B- A 47, USNM 72265; G-135, USNM 72266;
34. Stylaster complanatus Pourtales, 1867
FIGURE 41A-I
Stylaster complanatus Pourtales, 1867:115-116; 1871:36, pi.
2: figs. 16-17; 1878:210.—Moseley, 1881:87.—
FIGURE 40.—Stylaster aurantiacus: A, B, gastrostyle of paratype from ALB, USNM 16010, X 195, X 425, respectively (A is a stereo pair).
Boschma, 1953a:360-361.—Zibrowius and Cairns, 1982:210, 211.
Stenohelia complanata:—Kent, 1870:123.—Boschma, 1957:31; 1964b:67-69; 1964d:83-84; 1967:328-329;
1968b:438.
Cryptohelia virginis Lindstrom, 1877:14-15, pi. 2: fig. 24.—
Boschma, 1951b:45.
Stylaster virginis.—Moseley, 1881:87. [Not 5. virginis.—
Hicksonand England, 1905:13-14.]
Stylaster (Stenohelia) complanatus.—Broch, 1936:81-84 [in part: fig. 28d; only 2 of 36 branch fragments].
Stenohelia virginis.—Boschma, 1953b: 171; 1957:33;
1964b:68-69; 1964d:83-84.—Zibrowius and Cairns, 1982:211.
Calyptopora complanata.—Cairns, 1983b:430, 486.
DESCRIPTION.—Colonies uniplanar, small, and delicate. Coralla often broader than tall, up to 6.3 cm tall and 6.5 cm broad, with a basal branch diameter up to 5.5 mm. Coenosteum white. Coe- nosteal strips parallel and longitudinally ar-
FIGURE 39.—Stylaster aurantiacus (A-D, G, I, holotype; E, j , ALB-2160; F, H, ALB, USNM 16010): A, holotype colony, X
1.2; B, anterior branch face, X 9; C-D, cyclosystem viewed from anterior and lateral sides, X 45, X 66, respectively; E, broken cyclosystem revealing dactylostyles, X 65, stereo pair;
F, coenosteal texture, X 145; G, papillae, X 175; H, female ampullae with efferent pores, X 26; I, apical papilla of male ampulla, X 53; j , dactylostyle, X 440, stereo pair.
ranged on terminal branches and near cyclosys- tems: however, they are arranged in a reticulate pattern on larger-diameter branches. Strips 70- 80 ftm wide, covered by irregularly shaped gran- ules about 9 fim in diameter. There is no trace of imbrication. Tall, tubular, apically perforate papillae up to 0.10 mm tall cover the coenos- teum, producing a spiny texture. Papillae partic- ularly tall and abundant on ampullae. Apical pores irregularly shaped and large, up to 35 /xm in diameter.
Cyclosystems arranged unilinearly on anterior branch faces. Only in large-diameter basal branches are cyclosystems slightly alternating, suggesting a sympodial origin. Cyclosystems ellip- tical to strongly compressed, the greater axis of the ellipse transverse to branch axis. Cyclosys- tems average about 1.0 mm in diameter; how- ever, strongly compressed cyclosystems up to 1.4 X 0.7 mm in diameter. Based on 50 cyclosystems there is a range of 10-20 dactylopores per cyclo- system; the average is 14.34 (<r = 2.24), and the mode is 14. Diastemas sometimes present.
Upper gastropore chamber very shallow and strongly flared, bordered beneath by a horizontal shelf. A cyclindrical gastrostyle chamber pene- trates center of shelf, which is often ringed by a
-2**^
i'^>
low ridge. Gastrostyle chamber cylindrical, about 0.23 mm in diameter, bearing an annular ring palisade. Gastrostyle tall, slender, and pointed;
the tip extending just above level of shelf. Illus- trated style 0.43 mm tall and 72 /im in diameter (H:W = 6). Style bears large multitipped spines up to 33 nm tall, each having 5-7 slender points.
Spines not arranged in rows or on ridges. Dac- tylopore slits about 80 um wide. Pseudosepta on outer edge of cyclosystems often quite exsert, forming an abcauline lip. Dactylostyle composed of a row of blunt, cylindrical elements, each up to 45 fim tall and 12 fim in diameter. Small lateral dactylostyles also present, measuring about 16 X 18 /im. There is often another broad, squat ele- ment up to 23 fim in diameter opposite the dactylostyle, on the inner margin of the dactylo- pore chamber.
Female ampullae large hemispheres 0.75-0.85 mm in diameter, often with a small efferent pore.
