Dicharax robustus 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 : 70-71

Dicharax robustus Páll-Gergely & Hunyadi , n. sp.

FIGUrEs 19C , 29A–B , 45 .

Type material. HOLOTypE HNHM 99704 , HNHM 99726 /1 (fIGUrEd paraTypE, Ex COLL. K. OHara), OK/19 paraTypEs + 1 jUvENILE sHELL ( NOT paraTypE), PGB/2 paraTypEs ( Ex COLL. K. OHara), 20000319 CHINa, YUNNaN, KUNmING SHI, YUqIqU, BIjIaNsHaN, GUaNyINsI (TEmpLE), apprOxImaTE GPS daTa: 24°16.271'N, 102°49.726'E, LEG. K. OHara; HA/3 paraTypEs, 2011/5 CHINa, YUNNaN, YUxI SHI, CHENGjIaNG XIaN, LUCHONG CUN, 1778 m, 24°33.842'N, 102°50.614'E, LEG. A. HUNyadI, 18 Mar 2011 .

Etymology. THIs NEw spECIEs Is NamEd afTEr ITs rObUsT appEaraNCE.

Diagnosis. A mEdIUm sIzEd spECIEs wITH ELEvaTEd spIrE, LONG R2, mOdEraTELy LONG R3, bLUNT swELLING ON R3, aNd rELaTIvELy LONG dIsTaNCE bETwEEN THE TwO LIps Of THE pErIsTOmE. THE CrOss sECTION Of rIbs Of R2 arE T-sHapEd, THEIr TOps aLmOsT rEaCH EaCH OTHEr fOrmING TUNNELs bETwEEN THE rIbs.

Description. SHELL ( FIGUrE 19C ) Off-wHITE, aLTHOUGH mOsT avaILabLE sHELLs Had brOwNIsH-rEddIsH dIrT bETwEEN THEIr rIbs; spIrE ELEvaTEd, sHELL OUTLINE rOUNdEd frOm dOrsaL vIEw, bOdy wHOrL rOUNdEd; prOTOCONCH ( FIGUrEs 29A– B ) CONsIsTs Of apprOxImaTELy 2 wHOrLs, bUT bOUNdary bETwEEN prOTOCONCH aNd R1 NOT vIsIbLE CLEarLy IN aNy Of ExamINEd spECImENs, aLTHOUGH wE ExamINEd INTaCT (NOT wEaTHErEd) sHELLs; prOTOCONCH NOrmaLLy ELEvaTEd (NOT HIGHEr Or LOwEr THaN wHaT wOULd bE ExpECTEd frOm THE OvEraLL sHELL sHapE), IT Is maTTE, wITHOUT aNy NOTabLE sCULpTUrE; R1 apprOxImaTELy 1.5 wHOrLs IN LENGTH, rEGULarLy rIbbEd; IN frEsH sHELLs rIbs sHarp aNd sTrONGLy CUrvEd TOwards apErTUrE; TraNsITION bETwEEN R1 aNd R2 vEry CONspICUOUs bECaUsE R2 mUCH mOrE dENsEr rIbbEd THaN prECEdING arEa; R2 vEry dENsELy rIbbEd ( FIGUrEs 45A–C ); CrOss sECTIONaL vIEw Of R2 was ExamINEd IN TwO spECImENs ( FIGUrEs 45D , 68B ): aNTErIOr CrUsT fOrms a sIGNIfICaNTLy ELEvaTEd, sTrONG HOLLOw rIb, wHICH Has THE aNTErIOr aNd pOsTErIOr prOjECTIONs Of abOUT THE samE LENGTH; THIs rEsULTs IN T-sHapEd CrOss sECTIONaL vIEw; aNTErIOr CrUsT fOLds OvEr THE mUCH wEakEr pOsTErIOr CrUsT, wHICH Is NOT HOLLOw; mICrOTUNNEL NarrOw COmparEd TO rIbs, ITs CrOss sECTIONaL vIEw dEfOrmEd TEardrOp-sHapEd; R2 aNd R3 apprOxImaTELy 110 dEGrEEs TOGETHEr; R2 sOmEwHaT LONGEr THaN R3; R2 aNd R3 sEparaTEd by CONspICUOUs CONsTrICTION; R3 raTHEr IrrEGULarLy wrINkLEd; wrINkLEs apprOxImaTELy as dENsE as rIbs aT ENd Of R1; R3 wITH a bLUNT swELLING ON ITs mIddLE; apErTUrE rOUNdEd wITH sLIGHT UppEr INCIsION; pErIsTOmE rOUNdEd, NOT CrENULaTEd; INNEr LIp vEry sLIGHTLy THICkENEd, ExpaNdEd aNd prOTrUdING; pOsTErIOr LIp aLsO sLIGHTLy ExpaNdEd, rELaTIvELy sHarp, aTTaCHEd TO OUTEr LIp aT COLUmELLar rEGION, bUT bOUNdary bETwEEN TwO LIps CLEarLy vIsIbLE HErE as wELL; dIsTaNCE bETwEEN INNEr aNd OUTEr LIps bECOmEs LarGEr aT THE paLaTaL rEGION; UmbILICUs NarrOw.

