Caligus lagocephali Pillai, 1961

Boxshall, Geoff, 2018, The sea lice (Copepoda: Caligidae) of Moreton Bay (Queensland, Australia), with descriptions of thirteen new species, Zootaxa 4398 (1), pp. 1-172 : 75-77

Caligus lagocephali Pillai, 1961

( Fig. 32 )

Syn. Caligus fugu Yamaguti & Yamasu, 1959

Material examined. 1♀ from Lagocephalus lunaris (Bloch & Schneider, 1801) (TC17942) 6 July 2016, QM Reg. No. W53075; 1♂ (TC 17892) 5 July 2016, QM Reg. No. W53076; 1♂ (TC 17899) 5 July 2016, NHMUK 2017.274; 1♀ (TC17944) 6 July 2016, NHMUK 2017.275.

Site on host. Unknown (in body wash).

Differential diagnosis. Cephalothorax dorsoventrally flattened with well-developed marginal membranes along lateral zones of dorsal cephalothoracic shield; frontal plates with prominent lunules. Genital complex about 1.3 to 1.4 times longer than wide ( Fig. 32A ), with narrow anterior neck region; abdomen elongate, about 2.9 times longer than wide; genital complex about 1.3 times longer than abdomen. Antenna with tapering posterior process ( Fig. 32B ). Post-antennal process simple, tine slender, short and strongly recurved; associated papillae bisensillate. Anterior papilla of maxillule well developed with 1 large and 2 small setae; posterior process simple, tapering, without marginal flange ( Fig. 32B ). Maxilliped of female with robust proximal segment swollen proximally with transverse ridge and marginal fold in myxal area ( Fig. 32C ). Sternal furca with divergent tapering tines ( Fig. 30D ). Distal exopodal segment of leg 1 ( Fig. 32E ) lacking 3 plumose setae on posterior margin, only single naked vestigial seta present; distal margin spine 1 longer than other spines; spines 2 and 3 each with accessory process; seta 4 as along as spine 1 and ornamented with short pinnules bilaterally. Leg 2 with strong, distally tapering marginal spinules on endopodal segments 2 and 3 (as in C. ariicolous , cf. Fig. 18G ); outer spines on exopodal segments 1 and 2 very slender, aligned obliquely across surface of ramus ( Fig. 32F ). Leg 3 with patch of tiny spinules located laterally on apron: first exopodal segment with short straight spine but lacking inner seta; second and third segments armed with I-1; III,4. Leg 4 uniramous, 3-segmented; first and second exopodal segments with I and IV spines, respectively ( Fig. 32G ). Body length of female 4.16 mm; body length of 2 males 2.65 and 2.88 mm.

Remarks. The valid name of this species has recently changed. In their revision of the Caligus productus species group, Boxshall & El-Rashidy (2009) recognized the conspecific status of C. fugu Yamaguti & Yamasu, 1959 and C. lagocephali Pillai, 1961 , and treated the latter as a subjective synonym of the former. However, the subsequent recognition of the generic level synonymy of Pseudocaligus A. Scott, 1901 and Caligus by Dojiri & Ho (2013), resulted in the recognition of Caligus fugu ( Yamaguti, 1936) as a senior homonym. So, Caligus fugu Yamaguti & Yamasu, 1959 became a junior secondary homonym. According to Özak et al. (2013) the oldest available valid name for this taxon is Caligus lagocephali Pillai, 1961 .

The original description of Caligus fugu of Yamaguti & Yamasu (1959) revealed several distinctive characteristics: the tine of the post-antennal process is slender and set at a right angle to the base; the maxilliped has a robust proximal segment; leg 1 has unusually slender exopodal segments and the outer spines on the exopod of leg 2 are also unusually slender. The Moreton Bay material from Lagocephalus lunaris shares these features. There are minor differences such as the structure of the myxal surface of the female maxilliped which is shown as having a pointed process by Yamaguti & Yamasu (1959: Fig. 141). However, this apparent process can be also interpreted as a ridge and marginal fold as figured for the Moreton Bay material ( Fig. 32C ). The minute vestige of a posterior margin seta on the distal exopodal segment of leg 1 was probably overlooked by Yamaguti & Yamasu (1959). The synonymy proposed by Boxshall & El-Rashidy (2009) of C. fugu Yamaguti & Yamasu, 1959 and C. lagocephali Pillai, 1961 is maintained here, although this should be verified since the female figured by Pillai (1961) was somewhat damaged, as suggested by Pillai (1985).

The type host of C. lagocephali in Indian waters is Lagocephalus inermis and the Japanese material described by Yamaguti & Yamasu (1959) was from Takifugu rubripes (Temminck & Schlegel, 1850) , T. alboplumbeus (Richardson, 1845) , T. niphobles ( Jordan & Snyder, 1901) and T. pardalis (Temminck & Schlegel, 1850) (as Spheroides rubripes , S. alboplumbeus , S. niphobles and S. pardalis , respectively). This species (as C. fugu Yamaguti & Yamasu, 1959 ) has also recently been reported in Mediterranean waters, off the Turkish coast, on two Red Sea invasive hosts Lagocephalus spadiceus (Richardson, 1845) and L. suezensis Clark & Gohar, 1953 ( Özak et al., 2012). The new material from Moreton Bay is from L. lunaris . It appears that this copepod utilises a range of tetraodontid fishes as hosts.

Figures

FIGURE 18. Caligus ariicolus Wilson, 1928, female. A, habitus, dorsal; B, antenna, post-antennal process and maxillule drawn insitu; C, maxilliped; D, sternal furca,showing adjacent accessory processes; E, leg 1; F,outer margin spines onexopod of leg 2;G, ornamentation on lateral margin of endopodal segments 1and 2of leg 2; H, leg 4. Scale bars:1.0mm on A, 200 µm on B, C, E, H, 100 µm on D, 50 µm on F, G.

FIGURE 30. Caligus hyporhamphi sp. nov., holotype female. A, habitus, dorsal; B, right posterolateral corner of genital complex with leg 5, ventral; C, antennule; D, antenna, post-antennal process and maxillule drawn in situ; E, tip of maxilla showingmarginal corrugations; F, maxilliped; G,sternalfurca.Scale bars:1.0mm on A, 200 µm on C, D, F, 100 µm onB, E, G.

FIGURE 32. Caligus lagocephali Pillai, 1961, female. A, habitus, dorsal; B, antenna, post-antennal process and maxillule drawn in situ; C, maxilliped; D, sternal furca; E, leg 1; F, outer margin spines on exopod of leg 2; G, leg 4. Scale bars: 1.0 mm on A, 100 µm on B–D, F, G, 200 µm onE.