Distribution 



Spinocalanus elongatus is the only species of the 

 present study that is known only from the Arctic 

 Ocean. Bogorov (1946a) reported two female Arctic .S. 

 abyssalis, which he distinguished, by their size, from 

 S. longicornis; this is considered a record of S. 

 elongatus in the present study, since no other likely 

 species has been found in the Central Arctic. The 

 records of S. elongatus are summarized below: 



Arctic Ocean 



Central: Brodsky (1950, 1957), 25-3,000 m. 



Eurasian Basin: Bogorov (1946a), 10-750 m. 



Canadian Basin: Brodsky and Nikitin (1955), 

 100-3,826 m. —Dunbar and Harding (1968), 

 175-2,000 m. — Vidal (1971). —Present study, 

 300-2,500 m. 



26. Spinocalanus polaris Brodsky, 1950 



(Figures 114-129, 156) 



Spinocalanus polaris Brodsky, 1950, p. 133, fig. 53. 



— Grice and Hulsemann, 1965, p. 229-230, fig. 7g. 



—Park, 1970, p. 493, fig. 71-77. —Vidal, 1971, p. 18, 



fig. 36-37, 39. 

 Spinocalanus elongatus Brodsky, 1950 (part), p. 132- 



133, fig. 52; "male" but not "male variant." 



Type SPECIMEN: Unknown. 



Type Locality: Central Arctic Ocean, 800-2,500 m. 

 Material Studied: i male (1.60 mm), sample A17 

 (Table 1); 2 males (1.60, 1.64 mm), sample A26; 3 

 females (1.28, 1.32, 1.40 mm) and 1 male (1.68 mm), 

 sample A31; 12 females (1.36-1.56 mm, mean = 1.47 

 mm) and 1 male (1.56 mm), sample A48; 7 males 

 (1.44-1.68 mm, mean = 1.55 mm), sample A50; 6 

 females (1.30-1.42 mm, mean - 1.36 mm) and 7 males 

 (1.45-1.55 mm, mean = 1.49 mm), sample A51. 



Description 



Pi Ri with 1 inner seta; P2 Ri2 with no outer seta; 

 P3-P4 Ri3 with 1 outer seta. 



Female.— Length (1.02?-) 1.17-1.60 mm (Figs. 114, 

 115). Prosome in dorsal view fairly robust ovoid; head 

 abruptly narrow, rounded. In lateral view with fairly 

 abrupt forward slope. Th4 and Th5 separate; Th5 

 lateral corners prolonged, reaching midgenital seg- 

 ment; Thl-Th4 without lateral spinules. Prosome 

 length about 3% times urosome. Genital segment 

 slightly longer than wide, protruding ventrally one- 

 half depth of rest of urosome. Caudal rami length 1 '/a 

 times width, symmetrical. Caudal setae broken in all 

 specimens; bases symmetrical. 



Al exceeding caudal rami by about l'/2 segments; 



terminal segments (Fig. 156) of moderate length and 

 width. Armature as Table 4. 



A2 Rel with 1 seta. 



Mn B2 surface without setules; Rel outer distal sur- 

 face with row of setules. Blade (Fig. 121) with 4 sub- 

 equal outer teeth, ventral tooth 1 -pointed, others 3- 

 pointed; 4 shorter 2-pointed teeth, followed by dorsal 

 seta; midanterior surface with transverse row of long 

 spinules. 



Mxl gnathobase (Fig. 122) with 4 proximal setae on 

 posterior surface, without seta on distal anterior sur- 

 face. Posterior surface with proximal cluster of strong 

 denticles, central cluster of smaller denticles, and out- 

 er cluster of spinules. 



Mx2 with small setule- and hair-covered proximal 

 hump; no outer seta seen (Park, 1970, fig. 74, shows 

 outer seta). Distal hook on lobe-1 (Fig. 116) promi- 

 nent. Posterior surface of lobe-5 base without spines. 



Mxp (Fig. 123) Bl-2 without transverse spine- 

 combs. Bl anterior surface with 1 proximal and 3 dis- 

 tal transverse rows of long setules; outer longitudinal 

 row of setules and inner longitudinal row of spines 

 about midlength; longitudinal row of short, stiff hairs 

 near inner distal edge. B2 with longitudinal row of 

 short, stiff hairs. Ril inner distal edge with row of stiff 

 hairs. Ri4-5 outer setae unmodified, thin, relatively 

 short, probably lightly plumose; Ri5 inner edge 

 without spinules. 



PI (Fig. 117) Bl-2 anterior surface with few rows of 

 setules; Bl inner margin with setules; B2 inner 

 margin with setules and hairs. Rel anterior surface 

 with outer distal row of spines; Re2 posterior surface 

 with distal row of spines; Re3 surface nude. Rel -2 out- 

 er spines reaching base of following spine. Ri inner 

 midlength surface with spinules. Re terminal seta 

 relatively coarsely serrate. 



P2 (Fig. 118) Bl outer surface with setules, inner 

 margin with hairs. B2 inner posterior surface with few 

 setules. Re2 distal posterior surface with straight row 

 of spines; Re3 distal anterior and posterior surface 

 with group of small spines. 



P3 (Fig. 119) Bl proximal outer surface with few 

 setules; inner margin with hairs. Re2 posterior surface 

 with 1 distal row of long spines; Re3 distal anterior 

 and posterior surface with group of small spines. Ri3 

 proximal posterior surface with few small spines. 



P4 (Fig. 120) Bl inner margin with hairs; posterior 

 surface with transverse row of long spinules. Re2 

 posterior surface with 1 distal row of long spines; Re3 

 posterior surface with 3 evenly spaced longitudinal 

 groups of denticles. 



Re terminal seta with following number of primary 

 teeth: P2 (23-29); P3 (ca. 20); P4 (ca. 20; secondary 

 teeth relatively large, irregular.) 



Male.— Length 1.44-1.68 mm (Figs. 124, 125). 

 Prosome anterior somewhat rounded in dorsal view, 

 posterior somewhat rectangular; in lateral view with 

 gentle forward slope. Ce and Thl partly fused. 



50 