Measurements (in mm). D = 4.4–4.7, H = 3.3–3.6 (N = 4).

Operculum. THE OUTEr sUrfaCE Of THE OpErCULa Of sEvEraL spECImENs was ExamINEd: IT Is mULTIspIraL wITHOUT ELEvaTEd LamELLa.

Variation in specimens. NO NOTabLE varIabILITy was fOUNd wITHIN aNd bETwEEN pOpULaTIONs.

Differential diagnosis. THIs NEw spECIEs Is mOrE sTrONGLy bUILT OvEraLL THaN Dicharax alticola n. sp. MOrEOvEr, IT Has a LarGEr sHELL, a mOrE ELEvaTEd spIrE, dENsEr rIbs ON R2, aNd THE swELLING ON R3 Is sHarpEr, aNd sITUaTEd CLOsEr TO THE apErTUrE. Dicharax robustus n. sp. Has a mOrE ELEvaTEd spIrE, THICkEr pErIsTOmE, sHOrTEr R3 aNd LONGEr R2 THaN THE NEIGHbOUrING pOpULaTIONs Of D. cristatus . MOrEOvEr, THE swELLING ON R2 Is sITUaTEd mUCH CLOsEr TO THE pErIsTOmE IN D. robustus n. sp. THE mOsT sImILar spECIEs TO D. robustus N. sp Is THE BUrmEsE Dicharax vestitus ( BLaNfOrd, 1862) (maTErIaL ExamINEd: MOdITOUNG, NHMUK 1906.04.0 4.53, HOLOTypE), THaT dIffErs frOm THE NEw spECIEs by HavE HavING smOOTHEr R1, sHOrTEr R2, aNd THE OUTEr pErIsTOmE Is NOT ExpaNdEd, bUT TUrNs IN THE dIrECTION Of THE INNEr pErIsTOmE. SEE UNdEr Metalycaeus okuboi n. sp.

Distribution. THIs NEw spECIEs Is kNOwN frOm TwO LOCaLITIEs IN THE EasTErN parT Of THE CHINEsE YUNNaN PrOvINCE. THE dIsTaNCE bETwEEN THE TwO sITEs Is apprOxImaTELy 32 km ( 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 19. Shells of Dicharax species. A. Dicharax anthostoma (Möllendorff, 1885) (lectotype, SMF 39225). B. Dicharax anthostoma (syntype of Alycaeus pentagonus, MCZ 167215). C. Dicharax robustus Páll-Gergely & Hunyadi, n. sp. (holotype, HNHM 99704). Scale represents 5 mm. All photos: B. Páll-Gergely.

FIGURE 29. Protoconchs of Dicharax species. A – B. Dicharax robustus Páll-Gergely & Hunyadi, n. sp. (20000319, spec. 1, HNHM 99726, paratype from the type locality). C – D. Dicharax cristatus (Möllendorff, 1886) (20100508 A, coll. PGB). E – F. Dicharax depressus (Bavay & Dautzenberg, 1912), MAA 1, Specimen 2. All images: B. Páll-Gergely.

FIGURE 45. R 2 ribs Dicharax robustus Páll-Gergely & Hunyadi, n. sp. (20000319, spec. 1, HNHM 99726 paratype from the type locality). All images: B. Páll-Gergely.

FIGURE 68. Schematic diagram of cross sections of R 2 of Dicharax and Metalycaeus species. The aperture opens leftwards. A. Dicharax bison Páll-Gergely & Hunyadi n. sp. B. Dicharax robustus Páll-Gergely & Hunyadi, n. sp. C. Dicharax fimbriatus (Bavay & Dautzenberg, 1912). D. Dicharax depressus (Bavay & Dautzenberg, 1912). E. Dicharax (?) alticola Páll- Gergely & Hunyadi n. sp. F. Dicharax (?) immaculatus Páll-Gergely n. sp. G. Dicharax (?) moellendorffi (Kobelt & Möllendorff, 1886). H. Metalycaeus muciferus (Heude, 1885). I. Metalycaeus oharai Páll-Gergely & Hunyadi n. sp. J. Metalycaeus (?) okuboi Páll-Gergely & Hunyadi, n. sp. Abbreviations: a: anterior crust; p: posterior crust; t: tunnel.