“Pseudococculina gregaria n. sp.
Fig. 1, 6B, 7E-J, 12M-O; 13A; Table 11
Description. Shell up to 3.35 mm long, highly arched, rather thin, anterior end occupying 86.49-98.14% of shell length. Aperture elliptical, flat or shallowly concave from side to side. Anterior and posterior ends narrowly and similarly rounded, sides broadly rounded. Anterior slope convex, convexity increasing with increasing size, posterior and lateral slopes more or less flat.
Protoconch 167-183 µm long and 117-133 µm wide. Apical fold tapered to a small rounded point, suture apparently entire. Sculpture unknown – surface layer etched in all available specimens.
Teleoconch sculptured with strong, rather regularly spaced, concentric ridges with angulated summits. Interspaces with crowded, irregular, concentric threads and minute granules.
Animal (Fig. 6B) externally either uniform white, or white with minute grey spots on head, tentacles, gill, ventral surface of mantle, and on side of foot. Oral lappets rounded. Cephalic tentacles set with sensory papillae, dorsoventrally flattened, gradually tapered, tips rounded, left tentacle simple, right tentacle with a swollen base. Gonoduct broad, externally highly conspicuous, descending steeply to a point immediately below and behind posterior extremity of right tentacle, where it enters after a short, gentle ascent; passing through the tentacle and opening at a small, elliptical, dorsal pore that is covered by a short lobe. Two posterior epipodial tentacles. No ‘eyes’.
Radula (Fig. 1, 12M-O, 13A). Central tooth large, longer than broad, thin in section, cutting area broad and smooth. Lateral 1 large, lacking cutting area, tip pointed. Lateral 2-4 similar, small; lateral 1 with 1 or 2 cusps, laterals 3 and 4 each with 1 cusp. Lateral 5 largest, cutting area broad, with 3 or 4 strong, blunt cusps. Marginal 2 longest, outer marginals decreasing in size.
Type data. Holotype NMNZ M.75105 (length 2.45 mm, width 2.00 mm, height 1.00 mm, anterior length 2.10 mm) and 1405 paratypes (AMS, BMNH, LACM, MNHN, NMNZ (many), NZGS, NMNH): BS 925, 42°43.9’S, 176°08’E, Chatham Rise, New Zealand, 800-810 m, alive on wood, 28 Sep 1982, FV Kaltan.
Other material examined. NEW ZEALAND (195 specimens NMNZ): BS 927, 43°26.8’S, 168°54.2’E, off Jackson Bay, 132 alive on wood, 833-891 m, 15 Dec 1983, FRV James Cook stn J16/25/83; BS 930, 44°33.2’S, 173°42.3’E, off Timaru, 63 alive on wood, 750-738 m, 8 June 1984, FRV James Cook stn J10/4/84. NEW SOUTH WALES (962 specimens taken alive from wood): 33°02’S, 152°21’E, off Newcastle, 457 m, 18 Aug 1975, FRV Kapala stn K 75/05/03 (19 AMS); 33°40’S, 151°56’E, SE of Broken Bay, 714 m, 6 Dec 1977, FRV Kapala stn K 77/23/06 (22 AMS); 33°43’E, 151°51’E of Sydney, 457 m, 6 May 1977 FRV Kapala stn K 77/04/13 (25 AMS); 33°46’S, 151°50’E, off Broken Bay, 439 m, 8 June 1977, FRV Kapala stn K 77/06/07 (157 AMS); 34°17’S, 151°27’E, E of Wattamolla, 457 m, 23 May 1979, FRV Kapala stn K 79/05/07 (412 AMS, 9 NMNZ); 42 km E of Sydney, 457 m, W. F. Petterd (1 AMS); 35°33’S, 150°44’E, E of Brush I., 384 m, 30 Nov 1976, FRV Kapala stn K 76/22/07 (302 AMS, 15 NMNZ).
Known distribution. Southern New Zealand, 738-891 m; New South Wales, 384-714 m.
Remarks. P. gregaria closely resembles the North-Eastern Atlantic P. corrugata (Jeffreys, 1885) (syntypes BMNH 1885 : 11 : 5 : 4588-4589), the Indonesian P. cingulata (Schepman, 1908) (holotype ZMA), and the Japanese P. subcingulata Kuroda & Habe, 1949 (holotype NSMT Mo. 39761). It differs from P. corrugata in having more strongly rounded sides at the same stage of growth and in being more broadly elliptical (length/width ratio 1.12-1.29 cf. 1.31-1.41), from P. cingulata in being more highly arched (length/height ratio 1.87-2.93 cf. 3.37), and from P. subcingulata in being more broadly conical from end to end, in being more broadly elliptical (length/width ratio 1.12-1.29 cf. 1.44), and in having straight instead of dorsoventrally undulating concentric ridges. New Zealand specimens from BS 927 (M. 75212) and BS 930 (M. 75213) differ from all New South Wales specimens and New Zealand specimens form the type locality in having pigment spots on the head, gill, mantle and side of the foot. However, I can detect no other significant differences between pigmented and unpigmented New Zealand specimens, nor between specimens from New Zealand and New South Wales.”
Table 11 Pseudococculina gregaria. Shell measurements (mm) and proportions of New Zealand (n=14, BS 925) and New South Wales specimens (n=15, AMS C.139428).
Character
Range
Mean
SD
N.Z.
N.S.W.
N.Z.
N.S.W.
N.Z.
N.S.W.
Length
1.32-2.73
2.50-3.35
2.06
2.89
0.45
0.25
Width
1.10-2.25
2.05-2.80
1.69
2.42
0.36
0.26
Height
0.45-1.40
1.20-1.60
0.85
1.44
0.31
0.15
Length/Width
1.16-1.26
1.12-1.29
1.22
1.19
0.03
0.03
Length/height
1.93-2.93
1.87-2.55
2.53
2.01
0.35
0.13
Anterior length %
86.49-98.14
73.77-90.20
91.92
84.92
3.57
5.72
(Marshall, 1985: 522-524)
Pseudococculina gregaria is a species of small sea snail, a marine gastropod mollusk in the family Pseudococculinidae, the false limpets.[2]
This marine species is endemic to New Zealand.
Pseudococculina gregaria is a species of small sea snail, a marine gastropod mollusk in the family Pseudococculinidae, the false limpets.
