Sergestes consobrinus Milne 1968

Sergestes consobrinus Milne, 1968

Sergestes (Sergestes) consobrinus Milne, 1968:26–33, figs. 5–figs. 9.

TYPE-LOCALITY.—Great Bear cruise 199, IKMT haul 227 (off southern California: 33°44′N, 124°53′ W).

PRELIMINARY DISTRIBUTION.—This geographical form of S. consobrinus appears to be restricted to the outer sector of the California Current region.

3b. Central Form

MATERIAL.—SIO, Tethys: 27(1 ), 28(1 ). SIO, Naga: 61-341 (1 , 2 ). SIO, Styx VII: 68-447(2 ), 68-451(2 ), 68-468(1 , 1 ), 68-471(1 , 9 ), 68-478(2 , 1 ). SIO, Climax II: A6(1 , 1 ), A7(5 , 1 ), A9(2 , 2 ). SIO, FCRG 71-2: 68(1 , 1 ).

The material listed is deposited in the SIO Zooplankton Collections.

DESCRIPTION.—Max1 palp vestigial and without setae, or sometimes entirely absent (cf. S. edwardsii, Figure 5j).

Mxp3 dactylus (Figure 9h) with single mesial spines on outer margins of subsegments 1 and 2. Outer distal spine on subsegment 1 usually reaching well beyond midpoint of subsegment 2; outer distal spine on subsegment 2 usually reaching to or beyond subsegment 5; outer distal spine on subsegment 4 long, usually reaching beyond midpoint of subsegment 5. Outer terminal spine on subsegment 6 at least three-fourths as long as, sometimes longer than, inner terminal spine.

Per3 coxa in female (Figure 9j) very similar to that in California Current form.

Petasma (Figure 9d–f) very similar to that in California Current form but differing in following features: all distal lobes tending to be slenderer; LA outer lobe with flexure occurring proximally rather than distally and with only five to eight hooks on anterior face; PV a mere bud, not extending to inflection between LA and LC.

DISTRIBUTION.—The Central form of S. consobrinus occurs widely throughout the vast expanse of the subtropical North Pacific (Figure 10). Unfortunately, this region of the Pacific is poorly represented by the collections examined, and, hence, the range of the Central form is imprecisely known. The area in the eastern Pacific (ca. 15°–30° N, 130°–140° W) where the two forms of S. consobrinus are most likely to co-occur and perhaps intergrade is especially poorly sampled.