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"Fungiacyathus marenzelleri (Vaughan, 1906) [Re-description by Cairns, 1982]
Bathyactis symmetrica; Moseley, 1881, pp. 186-190 (part: Challenger sta. 133, 147, 157, 299, 325, 332), pi. 11, figs. 1-5, 7.—von Marenzeller, 1904b, p. 76.—Gravier, 1920, p. 97 (part).—? Eguchi, 1965, pp. 5-7, pi. 1, figs. 4a-4c.
Fungia symmetrica; Duncan, 1873, p. 334, pi. 49, figs. 16-19.
Bathyactis marenzelleri Vaughan, 1906b, p. 66, pi. 4, figs. 1, la, 1b.
Fungiacyathus symmetricus; Wells, 1958, pp. 267, pi. 2, figs. 1, 2.—Squires, 1962b, p. 13; 1969, p. 17, pi. 6, map 2.
Fungiacyathus marenzelleri; pi. 7, figs. A-K.— Cairns, 1979, pp. 35-37, pi. 2, figs. 8, 9, pi. 3, figs. 3, 8. Zibrowius, 1980, pp. 24, 25, pi. 6, figs. A-M.
Description. Base of corallum flat, center of base slightly raised. Largest specimen known measuring 40 mm across base; largest Antarctic specimen 38.5 mm in diameter. Forty-eight thin, ridged costae radiating from center of base, be coming more raised and sinuous toward calicular edge. Costae sometimes projecting as much as 1.5 mm from base at calicular edge. Base extremely thin and fragile, sometimes perforate, especially toward calicular edge. Five to seven synapticular plates occurring in every interseptal space, becoming increasingly larger and more oblique toward edge of corallum. Septa hexamerally arranged in four cycles. S1 largest septa and only ones reaching columella without fusion to other septa. Septa of remaining cycles progressively smaller. Each S2 reaching columella, there joined by pair of S3,all loosely fused or covered over by triangular canopy composed of thin calcareous plate. Pairs of S4 fused to
S3 by similar but larger and higher canopies, these extending from S2-S3 canopies to halfway to calicular edge. These canopies often perforate. Septa laterally carinate, S1 possessing about 7-10 carinae, or about 1 every 1.9 mm. Carinae about 0.4 mm high- and usually symmetrical on both sides of septum. Near columella, carinae more closely spaced and corresponding to high septal spines. Carinae vertical near columella, oblique midway between columella and calicular edge and almost horizontal near calicular edge. Most carinae extending from septal edge to base; some shorter, extending only halfway to base; some branching from other carinae. Near base most carinae curving toward columella, often degenerating
into rows of granules. If still solid, carinae may be confused with synapticulae but can usually be distinguished by their more oblique orientation, often intersecting synapticulae at an acute angle. Septa bearing elongate, slender spines near columella but becoming less serrate and usually lobate in profile toward calicular edge. Height of exsert lobes up to 10 mm above base. All septa but S4 bearing lobes, these lobes damaged in most specimens. Septa extraordinarily fragile and specimens rarely collected fully intact. Septal edges straight to irregularly sinuous. Columella variable in size, composed of loose fusion of inner
septal spines and additional trabeculae.
Discussion. F. marenzelleri was frequently reported as Bathyactis or F. symmetricus by earlier authors, probably because of Moseley's (1881) assumption that all small specimens were simply juveniles of a species with a larger adult corallum. F. symmetricus has subsequently been shown to be endemic to the western Atlantic (183-1644 m) and to be rarely larger than 14 mm in CD [Cairns, 1979 J • ][. marenzelleri is distinguished from F. symmetricus by its much larger corallum, broader distribution, and greater depth range. F. symmetricus also has higher septal spines and a more solid, well-defined base. Specimens from four localities (Eltanin stations 138, 426, 993, and 1545) differ from typical F. marenzelleri by having a much more crowded arrangement of septal carinae (about 20 per septum, or 1 every 0.8 mm) and more spinose septal faces. These specimens, all from the South Shetland Islands and east of South Orkney Islands, may represent a new species, but until the variation of F. marenzelleri is better understood, they are
assigned to this species. Eguchi's  B. symmetrica also seems to belong to this form. When the deeper records of Fungiacyathus spp. are reexamined (e.g., Moseley, 1881; Gardiner and Waugh, 1939; Keller, 1976), more synonyms for F. marenzelleri may result, and its geographic range may thus be increased. All records deeper than 1800 m should be reevaluated for this possibility. This species may eventually be found to be the most widespread and deepest-living species of scleractinian coral.
Material. Eltanin sta. 13 (5), USNM 47470; sta. 18 (23), USNM 47466; sta. 20-134 (5), USNM 47476;
sta. 138 (3), USNM 47475; sta. 353 (1), USNM 47471; sta. 426 (8), USNM 45673; sta. 993 (1), USNM 47473; sta. 997 (6), USNM 47474; sta. 1148 (1), USNM 47469; sta. 1545 (3), USNM 47477; sta. 1957 (1), USNM 47666. Hero sta. 721-1081 (4), USNM 47468. Glacier sta. 11 (6), USNM 47465. Albatross sta.
4397 (1), USNM 47467. Specimen identified as F. symmetricus by Wells , South Australian Museum H 70; specimens listed by Cairns , USNM. Types of B. marenzelleri.
Types. The holotype of F. marenzelleri is de posited at the United States National Museum (47415); three paratypes are at the Museum of Comparative Zoology. Type-locality: 8°07.5'S, 104°10.5fW (off Peru); 3820 m.
Distribution. Widely distributed throughout Atlantic Ocean as far north as Greenland; eastern
Pacific; circum-Subantarctic (including off lies Crozet); off South Shetland Islands; east of South Orkney Islands; Weddell Sea; ? off Prince Harald Coast and Enderby Land, Antarctica (Map 1). Depth range: 300-5870 m. There is a direct relationship between depth of occurrence and proximity to the Antarctic, the more southerly records being shallower. The shallowest records of this species (300-500 m) are represented by the four continental Antarctic records; the four records from the South Shetland Islands range from 300 to 1435 m. No other record is shallower than 1805 m." Cairns 1982, pp. 5-7, Plate 1, figs. 1, 2, 8