FLEMINGER: INTEGU MENTAL ORGANS IN GENUS EUCALANUS 



Table 5. — Number of perforations on anal segment of parki and lungae in copepodid stage V and 



adult females of Eucalamts. 



records of la}igae and parki (Table 1) are based 

 on relatively shallow tows with open nets from 

 300 m or less to the surface. Following the 

 shortest prevailing surface circulation in the 

 Pacific Ocean, shallow water passage from the 

 temperate zone of one hemisphere to that of 

 the other is at least 9,000 miles long. It would 

 begin necessarily in the eastern boundary cur- 

 rents and continue in the equatorial circulation 

 where crossover to the succeeding western 

 boundary current in the opposite hemisphere 

 might occur. Assuming a high rate of 1 knot 

 and an unrealistic expectation of continuous 

 and direct transport would require a transit 

 time exceeding 1 yr. 



Among my unpublished records of atteuuatus 

 s.l. neither la)tgae- nor parki-Uke individuals 

 of any copepodid stage appear in the equatorial 

 localities (cf. Fleminger and Hulsemann, 1973, 

 for geographical distribution of samples that 

 have been examined for EHcala)ius). Moreover, 

 no specimens that might be attributable to 

 la)igae or parki on the basis of unusually large 

 size appear among the published records of 

 attenuatiis s.l. collected from the vicinity of 

 the Pacific's equatorial circulation. 



Transhemispheric passage at subsurface 

 depths would be at transport rates that are 

 probably an order of magnitude less than sur- 

 face transport. Evidence of tropical submer- 

 gence by atteuuatus s.l. is lacking, however, 

 despite widespread studies on the vertical dis- 

 tribution of copepods in the upper 500 m of 

 the Pacific. Also, atte}nfati(s s.l. appears to be 

 a fine particle filter-feeder (Mullin, 1966; 

 Samyshev, 1970) and therefore not a likely 

 candidate to survive deep submergence to meso- 



I 



or bathypelagic depths for periods of one or 

 more years. In the light of this background 

 the relatively small but constant morphological 

 differences and an apparent allopatry, main- 

 tained by the formidable barrier of the tropical 

 and subtropical zones separating the ranges 

 of parki and Ia)igae, provide compelling reasons 

 for treating the two biantitropical (Brinton, 

 1962) populations as separate species. 



If langae could survive transport to temperate 

 waters of the Northern Hemisphere it could be 

 expected to appear in the North Atlantic Drift. 

 Despite the great intensity of study on oceanic 

 copepods of the North Atlantic no "giant" 

 atteuuatus s.l. forms have been noted from the 

 region. With (1915, p. 52-53, PI. 1. Figure 6a-c. 

 Text figure lOa-e) reports several large 

 atteuuatus s.l. stage V copepodids (9 — 5.18 

 mm, c5 = 5.0 mm) collected at two North Atlantic 

 localities lying roughly between Iceland and 

 Scotland. With notes that "The structure of the 

 mouth appendages . . . scarcely show differences 

 of any importance from Giesbrechfs description 

 . . .'". Thus it seems likely that the mandibular 

 basis in his specimens bore two setae as in 

 seweUi, a species that reaches a length in ac- 

 cord with With's measurements (Figure 16 and 

 see p. 993 above). The absence of other reports 

 of large attoixatus s.l. in excess of 6 mm in TL 

 from the North Atlantic even at considerable 

 depths (e.g., Roe, 1972) further substantiates 

 the lack of a North Atlantic temperate cog- 

 nate of parki and laugae. 



The species is named for Bui Thi Lang to 

 acknowledge her discovery (1965) of morpho- 

 logical and geographical complexity in atteuu- 

 atus s.l. 



997 



