Metalycaeus okuboi, 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 : 97-98

Metalycaeus (?) okuboi Páll-Gergely & Hunyadi , n. sp.

FIGUrEs 53A–B , 62C–D , 64 , 65C–F .

Type material. HOLOTypE HNHM 99713, PGB/1 paraTypE (Ex COLL. K. OkUbO), 20050313A CHINa, YUNNaN, HONGHEHaNIzUyIzU ZIzHIzHOU, LUxI XIaN, ZHONGsHU ZHEN, ALUGUdONG, LEG. K. OkUbO, 13 Mar 2005; OK/1 paraTypE, PGB/1 paraTypE (Ex COLL. K. OkUbO), 20060107A CHINa, YUNNaN, HONGHEHaNIzUyIzU ZIzHIzHOU, JIaNsHUI XIaN, YaNsHUIdONG, 1260 m, 23°38.16988'N, 103°03.10779'E, LEG. K. OHara, K. OkUbO & J.U. OTaNI, 0 7 JaN 2006; HA/32 paraTypEs, 2011/25 CHINa, YUNNaN, HONGHE HaNIzU YIzU ZIzHIzHOU, JIaNsHUI XIaN, MIaNdIaN XIaNG, YaNzIdONG E 1.5 km, DaTIaNsHaN CUN N, ENvIrONmENT Of THE CavE, 1280 m, 23°37.796'N, 103°04.074'E, LEG. A. HUNyadI, 26 Mar 2011; PGB/2 paraTypEs (Ex COLL. K. OkUbO), 20050314A CHINa, YUNNaN, HONGHEHaNIzUyIzU ZIzHIzHOU, KaIyUaN SHI, NaNdONG FENGjINGOU, LEG. K. OkUbO, 14 Mar 2005.

Etymology. THIs NEw spECIEs Is NamEd afTEr OUr frIENd, KaNjI OkUbO, wHO prOvIdEd sHELL maTErIaL fOr THIs rEvIsION.

Diagnosis. A mEdIUm sIzEd spECIEs wITH LONG R2, mOdEraTE R3, bLUNT swELLING ON R3, aNd a THICkENEd pErIsTOmE. BOTH THE aNTErIOr aNd pOsTErIOr CrUsTs Of R2 arE sTrONGLy dEvELOpEd. THE rIbs Of THE aNTErIOr CrUsT, wHICH Is sTraIGHT IN mOsT Metalycaeus spECIEs, Is OrIENTEd IN aNTErIOr dIrECTION IN THIs spECIEs.

Description. THE ONLy spECImEN wITH ITs OrIGINaL COLOUr (HOLOTypE: FIGUrE 62C ) Is yELLOwIsH IvOry; spIrE sLIGHTLy (20050313A, 20050314A, 20060107A) Or mOrE (2011/25) ELEvaTEd, sHELL OUTLINE rOUNdEd frOm dOrsaL vIEw, bOdy wHOrL rOUNdEd; aLL ExamINEd spECImENs Had sOmEwHaT wEaTHErEd apICEs, THErEfOrE bOUNdary bETwEEN prOTOCONCH aNd TELEOCONCH COULd NOT bE sEEN; prOTOCONCH ( FIGUrEs 53A–B ) aNd R1 arE 3–3.25 (20050313A, N = 2), 3.25–3.5 (2011/25, N = 3), 3.25 (20050314A, N = 2) wHOrLs TOGETHEr; prOTOCONCH mOdEraTELy ELEvaTEd; spIraL LINEs vIsIbLE ON THE sUppOsEdLy LasT wHOrL Of THE prOTOCONCHs Of sampLEs 20050313A, 20050314A aNd 20060107A; R1 IrrEGULarLy rIbbEd, rIbs LOw bUT rELaTIvELy sHarp aT THE ENd Of R1; THErE arE sIGNs Of vEry wEak spIraL LINEs bETwEEN rIbs ON R1; TraNsITION bETwEEN R1 aNd R2 CONspICUOUs bECaUsE rIbbING ON R2 mOrE dENsEr aNd IN mOsT spECImENs R2 sEEmINGLy bULGING; vIEwING frOm abOvE, R2 ( FIGUrEs 64A–B ) rIbs sEEmINGLy HavE a HOrIzONTaL, aNTErIOr prOjECTIONs, bUT IN faCT THOsE prOjECTIONs arE THE aNTErIOr CrUsTs; bOTH aNTErIOr aNd pOsTErIOr CrUsTs sTrONGLy dEvELOpEd ( FIGUrEs 64C–D ), aNTErIOr ONLy sLIGHTLy LarGEr THaN pOsTErIOr, aNd bOTH HOLLOw INsIdE; pOsTErIOr CrUsTs CUrvEd TOwards apErTUrE fOrmING a wIdE, varIOUsLy sHapEd (rOUNdEd, qUadraNGULar Or TrIaNGULar) mICrOTUNNEL wITH waLL Of aNTErIOr CrUsT; aNTErIOr CrUsTs CUrvEd TOwards apErTUrE, ITs bECk NEarLy paraLLEL wITH sHELL waLL; R2 aNd R3 NEarLy rEaCHING 180 dEGrEEs TOGETHEr, R2 sOmEwHaT LONGEr THaN R3; R2 aNd R3 sEparaTEd by a LOw CONsTrICTION; R3 raTHEr IrrEGULarLy wrINkLEd; wrINkLEs apprOxImaTELy as dENsE as THOsE aT ENd Of R1; R3 wITH a bLUNT swELLING ON ITs mIddLE; apErTUrE rOUNdEd wITH sLIGHT UppEr INCIsION Or ELONGaTEd IN dOrsOvENTraL dIrECTION; INNEr LIp vEry sLIGHTLy THICkENEd, ExpaNdEd aNd prOTrUdING; OUTEr LIp mOrE ExpaNdEd, rELaTIvELy sHarp (EspECIaLLy IN dIrECTION Of UmbILICUs); bOUNdary bETwEEN TwO LIps NOT aLways CLEarLy vIsIbLE; TwO LIps sIGNIfICaNTLy THICkENEd IN pOpULaTION 20050314A; UmbILICUs NarrOw Or rELaTIvELy NarrOw.

