Table Of ContentJ. Vidal Vasdcardium n.sp. NOVAPEX 4 (2-3): 57-59, 10juin2003
Two new species in the species-group
of Vasticardium assimile (Bivalvia: Cardiidae)
Jacques VIDAL
Attaché au MuséumNational d'Histoire Naturelle
Unité Taxonomie - Collections - 55 rue Buffon, 75005 Paris, France.
KEYWORDS. MoUusca, Bivalvia, Cardiidae, Vasticardium, Indo-Pacific.
ABSTRACT. Two new species ofthe species-group Vasticardium assimile, probably uncommon
and of limited geographical distribution, are described: Vasticardium subassimile sp. nov. and
Vasticardium lomboke sp. nov.
INTRODUCTION Material and methods
Four species of Vasticardium from the Indo-Pacific The material, deposited in the Muséumnational
which share a sufficient number of common d' Histoire naturelle de Paris (MNHN) is limited to
characters, hâve previously been grouped into the two paired valves for V. subassimile, only one valve
species-group of Vasticardium assimile (sec Vidal for the other. The material is in good condition and
1998). Two ofthèse species, the most abundant, were show sufficient characters and variations to warrant
described in the first part of the 19"^ century: description asnew species.
Vasticardium assimile (Reeve, 1844) and In the species-group of V. assimile, the main
Vasticardium rubicundum (Reeve, 1844). A spécial characterseparatingthe species istherib morphology
form of V. assimile, endémie to the Persian Gulf, which consists of rib structure (shape of the cross
previously known as Cardium lacunosum Reeve, section ofribs and interstices) and rib omamentation
1845, is considered as a subspecies. Thèse two (characters of the omaments of the ribs and
préviens species hâve been, for a long time, known interstices: tubercles, crenulations, ridges, scales
only from the coasts ofEastAfrica and northempart etc.). Consequently, particular attention has to be
ofthe Indian Océan to Sri-Lanka, but Vasticardium devoted to this rib morphology to enable
rubicundum has been recorded as widespread in a identification.
large part of the West-Indo-Pacific, and represented
by several forms, differing from each another by SYSTEMATICS
coloration only, and designated by several names: Family CARDIIDAE Lamarck, 1809
Cardium mindanense Reeve, 1844; Vasticardium Genus Vasticardium Iredale, 1927
compunctum Kira, 1959 and Acrosterigma Type species by original désignation: Cardium
kengaluorum Voskuil & Onverwagt, 1992. More elongatum Bruguière, 1789
recently, two additional species hâve been added to
the species group: Vasticardium rhegminum Oliver& Vasticardiumsubassimilesp. nov.
Chesney, 1997 and Vasticardium thomassini Vidal, Figs 1-3, 6
1998.
Ail the species in the assimile species-group share Type material. Holotype, two paired valves,
similar macroscopic characters such as shape, MNHN, collection Société d'Océanographie. Like ail
coloration, hinge structure, rib number, and hâve the shells ofthis collection, no locality data is given,
similarity in microstructure and microcoloration of but it is assumed that this animal survives in the
the ribs (Vidal 1998: 112). The two species V. Indo-Pacific.
assimile (Reeve) and V. rubicundum (Reeve) are
présent and abundant almost everywhere within their Description, Spécimen oflarge size, probably adult,
W
large areas of distribution ; V. thomassini Vidal is H = 65.4 mm, L = 49.1 mm, = 43.0 mm. Shape
less abundant and limited to the south-eastem regularly subovoid, almost equilateral but somewhat
tropical coast ofAfrica, while V. rhegminum Oliver posteriorly truncated, with ribs slightly curved
& Chesney is known from only one small area, close backwards in projection. Appreciably elongated (L/H
to Masirah Island(Oman). = 0.75) andtumid(W/L = 0.88).
Like V. rhegminum, the two new species described Lunule: Narrow, but well marked in the right valve,
hère are probably rare and of very limited purple coloured.
distribution, each one known only from one Colours: Extemally white with irregular splashes
spécimen. light brown when young, becoming pink marginally
57
.1. N'IPAI I iisriicinHiiiii ILS]!. N()\ API \ 4 (2-3): 57-59, 10 juin 2003
whoii adull. Iiilcnialh wluio wuh iwo. iliin. colouivd Vasticardium lomhoke sp. nov.
unibonal ra\s, and a \cr\ thm pnik niargin. Figs 4-5, 8
Hiiiiic: Modoratolx aivlicd (angle bctwccn cardiiials
and ihc iwo latcials = 130^) and slighlly Type matcrial. liolotype, a right valve of médium
asymmetrical (aniciior latéral doser to cardinals tlian si/e (subadult ?), from north-west coast of Lombok
posterior). The two eardinals slightly connected in Island (Indonesia), collected on a beach in front of
right \al\e. Posterior cardinal tooth in left \alve short Gili Islands, approximatively 1 I6°03'E-08°27'N.
and low. Foundation ot" anterior latéral in left valve Stored in MNHN, Vidal collection.
