Cantellius sextus Hiro 1938
Creators: name: Achituv, Yair
name: Tsang, Ling Ming
name: Chan, Benny Kwok Kan
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Sessilia
Pyrgomatidae
Cantellius
Cantellius sextus

description: 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.
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).
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).
description: Published as part of Achituv, Yair, Tsang, Ling Ming & Chan, Benny Kwok Kan, 2009, 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, pp. 15-28 in Zootaxa 2022 on pages 21-24, DOI: 10.5281/zenodo.186108