Ceratothoa gilberti

Ceratothoa gilberti (Richardson, 1904) (Fig. 2) Material examined. Boca del Caimanero, Mazatlán. Jun 7,2018, 1 female (TL 16.5) in the buccal cavity and 1 male (TL 8.7) in the gill chamber of Mugil cephalus (Mugilidae), (ICML-EMU 13783). Distribution. From SW California to Mazatlán, including the Gulf of California (see Hadfield and Smit, 2020). Previous known hosts. Mugil cephalus and Mugil hospes (see Hadfield and Smit, 2020). Remarks. According to Brusca (1981), the genus Ceratothoa Dana, 1852 and Cymothoa Fabricius, 1793 are two of the most common genera of tonguebiters (cymothoids found inside the buccal-cavity of fish). According to Hadfield et al. (2014), species of Ceratothoa can be easily identified by the presence of a triangular cephalon, contiguous antennular bases, pleonite 1 narrower than the other pleonites, and an elongate body (2.1–2.9 times as long as wide). Ceratothoa gilberti is easily distinguished from the other Ceratothoa species because it is the only species without a considerable expansion at the base of the latter pereopods 5–7 (Bruce and Bowman, 1989). According to Brusca (1981) and Espinosa-Perez and Hendrickx (2001), only two species of Ceratothoa have been found on the eastern Pacific coast, Ce. gilberti and Ce. gaudichaudii (species inquirenda). In a comprehensive review of the fish hosts of Ce. gaudichaudii elaborated by Muñoz and Olmos (2007), the authors mentioned that the species has been found in the buccal cavity, branchial arches, and gill chamber of 14 fish species of elasmobranch and teleost fishes. However, none of those species belongs to the family Mugilidae and Ce. gilberti has only been found infesting Mugilids (Hadfield and Smit, 2020).