126 



S. KARAYTUG AND G.A. BOXSHALL 



Table 2 Body length (BL) and width (BW) measurements (in urn) of Paracyclops poppei in various localities. (N = number of specimens measured) 



Locality 



Sex 



BL (mean ± SD) 



Range 



BL (mean ± SD) 



Range 



N 



Germany 



9 

 cf 



756 ± 34.7 

 736 



728-806 



282 ±8 

 282 



276-283 



4 

 1 



England 



9 



758 ± 16.7 



736-778 



288 ± 11.7 



274-309 



4 



Russia (St-Petersburg) 



9 



828 ± 43.6 



786-913 



297 ± 12.9 



278-317 



6 





cf 



655 ±21.4 



641-680 



236 ±3 



233-239 



3 



United States (Virginia) 



9 



725 ± 66 



640-849 



261 ± 19.4 



230-291 



10 





d" 



601 ± 33.8 



538-615 



219 ± 17.8 



198-235 



5 



United States (New Orleans) 



9 



741 ±50 



691-822 



239 ±19.8 



217-272 



5 





cf 



613 ± 8.5 



605-622 



207 ± 15.5 



198-225 



3 



Canada 



9 



819 ± 109.6 



741-896 



286 ±2.8 



284-288 



2 



Table 3 Caudal rami length (CL) and width (CW) measurements (in um) of Paracyclops poppei in various localities. L:W, ratio of length to width. (N 

 number of specimens measured) 



Locality 



Sex 



CL (mean ± SD ) 



Range 



CW(mean±SD) 



Range 



N 



L:W 



Germany 



9 



95 ± 6.7 



86-102 



28 ±0.8 



27-29 



4 



3.4 



England 



9 



102 ±5.7 



94-112 



30 ±0.8 



28-31 



8 



3.4 



Russia (St-Petersburg) 



9 



99 ± 9.2 



80-111 



29 ± 1.2 



27-31 



6 



3.4 



Mexico 



9 



95 ±7 



90-100 



29 ± 0.7 



28-29 



2 



3.2 



U.S.A. (New Orleans) 



9 



60 ± 7.9 



48-72 



25 ± 1.3 



23-28 



12 



2.4 



U.S.A. (Virginia) 



9 



84 ±8.3 



70-97 



26 ± 1.2 



24-28 



11 



3.2 



Japan (Lake Biwa) 



9 



104 ± 14.7 



86-120 



31 ±4 



25-33 



4 



3.4 



Variability, females. The length and width of the caudal rami 

 varied considerably especially in American specimens (Figure 9 A,B ), 

 and measurements are given in Table 3. One female from England 

 and one from Lake Biwa (Figure 9E) had antennules with an 

 incomplete suture line on the posterior margin subdividing segment 

 3. In some specimens from Virginia, U.S.A., the spinularrows on the 

 intercoxal sclerite of leg 4 were unusually small (Figure 9F). Finally, 

 in specimens from Lake Biwa (Japan), the dorsal spinular row of the 

 caudal rami reached almost midway along the ramus in some 

 specimens and the inner coxal spines of legs 2 and 4 were ornamented 

 with longer setules (Figure 9C,D) than in material from elsewhere. 

 However no other consistent variation was observed and these few 

 slight differences do not justify the creation of a new taxon. 



Differential diagnosis. P. poppei can easily be distinguished 

 from its congeners by the continuous line of spinules on the dorsal 

 surface of the caudal rami (Figure 8B) and by the possession of 2 large 

 modified setae (setae A and C arrowed in Figure 13E) on the first 

 segment of male antennule (Figure 1 3E,F). P. poppei also differs from 

 P. fimbriatus, P. chiltoni and P. imminutus in the form of the spinular 

 rows on either side of the anal operculum in the female (Figure 8B). 



Remarks and comparisons 



P. poppei was originally described by Rehberg (1880) but subse- 

 quently some authors considered that the differences between C. 

 fimbriatus and P. poppei were not significant and therefore assigned 

 this taxon firstly to Cyclops crassicornis O. F. Midler, 1 785 (Herrick, 

 188-2) and then to C. fimbriatus Fischer, 1853 (Herrick, 1884; 

 Schmeil, 1891; Byrnes, 1909; Marsh, 1892, 1910). Schmeil (1892) 

 claimed that the differences could allow P. poppei to be recognized 

 as a variety of P. fimbriatus and this opinion was shared by Van 

 Douwe (1909). Gurney (1933) had doubts as to its status as subspe- 

 cies and species, but its rank as subspecies was accepted by Lindberg 

 (1958), Yeatman ( 1959) and Harding & Smith (1960). It was Kiefer 

 (1929b) who first re-established P. poppei as a valid species and in 

 subsequent publications/? poppei gradually became accepted (Rylov, 

 1963; Dussart, 1969; Einsle, 1993; Ishida, 1993). 

 The material identified by Sars (1927) as Platycyclops poppei 



from South Africa is not P. poppei nor can it be assigned to any other 

 species of the genus. In fact, his material probably represents a new 

 species. Sars assigned his specimens to P. poppei on the presence on 

 the caudal rami of a single oblique row of small spinules across the 

 dorsal surface, and he noted similarities in outward appearance to P. 

 ajfinis. Indeed, the dorsal spinular rows across the caudal rami are 

 rather like P. ajfinis, however as Sars (1927) also stated, his species 

 can easily be distinguished from P. ajfinis by its 8-segmented 

 antennule. Sars"s species is also different from P. poppei as described 

 herein in the structure of leg 5. 



Distribution. P. poppei was considered to have a wide distribu- 

 tion (Dussart & Defaye, 1985). Although its presence in Europe, 

 North America and Japan has been confirmed, other records of P. 

 poppei, especially from Brazil and Paraguay (Lowndes, 1934), East 

 Africa (Van Douwe, 1912),Tunisia(Dumontetal., 1979) and Hawaii 

 (Sars, 1927) should be confirmed since there is insufficient descrip- 

 tion provided for unequivocal identification. For detailed references 

 concerning the distribution of P. poppei, see Karaytug (1998). 



Paracyclops oligarthrus (G. O. Sars, 1909) 



(Figures 14-20) 



Cyclops oligarthrus, Sars, 1909: Cunnington (1920) 

 Platycyclops oligarthrus (Sars, 1909): Gurney (1928) 



ORIGINAL DESCRIPTION. Cyclops oligarthrus Sars, 1909: Proc. 

 zool. Soc. Lond.: 31-77, pi. XXI. figs. 195-202. 



Type locality. Lake Tanganyika, Africa. 



Material examined. G. O. Sars, Lake Tanganyika 13 9 9. 

 5d"cf(Syntypes). BMNH 1909. 6. 24. 224-233. 



Redescription of adult female 



Body length (mean ± SD) 555 ± 32.6, range = 5 17-598, n = 8. Body 

 width 220 ± 8, range = 206-233, n = 8. Prosome (Figure 14C) 

 produced frontally, forming prominent rostral area. Fifth pedigerous 

 somite with strong fringe of elongate setules at posterior margin 



