Azooxanthellate Scleractinia (Cnidaria: Anthozoa) - Western ...

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half of corallum bears a unilinear row of shallow
circular to slightly elliptical pits, each about 50 pm
in diameter. In upper half of corallum, pits
arranged in 2 staggered rows, separated by a thecal
midline (Figure 6d). 5epta hexamerally arranged in
3 complete cycles (51)52>53). 51 about 0.22 mm
exsert, having straight axial edges that extend
about half distance to columella in upper fossa but
join to the columella lower in fossa. 52 equally
exsert and about 3/4 width of the 51, each bearing
a broad, low paliform lobe the inner edge of which
fuses to the columella. 53 relatively narrow (about
0.1 mm wide), the upper edges of each pair that
flank an 52 fusing to the 52 at calicular edge
(forming small lancets) and axial edges of each 53
angled toward and fusing to its adjacent 52 via 2
or 3 trabecular processes. Fossa of moderate depth;
columella a solid central fusion of inner edges of
51 and P2.
Remarks
Conocyathus gracilis is similar to and has been
confused with C. zelandiae, but is distinguished by
having a smaller, narrower corallum (GCD max.
1.7 mm and H:D = 3.1 vs GCD max. 3.4 mm and
H:D = 1.8); having much less exsert P2 (those of C.
zelandiae extend above the calicular edge); having
only 24 costae, the C4 of C. zelandiae beginning to
form at a height of 1.9-2.7 mm; having broader
intercostal region than costae, the reverse being
true for C. zelandiae; and in having uniformly wide
Cl-2 that do not change width at the origin of the
C3.
Distribution
Western Australia: known only from continental
shelf of northwestern coast off Broome and Glomar
Shoal; 101 m. Elsewhere: Arafura Sea (off Arnhem
Land, Northern Territory); 22-291 m.
Etymology
The species name gracilis (Latin gracilis, slender)
alludes to the slender corallum of this species,
which helps to distinguish it from C. zelandiae.
Genus Alatotrochus Cairns, 1994
Alatotrochus rubescens (Moseley, 1876)
Platytrochus rubescens Moseley, 1876: 553.
Sphenotrochus rubescens - Moseley, 1881: 157-159,
pI. 6, figs 8, 8a.
Alatotrochus rubescens - Cairns, 1994: 68-69, pI. 29,
figs g-l (synonymy); 1995: 84, pI. 24, figs. a-b.­
Cairns and Zibrowius, 1997: 141-142, fig. 18 h.
New Records
Lady: stn RW96-17, 3: 2 (NTM C8069 and C8074),
S.D. Cairns
1 (U5NM 98515); stn RW96-18, 1 (NTM); stn
RW96-19,1 (NTM C8084).
Distribution
Western Australia: south of Cartier Island; 180­
350 m. Elsewhere: western Pacific from Japan to
southern Norfolk Ridge; 187-751 m (Cairns and
Zibrowius 1997).
Genus Idiotrochus Wells, 1935
Idiotrochus kikutii (Yabe and Eguchi, 1941)
Placotrochides kikutii Yabe and Eguchi, 1941: 104.
ldiotrochus kikutii - Cairns, 1989: 36-37, pI. 18, figs.
a-b, d-h (synonymy and description); 1994: 69,
pI. 30, figs. a-d.-Cairns and Zibrowius, 1997:
148-149.
New Record
Soela: stn 02/82/13A, 3, WAM 90- and 96-84.
Distribution
Western Australia: continental slope of
northwestern coast off Port Hedland; 201 m.
Elsewhere: western Pacific from Japan through
Indonesia; 97-645 m (Cairns and Zibrowius 1997).
Genus Notocyathus Tenison Woods, 1880
Notocyathus venustus (Alcock, 1902b)
Citharocyathus venustus Alcock, 1902b: 119.
Notocyathus venustus Cairns, 1989: 27-28, pI. 12, figs.
c-h (synonymy and description); 1994: 64, pI. 27,
figs. k-l.-Caims and Zibrowius, 1997: 143.
New Records
Soela: stn 01/79/unnumbered, 2, WAM 32-85.
Umataka Maru: stn 6921, 10: 7 (WAM 150-84 and
325-89), 3 (U5NM 97010); stn 6927, I, WAM 103-84.
MV Kos 2: stn K67-182, 14°12'5, 123°02'E, 194 m,
I, AM5 G15353.
Lady: stn RW96-17, I, NTM C8072.
Distribution
Western Australia: northwestern coast from
Cartier Island to off Glomar Shoal; 90-300 m.
Elsewhere: western Pacific from southern Japan
through Indonesia; 70-555 m (Cairns and
Zibrowius 1997).
Genus Tropidocyathus Milne Edwards and
Haime, 1848a
Tropidocyathus lessonii (Michelin, 1842)
Flabellum Lessonii Michelin, 1842: 119.
TropidocyatllUs lessonii - Cairns, 1989: 33-34, pI. 16,
figs. d-l (synonymy and description); 1994: 67,