3217
Author
Raines, Bret
Author
Huber, Markus
text
Zootaxa
2012
2012-02-29
3217
1
106
journal article
11755334
Tellimya tahaia
sp. nov.
Figures 30 A–F
Type Material.
Holotype
: LACM 3161, 1 single RV,
6.9 mm
.
Paratypes
1–2: LACM 3162, 1 single RV,
6.8 mm
and 1 single LV,
5.5 mm
Motu Iti
,
Easter Island
, dredged in
65 m
.
Type
Locality.
Dredged
at
30–50 m
in fine sand, off the western coastline near
Tahai
,
Easter Island
,
27°07’20” S
,
109°26’30” W
.
Mode
of life and host are unknown
.
Description.
An ovate, comparatively large
Tellimya
species
fragile in structure with rounded posterior margin. Shell small, below
7 mm
, ovate, narrower and shorter posteriorly, equivalve, inequilateral with umbones closer to the rounded posterior end; thin; umbones rounded, broad, orthogyrate. Prodissoconch, P1 small, but typically worn away, P2 ovate, boundary ill defined, faint commarginal lines nearly obsolete, ca. 317 µm length by 220 µm height. Nepioconch with weakly raised radial lines. Adult shell white internally and externally with irregular opaque blotches; weakly inflated, non-gaping, surface superficially smooth. Hinge simple; in both valves with a strong anterior lateral, directed ventrally. Behind this front tooth follows a deep resilial recess. Its posterior end is followed by an oblique, characteristic, tooth-like ridge. Pallial line continuous and comparatively broad; muscle scars unequal, the narrowly shaped anterior scar is significantly larger; the posterior scar is rounded-ovate. Ligament internal and subumbonal. Margins smooth, very fragile.
TABLE 7.
Selected measurements from the type material.
|
T. tahaia
sp. nov.
|
Length (mm) |
Height (mm) |
P1 (L x H) (µm) |
P2 (L x H) (µm) |
| Holotype |
6.9 |
4.8 |
worn away |
300 x 200 |
| Paratype 1 |
6.8 |
4.9 |
worn away |
300 x 220 |
| Paratype 2 |
5.5 |
3.9 |
worn away |
350 x 240 |
FIGURE 30. A–F
,
Tellimya tahaia
sp. nov.
;
A
, Exterior RV, 5.2 mm in length;
B
, Exterior LV, 5.4 mm in length, SEM;
C
, Interior LV, ca. 5.2 mm in length, SEM;
D
, Inxterior RV, 5 mm in length, SEM;
E
, Close-up of the nepioconch, LV, SEM;
F
, Closeup of the prodissoconch, LV, SEM, arrows indicating boundaries.
Comparative diagnosis.
Comparable to the new species is
T. pauciradiata
also from
EI
. Both share a very similar dentition. However, the posterodorsal margin of
T. tahaia
is evenly rounded, not bulged as in
T. pauciradiata
and in the
type
species
T. ferruginosa
. The shape of
T. tahaia
is higher and significantly shorter. Consequently, the umbones are broader and more pronounced.
Tellimya tahaia
is not known to reach the large size of
T. pauciradiata
. Whereas
T. pauciradiata
is commonly encountered,
T. tahaia
has only been rarely found.
The three
New Zealand
species are significantly distinct in shape. Moreover,
T. benthicola
and
T. reinga
have an anterior lateral which is less pronounced and they live in deeper water.
Remarks.
There is nothing similar known from the Hawaiian or
Marquesas Islands
.
Distribution.
Tellimya tahaia
is rather rare and only known from the
type
locality and Motu Iti—
E1
.
Etymology.
The name reflects the
type
locality.