Dicharax draco Páll-Gergely & Hunyadi, 2017

Asami, Takahiro, 2017, Revision of the Alycaeidae of China, Laos and Vietnam (Gastropoda: Cyclophoroidea) I: The genera Dicharax and Metalycaeus, Zootaxa 4331 (1), pp. 1-124 : 52-54

Dicharax draco Páll-Gergely & Hunyadi n. sp.

FIGUrE 34A .

Type material. HOLOTypE HNHM 99705 , Ex COLL. K. OHara, OK/3 paraTypEs, OKA /1 paraTypE, PGB/1 paraTypE, 20060109A CHINa, YUNNaN, WENsHaNzHUaNG ZUmIaOzU ZIzHIzHO, GUaNGNaN XIaN, LIjI, 1611 m, 23°45.54175'N, 104°59.55567'E, LEG. K. OHara, K. OkUbO & J.U. OTaNI, 0 9 JaN 2006 .

Etymology. THE apErTUrE Of THIs NEw spECIEs rEsEmbLEs a bITING mOUTH Of a draGON ( draCO IN LaTIN). DraCO Is UsEd as a NOUN.

Diagnosis. A smaLL spECIEs wITH sOmEwHaT ELEvaTEd spIrE, sHOrT R2 aNd R3, TypICaL Dicharax - TypE rIbs ON R2, sHarp swELLING ON R3, aNd sTrONGLy CrENULaTEd pErIsTOmE.

Description. SHELL ( FIGUrE 34A ) LIGHT GrEy; sHELL OUTLINE rOUNdEd frOm dOrsaL vIEw, spIrE ELEvaTEd, EdGE Of bOdy wHOrL rOUNdEd; aLL ExamINEd spECImENs wErE sOmEwHaT wEaTHErEd, THErEfOrE THEIr OrIGINaL COLOUr COULd NOT bE ObsErvEd; prOTOCONCH CONsIsTs Of 1.75–2 wHOrLs (N = 2), LOw, raTHEr GLOssy; R1 CONsIsTs Of apprOxImaTELy 1.75 wHOrLs (N = 2), wITH LOw, rEGULar rIbs, vIsIbLE ON EdGE Of wHOrLs as wELL; rIbbING wEakEr aT bEGINNING Of R1 (HErE aLmOsT smOOTH), bUT sTrONGEr aT ENd Of R1; bOUNdary bETwEEN R1 aNd R2 CONspICUOUs bECaUsE Of dENsE R2 rIbs; R2 wITH rIbs CUrvEd TOwards apErTUrE; rIbs NEarLy rEaCH EaCH OTHEr, fOrmING aN aLmOsT smOOTH sUrfaCE; CrOss-sECTIONaL vIEw Of R2 COULd NOT bE ExamINEd, bUT prObabLy sImILar TO THOsE Of OTHEr spECIEs HavING CUrvEd rIbs; R2 aNd R3 vEry sHOrT, apprOxImaTELy 90 dEGrEEs COmbINEd; R2 aNd R3 Of abOUT THE samE LENGTH; sCULpTUrE Of R3 sImILar TO THaT Of R1, THErEfOrE bOUNdary bETwEEN R2 aNd R3 CONspICUOUs, INdICaTEd by a dEEp CONsTrICTION; mIddLE Of R3 wITH a prOmINENT, sHarp swELLING; apErTUrE ExTErNaLLy sLIGHTLy, INTErNaLLy vEry sTrONGLy CrENULaTEd by HavING fOUr TrIaNGULar swELLINGs ExTENdING bEyONd THE apErTUrE; THEsE fOUr swELLINGs dETErmINE fIvE LObEs; OUTEr LIp Of THE pErIsTOmE THIN, sHarp, ExpaNdEd aNd sLIGHTLy rEfLECTEd, EspECIaLLy IN dIrECTION Of UmbILICUs; UmbILICUs vEry NarrOw.

Measurements (in mm). D = 3.1–3.3, H = 2.5–2.7 (N = 2, TypE sErIEs).

Operculum. THE OpErCULUm Is prEsENT IN ONE wEaTHErEd spECImEN (COLL. OK). THE OUTEr sIdE Is CONCavE, NEarLy smOOTH, bUT ITs mULTIspIraL sTrUCTUrE Is jUsT vIsIbLE; THE INNEr sUrfaCE Is wITH a sIGNIfICaNTLy ELEvaTEd, pOINTEd NIppLE.

