Flabellum (Flabellum) magnificum Marenzeller 1904

Flabellum (Flabellum) magnificum Marenzeller, 1904

?Flabellum suluense Alcock, 1902a:31–32, pl. 4: figs. 29a,b.—Faustino, 1927:58, pl. 4: figs. 3–5.

Flabellum magnificum Marenzeller, 1904:276–277, pl. 17: fig. 13.—Utinomi, 1965:255.—Zibrowius, 1974:18.

Not Flabellum magnificum.—Harrison, 1911:1020–1021, pl. 57: figs. 1–3 [= Rhizotrochus lypus].

Flabellum pavoninum.—Faustino, 1927:46 [in part: ALB-5118, 5412, 5586].—Yabe and Eguchi, 1942a:90–91, pl. 5: figs. 2a-c [in part: sta 437]; 1942b:129, pl. 11: figs. 7a-c.—Squires, 1964a:15–21 [in part: ALB–5118, 5280,5281,5412,5523,5590].

Flabellum pavoninum magnificum.—Yabe and Eguchi, 1942a:89–90, pl. 5: figs. la-c; 1942b: 129, pl. 11: figs. 8a–c.

DESCRIPTION.—Angle of thecal edges, exclusive of crests, 140°–172°; inclination of thecal faces, 44°–58°. Largest specimen examined (ALB-5590) 88.0×45.0 mm in calicular diameter and 60.0 mm tall. Thecal faces flat to very slightly concave, meeting in acute thecal edges (rarely rounded), usually with a poorly developed, discontinuous crest up to 3.9 mm tall. Length of a thecal edge from calice to upper pedicel (LEL) up to 45.6 mm in larger specimens. Ratio of LEL:H = 0.60–0.78. C1–4 slightly ridged; transverse chevron-shaped growth lines common. In well-preserved coralla, theca bears reddish brown stripes, those associated with C1–4 about 0.5 mm wide, those following the C5–6, about 0.2 mm wide. Most coralla, however, are uniformly white to gray and rarely encrusted. Pedicel 2–3 mm tall and 1.5–2.3 mm in diameter. Ratio of GCD:LCD = 1.65–1.96, this ratio tending to increase with increasing greater calicular diameter. Ratio of GCD:H = 1.29–1.71.

Septa hexamerally arranged in seven cycles, the last cycle never complete. One of the largest specimens (ALB-5280) has 376 septa: a full sixth cycle and all but four pair of S7. The first-formed S7 pairs usually begin to form in systems along the middle of the thecal faces. S1–4 equal in size and not exsert, being the same relatively narrow width as higher-cycle septa in the vicinity of calicular edge, which results in a very high septal concavity index of 10–19. Ten to 12 mm lower in fossa, the S1–4 gradually widen into broad lobes. Toward the lateral thecal edges, the transition from the narrow upper septal width to wide septum is much shorter, occurring 4–5 mm below the calicular edge. Upper edges of S1–4 slightly sinuous and finely serrate, bearing small teeth about 0.1 mm tall spaced 0.2 mm apart (Plate 25d,g); lower, inner edges quite sinuous. S1–4 easily distinguished from higher-cycle septa by their much greater width, very sinuous lower edges (SSI = 2.3–6.6), and by being the only ones to fuse with the columella. S5 half size of S1–4, having straight inner edges. S6 about width of S5, extend about halfway down the thecal face, and also have straight inner edges. S7, when present, about width of S6, extending only 2–10 mm down inner thecal face. Septal granules pointed but sparse, 0.08–0.14 mm tall.

Fossa deep, long, and narrow but easily affording a view of the rudimentary columella formed by the lower, inner edges of the S1–4.

Flabellum (F.) magnificum Marenzeller, 1904

Flabellum magnificum Marenzeller, 1904a:276–277, pl. 17: fig. 13.—Utinomi, 1965:255.—Cairns, 1989a:50–51, pl, 25: figs. a–j [synonymy].

Flabellum pavoninum.—Yabe and Eguchi, 1942a:90–91, pl. 5: fig. 2a–c [in part: Soyo Maru-437]; 1942b:129, pl. 11: fig. 7a–c.

Flabellum pavoninum magnificum.—Yabe and Eguchi, 1942a:89–90, pl. 5: fig. 1a–c; 1942b:129, pl. 11: fig. 8a–c.

DIAGNOSIS.—Angle of thecal edges 140°–172°; inclination of planar thecal faces quite open, 44°–58°. Discontinuous edge crests usually not present. Thecal faces bear reddish brown stripes associated with each costa. Pedicel narrow, only 1.5–2.3 mm in diameter. Ratio of GCD:LCD = 1.65–1.96. Septa hexamerally arranged in 7 cycles, the last cycle never complete, the largest known specimen having 376 septa. Septal formula: S1–4>S5>S6>S7. Columella well developed.

azooxanthellate

225-740 m