Male ampullae also superficial, about 0.45 mm in diameter, and clustered on the posterior branch faces.
Coenosteal papillae contain dense concentra- tions of large nematocysts 16-18 X 5 jttm. Gas- trozooid nematocysts 6 X 2 ^m-
DISCUSSION.—Stylaster complanatus is the third of three species of Stylaster characterized by an- terior to anterolateral cyclosystems, gastropore shelves, abcauline cyclosystem lips, and lateral dactylostyles (Table 2). It is the only species having a gastrostyle that extends beyond the gastrostyle chamber and predominantly anterior- facing cyclosystems. In this last character it is similar to Calyptopora, and I previously placed it in that genus (Cairns, 1983b). I now believe that this species belongs to Stylaster and is closely related to the two previously described species.
FIGURE 41.—Stylaster complanatus (A, ALB-2343, B - I , G- 169): A, colony, X 1.15; B, terminal branches, X 17; c, cyclosystem, X 42; D - E , coenosteal texture and tubular pa- pillae, X 86, X 200, respectively (D is a stereo pair); F-G, gastrostyle and shelf, X 82, X 450, respectively (F is a stereo pair); H, ampulla covered with papillae, X 59, stereo pair; I, dactvlostyles, x 175.
Stylaster complanatus differs from Calyptopora in that its cyclosystem lip is composed of several pseudosepta and is not consistently present, whereas the lid of Calyptopora is composed of one greatly enlarged pseudoseptum that is con- sistently present. Also, the cyclosystems of S.
complanatus are sometimes slightly alternating, whereas those of Calyptopora are always unili- nearly arranged on the anterior face. Further- more, Calyptopora does not have lateral dactylo- styles or gastropore shelves.
The type of Crypthelia virginis Lindstrom, 1877, was examined and found to have cyclosys- tems about 1.3 X 0.9 mm in diameter, not 2 mm as stated by Lindstrom. It is a junior synonym of S. complanatus.
Broch's (1936) report of 5. complanatus from off Cozumel (.AZJ3-2354) is based on 36 branch fragments. This particular station and geo- graphic area is an extremely rich one for stylas- terids, and at least three species are represented in Broch's identified material of 5. complanatus:
S. inornatus (17 branches), 5. complanatus (2 branches), and Errina sp. cf. E. altispina (1 branch); 16 fragments are too small or worn for identification. Except for figure 28rf, all of Broch's illustrations and the text pertain to S.
inornatus. Only figure 28rf is S. complanatus.
MATERIAL EXAMINED.—BL-16, MCZ and
USNM 16062; BL-68, MCZ and USNM 16063;
BL-69, MCZ; BL-76, MCZ; 51-100, MCZ; ALB- 2152, USNM 16025; ALB-2157, USNM 7195;
ALfl-2343, USNM 10245; ALB-2672, USNM 16026; G-169, USNM 72305 MCZ, and UMML;
G-386, UMML and USNM 72306; G-889, USNM 72307; Discoverer, 31°55'N, 78°25'W, 531 m, USNM 72308. Syntypes of 5. complana- tus; holotype of C. virginis; Broch's (1936) spec- imens of 5. complanatus from ALB-2354 (RM, Stockholm #42).
TYPES.—Three syntypes of 5. complanatus are at the MCZ (5516, 5517), one at the USNM (71826), and one at the YPM. The holotype of C. virginis is at the RM, Stockholm (3088).
TYPE-LOCALITY.—The syntypes of 5. complan- atus were collected off Havana, Cuba, 494 m.
MAP 20.—Distribution of Stylaster complanatus (stars) and Stenohelia profunda (circles). 5.
profunda is known also from off Surinam.
The holotype of C. virginis is from Salt Island, Virgin Islands, 366-585 m.
DISTRIBUTION.—Blake Plateau off Georgia;
Little Bahama Bank; off Yucatan Peninsula; off Virgin Islands (Map 20; pattern 4); 183-707 m.
Stenohelia Kent, 1870
DIAGNOSIS.—Cyclosystems exclusively on an- terior side. Coenosteum usually reticulate-gran-
ular but sometimes linear-imbricate. Gastropores long and usually strongly curved; gastrostyles present and usually accompanied by a robust ring palisade. Cyclosystems lacking lids and lips; pseu- dosepta concave above. Dactylostyles rudimen- tary. Ampullae superficial, often clustered around base of cyclosystem.
TYPE-SPECIES.—Allopora maderensis Johnson, 1862, by subsequent designation (Broch, 1936).