A new species of Cantellius and a redescription of C. sextus (Hiro, 1938) (Cirripedia, Balanomorpha Pyrgomatidae) from the elephant skin coral, Pachyseris speciosa (Dana, 1846) (Scleractinia, Agariciidae) from Taiwan Author Achituv, Yair Author Tsang, Ling Ming Author Chan, Benny Kwok Kan text Zootaxa 2009 2022 15 28 journal article 10.5281/zenodo.186108 5c5e61c4-dd2e-4d61-a609-cae3d22ee6dc 1175-5326 186108 CE50DECB-119D-41C7-BC4F-384818ADD448 Cantellius sextus ( Hiro, 1938 ) Figs 4–6 Pyrgoma (Creusia) spinolosa var. 6 subvar. 3. - Darwin, 1854 : 379, figs 6n-6q Materials examined. ASIZCR 2006-2008 , Dong-Qing-Wan, Lanyu Island, Taiwan (22°01’, 121°32’), 5–10 m , coll. B.K.K. Chan. FIGURE 4. Cantellius sextus . Hard parts. A) Inner view of parietes under SEM; B) inner view of one of the paries; C) scutum, outer view; D) scutum, inner view; E) apical end of scutum showing honeycomb-like structure; F) tergum, outer view; and G) tergum, inner view. FIGURE 5. Cantellius sextus . Trophi. A) Labrum, general view; B) labrum, showing sharp, deep notch; C) large teeth on the edge of labrum; D) mandible, general view; E) serrulate setae on the side of mandible; F) lower margin of mandible; G) maxillule, general view; H) serrulate setae on maxillule; I) mandibulatory palp; J) serrulate setae on mandibulatory palp; K) maxilla; and L) serrulate setae on maxilla. Scale bar in μm. Diagnosis. Wall with approximately 23 internal ribs ( Fig. 4 A, B); basal margin of scutum longer than tergal margin ( Fig. 4 C), adductor plate extending beyond basal margin ( Fig. 4 D). Tergum with broad spur, external spur furrow shallow; spur length approximately 1/2 length of scutal margin ( Fig. 4 F, G). FIGURE 6. Cantellius sextus . Cirri. A) Cirrus I, general view; B) serrulate setae on endopod of cirrus I; C) serrulate setae on exopod of cirrus I; D) plumose setae on rami of cirrus I; E) cirrus II, overview; F) bidentate serrate setae on rami of cirrus II; G) serrulate setae on rami of cirrus III; H) cirrus III, general view; I) serrate setae on rami of cirrus III; J) plumose setae with long, loose setae on protopod of cirrus III; K) cirrus IV, general view; L) serrulate setae on rami of cirrus IV. Cirrus V and VI not shown as they are similar to cirrus IV. Scale bar in μm. Description. Parietes (shell): Slightly projecting above the coral surface covered by coral skeleton overlying external ribs, number of ribs indistinct. Rostro-carinal diameter to 4 mm ; wall of 4 parietes, approximately 23 internal radial ribs radiating from central orifice, some secondary ribs reaching 1/2 way between wall circumference and orifice ( Fig. 4 A, B). Tubes between sheath and parietes largely filled ( Fig. 4 B). Orifice oval, 1/5 of rostro-carinal diameter ( Fig. 4 A). Sheath pigmented, orange, with concentric growth ridges extending less than 1/2way down internal surface of parietes. Carina wider than rostrum. Opercular valves white, thin. Scutum ( Fig. 4 C, D) triangular, externally growth ridges coarse, crossed by fine striae, alternate ridges forming teeth on occludent margin (and on tergal margins). Length of tergal margins approximately 2/3 occludent margin. Tergal portion of scutum strongly inflected. Apical angle approximately 60°, approximately 13–16 rows of pits at apical angle forming honeycomb-like surface ( Fig 4 E). Basal margins sinusoidal. Internally adductor plate extending beyond basal margin forming conspicuous basal ledge ( Fig. 4 C). Basi-occuludent angle with distinct rostral tooth, pit of lateral depressor muscle small ( Fig 4 D). Tergum ( Fig. 4 F, G) with blunt spur, spur width approximately 1/2 tergal width, external furrow shallow, open from apex to spur base, angle between spur and basal margin obtuse. Pits similar to those on scutum, at apex, forming honeycomb-like surface. Sinusoidal fine growth ridges on tergum surface. Tergal wing height approximately1/2 tergal length (including spur). Internally small pits for tergal depressor muscle ( Fig. 4 F). Trophi: Labrum with deep V-shaped notch ( Fig 5 A, B), 2 large teeth on each side of notch ( Fig. 5 d, F). Mandible quadridentoid, teeth simple; lower margin straight, without setae or spines ( Fig. 5 D, F). Setae on surface of mandible serrulate with short setules ( Fig. 5 E). Maxillule without obvious notch, approximately 9 strong spines ( Fig 5 G), serrulate setae with short setules at base of spines ( Fig 5 H). Mandibular palp and maxilla bearing serrulate setae with short, sparse setules ( Fig. 5 I–L). Cirri: Cirrus I with rami unequal, exopodite longer than endopod, 9 and 5 articles, respectively ( Fig. 6 A); exopodite bearing thin, serrulate setae with sparse setules ( Fig. 6 B, D, G), endopodite bearing thick, serrulate setae with dense, short setules ( Fig. 6 B). Protopodite bearing plumose setae with sparse setules ( Fig. 6 C). Cirrus II with exopodite and endopodite similar lengths, 7–8 articles ( Fig. 6 E). Rami bearing serrate, bidentate setae ( Fig. 6 F). Protopod bearing serrulate setae with fine setules ( Fig. 6 J). Cirrus III with exopodite and endopodite similar lengths, approximately 10 articles ( Fig. 6 H), rami bearing serrate setae with 3 rows of setules ( Fig. 6 E). Protopod bearing plumose setae with long, loose setules ( Fig. 6 G, I). Cirrus IV–VI similar, rami subequal, articles bearing 3–4 pairs of serrulate setae with short setules ( Fig. 6 K, L).