Table 4. — Percentage of specimens of four worldwide species of needlefishes infested by 10 species of copepods 



Three species of copepods are common on the first 

 three species of needlefislies : Caligodes laciniatus, 

 Lermanthropus tylosuri, and Ooloiomatus good- 

 ingi. There are only a few accidental records of 

 Caligodes and Lemanthropus from Platybelone 

 and none at all of Coloioinatus. Yet all four 

 species of needlefishes are commonly infest«d with 

 Parahomoloclms hellones or its eastern Pacific 

 analog P. constrictus. Collette (in Collette and 

 Parin, 1970) considered Ablennes and Tylo- 

 sums as closely i-elated ; the high incidence of Cali- 

 godes, L. tylosuri, and Col^obomatus infestation in 

 these genera could be considered as parasitological 

 support for this view. Parin (in Collette and 

 Parin, 1970), however, considered the similari- 

 ties between Ablennes and Tylosurus as convergent 

 evolution associated with occupation of a similar 

 ecological niche. The parasitological data could 

 be equally well applied to the support of this point 

 of view. 



Examination of the copepods associated with 

 16 other marine species of needlefishes (table 5) 

 may help in deciding between the alternatives. 

 Caligodes is found on one of the two other species 

 of Tylosurus — T. choram. Caligodes is also found 

 on LhotsMa gaviahides, a species placed in Tylo- 

 surus by Collette and Berry (1965) but referred 

 to the monotypic Lhotskia by Parin (1967). The 

 sixth species infested with Caligodes, Strongylura 

 Uiura, is the only member of its genus to be so 

 infested. S. leiura is definitely not closely related 

 to Ablennes or Tylosunis. Its only characters in 

 common with the other Caligodes hosts are : large 



size (501 mm. BL compared to 665-950 mm. BL), 

 wide distribution, and apparent intolerance of 

 estuarine conditions. Thus, we conclude that 

 Caligodes is not host-specific — it is associated with 

 large, widely distributed, oceanic species of needle- 

 fishes. 



The contrast is sharp among Ablennes, Ty- 

 losurm acus, and T. crocodilus, which are com- 

 monly infested with Lemanthropus tylosuri, and 

 most of the species of Strongylura, which are usu- 

 ally infested with L. belones, particularly in the 

 western Atlantic and eastern Pacific. The situation 

 is confused in the Indo-West Pacific where nearly 

 half of the ^S*. a-nastomella examined were infested 

 with L. tylosuri, and several other species of 

 Strongylura have L. belones, or L. tylosuri, or both. 

 S. strongylura has about an equal percentage of 

 infestation of both species of Lemanthropus. The 

 common Character of L. tylosuri hosts is avoidance 

 of estuarine areas. Most of the hosts are large off- 

 shore species as is true of Caligodes hosts. The 

 common character of L. belones hosts is its likeli- 

 hood of being taken in estuarine situations. We 

 conclude that the reason for host differences be- 

 tween L. belones and L. tylosuri is that L. belones 

 is euryhaline and L. tylosuri stenohaline. 



Bomolochid copepcxis associated with needle- 

 fislies are apparently not host specific. Tables 4 and 

 5 show Parabomolochus bellones common on all 

 seven species in four genera in the western At- 

 lantic, on five of seven species in five genera in the 

 eastern Atlantic, and on seven species of Lhotskia 

 and Strongylura in tlie Indo-West Pacific. P. bel- 



408 



U.S. FISH AND WILDLIFE SERVICE 