(muomdbeornaatleKshupopookr-tsha=ped".steNroignmica"d)ialinshtohret wucmabkonrailb Description. Shell médium sized, H = 28.9 mm, L =
24.3mm, shape regularly subovoid, symmetrical with
ea\ity.
Rib nuniber: 3'-) in each \al\e. a very slight truncation on posteriormargin.
Rib morpholo<iy: The junenile médian part of shell Lunule: Veiy nan-ow but well marked, bearing five
beats high ribs. rounded in section, sniooth and oblique riblets unconformable with the main ribs of
without any side crenulations. On the adult médian the shell, purple coloured.
and anterior part, ribs become trapezoid and slightly Colours: Externally off-white with more or less
asymmetrical (anterior part higher), with latéral concentrically disposed light brown stains. On the
crenulations joined on the top of rib fonning coloured zones, the top ofthe ribs remains thinly and
incurxed bars; the latéral crenulations overhang the regularly white, as in ail the shells of the group.
interstices, which are slightly striated. Intemally white, umbonal cavity strongly purple
The posterior quailer of shell has low squared ribs coloured.
separated by wide interstices, which bear regularly Hinge: Almost symmetrical ; in this right valve,
cardinals cormected at base by a relatively high
disposed, slightly twisted tubercular lamellae,
bridge.
obHquely placed on top ofribs.
In the medio-posterior part, ribs become very Rib number: 35.
asymmetrical with posterior flank wider bearing long Rib morphology : On juvénile part, ribs triangular,
oblique ridges, homologous ofthe posterior lamellae, smooth on top and finely ridged both sides along the
between which other shorter tubercles or lamellae flanks, down to the interstices which are finely
become progressively and regularly intercalated striated. On adult posterior and médian parts ofshell,
(ver>' unique omamentation, Fig. 6) ribs become asymmetrical, fiât topped, with
successive zones of broadening (Fig. 8). On adult
anterior part, the symmetry of ribs progressively
Distribution. Unknown.
changes, latéral ridges become less numerous, butthe
top remains flatand smooth.
Remarks. Vasticardiiim subassimile is similar to V.
assimile in dimensions, shape andcolours, butclearly Distribution. Only one locality cited above in
differs by: shallowreefenvironment
1) Highernumberofribs (39 against 32 to 36).
2) Hinge variation with higher "intercardinal" thin Remarks. Vasticardium lomboke differs from similar
bridge in right valve. species in the group by its unique rib morphology,
3) Rib morphology in juvénile and adult parts, particularly with no variation and contrast between
particularly on posterior and medio-posterior areas. the posterior quarter and the rest of the shell (
[Comparison between Fig. 6 ( subassimile) and Fig. 7 compare Fig. 8 with Figs 6 and 7), which is
{assimile)]. exceptional inail the Vasticardium species.
Etymology. From LombokIsland, Indonesia.
Et^mology. Similarto assimile.
REFERENCE
Vidal , J. 1988. Taxonomic revision ofthe Indo-
Pacific Vasticardium assimile species-group
(Mollusca, Cardiidae). APEXU{1,): 11 1-125.
Figures 1-8
MNHN
1-3. Vasticardium subassimile sp. nov., holotype 1. Exteriorofleft valve; natural size; 2. Interiorof
right valve, natural size; 3. Exteriorofright valve, natural size.
4-5. Vasticardium lomboke sp. nov., Lomboke Id, holotype MNHN 4. Exterior, scale x 2; 5. Interior, scale x 2.
6. Holotype of Vasticardiumsubassimile sp. nov. View ofposteriorpart ofleft valve, showing spécial
omamentation ofribs, scale x 2; 7. Vasticardium assimile (Reeve, 1844) Mozambique: viewofposteriorpart of
left valve, scale x 2; 8. Holotype of Vasticardium lomboke sp. nov. View ofposteriorpart ofrightvalve
(photograph reversed), showing spécial omamentation ofribs, scale x4.5.
58
Vidal
J. Vasticardium n.sp. NOVAPEX4 (2-3): 57-59, 10juin 2003
