Comprehensive Description

provided by Smithsonian Contributions to Zoology
Truncatoflabellum gardineri Cairns, 1993

Truncatoflabellum gardineri Cairns in Cairns and Keller, 1993:266, figs. 11B–D.

DESCRIPTION.—Coralla elongate and compressed, having a relatively low thecal edge angle of 21°–39°, the thecal edges becoming almost parallel in upper region of some coralla. Inclination of thecal faces, 18°–23°. Largest specimen from Japan (TM (KT9202, OS3) 16.7 × 11.3 mm in calicular diameter and 19.8 mm in height, with a basal scar diameter of 3.7 × 4.5 mm. Calicular edge smooth; GCD:LCD = 1.30–1.48. Basal scar of anthocyathus rather small and elliptical, almost circular, ranging from 4.5–4.7 × 3.3–3.7 mm in diameter. Thecal edges rounded except for region approximately 3–10 mm above basal scar, which extends as a single narrow crest up to 2.5 mm in height. Theca bears narrow longitudinal striae corresponding to each septum as well as chevron-shaped growth lines that peak at all but last septal cycle. In one well-preserved corallum, the theca was reddish brown with an indication of longitudinal striping along the major septa.

Septa hexamerally arranged in 4 complete to 5 incomplete cycles according to the formula: S1–2>S3>S4>S5. Coralla less than 11 mm GCD usually have 48 septa arranged in 4 complete cycles. Between a GCD of 11–14 mm pairs of S5 begin to appear in the quarter-systems directly adjacent to the 2 principal septa (50–56 septa) with a corresponding increase in the width of the flanked S4 to the size of an S2 and the acceleration of the adjacent S3 to the size of an S1–2. Above a GCD of 15 mm additional pairs of S5 may occur in the remainder of the end half-systems and even quarter-systems adjacent to those, up to a total of 66 septa. S1–2 wide and have thickened, sinuous lower inner edges that fuse with the columella. S3 about half width of S1–2 and do not attain the columella, unless it is adjacent to an S5 (see above), in which case it is almost as wide as an S1–2 and fuses with the columella. S4 small, only about one third width of an S3, larger if flanked by a pair of S5. S5 rudimentary. Septa widely spaced, separated from one another by 2–3 septal thicknesses. Fossa deep and narrow, containing a well-developed elongate fossa about 1.8 mm wide.
bibliographic citation
Cairns, Stephen D. 1994. "Scleractinia of the temperate North Pacific." Smithsonian Contributions to Zoology. i-150. https://doi.org/10.5479/si.00810282.557.i