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coronatus (Pourtalès, 1867)
Platytrochus coronatus Pourtalès, 1867: 114.
Trochocyathus ? coronatus: Pourtalès, 1871: 14-15, p1. 6, fig. 16.-Moseley, 1876: 550‑
551.-Pourtales, 1880: 96, 106.
Odontocyathus coronatus: Moseley, 1881: 148‑151, pl. 2, figs. 4ab, 5ab, text-fig. Stephanocyathus (Odontocyathus) coronatus: Gardiner & Waugh, 1938: 191.-Zibrowius, 1976: 165.
Stephanocyathus (Odontocyathus) sp. Keller, 1975: 179.
Material Examined.-Types: MCZ 2769, holotype, 30°41'N, 77°03'W, 841 m.-Other Material: Blake Plateau: G-182 (6), 27°55'N, 78°40'W, 860-897 m; 6-187 (1), 27°14'N, 77°47'W, 715-796 m: 6-403 (3), 27°49'N. 78°50'W, 824 m; 6-674 (1), 27°52'N, 78°32'W, 911 m.—Straits of Florida: G-93 (2), 25°03'N, 79°45'W, 733 m; G-131 (1), 24'11'N, 80°57'W, 733-787 m; G-143 (1), 24° 28'N, 80°12'W, 805 m; G-375 (I), 23°54'N, 81° 27'W, 1153-1190 m; G-448 (1), 23"54'N, 82°21'W, 620-647 m; 6-872 (I), 24°21'N, 80°10'W, 841-847 m; 6-1111 (1), 23°52'N, 80'42'W, 1080-1089 m; ATL-2990B (3), ATL-2991 (16), ATL-2992A (3), ATL-2994 (2), ATL-2995 (3), ATL-3454 (1), ATL-3457 (3), ATL-3470 (1).—Antilles: P-741 (1), 11°48'N, 66°07'W, 1052-1067 m; P-754 (1), 11°37'N, 68°42'W, 684-1574 m; P-830 (3), 18° 40'N, 65°58'W, 1446-1510 m; P-846 (1), 11°38'N, 60°37'W, 659-1126 m; P-892 (4), 14°17'N, 61° 45'W, 1116-1354 m; P-954 (1), 16°55'N. 62°43'W, 686-1043 m; P-1187 (10), 18°17'N, 75°07'W, 1034 m; P-1262 (4), 17°21'N, 77°35'W, 805-1089 m; GILLISS-31 (4), 16°58'N, 79°28'W, 1088-1116 m; BL-141 (1), BL-175 (2), BL-185 (1), BL-XI (1), ATL-3366 (11), ATL-3367 (2), ATL-3369 (4), CHALLENGER-24 (5).—Off British Honduras: P607 (2), 18°30'N, 87°37'W, 715-787 m.
Description.-The corallum has a nearly horizontal base, which, at its center, bears a small raised scar of attachment in the form of a pedicel. At a basal diameter between 12-18 mm the wall rises vertically, forming an angle of 60-80" with the plane of the base. The largest corallum examined measures 34.5 mm in calicular diameter, 25.0 mm in basal diameter and is 35.0 mm in height. On the base, the C1 and C2 bear three to four spines, which are progressively larger toward the edge. At the edge of the base each of the twelve costae bears a massive, elongate tubercle, sometimes very irregular in shape, measuring up to 9 mm in length. These 12 tubercles project outward, forming an expanded base of support. The theca is usually smooth, without evidence of costae or granulation. However, one worn specimen revealed flat, unequal costae (C1 and C3 wider than C3-5) , covered by a fine granulation and separated by shallow, narrow intercostal striae.
Septa are arranged in six systems and five cycles, but the last cycle is never complete; 72 septa seem to be the maximum number. S1 and S2 are the largest septa, equal in size and highly exsert. The higher cycle septa are progressively smaller and much less exsert. The inner edges of all septa are straight and entire. The septal faces are covered by numerous, small, low granules arranged in poorly defined rows perpendicular to the septal edge.
Each septum, except the S5, has a distinct paliform lobe, which is separated from it by a deep but broad notch. P1 and P2, which are equal in size, are the smallest and lowest lobes closest to the columella. They are extremely variable in shape, often tall and rounded, standing well above the columella and encircling it, but sometimes elongate and pointed, overhanging the columella. In the extreme case, they can be quite long, slender and pointed, indistinguishable from the columellar elements. Finally, especially in small coralla, the upper edges of the P1 and P2 can be horizontal, merging directly with the columella, all at the same level. P3 are two to three times larger, terminating higher in the fossa, and are recessed from the columella. They are connected to the columella by a smaller, much lower lobe, which terminates at the level of the columella. When two flank an S5 the S4 bears a paliform lobe of equal size and height to that of the P3, but slightly more recessed from the columella. The P4 do not reach the columella; instead, their inner edges are loosely joined to the inner edges of the P3. When an S4 is not flanked by two S5 it remains quite small, rudimentary toward the base, and bears only a slight, sometimes dentate, elevation of the septa about halfway to the base.
The columella is small, elongate and quite variable from one specimen to another. It is often composed of several poorly individualized, stout rods, which are strongly fused basally, surrounded by the P1 and P2 and the inner lobes of the P3. Sometimes it occurs as a low, level, spongy mass or, at the other extreme, as long, slender, contorted rods.
Discussion.-S. coronatus is very distinctive; the only species that resembles it is the eastern Atlantic S. nobilis, which is very similar in shape and septal arrangement but lacks the prominent costal spines and paliform lobes. There are at least two other Recent species belonging to the subgenus Odontocyathus, both of which are confined to the Indo-west Pacific: S. (O.) spiniger Marenzellcr, 1888, and S. (O.) ixine Squires, 1958.
Type-Locality.—30°41'N, 77°03'W (Blake Plateau, off northern Florida), 841 m.
Geographic Distribution.—Off Florida (to 30°41'N, 77°03'W); Straits of Florida; Antilles; off British Honduras.
Bathymetric Range.—608-1170 m.”