Dicharax imitator 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 : 64-65

Dicharax imitator Páll-Gergely & Hunyadi n. sp.

FIGUrEs 34B , 38E–F , 42A–B .

Type material. HOLOTypE HNHM 99706 , HA/4 paraTypEs, 2013/4 CHINa, GUaNGxI, BOsE SHI, LEyE XIaN, MOLI CUN, CLIffs S Of THE vILLaGE ON THE LEfT sIdE Of THE BULIU RIvEr, 540 m, 24°39.436'N, 106°43.245'E, LEG. A. HUNyadI & M. SzEkErEs, 0 8 SEp 2013 .

Etymology. THE NamE ImITaTOr (NOUN) rEfErs TO THE sHELL sHapE, wHICH Is vEry sImILar TO THOsE Of THE GENUs Dioryx .

Diagnosis. A smaLL spECIEs wITH CONspICUOUsLy ELEvaTEd spIrE rEsULTING IN a CONICaL sHELL sHapE (sHELL HEIGHT rOUGHLy maTCHEs sHELL wIdTH), TypICaL Dicharax - TypE rIbs ON R2, sHOrT R3 wITH CENTraL swELLING, TrIaNGULar apErTUrE, pErIsTOmE NOT CrENULaTEd.

Description. SHELL ( FIGUrE 34B ) LIGHT brOwNIsH Or LIGHT GrEy, GLObOsE-CONICaL, TaLLEr THaN wIdE, Or sHELL HEIGHT EqUaL TO sHELL wIdTH; sHELL OUTLINE rOUNdEd frOm dOrsaL vIEw; bOdy wHOrL rOUNdEd; prOTOCONCHs Of aLL THrEE sHELLs wErE wEaTHErEd ( FIGUrEs 42A–B ), THUs bOUNdary bETwEEN prOTOCONCH aNd TELEOCONCH was NOT dETECTEd; prOTOCONCH wITHOUT aNy rECOGNIsabLE sCULpTUrE; wHOLE sHELLs CONsIsTs Of 4.5–4.75 wHOrLs; R1 smOOTH, GLOssy, wITH sHarp, wIdELy-spaCEd, rEGULar rIbs NEar sUTUrE aNd INsIdE UmbILICUs; bOUNdary bETwEEN R1 aNd R2 vEry CLEarLy vIsIbLE dUE TO sUddEN CHaNGE Of sCULpTUrE; R2 aNd R3 Is apprOx. 160 dEGrEEs TOGETHEr, R2 LONGEr THaN R3; R2 fINELy, dENsELy rIbbEd ( FIGUrEs 38E–F ), rIbs wITH fLaT baCks, wHICH arE CUrvEd TOwards apErTUrE aT ENd Of R2, bUT IN CUrvEd IN pOsTErIOr dIrECTION aT bEGINNING Of R2; EvEN wITH HavING CUrvEd baCks, THE spaCE bETwEEN THE rIbs NEarLy as wIdE as rIbs THEmsELvEs; CrOss-sECTIONaL vIEw Of R2 COULd NOT bE ExamINEd, bUT prObabLy sImILar TO THOsE Of OTHEr spECIEs HavING CUrvEd rIbs ON R2; CONsTrICTION vEry dEEp, wITH a bLUNT, bUT ELEvaTEd swELLING ON R3; R3 smOOTH, GLOssy; UmbILICUs vEry NarrOw; apErTUrE raTHEr TrIaNGULar, paLaTaL sIdE CUrvEd, parIETaL aNd COLUmELLar sIdEs sTraIGHT; pErIsTOmE sLIm IN HOLOTypE bUT sLIGHTLy THICkENEd IN paraTypEs; bOUNdary bETwEEN INNEr aNd OUTEr LIps HardLy vIsIbLE; THE OvEraLL pErIsTOmE sLIGHTLy ExpaNdEd IN dIrECTION Of UmbILICUs.

Measurements (in mm). D = 3.2–3.5, H = 3.4–3.4 (N = 3, TypE sampLE).

Operculum. UNkNOwN.

Variation in specimens. ExCEpT fOr THE dIffErENCEs IN THE THICkNEss Of THE pErIsTOmE, NO NOTabLE varIabILITy fOUNd IN TErms Of sHELL CHaraCTErs.

Differential diagnosis. THIs NEw spECIEs CaN bE EasILy dIsTINGUIsHEd frOm aLL OTHEr CHINEsE aNd VIETNamEsE Dicharax spECIEs by ITs HIGHEr spIrEd sHELL. SImILar spECIEs wErE dEsCrIbEd frOm INdIa. Dicharax conicus (GOdwIN- AUsTEN, 1871) (ExamINEd sampLE: SamIamrI, E Of THE KOpILI R., LEG. GOdwIN-AUsTEN, NHMUK 1903.07.0 1.2674, 12 syNTypEs) Is smaLLEr; IT Has sHOrTEr R2 wITH fEwEr rIbs pEr arEa, aNd LaCk THE swELLING ON R3. MOrEOvEr, THE apErTUrE Of THE NEw spECIEs Is NEarLy TrIaNGULar dUE TO THE UppEr aNd LOwEr INCIsIONs, wHErEas IT Is rEGULarLy rOUNdEd IN Dicharax conicus . ALL Dioryx spECIEs dIffEr frOm Dicharax imitator n. sp. by THE vEry sHOrT R3 LaCkING a CENTraL swELLING, aNd THE smOOTH R2.

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

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.

FIGURE 38. R 2 ribs of Dicharax species. A – B. Dicharax fimbriatus (Bavay & Dautzenberg, 1912) 20060111 D, coll. PGB. C – D. Dicharax fimbriatus, MAA 1, coll. PGB. E – F. Dicharax imitator Páll-Gergely & Hunyadi n. sp. (holotype, HNHM 99706). All images: B. Páll-Gergely.

FIGURE 42. Protoconchs of Dicharax species. A – B. Dicharax imitator Páll-Gergely & Hunyadi n. sp. (holotype, HNHM 99706). C – D. Dicharax micropolitus Páll-Gergely & Hunyadi, n. sp. (holotype, HNHM 99709). E – F. Dicharax planorbulus (Heude, 1885) (syntype, MCZ 167136). All images: B. Páll-Gergely.