Sampling the depth: New data on the Caecidae (Mollusca, Gastropoda) from northeastern Papua New Guinea
Author
Walter, Angelo Vannozzi
Via M. L. Longo 8, 00151 Rome (Italy)
ang.vannozzi@gmail.com
Author
Renda, Walter
Via Bologna 18 / A, 87032 Amantea (CS) (Italy)
w.renda1@tin.it
text
Zoosystema
2024
2024-06-07
46
14
327
347
journal article
299020
10.5252/zoosystema2024v46a14
b5619e29-fcbd-4ddc-9231-138300251568
1638-9387
12548683
23D972D0-F573-429C-816B-F42AFF02D0B1
Caecum dakuwaqa
Pizzini, Raines & Vannozzi, 2013
(
Fig. 6
A-E)
Caecum dakuwaqa
Pizzini
et al.
2013: 19
, fig. 10K-O.
TYPE
MATERIAL
. —
Holotype
.
Fiji
• sh;
SE
of
Viti Levu
;
18°18.5’S
,
178°05.8’E
;
MNHN-IM-2000-24843
.
Paratypes
.
Fiji
•
8
sh; same data for holotype;
MNHN-IM-2000-24844
•
2
sh;
Bligh Water
,
MUSORSTOM
10 Stn DW1314;
17°16’9”N
,
178°14’51”E
;
656-670 m
depth;
5.VIII.1988
;
MNHN-IM-2000-24847
•
8
sh;
Bligh Water
,
MUSORSTOM
10 Stn DW1333;
16°50’21”N
,
178°12’33”E
;
200-215 m
depth;
8.VIII.1988
;
MNHN-IM-2000-24848
•
2
sh;
Bligh Water
,
MUSORSTOM
10 Stn DW1334;
16°51’22”N
,
178°13’56”E
;
251-257 m
depth;
9.VIII.1988
;
MNHN-IM-2000-24849
•
3
sh;
S
Viti Levu
,
MUSORSTOM
10 Stn DW1365;
18°12’43”N
,
178°32’22”E
;
295- 302 m
depth
;
15.VIII.1988
;
MNHN-IM-2000-24850
•
1
sh;
S
Viti Levu
,
MUSORSTOM
10 Stn DW1376;
18°18’40”N
,
178°9’4”E
;
497-504 m
depth
;
17.VIII.1988
;
MNHN-IM-2000-24851
•
2
sh;
S
Viti Levu
,
MUSORSTOM
10 Stn DW1381;
18°17’46”N
,
177°54’25”E
;
275-430 m
depth
;
18.VIII.1988
;
MNHN-IM-2000-24852
•
2
sh;
SE
Viti Levu
,
MUSORSTOM
10 Stn CP1354;
17°42’36”N
,
178°54’58”E
;
959-963 m
depth
;
12.VIII.1988
;
MNHN-IM-2000-24853
•
4
sh;
S
Viti Levu
,
MUSORSTOM
10 Stn CP1363;
18°12’23”N
,
178°33’0”E
;
144-150 m
depth
;
15.VIII.1988
;
MNHN-IM-2000-24854
•
9
sh;
S
Viti Levu
,
MUSORSTOM
10 Stn CP1366;
18°12’21”N
,
178°33’3”E
;
149- 168 m
depth
;
15.VIII.1988
;
MNHN-IM-2000-24855
•
14
sh;
S
Viti Levu
,
MUSORSTOM
10 Stn CP1369;
18°11’7”N
,
178°23’26”E
;
392-433 m
depth
;
16.VIII.1988
;
MNHN-IM-2000-24856
.
Vanuatu
•
1
sh;
S-SE
Santo
,
MUSORSTOM
8 Stn DW1072;
15°39’53”N
,
167°19’36”E
;
622-625 m
depth
;
4.X.1994
;
MNHN-IM-2000-24845
•
15
sh;
E
Santo
,
MUSORSTOM
8 Stn DW1105;
15°2’35”N
,
167°7’29”E
;
154-179 m
depth
;
7.X.1994
;
MNHN-IM-2000-24846
.
TYPE
LOCALITY
. — Pacific Ocean,
Fiji
, southeast of
Viti
Levu,
18°18.5’S
,
178°05.8’E
,
260-305 m
depth.
MATERIAL
EXAMINED
. —
Papua New Guinea
•
1
sh;
New Ireland
;
2°44’S
,
150°35’E
;
240-305 m
depth
;
3.IX.2014
;
KAVIENG
2014 Stn DW4463;
MNHN
•
2
sh (
1
juv);
New Ireland
;
2°45’S
,
150°37’E
;
163- 358 m
depth
;
3.IX.2014
;
KAVIENG
2014 Stn DW4470;
MNHN
.
DISTRIBUTION
. — Northeastern
PNG
(new record),
Vanuatu
,
Fiji
(
Pizzini
et al.
2013
;
Vannozzi 2019b
).
FIG
. 5. —
Caecum miliarium
n. sp.
:
A -D
, holotype MNHN-IM-2000-38946;
E -I
, paratypes MNHN-IM-2000-38947;
E
, growth stage;
F
, specimen with partially worn temporary septum;
H -I
, postlarval specimen, different views. Scale bar: 1 mm, details not to scale.
DIAGNOSIS
. — Shell small for the genus, colourless, transparent, with several brownish annular bands separated by three-four times as-wide interspaces. Protoconch unknown. Teleoconch tubular, slightly arched, dextrally twisted, with very fine rings. Early teleoconch conical. Adult shell slender, subcylindrical, flaring toward the aperture, then contracting and ending with a reflected lip. Septum almost flat without mucro, recessed below the cutting plane. Operculum and soft parts unknown. Adult shell length
1.8 mm
.
REMARKS
This species is distinctive due to the subcylindrical twisted tube with bell-shaped aperture. The specimens recorded from
PNG
are very fresh and allowed to recognise the presence of a colour pattern in this species, never reported so far. In fact, this species is characterised by a colourless transparent shell with narrow brown annular bands separated by three or four times as-wide interspaces. Further knowledge on this species came from a juvenile specimen (
Fig. 6C, D
), showing a more twisted and more tapering tube. This species occurs in several IWP localities but was recorded always below
100 m
depth, suggesting that its habitat occurs in the mesophotic-aphotic zone.