J. 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