Stephanophyllia fungulus Alcock 1902

Stephanophyllia fungulus Alcock, 1902

Stephanophyllia fungulus Alcock, 1902a:40, pl. 5: figs. 35 a.b.—Faustino, 1927:245–246, pl. 77: figs. 9–11.—Yabe and Eguchi, 1932b:443; 1932c:58, 60–61, pl 8: figs. 1–6, pl. 9: figs. 1–8; 1934:278.—Gardiner and Waugh, 1939:234.—Yabe and Eguchi, 1942b:138.—Squires, 1967:506.—Van Soest. 1979:109.

Stephanophyllia complicata.—Alcock. 1902a:40 [in part: 1 of 3 specimens from Siboga 59].

Micrabacia fungulus.—Vaughan and Wells, 1943:312, pl. 20: figs, la.b.—Uchida, 1963:17–21, pl. 2: figs. 1–3.

DESCRIPTION.—Corallum robust, up to 15.6 mm in calicular diameter (ALB-5586), with GCD:H ratios of 2.1–2.6. Base variable in shape, ranging from flat to slightly concave or convex, but the peripheral edges are always slightly upturned. Costae equal in width (0.14–0.21 mm near calicular edge), having rounded edges. Costal ornamentation complex, the proximal 3.2–3.7 mm of each costa covered by a medial series of low, closely spaced granules, each about 0.14 mm in diameter and corresponding to the intersection of each costa and transverse synapticulae. These coarse granules are flanked on both sides by a row of much smaller slender granules about 0.02 mm in diameter and 0.03 mm tall. With increasing distance from the epicenter, the coarse granules of the medial row diminish in size and the lateral slender granules increase in size until, at a calicular radius of about 3.5 mm, the middle part of the costa is flat and the lateral edges bear spines about 0.04 mm in diameter and 0.10 mm tall. This ornamentation persists to the calicular edge. Costae (base) robust, increasing in thickness toward calicular edge, where it may be up to 1.0 mm vertical thickness. Six costae originate at the epicenter and quickly bifurcate twice, resulting in four costae per system. Each of these four costae also bifurcates twice at different but consistent distances from the epicenter, complementing the adjacent septal bifurcations above, resulting in 16 terminal costae per system (Figure 3). Intercostal spaces narrow, 0.10 mm wide near calicular edge of a larger corallum, and traversed in a regular manner by massive synapticulae 0.18–0.25 mm wide and as tall as the costae that it joins. Parallel transverse synapticulae spaced such that a single series of round pores about 0.18 mm in diameter are formed along an intercostal area.

Septa arranged in typical micrabaciid fashion: the first two cycles of septa straight and nonbifurcate, the S3 having multiple bifurcations and meandering to calicular edge. S1 smallest of septa, entirely independent of other septa, except for synapticulae. S1 composed of 14–16 trabeculae (depending on calicular diameter), each trabeculum projecting up to 0.3 mm as a tall, transversely flattened spine, the innermost spines the largest and inclined toward the columella. At the S3–S2 delta stands one massive incurved septal spine. The S2 and all S3 also bear slender septal spines on their upper, inner margins. S3 bifurcate in a complex but consistent pattern (Figure 3). Within a half-system, an S3 splits into two equal length S3I: the S3I adjacent to the S2 bifurcates three more times, resulting in 4 septa; the S3I adjacent to the S1 bifurcates only twice, resulting in 3 septa. The bifurcations occur in a definite sequence resulting in arms of differential lengths, and a typical half-system composed of:S1, S3II, S3III, S3III, S3II, S3IV, S3IV, S3III, S2, and a corallum of 96 septa. The 96–septum stage is usually attained at a calicular diameter of 8–10 mm. Massive, elongate compound synapticulae up to 1.0 mm long and 0.3 mm wide unite all adjacent septa, often extending to the upper septal edges. Synapticulae aligned in rows corresponding to trabeculae on the outer half of each septal face, and, along with the thick base, produce a very solid corallum. Aligned, elongate septal granules (= vepreculae), similar to synapticulae in size and orientation, occur on the inner septal faces. Septa perforate on lower edges and at points of bifurcation (Plate 11b, visible only in a damaged corallum. Marginal shelf not present; however, costae project about 0.2 mm beyond the septal outer edges.

Fossa shallow, containing a prominent, solid columella, lenticular to rectangular in cross section and aligned with the two principal S1.

Stephanophyllia fungulus Alcock, 1902

Stephanophyllia fungulus Alcock, 1902b:122; 1902c:40, pl. 5: fig. 35a,b.—Yabe and Eguchi, 1932b:443; 1932g:58, 60–61, pl. 8: figs. 1–6; pl. 9: figs. 1–8; 1942b: 138.—Eguchi, 1934:368.—Uchida, 1963:17–21.—Cairns, 1989a:21–23, pl. 10: figs. c–k; pl. 11: figs. a,b [synonymy].—Cairns and Keller, 1993:231.

DESCRIPTION.—Corallum circular, with a flat base and evenly rounded convex calice having a D:H of 1.9–2.1. Largest northwestern Pacific specimen (Alb-5311) 12.9 mm in diameter. Base quite thick (up to 0.6 mm) and usually upturned at calicular edge as much as 1 mm. Costae flat, about 0.15 mm wide, and separated by narrow intercostal spaces 70–100 μm wide. Each costa bordered on both edges by a row of very small (0.02 mm in diameter) granules (Plate 16f). Costae solidly fused via rings (about 13 in figured specimen) of massive mural synapticulae termed fulturae by Gill (1979) (Plate 16c,d), altogether producing a sturdy, robust corallum. Mural fulturae closely spaced and parallel in orientation, each about 0.2 mm thick but of variable height, increasing in size from center of calice to peripheral edge (0.2 to 0.8 mm). Corallum white.

Septal arrangement quite conservative, all specimens above a calicular diameter of about 6.9 mm having 96 septa arranged in typical micrabaciid fashion as illustrated by Cairns (1989a, text-fig. 3, but having 96 septa, not 98 as I mistakenly indicated in the caption). S1–2 straight, extending from columella to calicular edge, nonbifurcate, and composed of 20–22 trabeculae, each trabeculum projecting about 0.3 mm above septal edge as a transversely flattened spine. A pair of S3 originate from each S2 very close to the columella: the S31 closest to the S1 invariably divide twice to form 3 terminal septa, the S31 closest to the S2 divide 3 times to form 4 terminal septa. Septa fairly solid, perforate only near base and at points of S3 bifurcation. All septa structurally reinforced by massive septal fulturae, which are irregular in distribution and parallel to septal trabeculae. Columella usually consists of a massive lamella, lenticular in cross section, and aligned with the 2 principal septa. Often additional papillae surround the central structure. Occasionally, especially in small specimens, the columella is formed of a massive fusion of aligned tubercles.

azooxanthellate

15-653 m