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52
Paracyathus pruinosus Alcock, 1902
PLATES 22/,;, 42a
Paracyathus pruinosus Alcock, 1902c: 18, 19, pi. 3: figs. 17, 17a.—Van der
Hoist, 1931:9, pi. 1: figs. 9,11; pi. 2: fig. 6.—Yabe and Eguchi. 1942b: 126.
pi. 11: fig. 1.—Eguchi, 1965:287, fig.—NotZou, 1988:76, pi. 5: figs. 10, 11.
REDESCRIPTION OF FIGURED SYNTYPE (ZMA Coel. 1307).—
Corallum robust and dense, 20.1 x 15.6 mm in calicular
diameter, and 21.9 mm in height, with a pedicel diameter of
11.8 mm (PD:GCD = 0.59). Theca worn and encrusted, but
near calice costae are flat and equal in width (about 1 mm),
covered with very small granules 5-6 across the width of a
costa. Intercostal striae thin and shallow. Corallum light brown.
Septa arranged in 13 half-systems accordingly: 13:13:26:4 (56
septa). The other, slightly larger (GCD = 20.6 mm) syntype
(ZMA 1089) has 82 septa, but its symmetry is obscured by the
polyp. Eleven of the half-systems are composed of two thick
bordering primary septa, a secondary septum, and a pair of
tertiary septa, whereas 2 of the half-systems also have a pair of
quateraries. Primary septa only slightly exsert (about 1.8 mm)
and have straight, entire inner edges, each bordered by a thick
palus 1-2 mm wide that is adjacent to the columella.
Secondary and tertiary septa only slightly less exsert than
primary septa (about 1.6 mm), the secondaries about 80%
width of a primary and also bordered by a palar crown, each P2
standing taller in the fossa and frequently divided into 2-4
subelements. Tertiary septa of about the same width as
secondaries but much less thick. All septa closely spaced and
covered with prominent ridge-like granules, the orientation of
the ridges parallel to the septal edges. Palar faces also
prominently ridged. Fossa shallow, containing a large elliptical
and slightly convex papillose columella composed of about 25
elements.
DISCUSSION.—The two Japanese specimens examined (Soyo
Maru-235) are 18.0 and 14.8 mm in GCD and appear to be
conspecific. Although the septal symmetry is difficult to
distinguish, both specimens seem to have hexamerally arranged
septa in five cycles, the last incomplete. The larger
specimen contains 66 septa: 6 half-systems having no S5, 3
half-systems having 1 pair of S5, and 3 half-systems having 2
pairs of S5. The smaller specimen has 70 septa: 4 half-systems
without S5, 5 with 1 pair of S5, and 3 with 2 pair of S5. The
half-systems that lack pairs of S5 are invariably those on the
lateral faces of the calicular ellipse; those having 2 pairs
invariably in the end half-systems. The most similar species to
P. pruinosus in the North Pacific is Trochocyathus caryophylloides,
both species having a similar corallum shape, size,
columella, and palar configuration. Paracyathus pruinosus is
distinguished by having divided paliform lobes (P3); little
exsert, very thick septa; highly granular septal and palar faces;
and a shallower fossa.
MATERIAL EXAMINED.—New Records: None. Previous
Records: Soyo Maru-235, 2, TIUS 53681 (Yabe and Eguchi,
1942b) (Plate 42a); syntypes of P. pruinosus.
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
TYPES.—Two syntypes (Plate 22/J) of P. pruinosus are
deposited at the ZMA (Coel. 1307, 1089). Type Locality:
Siboga-96: Southeast of Pearl Bank, Sulu Archipelago;
?15 m.
DISTRIBUTION.—Japan: Off Hochijo Jima (off Sagami Bay);
176-198 m. Elsewhere: Sulu Archipelago; Saya de Malha,
Indian Ocean; [15]-150 m.
Trochocyathus Milne Edwards and Haime, 1848a
DIAGNOSIS.—Corallum solitary, turbinate to ceratoid, fixed
or free. Septotheca costate, sometimes covered with a thin
epitheca. Pali before all but last cycle in two crowns; columella
papillose.
TYPE SPECIES.—Turbinolia mitrata Goldfuss, 1827, by
subsequent designation (Milne Edwards and Haime,
1850a:xiv).
Trochocyathus caryophylloides Alcock, 1902
PLATE 23a-c,h
Trochocyathus caryophylloides Alcock, 1902a:94; 1902c:14-15,pl. 2: figs. 10,
10a.—Yabe and Eguchi, 1942b: 123-124, pi. 10: fig. 21.—Not Zou.
1988:76, pi. 5: fig. 5, 5a.
DESCRIPTION OF SPECIMEN FROM Alb-4891.—Corallum
trochoid: 15.6 x 13.9 mm in calicular diameter, 15.2 mm in
height, and 6.8 mm in pedicel diameter (PD.GCD = 0.44).
Costae broad (0.6-0.7 mm), flat, and equal in width, covered
with small (0.10 mm in diameter) granules up to 4 across a
costal width near the calice; intercostal striae quite thin (0.05
mm) and shallow. Corallum white.
Septa arranged in 15 sectors accordingly: 15:15:30:2 (62
septa). Primary septa only slightly exsert (about 1.7 mm) and
extend about two-thirds distance to columella, where each is
bordered by a small (0.7 mm width), low palus, together
forming a palar crown tightly encircling the columella.
Secondary septa only slightly less exsert (about 1.5 mm), half
width of primaries, and have sinuous inner edges. Each
secondary septum bordered by a broad (about 1.8 mm wide),
sinuous, highly granular palus, together forming a second palar
crown that is much more prominent than the first. Tertiary septa
only slightly less exsert and less wide than secondaries. In one
(developing?) sector, a pair of quaternaries encloses the tertiary
septum, the latter bearing a palus, thus resulting in 31 pali in the
corallum. Fossa of moderate depth, containing an columella
composed of an elliptical field of 15 discrete, papillose
elements.
DISCUSSION.—The Albatross specimen differs from the
syntypes (GCD up to 21 mm) in having a smaller corallum, two
less septa and one less palus, and a wider pedicel. The lesser
number of septa and pali are probably due to the smaller size of
the Albatross specimen, one of its sectors apparently being in
the process of enlarging. Alcock (1902c) illustrated only one of
the six syntypes, one having a very narrow pedicel (PD:GCD =