Abstract.- The phylogeny and 

 historical biogeography of hakes 

 {Merhicciu^) are reexamined using a 

 cladistic analysis of Inada's (1981) 

 osteological data. One of the 188 most 

 parsimonious trees (cladograms), 

 which also has the lowest (best) F 

 value, is congruent with the scheme 

 of evolution proposed by Ho (1974) 

 for the hake-specific copepod para- 

 sites. Offshore hake M. albidus is the 

 sister group of all other extant hakes. 

 Silver hake M. bilmearis is the sister 

 group of the three eastern Pacific 

 hakes: Chilean hake M. gaiji, Pana- 

 manian hake M. angustimanus, and 

 Pacific hake M. produetus. The five 

 Eastern Atlantic species, European 

 hake M. nierluccius, Senegalese hake 

 M. senegalensis, Benguelan hake M. 

 polli, shallow-water cape hake M. 

 capensis, and deep-water cape hake 

 M. paradoxus, are monophyletic and 

 constitute the sister group that 

 forms a trichotomy with Argentine 

 hake M. huhbsi and New Zealand 

 hake M. australiH. The biogeography 

 inferred from the most parsimonious 

 phylogenetic hypothesis of hakes dif- 

 fers from the views given by both 

 Inada (1981) and Kabata and Ho 

 (1981). The ancestral hake in the 

 eastern seaboard of North America 

 diverged into two stocks. Subse- 

 quently, one of them vicariated into 

 a northern and a southern popula- 

 tion. The southern population moved 

 southward first and then separated 

 into three stocks, with one of them 

 moving eastward and crossing the 

 Atlantic in the region of low lati- 

 tudes. One of the two remaining 

 stocks moved further southward and 

 entered the Pacific through the 

 Drake Passage. After further diver- 

 gence, a descendant stock of the 

 northern population off the coast of 

 North America also moved south- 

 ward; it did not enter the south 

 Atlantic, but, instead, moved into the 

 Pacific over the submerged Panama- 

 nian Isthmus. Some geologic events 

 are discussed for their possible ef- 

 fects in the formation of the present 

 pattern of hake distribution. 



Phylogeny and Biogeography of 

 Hakes [Merluccius; Teleostei): 

 A Cladistic Analysis 



Ju-shey Ho 



Department of Biology, California State University 

 Long Beacfi, California 90840-3702 



Manuscript accepted 28 August 1989. 

 Fishery Bulletin. U.S. 88:95-104. 



In 1981, two views on the historical 

 biogeography of hake were proposed: 

 one by T. Inada and the other jointly 

 by Z. Kabata and J.S. Ho. Although 

 inferred from different sets of bio- 

 logical information, ichthyological vs. 

 parasitological, the two views are re- 

 markably ahke in most major points. 

 Both views (Fig. 1) suggest that the 

 hakes originated in the eastern North 

 Atlantic and dispersed southward via 

 two routes: one along the west coast 

 of Europe and the other along the 

 east coast of North America. These 

 authors also arrived at the same con- 

 clusion that hakes entered the Pacific 

 over the submerged Panamanian 

 Isthmus. The major discrepancy be- 

 tween the two views lies in their ac- 

 counts of the origin and dispersal of 

 Argentine hake Merluccius hubbsi. 

 Using the coevolutionary relation- 

 ships between hakes and their cope- 

 pod parasites, Kabata and Ho (1981) 

 suggested that the Argentine hake 

 was derived from the western North 

 Atlantic stock because it shares the 

 subspecies of copepod parasite Neo- 

 brarhidla insidiosa lagenifor-mes with 

 the silver hake M. bilinearis occur- 

 ring off the east coast of North Ameri- 

 ca. However, in contrast, Inada (1981) 

 proposed that the Argentine hake 

 was derived from an eastern South 

 Pacific stock that rounded Cape Horn 

 to reach Argentina. The Pacific ori- 

 gin of Argentine hake was first pro- 

 posed by Szidat(1955, 1961), but Ho 

 (1974) questioned its validity based 

 on his studies on the copepod para- 

 sites of European hake M. merluc- 

 cius, silver hake Af. bilinearis, Chile- 



an hake M. goyi, and shallow-water 

 cape hake M. capensis. Contrary to 

 the conclusion of Kabata and Ho 

 (1981), Ho (1974) speculated that 

 hakes originated in the western 

 North Atlantic. 



Recently, Fernandez (1985) studied 

 the parasites of a population of New 

 Zealand hake occurring at Guafo 

 Island, Chile (lat. 43°36'S. long. 

 74°43"W), and corroborated the view 

 of Kabata and Ho on hake biogeog- 

 raphy. Since her study methods are 

 the same as that of Kabata and Ho 

 (1981), the above-mentioned disagree- 

 ment between ichthyologist and 

 parasitologist on the origin and dis- 

 persal of Argentine hake remains 

 unresolved. A third method of inves- 

 tigation is needed. 



Cladistic analysis is a systematic 

 method that attempts to discover 

 genealogical (phylogenetic) relation- 

 ships of taxa (Hennig 1966, Wiley 

 1981). Since a detailed phylogenetic 

 hypothesis for a group of organisms 

 can and shotild serve as a basis for in- 

 ferring the biogeographic history 

 (Hennig 1966, Brundin 1966, Nelson 

 and Platnick 1981, Humphries and 

 Parenti 1986), I have used this ap- 

 proach to reexamine the phylogenetic 

 relationships and biogeography of 

 hakes. This paper reports my results. 



Character analysis 



In his revision of Merluccius Rafines- 

 que, Inada (1981) recognized 12 spe- 

 cies of hake (Table 1) and provided 

 detailed redescription of each spe- 

 cies, including measurements of 28 



95 



