Caligus pauliani Nuñes-Ruivo & Fourmanoir, 1956

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 : 559

Caligus biseriodentatus Shen, 1957 and

Caligus pauliani Nuñes-Ruivo & Fourmanoir, 1956

Caligus bioseriodentatus was originally described in detail from material of both sexes taken from a Scomberomorus commerson (Lacepède, 1800) (as Cybium commersoni ) caught off Hainan Island, China ( Shen, 1957). It was not reported widely until 1980 when Cressey & Cressey (1980) recognised Caligus obovatus Heegaard, 1962 , Caligus proboscidatus Heegaard, 1962 and Caligus auxisi Pillai, 1963 as junior synonyms of C. biseriodentatus . In the same monograph on scombrid parasites, Cressey & Cressey (1980) redescribed both sexes of C. biseriodentatus and also figured an immature male specimen which exhibits several distinctive character states: the abdominal somites are each about 1.5 times longer than wide, and together they are longer than the genital complex; the three posterior margin setae on the second exopodal segment of leg 1 are shorter than the segment and shorter than seta 4, and the distal exopodal segment of leg 4 carries four subequal spines which are smaller than the spine on the first segment ( Cressey & Cressey, 1980: Fig. 59c).

In contrast, C. pauliani is poorly known and was inadequately described. It is based on five specimens collected from the body surface and around the base of the pelvic and anal fins of Sphyraena barracuda (Edwards, 1771) (as Sphyraena commersonii Cuvier & Valenciennes ) caught off the coast of Madagascar ( Nuñes-Ruivo & Fourmanoir, 1956). The specimens were identified as males by Nuñes-Ruivo & Fourmanoir (1956) and their body length was given as 5 mm. The original description is incomplete and is supported by a habitus drawing plus figures of leg 1 and leg 4 only. However, the specimens do exhibit the same distinctive character states as C. biseriodentatus : the two free abdominal somites are each about 1.4 to 1.5 times longer than wide, and together they are longer than the genital complex; the three plumose setae on the posterior margin of the second exopodal segment of leg 1 are reduced (all three are shorter than the segment and shorter than seta 4), and the four spines carried on the distal exopodal segment of leg 4 are subequal and smaller than the outer margin spine carried on the first exopodal segment.

We conclude that these two species are synonymous and, unfortunately, the poorly described and virtually unused Caligus pauliani Nuñes-Ruivo & Fourmanoir, 1956 has priority over C. biseriodentatus Shen, 1957 .

Although Cressey & Cressey (1980) and Cressey et al. (1983) showed that this is a widespread species occurring across the Indian Ocean ( Malagasy Republic, Somalia, Arabian Sea, Sri Lanka, Thailand, Zanzibar) and the Indo-West Pacific ( China, Philippines, Indonesia) as far south as Papua New Guinea and Australia, and that it has been recorded from seven species of Scomberomorus Lacepède, 1800 as well as from Auxis thazard (Lacepède, 1800) ( Boxshall, 2018) , the name C. biseriodentatus has not been mentioned in more than 25 publications by a minimum of ten different authors in the past 50 years. It is, therefore, not possible to maintain prevailing usage under Article 23.9.1.2. of the International Code of Zoological Nomenclature.