Laophontella horrida dentata Mielke, 1992

Karanovic, Tomislav, 2019, Three new harpacticoid copepods for Korea from marine interstitial habitats, Journal of Species Research 8 (3), pp. 268-282 : 279

Laophontella horrida dentata Mielke, 1992

( Figs. 6 & 7 )

Specimens examined. One adult male on one SEM stub and one juvenile female in alcohol from Korea, South Sea, Goseong, Dongdong, Bongam-ri, tiny gravel beach next to a fishing harbor, 34°59.629 ʹ N 128°26.201 ʹ E, 4 April 2012, collected by T. Karanovic .

Supplementary description. Male. Body length, measured from tip of rostrum to posterior margin of caudal rami (excluding caudal seate and appendages) about 800 μm. Habitus ( Fig. 6A, D ) spindle-shaped, widest at distal part of cephalothorax. Cephalothoracic shield ( Figs. 6B, E, F , 7A ) strongly chitinized and heavily sculptured, with numerous ridges and deep pits of various sizes among large sensilla, with anterior notch and pointed postero-lateral processes. Free prosomites ( Fig. 6G ) and all urosomites ( Fig. 6D ), except anal somite, with postero-lateral processes, becoming smaller towards posterior end. All posterior processes heavily sculptured and with sensilla ( Fig. 6H ). Anal somite ( Fig. 6D ) nearly as long as two preceding somites combined, without prominent postero-lateral processes, but with lateral central bulge instead.

Caudal rami ( Figs. 6C , 7D- F ) conical, about three times as long as wide, 1.3 times as long as anal somite, heavily sculptured and with several small processes, with two proximal lateral setae (one very small, see Fig. 7E ) inserted at about 1/5 of ramus length; dorsal seta about as long as distal lateral seta, while larger proximal lateral seta only half as long, and smaller proximal lateral seta only about as big as average sensilla; principal apical seta without breaking planes, very strong, with longitudinal ridges; all setae, except principal apical one, smooth and slender.

Antennula ( Fig. 7A ) short and strongly chirocer, with numerous small and slender setae.

First swimming leg ( Fig. 7B ) with comb-like inner margin and smooth outer margin on both apical endopodal setae.

Fourth swimming leg ( Fig. 7C ) with extremely large and slightly curved outer spine on second exopodal segment; third exopodal segment with two slender and short outer elements, two slender and long apical elements, and one strong and long inner element.

Sixth leg ( Fig. 7C ) simple cuticular plate, with three slender and smooth setae.

Discussion. Laophontella horrida ( Por, 1964) was described from Israel by Por (1964) in the newly proposed genus Willeyella Por, 1964 , which proved to be a junior synonym of Laophontella Thompson and Scott A., 1903 (see Lang, 1965: p. 386). The genus today contains only three species, two of them with recognized subspecies ( Walter and Boxshall, 2019). Laophontella horrida was later also found in other parts of the Mediterranean (Bodi- ou and Soyer, 1973) and possibly even in the Northern Atlantic ( Por, 1984). Mielke (1992) described a new subspecies, L. h. dentata Mielke, 1992, from the Pacific Coast of Costa Rica, and Kunz (1994) described another new subspecies, L. h. namibiensis Kunz, 1994 from Namibia. Both Mielke (1992) and Kunz (1994) agreed that French specimens, illustrated by Bodin (1964) and report- ed as “ Phyllopodopsyllus sp ?”, belong to the nominotypical subspecies of L. horrida . Major differences between these populations were listed in a table by Kunz (1994). Korean specimens agree more with those from Costa Rica than with the other two subspecies, especially in the elongated caudal rami. This is the second record of L. horrida dentata , which extends its range into the Western Pacific. Also, this is the first record of the genus in Korea.

Figures

Fig. 6. Laophontella horrida dentata Mielke, 1992; A-C, CLM photographs; D-H, SEM photographs, adult male; A, adult male (right) and juvenile (left), habitus, lateral view; B, adult male, postero-lateral processes on cephalothorax and first free prosomite; C, adult male (right) and juvenile (left), caudal rami; D, habitus; E, anterior part of cephalothoracic shield; F, posterior part of cephalothoracic shield; G, postero-lateral processes on free prosomites; H, tip of postero-lateral process on first free prosomite.

Fig. 7. Laophontella horrida dentata Mielke, 1992, SEM photographs, adult male, lateral view; A, anterior part of cephalothorax and first segment of antennula; B, apical setae on first leg endopod; C, sixth leg and last two exopodal segments of fourth swimming leg; D, caudal ramus; E, detail of armature and ornamentation of proximal part of caudal ramus; F, detail of principal caudal seta.