3217
Author
Raines, Bret
Author
Huber, Markus
text
Zootaxa
2012
2012-02-29
3217
1
106
journal article
11755334
Nuculana
(s.l.)
anakena
sp. nov.
Figures 3 A–E
Type Material.
Holotype
: LACM 3148, 1 articulated specimen,
2.2 mm
.
Paratypes
1–3: LACM 3149, 3 single valves,
2.3–3.9 mm
.
Type
Locality.
Along
the base of cliffs in sand and rubble at
20 m
off
Punta Rosalia
, east side of
Anakena
,
Easter Island
,
27
o
04’18” S
,
109
o
19’45” W
.
Description.
A small, semi-translucent white
Nuculana
species
, with raised subcentral umbones. Shell small (up to
4 mm
in length), not very fragile, subtriangular, only slightly inflated, equivalve. Umbones raised, nearly centrally located. Prodissoconch, P1 round, smooth, boundary often weakly defined, ca. 247 µm length by 186 µm height, P2 not present. Anterior and posterior margins of adult valves subequal, with posterior margin shorter. Exterior surface smooth with commarginal growth lines, increasing in strength towards ventral margin. No posterior sulcus.
Interior
non-nacreous, lacks deep pallial sinus. Hinge line highly arched, consisting of split dentition with central resilifer; anterior with 7–9 teeth, posterior with 4–6 teeth. Color white.
TABLE 2.
Selected measurements from the type material.
|
N.
(s.l.)
anakena
sp. nov.
|
Length (mm) |
Height (mm) |
P1 (L x H) (µm) |
P2 (L x H) (µm) |
| Holotype |
2.2 |
1.6 |
250 x 200 |
– |
| Paratype 1 |
3.9 |
2.6 |
250 x 190 |
– |
| Paratype 2 |
2.5 |
1.8 |
240 x 170 |
– |
Comparative diagnosis.
A non-nacreous interior together with the shape excludes the genus
Ennucula
(=
Leionucula
auctt.). The shape, lack of a deep pallial sinus, and solid structure excludes the genera
Yoldiella
Verrill & Bush, 1897
, and
Scissileda
Kilburn, 1994
. The presence of a resilifer rules out all malletiids including
Neilonella
Dall, 1881
. The lack of a sulcus combined with a rather shallow depth rules out the genus
Ledella
Verrill & Bush, 1897
. The lack of a very thin hinge with few weak teeth and distinct shape exclude all
Sareptidae
Stoliczka, 1870
.
Remarks.
Although the shape and weak commarginal sculpture do not match typical
Jupiteria
very well, the closest species appears to be
Nuculana
(
Jupiteria
)
manawatawhia
Powell, 1937
, from
New Zealand
. More and better material is needed to determine, if a new genus is warranted.
Distribution.
Nuculana
(s.l.)
anakena
is occasionally found at several locations around
EI
, in sand or rubble, from
10–100 m
—
E1
.
Etymology.
Named after the
type
locality.