Nizinski et al Separation of Ammodytes amencanus and A dubius in western North Atlantic 



251 



The majority of individuals have been collected either 

 inshore (^4. americanus) or offshore (A. dubius) with 

 little syntopic occurrence. We conclude, therefore, that 

 two distinct species, A. americanus and A. dubius, 

 occur in the western North Atlantic Ocean. 



A similar case has been reported for the species of 

 Ammodytes {A. personatus and A. hexapterus) found 

 off Japan. Populations of morphologically and meris- 

 tically similar individuals are difficult to distinguish 

 from one another. Electrophoretic data, however, 

 suggest that two sympatric, genetically distinct groups 

 do occur among these Ammodytes species (Okamoto 

 1989). Perhaps a similar analysis is needed for the 

 western North Atlantic ammodytids to confirm species 

 designations. 



As previously mentioned, this study is a preliminary 

 step toward understanding a more complex problem. 



Many other questions, including the taxonomic status 

 of Greenland j4mmod2/te.s, remain unanswered. Speci- 

 mens examined in our study (A'^ = 51) had high counts, 

 similar to those obtained for A. dubius. But counts for 

 these individuals were highly variable and did not agree 

 completely with those of ^. dubius from the western 

 North Atlantic. In particular, some specimens had low 

 vertebral counts and extremely high plicae counts. 

 Others with low plicae counts, albeit still in the range 

 for A. dubius, tended to have high vertebral counts. 

 Based on meristic combinations and computed PCA 

 scores, the Greenland sand lance is most similar to 

 A. dubius. This finding adds to the existing conflict 

 over which species are found in Greenland. Published 

 accounts indicate two species of sand lances occur in 

 this region: high-meristic A. dubius, and a low-meris- 

 tic, inshore species that has been called A. marinus by 

 Winters and Dalley (1988) as were all western Atlan- 

 tic A. am£ricanus. However, there is some question to 

 the identity of the low-meristic sand lance occurring 

 in Greenland. Counts for these specimens match those 

 of A. americanus as well as the European A. marinus. 

 The low-meristic Greenland species has reportedly been 

 dipnetted and seined on shallow beaches and in pro- 

 tected fjords. Ammodytes marinus, on the other hand, 

 is described as the commonly occurring offshore, 

 deeper-water species in the eastern North Atlantic 

 (Richards et al. 1963, Wheeler 1969, Reay 1970), al- 

 though this species has also been reported from inshore 

 stations (Raitt 1934, Kirillov 1936). 



A limited number of A. marinus from the British 

 Isles were examined; however, the data from these fish 

 posed more questions than solved existing problems. 

 Meristic features of these specimens spanned the 

 ranges recorded for A. americanusl dubius, and mor- 

 phological differences between these three species 

 were not distinctive. The problem is further compli- 

 cated since A. dubius and A. marinus are believed to 

 be on opposite shores of the Atlantic (Reay 1970) yet 

 both have been reported from Greenland. The tax- 

 onomic status of Ammodytes occurring in Greenland 

 waters cannot be resolved until meristic and geograph- 

 ic ranges of European A. marinus are determined. 



Taxonomic confusion is not restricted to Atlantic 

 species; the taxonomy of North ¥ac\i\c Ammodytes is 

 problematical as well. Researchers agree that A. hex- 

 apterus and A. personatus occur in Japanese waters 

 (Kitaguchi 1979, Hashimoto 1984), with A. hexapterus 

 reported as the more northern species and A. persona- 

 tus as the more southerly species. But these species 

 also are similar morphologically and have overlapping 

 counts (vertebrae and dorsal and anal fin rays). Addi- 

 tionally, high variability with two existing modes in the 

 meristic data suggest the presence of two subpopula- 

 tions in the southern A. personatus group (Hashimoto 



