3217
Author
Raines, Bret
Author
Huber, Markus
text
Zootaxa
2012
2012-02-29
3217
1
106
journal article
11755334
Divarilima
aff.
sydneyensis
(
Hedley, 1904
)
Figures 23 D–F
Lima sydneyensis
Hedley, 1904
: p. 200
.
Divarilima sydneyensis
(
Hedley, 1904
)
—
Brook & Marshall, 1998
: p. 212
;
Spencer
et al.
, 2011
: p. 1
.
Material examined.
More than fifty single valves up to
4.5 mm
(BK).
Diagnosis.
Shell small, thin, translucent, semicircular, strongly convex. Umbones well elevated and located anteriorly. The lunule is deeply excavated. Dorsal margin straight and relatively short. Anterior margin relatively short and concave along the dorsal area. Exterior of valves completely covered with delicate punctations which are arranged in such a way to form numerous divaricate or zigzag rows.
Interior
smooth with pallial sinus running from muscle to muscle. Hinge plate very wide and triangular. Color translucent white.
Remarks.
Of the six
Divarilima
species
described from the Indo-Pacific, only
D. sydneyensis
approaches the
EI
species.
Divarilima abscisa
(
Barnard, 1964
)
, from
South Africa
was excluded based on morphology and biogeography. Equally excluded was
D. elegans
Hayami & Kase, 1993
, from Okinawa, which is understood to be distinct from
D. abscisa
. The Japanese
Divarilima iwaotakii
(
Habe, 1961
)
, does not match in either biogeography or morphology.
Nothing similar has been recorded from the Hawaiian Islands, and the deeper water fauna of the Marquesas Islands is barely known. Of the described species, the
type
species
D. sydneyensis
from
Australia
appears to be closest to the
EI
species. On the other hand,
Spencer
et al
. (2009: 198)
recorded five
Divarilima
from
New Zealand
, of which, four are unnamed. Moreover,
D. sydneyensis
may be restricted to the
Australia
region. This complex group needs much more work and more material. At present it can neither be excluded that the
EI
species is conspecific with a western species, nor that it represents a valid and endemic
Divarilima
species.
Habitat.
Commonly found at many locations around
EI
, in sand and rubble, from
100–200 m
.
Distribution.
Unknown at present. The conspecifity with other western species cannot be excluded. However,
D. sydneyensis
is reliably known from eastern
Australia
and
Norfolk Island
only. The records from
New Zealand
or Kermadec Islands may refer to undescribed species—
E5
.