Variation in specimens. NO TraITs fOUNd TO bE varIabLE IN THE sINGLE kNOwN pOpULaTION.

Differential diagnosis. Dicharax draco n. sp. CaN bE dIsTINGUIsHEd frOm aLL CONGENErs INHabITING CHINa aNd VIETNam ON THE basIs Of THE vEry sTrONGLy CrENULaTEd pErIsTOmE, THE sHOrT R3 HavING a prOmINENT swELLING IN ITs mIddLE (CLOsE TO THE apErTUrE). SEE aLsO UNdEr D. microcostatus n. sp.

THE INdIaN Dicharax plectocheilus ( BENsON, 1859) Is sImILar TO D. draco n. sp. IN sHapE, bUT ITs R2 Has NO dIsTINCT rIbs, ONLy wITH NarrOw LIGHT aNd THICk dark TraNsvErsE sTrIpEs aLTErNaTE, fOrmING a NEarLy smOOTH arEa. MOrEOvEr, THE pErIsTOmE Is CrENULaTEd IN Dicharax plectocheilus , bUT sTraIGHT frOm LaTEraL vIEw IN D. draco n. sp.

Distribution. Dicharax draco n. sp. Is kNOwN frOm THE TypE LOCaLITy ONLy ( FIGUrE 7 ).

Remarks. WE HavE CONsIdErEd INTErprETING Dicharax draco n. sp. as aN UNUsUaL LOCaL fOrm Of THE vEry varIabLE D. fimbriatus . HOwEvEr, THE GENEraL sHELL sHapE, THE LENGTH Of THE sHELL rEGIONs aNd THE pOsITION Of THE swELLING Of R3 faLL OUTsIdE Of THE mOrpHOLOGICaL raNGE Of D. fimbriatus . MOrEOvEr, THE sINGLE kNOwN LOCaLITy Of Dicharax draco n. sp. Is sUrrOUNdEd by "NOrmaL LOOkING" D. fimbriatus pOpULaTIONs.

Figures

FIGURE 7. Distribution of narrow range or single-site endemic Dicharax species. Filled circle. Dicharax tangmaiensis (Chen & Zhang, 2001). Filled triangle, top up. Dicharax (?) alticola Páll-Gergely & Hunyadi n. sp. Filled diamond. Dicharax (?) immaculatus Páll-Gergely n. sp. Empty diamond. Dicharax microcostatus Páll-Gergely n. sp., Dicharax micropolitus Páll- Gergely & Hunyadi, n. sp. and Dicharax bison Páll-Gergely & Hunyadi n. sp. Filled triangle, top down. Dicharax robustus Páll-Gergely & Hunyadi, n. sp. Empty triangle, top down. Dicharax draco Páll-Gergely & Hunyadi n. sp. Empty square. Dicharax imitator Páll-Gergely & Hunyadi n. sp. Empty triangle, top up. Dicharax (?) moellendorffi (Kobelt & Möllendorff, 1886). Filled square. Dicharax (?) ellipticus n. sp. Cross. Dicharax (?) abdoui Páll-Gergely n. sp. Empty circle shows the position of Tchen K’eou (Chengkou), which is the type locality of Alycaeus pentagonus Heude, 1886 (synonym of Alycaeus anthostoma Möllendorff, 1885), Dicharax diminutus (Heude, 1885), Dicharax (?) fargesianus (Heude, 1885), Dicharax planorbulus (Heude, 1885), Metalycaeus muciferus (Heude, 1885), Alycaeus dolomiticus Heude, 1890 (synonym of Alycaeus rathouisianus Heude, 1882), Dicharax (?) dolichodeiros (Heude, 1890), Metalycaeus (?) elevatus (Heude, 1886), Metalycaeus (?) expansus (Heude, 1890).

FIGURE 34. Shells of single site endemic Dicharax species. A. Dicharax draco Páll-Gergely & Hunyadi n. sp. (holotype, HNHM 99705). B. Dicharax imitator Páll-Gergely & Hunyadi n. sp. (holotype, HNHM 99706). C. Dicharax microcostatus Páll-Gergely n. sp. (holotype, HNHM 99708). D. Dicharax micropolitus Páll-Gergely & Hunyadi, n. sp. (holotype, HNHM 99709). Scale represents 5 mm. All photos: B. Páll-Gergely.