FISHERY BULLETIN: VOL. 72, NO. 1 



0.2 mm 

 0.2mm 



a,b 



Figure 14. — Poniellina sobrina sp.n., adult male: a. 

 ThIV-V, part of urosome and P5, lateral view [TO-58-1 

 (Scot) 33] ; b. variation observed in ThlV-V spine, lateral 

 view (left to right: Bonacca 55; Bonacca 43; 2 specimens 

 Bonacca 51); c. P5, posterior view (La Creuse 21); 

 d. chela P5, lateral view (Shellback 5 1). 



Types 



Holotype: Adult male. TL 1.42 mm, PUR 

 3.44:1, sorted from plankton sample taken at 

 Bonacca stn. 51, lat. 13°44'N, long. 90°51'W, 

 19 Aug. 1963, Vz-m net, oblique tow, maximum 

 cable out 200 m. USNM No. 141617. 



Allotype: Adult female, TL 1.52 mm, PUR 

 3.75:1, right furcal ramus length 0.080 mm, 

 width 0.075 mm, from same sample as male. 

 USNM No. 141618. 



Paratypes: 56, 59 from same sample. USNM 

 No. 141619. 



Reference specimens: 56, 59, La Creuse stn. 

 15, lat. 08°41.2'N, long. 79°31.2'W, 4 May 1962, 

 GV net towed between and 4 m. USNM No. 

 141620. 



Distribution 



P. sobrina is obviously indigenous to the 

 eastern tropical Pacific Ocean (Figure 15). The 

 species was found only at Pacific stations east 

 of long. 130°W. Occurrences at latitudes higher 

 than 20° were restricted to a few samples taken 

 near the mouth of the Gulf of California. Thus, 

 the apparent boundaries coincide in general with 

 the North and South Equatorial Currents, and 

 its westernmost limits lie in the path of the 

 Equatorial Countercurrent. 



In 31 quantitative samples containing sobrina 

 abundance varied from 0.01 to 0.66 individuals 

 per m•■^ the median being 0.04. In the sets of 

 samples selected for quantitative analysis 

 (Figure lb) sobritia showed mean abundance 

 values (ranging from 0.02 to 0.09 individuals per 

 m^) similar to those of morii in the Indian Ocean 

 and to plionata outside of the eastern tropical 

 Pacific (see Figure 35, Table 18). 



DEVELOPMENTAL STAGES 

 AND BREEDING 



Immature specimens of Pontellina were sort- 

 ed routinely together with adults. They were 

 neither as abundant nor as frequent as the 

 adults, a difference that is at least partially 

 attributable to escapement of younger stages 

 through the relatively coarse mesh (~0.5 mm) of 

 most of the nets used to obtain our samples. 

 General Pontelli)ia habitus characteristics such 

 as appearance of the prosome in dorsal view, 

 rostrum, strong Mx2, and relatively long 

 setae on A2 and Mnd served to distinguish 

 the specimens. The number of swimming legs 

 and body segments as well as total body length 

 were used to determine their ontogenetic stage. 

 Identification to species was reasonably certain 

 only for stage V copepodids; details are present- 

 ed below. Specimens of stages III and IV 

 were tentatively assigned to species on the 

 basis of their geographical origin. The following 



86 



