Flabellum (Ulocyathus) deludens Marenzeller 1904

Flabellum (Ulocyathus) deludens Marenzeller, 1904

Flabellum japonicum.—Marenzeller, 1889:45–46.

Flabellum laciniatum.—Wood-Mason and Alcock, 1891b:450–451; Alcock, 1898:21–23, pl. 2: figs. 4, 4a; 1902b:150, fig. 19.

Flabellum deludens Marenzeller, 1904:269–272, pl. 17: figs. 10, 10a.—Faustino, 1927:48–50, pl. 2: figs. 7–8 [in part: 16 of 24 stations, see text].—Gardiner, 1929:305.—Yabe and Eguchi, 1942a:101–103, pl. 5: figs. 9–11; 1942b:135–136, pl. 12: fig. 1.—Utinomi, 1965:256.—Eguchi, 1965:292, fig.; 1968:C44, pl. C22: fig. 45, pl. C25: figs. 3, 4.—Zibrowius, 1974:21.—Zibrowius and Grygier, 1985:122, figs. 16–17.

Not Flabellum deludens.—Vaughan, 1907:63–64, pl. 3: figs. 5a,b [= F. marcus Keller, 1974]; 1919, pl. 12: figs. 3, 3a [= F. marcus].—Gravier, 1920:69–71, figs. 118, 119 [= F. angulare Moseley, 1876].—Pax, 1934:57 [= F. macandrewi].—Ralph and Squires, 1962:12, pl. 4: figs. 7, 8 [= F. raukawaensis Squires and Keyes, 1967].

Not Flabellum apertum deludens.—Squires, 1958:68, pl. 13: fig. 13.

Not Flabellum cf. deludens.—Wells, 1984:215, pl. 4: figs. 8–10 [in part: figured specimen is F. aotearoa Squires, 1964b].

DESCRIPTION.—Angle of thecal edges 115°–150°, most about 135°; inclination of thecal faces, 64°–80°. Largest specimen examined 53.0 × 39.0 mm in calicular diameter and 29.4 mm tall (ALB-5110); however, entire populations are composed of specimens smaller than 30 mm in greater calicular diameter (e.g., ALB-5453, 5273). Thecal faces virtually flat, with very little convexity, meeting at an acute angle at thecal edges. Each thecal edge bears a continuous low (rarely over 2 mm tall), thin (0.1 mm) crest. Theca and septa fragile; upper septal edges invariably broken. C1–2, including thecal crests, and upper, outer edges of S1–2 reddish brown, producing a distinctive pattern of radiating stripes on a white background. C3 also reddish brown, but less conspicuous than pigmentation of C1–2. Theca of some specimens uniformly reddish brown. C1–2 slightly ridged in larger coralla, ridges composed of finely granulated chevron-shaped growth lines. Pedicel usually elliptical in cross section and basally grooved, reflecting a probable original attachment to a small-diameter cylindrical substrate, although none of the over 1000 specimens examined showed signs of attachment. Instead, only sand grains were normally found to be incorporated into the pedicel scar. Pedicel scar up to 2.3 mm long and about 1.0 mm wide, the greater axis aligned with the thecal edges.

Septa hexamerally arranged in five incomplete cycles according to the formula: S1–2>S3>S4>>S5. S1–2 extremely exsert, having straight to slightly sinuous vertical inner edges. S3 about size of S1–2, not exsert, and have sinuous inner edges. S4 to size of S3 but considerably taller than the S3, each S4, together with its adjacent S1 or S2, projecting upward as a rectangular thecal extension 1.6–2.0 mm wide and up to 6.5 mm beyond the adjacent calice. At a greater calicular diameter of 28–42 mm, rudimentary S5 begin to form, but only in spaces between S3 and S4, not in those spaces between the S4 and the S1 or S2 on the thecal extensions, which often results in a corallum of 72 septa. Only in the largest coralla (e.g., greater calicular diameter over 50 mm) are additional S5 present in end half-systems. S5 present in thecal extensions are greatly enlarged—almost to the size of an S4—and merge with adjacent S4 at their inner edges. These accelerated S5 often have rudimentary pairs of S6 flanking them, adding another 24 septa to the calice, resulting in 96 septa, but with curiously incomplete fifth and sixth cycles. The upper, outer edges of S1–2 form acute apices on the thecal extensions, and their adjacent S4 also form smaller apices; upper, outer edges of S3 also terminate in apices. Septal apices and thecal extensions contribute to a very lacerate calicular margin. Septal faces corrugated, the ridges oriented perpendicular to septal edges. Each ridge covered by a diffuse, unilinear row of fine granules (0.15–0.16 mm in diameter), sometimes becoming multiple rows on those ridges near the theca (Plate 29f).

Fossa elongate. Rudimentary columella formed by fusion of thickened lower, inner edges of S1–2. S3 also fused to columella.

Flabellum (U.) deludens Marenzeller, 1904

Flabellum japonicum.—Marenzeller, 1888a:45–46.

Flabellum deludens Marenzeller, 1904a:269–272, pl. 17: figs. 10, 10a.—Yabe and Eguchi, 1932a:387; 1942a:101–103, pl. 5: figs. 9a,c, 10a,c, 11a,c; 1942b:135–136, pl. 12: fig. 1a–c.—Eguchi, 1938: table 2; 1965:292, 2 figs; 1968:C44–45, pl. C22: figs. 4, 5; pl. C25: figs. 3. 4.—Utinomi, 1965: 256.—Eguchi and Miyawaki, 1975:58.—Cairns, 1989a:55–56, pl. 29: figs. a–f [synonymy].

?Flabellum cf. apertum.—Yabe and Eguchi, 1942a:89, pl. 5: fig. 12a,c; 1942b:136, pl. 12: fig. 3a–c.

DESCRIPTION.—Corallum highly compressed, with virtually planar thecal faces joined at sharp, carinate thecal edges. Thecal edge crests up to 2 mm in height and usually extend from pedicel to calice. Angle of thecal edges, 115°–150°; inclination of lateral faces, 44°–80°. GCD:LCD = 1.3–1.5. Largest Japanese specimen examined (Alb-4915) 47.9 × 37.7 mm in calicular diameter; however, Cairns (1989a) reported a larger specimen from the Philippines of 53 mm GCD. Thecal faces flat (unridged) and bear a uniform coarse granulation in addition to chevron-shaped growth lines looped between all costae but the C5. Calicular edge deeply lacerate, a tall (up to 6 mm), rectangular thecal extension corresponding to each S1–2 and adjacent pair of S4 (S5 rarely developed adjacent to S1–2). A smaller, triangular calicular apex up to 1.7 mm in height corresponds to each S3. Theca and septa fragile. Base color white, with reddish brown stripes corresponding to the C1–2 and occasionally the C3; septal faces of S1–2 also reddish brown near theca.

Septa hexamerally arranged in 5 cycles, the fifth cycle never complete even in large specimens. Medium-sized specimens (about 35 mm GCD) often have only 4 cycles of septa; larger specimens have pairs of S5 that form adjacent to S3 up to a total of 72 total septa. S5 rarely form adjacent to S1–2. S1–2 equal in size and have vertical, sinuous inner edges that define a deep, narrow fossa. S3 about three-quarters width of an S1 and also have sinuous inner edges. S4 half to three-quarters width of an S3 and have free inner edges, not fused to adjacent S3 or the columella. When present, S5 rudimentary. Lower, inner edges of S1–2 form an elongate columella; inner edges of S3 barely attain the columella.

Flabellum deludens est une espèce de coraux appartenant à la famille des Flabellidae.

azooxanthellate

106-1035 m