Caligus alalongae Krøyer, 1863

Boxshall, Geoffrey A. & Bernot, James P., 2023, Resolving taxonomic and nomenclatural problems in the genus Caligus O. F. Müller, 1785 (Copepoda: Caligidae), Zootaxa 5360 (4), pp. 545-567 : 563

Caligus alalongae Krøyer, 1863

Krøyer (1863) described Caligus alalongae based on material collected from Thynnus alalunga (Bonnaterre, 1788) (as Thynnus alalonga ) from an unknown locality. Wilson (1905) considered C. carangis Krøyer, 1863 and C. alalongae to be synonymous and used only the latter name in his key to species. Krøyer’s (1863) description of C. alalongae showed a similar gross morphology to C. carangis in terms of body proportions but the only other illustrations (sternal furca and lunule plus antennule) don’t provide for easy comparison with those he provided for C. carangis . However, one of the reliable diagnostic features for members of the C. confusus -species group is the possession of an elongate distal antennulary segment. This is illustrated by Krøyer (1863) for C. carangis but is not shared by C. alalongae . We therefore consider that C. alalongae is distinct from C. carangis .

Other species have been confused with C. alalongae . Kirtisinghe (1937) described both sexes of a caligid identified as “ C. alalongae ” collected from Alepes dJedeba (Forsskål, 1775) (as Caranx kalla ) and two “other Caranx species ” in Sri Lankan waters. As noted by Capart (1953) and Shiino (1959), “ C. alalongae ” of Kirtisinghe (1937) is not conspecific with C. alalongae of Krøyer (1863). Pillai (1961) considered that Kirtisinghe’s (1937) material represented a new species, C. confusus Pillai, 1961 that he had just described based on material collected from Caranx sansun (Forsskål, 1775) in Indian waters. Kirtisinghe (1964) subsequently followed Pillai’s synonymy. Yamaguti (1954) recorded “ C. alalongae ” on Elagatis sp. and Caranx sp. caught off Macassar ( Indonesia) but his material is not conspecific with C. alalongae of Krøyer (1863). Yamaguti’s material is also identifiable as C. confusus . Lewis (1967) concurred that “ C. alalongae ” of both Kirtisinghe (1937) and Yamaguti (1954) were conspecific with C. confusus .

Capart (1953) reported “ C. alalongae ” from Mobula rochebrunei (Vaillant, 1879) caught off Gorée in Senegal. This record was based on a single juvenile female for which no description was provided and is considered doubtful. Capart (1959) subsequently reported “ C. alalongae ” from Thunnus obesus caught of the west coast of southern Africa but his illustrations clearly show that his species was identifiable as C. productus Dana, 1852 . Capart (1959) placed the material from his 1953 account in the synonymy of “ C. alalongae ”, so we conclude that neither of his records applies to C. alalongae of Krøyer (1863).

None of the other records listed for C. alalongae by Margolis et al. (1975) provides sufficient morphological detail to allow verification. Therefore, the only available description of “typical” C. alalongae is the original description by Krøyer (1863) and this does not provide enough detail to allow a robust identification. We therefore consider C. alalongae Krøyer (1863) to be a species inquirendum.