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).