Measurements (in mm). D = 4.5–5.3, H = 3.4–3.9 (N = 4).

Operculum. TwO OpErCULa Of THE sampLE 20050313A wErE ExamINEd ( FIGUrEs 65C–F ). OpErCULUm ONLy sLIGHTLy CONCavE (NEarLy fLaT), THICk; ON THE OUTEr sIdE THErE Is a CLOsELy COILEd, HymEN-LIkE LOw LamELLa; INNEr sIdE NEarLy fLaT, wITH vEry sLIGHTLy ELEvaTEd CENTraL NIppLE.

Variation in specimens. SOmE varIabILITy Has bEEN fOUNd IN sHELL sIzE, spIrE HEIGHT aNd THE THICkNEss Of THE pErIsTOmE.

Differential diagnosis. Metalycaeus okuboi n. sp. dIffErs frOm OTHEr Metalycaeus spECIEs (mOsT sImILar IN sHapE Is M. oharai n. sp.) by THE UNUsUaL sTrUCTUrE Of THE rIbs ON R2.

Dicharax robustus n. sp. LIvEs GEOGrapHICaLLy CLOsE TO M. okuboi n. sp. BEsIdEs LaCkING spIraL sTrUCTUrE ON THE wHOLE sHELL, IT maINLy dIffErs frOm M. okuboi n. sp. by THE mOrpHOLOGy Of THE rIbs aLONG THE TUbE. NamELy, D. robustus n. sp. Has a sTrONGLy dEvELOpEd, LarGE aNTErIOr CrUsT HavING T-sHapEd CrOss sECTIONaL vIEw, aNd vEry smaLL pOsTErIOr CrUsTs, wHICH fOrm NarrOw mICrOTUNNELs wITH THE waLLs Of THE aNTErIOr CrUsTs. IN CONTrasT, M. okuboi n. sp. Has bOTH CrUsTs dEvELOpEd NEarLy EqUaLLy, fOrmING a wIdE mICrOTUNNEL, aNd THE aNTErIOr CrUsT Is CUrvEd IN aNTErIOr dIrECTION.

Distribution. THIs NEw spECIEs Is kNOwN frOm THrEE LOCaLITIEs IN sOUTH-EasTErN YUNNaN PrOvINCE ( FIGUrE 56 ).

Figures

FIGURE 53. Protoconchs of Metalycaeus species. A – B. Metalycaeus (?) okuboi Páll-Gergely & Hunyadi, n. sp. (holotype, HNHM 99713). C – D. Metalycaeus heudei (Bavay & Dautzenberg, 1900), 20030318 B. All images: B. Páll-Gergely.

FIGURE 56. Distribution of Metalycaeus species. Filled triangle, top up. Metalycaeus (?) okuboi Páll-Gergely & Hunyadi, n. sp. Empty triangle, top up. Metalycaeus (?) ibex Páll-Gergely & Hunyadi n. sp. Filled circle. Metalycaeus (?) libonensis (Chen, Li & Luo 2003). Empty circle. Metalycaeus latecostatus (Möllendorff, 1882). Empty square. Metalycaeus sinensis (Heude, 1882). Filled square. Metalycaeus rathouisianus (Heude, 1882).

FIGURE 62. Shells of Metalycaeus species. A. Metalycaeus oharai Páll-Gergely & Hunyadi n. sp. (holotype, HNHM 99712). B. Metalycaeus oharai, 20061015 A (paratype), coll. PGB. C. Metalycaeus (?) okuboi Páll-Gergely & Hunyadi, n. sp. (holotype, HNHM 99713). D. Metalycaeus (?) okuboi, paratype (20050314 A, coll. PGB). A Scale represents 5 mm. All photos: B. Páll-Gergely.

FIGURE 64. R 2 ribs of Metalycaeus (?) okuboi Páll-Gergely & Hunyadi, n. sp., 20050313 A, coll. OKA. All images: B. Páll- Gergely.

FIGURE 65. Opercula of Metalycaeus species. A – B. Metalycaeus rathouisianus (Heude, 1882) (MCZ 167209; syntype of Alycaeus dolomiticus). C – F. Metalycaeus (?) okuboi Páll-Gergely & Hunyadi, n. sp. (holotype, HNHM 99713). All images: B. Páll-Gergely.