PDF (Hi-Res) - Smithsonian Institution Libraries

56
separated from its septum by a relatively wide notch. S3
slightly less exsert and usually do not bear pali, but, if present,
pali are irregular in occurrence and usually quite small. S4
equally exsert as S3, each bearing a very wide (up to 4 mm), tall
palus, together producing a prominent and distinct palar crown
of up to 24 lobes. In a half-system lacking all 4 S5, the S3
within that half-system resembles an S4 and has a correspondingly
large palus. Inner edges of paired P4 merge with inner
edges of adjacent S3 near columella. S5 rudimentary, each
connected to its adjacent S4 through a porous lamella in the P4
region, but close to basal theca. Fossa shallow, containing a
circular to elliptical columella in the form of an undercut,
horizontal platform, through which irregularly shaped papillae
penetrate.
DISCUSSION.—Only two species of Deltocyathus are known
to attain five cycles of septa in the adult state: D. magnificus
and D. rotulus. The latter is distinguished from D. magnificus,
as well as all other congeners, by its prominent P4 crown and
distinctively serrate calicular margin. Its bowl-shaped corallum
and unique columella also serve to distinguish it from D.
magnificus.
MATERIAL EXAMINED.—New Records: Alb-4957,6, CAS
16331 and 80934; Alb-4970, 3, USNM 82157; Alb-4972, 18,
CAS 80942; Alb-4973, 8, USNM 82155, 1, ORI; Alb-5079,1,
USNM 92726; Alb-5582, 8, USNM 92727.
TYPES.—The holotype of Trochocyathus rotulus is presumed
to be deposited at the Indian Museum, Calcutta. Type
Locality: North Maldive Atoll (probably Investigator station
216), 1408-1756 m.
Six syntypes of Deltocyathus fragilis are deposited at the
ZMA (Coel. 1188). Type Locality: Siboga-45: 7°24'S,
1 lS 0 ^^ (Flores Sea), 794 m.
DISTRIBUTION.—Off southeastern Japan from off Hamamatsu,
Honshu to the Bungo Strait (new record for Japanese
waters); 799-1187 m. Elsewhere: Flores and Celebes Seas;
Indian Ocean from Durban, South Africa to Sri Lanka;
510-1986 m.
Deltocyathus magnificus Moseley, 1876
PLATE 2Ad.ejJi
Deltocyathus magnificus Moseley, 1876:552-553: 1881:147-148, pi. 4: fig.
10; pi. 13: figs. 1. 2.—Alcock, 1902c:20.—Yabe and Eguchi, 1937:138, pi.
20: figs. 13a-c. 14a-e.—Eguchi, 1938, table 2; 1942b:126; 1965:286, 2
figs.—Utinomi, 1965:254.—Eguchi and Miyawaki, 1975:57.—Cairns and
Parker, 1992:27-28, pi. 7: figs, j-l; pi. 8: fig. a.
DESCRIPTION.—Corallum discoidal, with a flat to slightly
concave base that is not upturned at its edges. Largest Japanese
specimen examined (Tsuchida-102) 30.0 mm in calicular
diameter and 8.4 mm in height; however, Yabe and Eguchi
(1937) reported a specimen 33.5 mm in diameter, and a
specimen from the USNM collection from the Philippines
(Alb-5444) measures 37.5 mm in diameter. Costae thin (0.2
mm), straight, finely serrate ridges separated by rather wide,
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
flat intercostal spaces 3-4 times a costal width. All costae
project about 1.5 mm beyond calicular edge and are continuous
with their corresponding septa above. Corallum white; according
to Moseley (1881), the coenosarc is ochre-yellow in color,
somewhat red toward the margin, the polyps having white
tentacles.
Septa hexamerally arranged in 5 complete cycles (96 septa),
a juvenile 6.2 mm in calicular diameter having only 4 cycles,
but a slightly larger corallum of 8.2 mm having all 96 septa.
One large specimen (Tsuchida-102) has 2 S6, for a total of 98
septa. S1 are the only independent septa, joining the columella
through a wide (about 4.5 mm) palus. S2 equal in height to S1
but slightly less wide, due to their even wider (about 6 mm)
palus, which reaches to the columella. S3 also equal in height
but considerably less wide, each bearing a broad palus that is
connected to its adjacent P2 near the columella. S4 much lower
in height than S^_3 and only 3-4 mm wide, but bordered
internally by a broad palus that is fused to the adjacent P3
through a porous lamella. S5 least exsert septa but equally as
wide as an S4, each S5 usually bordered by a narrow P5, each
pair fused to the adjacent P4 through porous lamellae. Notch
separating P5 from S5 sometimes quite broad or poorly formed,
making the distinction of the P5 ambiguous. Fossa absent;
columella an elongate fusion of irregular papillae.
DISCUSSION.—Deltocyathus magnificus is relatively easy to
distinguish from D. rotulus, the only other congener having
five cycles of septa (see Discussion of D. rotulus). Furthermore,
in the Japanese region, D. magnificus consistently is
found at shallower depths than D. rotulus (88-393 m vs
869-1187 m).
Material Examined.—Mew Records: Alb-4903, 1, USNM
92728; Alb-5444, 1, USNM 62712; TM (KT9015, BS2), 10,
USNM 92729, 2, ORI; TM (KT9309, AM8), 2, ORI;
Tsuchida-102, 1, USNM 92730; Tsuchida-851, 2, USNM
92731. Previous Records: Syntype of D. magnificus, BM.
TYPES.—The single remaining syntype (Plate 24d,e) of D.
magnificus is deposited at the BM (uncataloged). Type
Locality: Challenger-192: 5°49'S, 132° 14^ (off Kei Islands,
Banda Sea), 236 m.
DISTRIBUTION.—Off Pacific coast of Japan from Kii Strait to
Makejima, northern Ryukyu Islands; East China Sea off
southwestern Kyushu, including Danjo Gunto; 88-422 m.
Elsewhere: Sulu Archipelago, Moluccas, off southern Australia,
and Bass Strait; 118-1500 m.
Stephanocyathus Seguenza, 1864
DIAGNOSIS.—Solitary, patellate to bowl-shaped, and free.
Costae usually well developed, some of which are sometimes
highly spinose< Paliform lobes usually present on all septa.
Columella trabecular, papillose, of fused.
TYPE SPECIES.—Stephanocyathus elegans Seguenza, 1864,
by subsequent designation (Wells, 1936).