal spine of leg 2 (Figure 18A) 

 strong, about as long as segment; coxa with complex ornamentation 

 on posterior surface (Figure 18B). Intercoxal sclerite of leg 3 with 

 spinules on anterior surface (Figure I8D) and with spinular row on 

 posterior surface (Figure 18C); coxa with complex ornamentation 

 on posterior surface (Figure 18C). Intercoxal sclerite of leg 4 with 

 row of setules on anterior surface (Figure 17A) and with two 

 spinular rows on posterior surface (Figure 17B); distal row well 

 developed; inner coxal spine without cluster of setules posteriorly 

 (Figure 17A); basis with long plumose outer angle seta; lacking 

 setules along inner margin (Figure I7A); coxa with complex orna- 

 mentation on posterior surface (Figure 17B); exopodal spines with 

 dense spinules along margins (Figure 17A). 



Spine and seta formula as follows: 



Coxa 



Basis 



Exopod 



Endopod 



Legl 



0-1 



Leg 2 



0-1 



Leg 3 



0-1 



Leg 4 



0-1 



1-1 



1-0 

 1-0 

 1-0 



I-1;I-1;III.5 

 I-1;1-1;III,I.5 

 I-1;I-1;III.I,5 

 [-1:1-1:111,5 



0-1 

 0-1 

 0-1 

 0-1 



0-1; 1,1,3 

 0-2; 1,1,4 

 0-2:1.1,4 

 0-2:1.11.2 



Leg 5 (Figure 15C) comprising single free segment, armed with 1 

 short well developed outer spinulose seta, 1 strong inner spine and 1 

 strong plumose seta (slightly longer than inner spine) centrally. 



Description of adult male 



Body length (mean ± SD) 444 ± 14.8, range = 433-454, n = 2. Body 

 width 179 + 2.8, range = 177-181, n = 2. Urosomal somites without 

 surface ornamentation (Figure 19A,B). Caudal rami short about 2 

 times longer than broad. 



Antennule digeniculate (Figure 20A.B), indistinctly 15-seg- 

 mented. Segment 1 armed with 8 setae (Figure 20E.F); seta A large 

 and modified by ornamentation of strong spinules in proximal and 

 mid sections, tapering to fine point distally; aesthetasc absent. 

 Segment 1 1 bearing strongly curved seta ornamented along convex 

 surface with double row of strong denticles, plus 1 plumose seta 

 (Figure 20E). Segmental fusion pattern as follows I-V, VI-VII, VIII. 



IX, X, XI, XII, XIII, XIV. XV, XVI, XVII, XVIII-XX, XXI-XXIII, 

 XXIV-XXVIII. 



One seta on terminal exopodal segment of leg 1 semispinulose 

 (Figure 17C). Intercoxal sclerite of leg 4 with stronger terminal 

 spinular row than in female (Figure 19D). Fifth leg with strong inner 

 spine and reduced outer and middle setae (Figure 19E). Sixth leg 

 (Figure 19A,C) armed with 1 strongly developed inner spine sur- 

 rounded by spinules at base, and 2 outer setae, outermost seta shorter 

 than middle seta. 



Variability. Inner margin of basis of leg 4 lacks setules in most 

 females examined and in one of the two males but was ornamented 

 with setules in some females and the other male. 



Differential diagnosis. P. oligarthms can be distinguished 

 from other Paracyclops species by the structure of the fifth leg in 

 both sexes (Figures 15C; 19A.E), by the structure of the seminal 

 receptacle (Figure 15B), by the 7-segmented antennule (Figure 16A 

 and see remarks), by the absence of the proximal inner seta on the 

 terminal endopodal segment of leg 1 (Figure 17D), by carrying 2 

 semispinulose setae on the terminal exopodal segment of legs 2—4 

 (Figures 18A.D; 17 A) and by the sixth leg of the male being fully 

 incorporated into the genital somite (Figure 19A). 



Remarks and comparison 



P. oligarthms is unique in the loss of the proximal inner seta on the 

 terminal endopodal segment of leg 1 (Figure 17D). This segment 

 carries 4 inner setae in all other species. P. oligarthms also has 2 

 semispinulose setae on the terminal exopodal segment of legs 2-4 

 (arrowed in Figures 17A; 18A.D). The male sixth leg is unusual in 

 the relatively large size of the inner spine and in being fully incorpo- 

 rated into the genital somite (Figure 19 A). 



Sars's (1909) interpretation of the antennule as 6-segmented is 

 incorrect. He appears to have overlooked the partial division of the 

 proximal segments. 



Distribution. P. oligarthrus is endemic to Lake Tanganyika, 

 Africa. 



Paracyclops canadensis (Willey, 1934) 



(Figures 21-25) 



Cyclops affinis var. canadensis Willey, 1934 

 Paracyclops affinis (Sars, 1863) sensu Smith & Fernando (1977, 

 1978) 



Original description. Cyclops affinis var. canadensis Willey, 

 1934: Trans. R. Can. Inst. 20 (I): 77-98. 



Type locality. 

 original paper) 



Canada. Quebec (no other detail is given in the 



Type material. The type material of Willey ( 1 934) could not be 

 located. It is not deposited in the CMNC or the USNM. 



Material examined 



The redescription of P. canadensis is based on 2 9 9 which were 

 obtained from Canadian Museum of Nature. Catalogue number: 

 CMNC 1996-0019. Locality: Canada, Ontario, Parry Sound Dis- 

 trict, 40 km N of Parry Sound on Hwy 69; collected by C. H. 

 Fernando on 7 July 1972. 



- U.S.A, West Virginia; 8 9 9 collected on 23 May 1995 in Big 

 Run Bog in the Monongahela National Forest by Robert Hamil- 

 ton, Tucker County, 39°07' N, 79°35' W USNM Ace. 417235. 



- CANADA, Jack Lake, Nova Scotia 3 9 9 dissected and mounted 

 on 1 slide, 2 9 9 undissected and mounted on 1 slide, 1 9 dissected 

 and mounted on 1 slide, 2 9 9 and 1 a" undissected and mounted 



