Caligus schlegeli Ho & Lin, 2003

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 : 116-118

Caligus schlegeli Ho & Lin, 2003

( Fig. 53 )

Syns: Caligus pagrosomi: Roubal (1981) Caligus epinepheli: Byrnes (1987)

Caligus pagrosomi schelegeli Ho & Lin, 2003 C. schelegeli: Boxshall & El-Rashidy, 2009

Material examined. 2♀♀, 1 chalimus from Acanthopagrus australis (Günther, 1859) (TC17123) 14 January 2016, QM Reg. No. W53097; 2♀♀, 3♂♂ (TC17126) 14 January 2016, QM Reg. No. W53098; 1♀ (TC17133) 14 January 2016, QM Reg. No. W53099; 2♀♀, 1 chalimus (TC17135) 14 January 2016, QM Reg. No. W53100; 5♀♀ (TC17145) 14 January 2016, QM Reg. No. W53101; 1♀ (TC17250) 18 January 2016, QM Reg. No. W53102; 3♀♀ (TC17310) 20 January 2016, QM Reg. No. W53103; 9♀♀, 2♂♂, 7 chalimus (TC17316) 20 January 2016, QM Reg. No. W53104; 1♀ (TC17544) 24 June 2016, QM Reg. No. W53105; 3♀♀ (TC17580) 25 June 2016, QM Reg. No. W53106; 1♀, 1 immature ♀, 2♂♂, 2 chalimus (TC17624) 27 June 2016, 7♀♀ (TC17855) 4 July 2016, 1♂, 4 chalimus (TC17583) 25 June 2016, 1♀, 2♂♂ (TC17629) 27 June 2016, 1♂, 4 chalimus (TC17716) 29 June 2016, 1♀ (TC17727) 29 June 2016, 7♀♀, 3 immature ♀, 5 ♂♂ (TC 17 786) 1 July 2016, 1♀ (TC17814) 3 July 2016; NHMUK 2017.312–321. 1♂ from Apogon doederleini Jordan & Snyder , 1901 (TC17160) 14 January 2016, NHMUK 2017.359 ;1♀, 1♂, 1 chalimus from Girella tricuspidata (Quoy & Gaimard, 1824) (TC17604) 26 June 2016, 4♀♀, 2♂♂ (TC17146) 14 January 2016, 1 immature (TC17130) 14 January 2016, 1♂ (TC 17803) 2 July 2016, 2♀♀ (TC 17820) 3 July 2016; NHMUK 2017.403–407. 1 immature ♂ from Pentapodus paradiseus (Günther, 1859) (TC17600) 26 June 2016, NHMUK 2017.360;1♀ from Rhabdosargus sarba (Forsskål, 1775) (TC17318) 20 January 2016, 2♂♂ (TC17324) 20 January 2016;5♀♀ from Selenotoca multifasciata (Richardson, 1846) (TC17062) 13 January 2016, QM Reg. No. W53107; 7♀♀ (TC17099) 13 January 2016, 1♀ (TC17137) 14 January 2016, 10♀♀ (TC17153) 14 January 2016, 5♀♀, 6♂♂ (TC 17169) 15 January 2016, 2♂♂ (TC 17225) 18 January 2016, QM Reg. No. W53108; 1♀, 1♂ (TC17303) 20 January 2016; NHMUK 2017.408–417. 1♂ from Sillago maculata Quoy & Gaimard, 1824 (TC17546) 24 June 2016, NHMUK 2017.361.

Site on host. Roof of mouth, oral cavity, tongue.

Differential diagnosis. Cephalothorax dorsoventrally flattened with well-developed marginal membranes. Frontal plates with large lunules. Genital complex with waist-like anterior region, lateral margins tapering anteriorly more-or-less parallel posteriorly, about 1.2 times longer than wide, without posterolateral lobes ( Fig. 53A ); abdomen indistinctly 2-segmented; about 2.1 times longer than wide and shorter than genital complex. Proximal segment of antenna with short rounded posterior process provided with marginal flange ( Fig. 53B ). Postantennal process strongly curved; associated papillae bisensillate. Maxillule with slight marginal flange on posterior process ( Fig. 53B ). Sternal furca with incurved tines; accessory processes present on ventral surface of cephalothorax either side of sternal furca. Distal exopodal segment of leg 1 with 1 minute, unarmed vestigial seta on posterior margin ( Fig. 53C ), lacking plumose setae; distal spines 2 and 3 each with accessory process; seta 4 about 40% longer than spine 1, shorter than segment. Leg 2 outer spines on first and second exopodal segments aligned obliquely across ramus; proximal outer spine on third segment short, distal outer spine with extensive bilateral membrane ( Fig. 53D ). Leg 3 with 3-segmented exopod; first segment bearing weakly curved outer spine, lacking inner seta; second with outer spine and inner seta; third with 3 spines and 4 setae: endopod 2-segmented; first segment forming well developed velum, bearing inner seta; compound distal segment with 6 plumose setae. Leg 4 uniramous, 3-segmented ( Fig. 53E ); exopodal segments with I; IV spines; outer spine on first segment reaching almost to middle of lateral spine; lateral spine just reaching base of outermost distal spine, apical spine longest, middle distal spine 0.8 times as long as apical, outermost distal spine 0.6 times as long as apical. Mean body length of female 3.14 mm, range 2.81 to 3.42 mm (based on 10 specimens); mean body length of male 2.41 mm, range 2.15 to 2.62 mm (based on 10 specimens).

Remarks. This species is a member of the C. productus -group of species characterized by the extreme reduction or loss of the three plumose setae on the posterior margin of the distal exopodal segment of leg 1 (Boxshall & El-Rashidy, 2009). It was originally recognised as a subspecies of C. pagrosomi by Ho & Lin (2004), but Boxshall & El-Rashidy (2009) subsequently raised this subspecies to species level, as C. schelegeli Ho & Lin. 2004 . It is proposed here to amend the spelling of the name: Ho & Lin (2004) spelled the name C. schelegeli in the section heading, but in the legends of figures 121 to 123 in the same work, the name was given as C. schlegeli . Whilst not explicitly stated, the name choosen by Ho & Lin (2003) appears to refer to the name of its “ major ” host Acanthopagrus schlegeli (Bleeker, 1854) (Ho & Lin, 2004) which, in turn, honours the nineteenth Century German biologist Hermann Schlegel. The change to C. schlegeli can be considered a justified emendation. The Moreton Bay material from A. australis keys out to C. schlegeli (as C. schelegeli ) using Boxshall & El-Rashidy (2009).

In Moreton Bay C. schlegeli is a common species occurring at high abundance on its preferred host A. australis . This species has previously been reported from localities off New South Wales and Queensland by Roubal (1981), as C. pagrosomi , and by Byrnes (1987), as C. epinepheli . Ho & Lin (2004) explicitly included C. epinepheli of Byrnes in the synonymy of their new subspecies, Caligus pagrosomi schelegeli . In Moreton Bay C. schlegeli was found on six different hosts in addition to A. australis : Rhabdosargus sarba , Selenotoca multifasciata , Girella tricuspidata , Apogon doederleini , Pentapodus paradiseus and Sillago maculata , although from the last three host species only single male specimens were recovered.

Figures

FIGURE 53. Caligus schlegeli Ho & Lin, 2003, female. A, habitus, dorsal; B, antenna, post-antennal process and maxillule drawn in situ; C, exopod of leg 1, ventral; D, outer margin spines on exopod of leg 2; E, exopod of leg 3; F, leg 4. Scale bars: 1.0 mm on A, 100 µm on B, C, F, 50 µm on D, E.