Crispatotrochus rubescens (Moseley 1880)

Corallum ceratoid, elongate, slightly curved, and flared distally. Pedicel robust ranging from 4.2 to 5.5 mm in diameter (PD:GCD = 0.26–0.31), expanding to a thin encrusting base. Largest specimen known 21 x 16.8 mm in CD and 37.2 mm in height. Costae more prominent (as low ridges) near calicular edge, fading to pedicel. Theca granular. Corallum white. Septa hexamerally arranged in five complete cycles according to formula S1–2>S3>S4>S5, but largest specimen displays some rudimentary S6. S1–2 highly exsert, with sinuous vertical axial edges that fuse to columella. S3 four fifths width of S1–2 with slightly less sinuous inner edges. S4 three fourths width of S3, with less sinuous axial edges. S5 half width of S4. S6, if present, rudimentary and present only at calicular margin. Fossa of moderate depth, containing an elongate columella consisting of 4–9 slender, twisted elements.

New Caledonia; Wallis and Futuna; Vanuatu – Tanna; Australia – off Queensland; Philippines –Lubang Island, south of Negros (Bohol Sea), Sulu Archipelago (Sulu Sea); Indonesia – Kai Islands (Banda Sea), south of Tanimbar Islands (Arafura Sea), Sumba (Savu Sea); China – southern Formosa Strait (south China Sea); Japan – Sagami Bay and off Kushimoto (Honshu), Shikoku, and off Koshiki (Kyushu); Hawaii – Maui, Moloka‘i, O‘ahu, and Kaua‘i, and Nihoa, Blank, and Brooks Banks; Christmas Islands; 110–634 m.

Among the species of Crispatotrochus that have 5 complete hexamerally arranged septal cycles (C. rubescens, C. foxi, and C. niinoi), all of which occur in temperate Pacific, C. rubescens is distinguished by having sinuous axial septal edges for S1 and S2, and costate theca at least near the calicular margin.

Crispatotrochus rubescens (Moseley, 1881)

Cyathoceras rubescens Moseley, 1881:157, pl. 2: fig. 8a–c.—Marenzeller, 1888b:21–22.—Yabe and Eguchi, 1942b:117.—Cairns, 1984:15.

Cyathoceras diomedeae Vaughan, 1907:77–78, pl. 7: figs. 1, 2.

Cyathoceras diomedae [sic].—Yabe and Eguchi, 1942b:116–117, pl. 9: fig. 8.

Crispatotrochus rubescens.—Cairns, 1991a:15.

DESCRIPTION.—Corallum ceratoid, with a flared calice and a firmly attached pedicel about one-quarter diameter of calice. Illustrated specimen (Soyo Maru-33) 24.3 × 20.6 mm in calicular diameter and 30.4 mm in height, with a pedicel diameter of 6.6 mm. Costae ridged only near calice, otherwise consisting of broad, flat, finely granulated strips. Corallum white or reddish brown.

Septa hexamerally arranged in 5 cycles: S1–2>S3>S4>S5. S1–2 highly exsert (as much as 7 mm), and have sinuous, vertical inner edges that join the columella. S3 considerably less exsert (about 4 mm), but as much as 80% as wide as S1–2 and also have sinuous inner edges. S4–5 equally exsert (about 2.5 mm), the S4 about half size of S3 and the S5 about half size of S4. Fossa moderately deep, containing a crispate, fascicular columella composed of 15–20 slender, twisted elements.

azooxanthellate

110-634 m