Metalycaeus sinensis ( Heude, 1882 )

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 : 103-104

Metalycaeus sinensis ( Heude, 1882)

FIGUrE 55D .

Alycaeus sinensis Heude, 1882: 7 , pl. 12, figs 13, 13a.

Alycaeus sinensis — Möllendorff, 1882: 345.

Alycaeus (Chamalycaeus) sinensis — Kobelt & Möllendorff, 1897: 149. Alycaeus (Chamalycaeus) sinensis — Kobelt, 1902: 363.

Types examined. 3 syNTypEs MCZ 167216, CHINa, TONG-LIEOU. ONE Of THE syNTypEs Is a sUbadULT M. rathouisianus (MCZ 384425). THErEfOrE, TO avOId fUTUrE mIsUNdErsTaNdINGs, THE mOsT wELL-prEsErvEd sHELL Is sELECTEd TO bE THE LECTOTypE (MCZ 167216). THE paraLECTOTypE Is rEGIsTErEd wITH THE INvENTOry NUmbEr MCZ 384424.

Museum material examined. NHMW 111545 /4, HUNaN.

Diagnosis. A smaLL spECIEs wITH LOw spIrE, mOdEraTELy LONG R2 aNd R3, R3 wITH TypICaL Metalycaeus -TypE rIbs, R3 wITH bLUNT swELLING.

Description. ONLy ONE spECImEN ( FIGUrE 55D ) Had ITs OrIGINaL COLOUr, wHICH was yELLOwIsH-COrNEOUs; spIrE vEry sLIGHTLy ELEvaTEd, sHELL aLmOsT fLaT, bOdy wHOrL rOUNdEd; bOTH ExamINEd spECImENs Had sOmEwHaT wEaTHErEd apICEs, THErEfOrE bOUNdary bETwEEN THE prOTOCONCH aNd TELEOCONCH COULd NOT bE sEEN; prOTOCONCH aNd R1 arE ExaCTLy Or vEry sLIGHTLy LEss THaN 3 wHOrLs TOGETHEr; prOTOCONCH rELaTIvELy LOw, wITH vEry fINE maTTE sUrfaCE aNd barELy vIsIbLE spIraL LINEs; R1 wITH raTHEr rEGULar rIbs aNd mUCH wEakEr spIraL LINEs bETwEEN; rIbs bECOmE mOrE wIdELy-spaCEd TOwards THE ENd Of R1; TraNsITION bETwEEN R1 aNd R2 NOT CONspICUOUs, rIbs ON R2 ONLy vEry sLIGHTLy dENsEr THaN ON prECEdING arEa Of R1; R3 wITH sLIGHT, bLUNT swELLING aT ITs mIddLE; R2 wITH rELaTIvELy LOw, wIdELyspaCEd rIbs, bUT avaILabLE sHELLs wErE aLL wEaTHErEd; CrOss sECTION Of rIbs COULd NOT bE ExamINEd; R2 sEparaTEd frOm R3 by a mOdEraTE CONsTrICTION; R2 aNd R3 arE apprOx. 100 dEGrEEs TOGETHEr, R2 sLIGHTLy sHOrTEr THaN R3; R3 IrrEGULarLy wrINkLEd, wrINkLEs dENsEr THaN rIbs ON R2; apErTUrE rOUNdEd; INNEr LIp vEry sLIGHTLy THICkENEd aNd prOTrUdING; OUTEr LIp vEry sLIGHTLy ExpaNdEd, sHarp IN dIrECTION Of UmbILICUs; bOUNdary bETwEEN TwO LIps NOT CONspICUOUs, bUT vIsIbLE.

Measurements (in mm). D = 3.1–3.2, H = 1.8 (N = 2, LECTOTypE + paraLECTOTypE).

Operculum. THE OUTEr sIdE Of THE OpErCULUm Of THE LECTOTypE was ExamINEd; IT Is mULTIspIraL, THIN, wITHOUT ELEvaTEd LamELLa.

Variation in specimens. THE fEw avaILabLE sHELLs rEvEaLEd NO NOTabLE varIabILITy.

Differential diagnosis. Metalycaeus sinensis Is smaLLEr THaN M. rathouisianus , IT Has a LOwEr spIrE, mOrE OvaL sHELL ( M. rathouisianus Is mOrE rOUNdEd), aNd Has wEakEr spIraL sTrIaE. Chamalycaeus sinensis Is smaLLEr aNd fLaTTEr THaN THE CONGENErIC JapaNEsE spECIEs ( M. hirasei , M. nipponensis , M. satsumanus ). SEE aLsO UNdEr Dicharax dolichodeiros .

Distribution. THIs spECIEs Is kNOwN frOm THE TypE LOCaLITy ONLy ( FIGUrE 56 ).

Figures

FIGURE 55. Shells of Metalycaeus species. A – C. Metalycaeus rathouisianus (Heude, 1882). A. syntype (SMF 39243) of M. rathouisianus. B. syntype (MCZ 167209) of Alycaeus dolomiticus Heude, 1890. C. MCZ 167222, labelled as Alycaeus neglectus Heude, 1886. D. Metalycaeus sinensis (Heude, 1882) (lectotype, MCZ 167216). E. Metalycaeus (?) ibex Páll- Gergely & Hunyadi n. sp., (holotype, MNHN IM- 2012 - 27042). Scale represents 5 mm. All photos: 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).