Brown Stony Coral

Paracyathus stearnsii Verrill, 1869

Paracyathus stearnsii Verrill, 1869:393–394; 1870a:537–538; 1870b:560.—Durham, 1947:35, pl. 2: figs. 1, 2, 5, 6; 1949:153–156, 161, pl. 4: fig. 12; pl. 5: fig. I, text-figs. 8–1, 9, 17-9.—Durham and Barnard, 1952:92–93, pl. 13: fig. 55a-e.—?Hertlein and Grant, 1960:80–81, pl. 19: figs. 8–13.—Lewbel et al., 1981:165.—Fadlallah and Pearse, 1982b:233–238, 6 figs.—Fadlallah, 1983a:132.—Bythell, 1986:17, pl. 3: fig. C; pl. 9: figs. A-F.—Kozloff, 1987:72.—Cairns et al., 1991:47.—Chadwick, 1991:42–47.

Paracyathus caltha Verrill, 1869:394; 1870a:537, pl. 9: figs. 9, 9a; 1870b: 560.—Whiteaves, 1886:115.—Hickson, 1917:24.—Durham, 1947:34.—Austin, 1985:81.

Paracyathus tiburonensis Durham, 1947:35–36, pl. 3: figs. 5, 6 [new synonym]; 1949:156.—Durham and Barnard, 1952:94, pl. 13: fig. 56.—Squires, 1959:423.

Paracyathus stearnsi.—Austin, 1985:81.—Kozloff, 1987:72.

Paracyathus calthus.—Cairns et al., 1991:47.

DESCRIPTION.—Corallum trochoid, firmly attached through a robust pedicel 40%-65% that of GCD, and firmly anchored to gastropod or bivalve shells or small pebbles by a thin expansive base up to twice calicular diameter in size. Young coralla (Plate 7a–c) demonstrate a polycyclic basal development, older coralla having up to 6 concentric basal thecal rings (Durham, 1949). Largest corallum examined (USNM 92603) 26.5 × 17.6 mm in calicular diameter and 18.3 mm in height. Calice elliptical; smaller coralla occasionally circular. Costae equal in width, low, and rounded, separated by relatively narrow and shallow intercostal striae about one-quarter width of costae. Costae covered with low, rounded granules, 2–3 occurring across the width of a costa. In some coralla, costae are slightly ridged near the calice, in which case the granules are less apparent and the intercostal striae are wider. Upper quarter to third of well-preserved coralla, including all calicular elements, pigmented a light to dark brown.

Septa hexamerally arranged in 5 cycles accordingly: S1–2>S3>S4>S5. A full fourth cycle is obtained at a GCD as small as 3.5 mm; the fifth cycle is usually complete at a GCD of 12–14 mm; and additional pairs of S6 occur in larger coralla, up to 146 septa in the largest specimen examined (USNM 92603). All septa exsert, but only moderately so, their inner edges straight and vertical (not sinuous). S1–2 easily distinguished from others by their much larger size, each bordered internally by an undivided, rounded paliform lobe that sits low in the fossa directly adjacent to the columella. P3 located higher in fossa, slightly recessed from columella, and often dissected into 2 or 3 lobes, the lowermost indistinguishable from columellar elements. P4 located highest in fossa, most recessed from columella, and also frequently dissected into several lobes. If not fragmented, P4 are the broadest paliform lobes, and, each pair, together with the enclosed P3, form a chevron in each half-system. Septal faces bear prominent, pointed granules; palar faces often bear short carinae and/or granules. Paliform lobes thick as septa.

Fossa of variable depth but usually deep, containing multiple paliform crowns and a large, elliptical columella. Columella composed of a field of 2–40 small cylindrical, irregularly-shaped pillars, all pillars terminating at the same height several mm below the P1–2.

azooxanthellate

20-134 m