Metalycaeus laosensis Páll-Gergely, 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 : 86-87

Metalycaeus laosensis Páll-Gergely , n. sp.

FIGUrE 47C .

Type material. HOLOTypE MNHN IM-2012-27172 , 26 L04 NOrTHErN LaOs, PHONGsaLy PrOvINCE, OLd fOrEsT NEar sTrEam apprOx. 1 km SW Of a sTrEam aNd Nam OU (rIvEr) CONfLUENCE, 493 m, 21°44.663'N, 102°10.999'E, LEG. A. AbdOU, I.V. MUraTOv, N. PHOTHIHOUmpHaNH, 0 4 DEC 2004 ; MNHN IM-2012-27176 /1 paraTypE, 5L05 NOrTHErN LaOs, PHONGsaLy PrOvINCE, NE Of PHONGsaLy, aT NE parT Of PHOUfa MOUNTaIN rIdGE, 883 m, 21°43.381'N, 102°09.813'E, LEG. A. AbdOU, I.V. MUraTOv, 0 7 Mar 2005 ; MNHN IM-2012-27175 /1 paraTypE, 35L05 NOrTHErN LaOs, PHONGsaLy PrOvINCE, OLd fOrEsT ON THE wEsTErN parT Of SEN SI LENG TsU mOUNTING raNGE, dIvIdING Nam SING NHa aNd Nam ONG, 1030 m, 21°43.021'N, 102°17.477'E, LEG. A. AbdOU & I.V. MUraTOv, 24 Mar 2005 ; MNHN IM- 2012-27174 /1 paraTypE, 28L05 NOrTHErN LaOs, PHONGsaLy PrOvINCE, OLd fOrEsT NEar smaLL sTrEam aT THE UppEr rEaCHEs Of Nam PUHa rIvEr basIN, 798 m, 21°46.507'N, 102°25.638'E, LEG. A. AbdOU, I.V. MUraTOv, 21 Mar 2005 ; MNHN IM-2012-27173 /1 (vEry smaLL, jUvENILE sHELL, NOT paraTypE), 07L04 NOrTHErN LaOs, PHONGsaLy PrOvINCE, OLd fOrEsT ON PHOUfa MOUNTaIN (1625 m) jUsT NOrTH Of PHONGsaLy, 1430–1618 m, 21°41.333'N, 102°06.493'E, LEG. A. AbdOU & I.V. MUraTOv, 17–18 NOv 2004 .

Etymology. Metalycaeus laosensis n. sp. Is NamEd afTEr THE COUNTry wHErE IT OCCUrs.

Diagnosis. A mEdIUm sIzEd spECIEs wITH sHOrT, INfLaTEd R2 HavING CUrvEd rIbs (aT LEasT THE mOsT aNTErIOr ONEs), a vEry sHOrT R3, a dEEp CONsTrICTION bETwEEN R2 aNd R3, aNd a rEfLECTEd pErIsTOmE.

Description ( FIGUrE 47C ). OrIGINaL sHELL COLOUr LIGHT brOwN TO GrEENIsH-yELLOwIsH, bUT mOsT sHELLs wErE sOmEwHaT wEaTHErEd; sHELL OUTLINE rOUNdEd frOm dOrsaL vIEw wITH CONspICUOUsLy INfLaTEd R2; spIrE rELaTIvELy sTrONGLy ELEvaTEd; bOdy wHOrL rOUNdEd; prOTOCONCH ELEvaTEd, spIraLLy sTrIaTEd, CONsIsTs Of 1.75 wHOrLs; bOUNdary bETwEEN prOTOCONCH aNd TELEOCONCH sHarp; R1 CONsIsTs Of 1.5 wHOrLs, wITH IrrEGULar, LOw, wIdELy-spaCEd rIbs aNd fINE spIraL sTrIaTION; TraNsITION bETwEEN R1 aNd R2 NOT CONspICUOUs, bECaUsE rIbs Of R2 INCrEasE GradUaLLy; R2 sHOrT, rEGULarLy, dENsELy rIbbEd, rIbs raTHEr sTraIGHT IN pOsTErIOr parT Of rEGION, rIbs GradUaLLy CUrvEd TOwards apErTUrE; R3 vEry sHOrT; bOUNdary bETwEEN R2 aNd R3 Is INdICaTEd by a dEEp CONsTrICTION; apErTUrE wIdE, rOUNdEd; INNEr pErIsTOmE NOT CONspICUOUs; OUTEr pErIsTOmE ExpaNdEd aNd rEfLECTEd (EspECIaLLy IN THE paLaTaL rEGION); bOUNdary bETwEEN INNEr aNd OUTEr pErIsTOmEs HardLy vIsIbLE; UmbILICUs dEEp.

Measurements (in mm). D = 4.6–5.2; H = 3.6–3.8 (N = 3).

Operculum. UNkNOwN.

Variation in specimens. ExCEpT fOr sOmE mINOr dIffErENCEs IN sHELL sIzE, THErE arE NO NOTabLE dIffErENCEs bETwEEN THE spECImENs IN sHELL CHaraCTErs.

Differential diagnosis. Metalycaeus laosensis n. sp. Is mOsT sImILar TO M. awalycaeoides n. sp. dUE TO THE dEEp CONsTrICTION aNTErIOr TO R2 aNd THE rIbs, wHICH arE CUrvEd TOwards THE apErTUrE. HOwEvEr, M. laosensis n. sp. Is LarGEr, Has a mOrE ELEvaTEd spIrE aNd a dEEpEr UmbILICUs, THE pOsTErIOr rIbs Of R2 arE NEarLy sTraIGHT, aNd IT Has a mUCH mOrE ExpaNdEd pErIsTOmE. Metalycaeus muciferus Has sTraIGHT rIbs ON R2 aNd THE CONsTrICTION bETwEEN R2 aNd R3 Is sHaLLOwEr.

Distribution. THIs NEw spECIEs Is kNOwN frOm fIvE LOCaLITIEs IN PHONGsaLy PrOvINCE, NOrTHErN LaOs ( FIGUrE 57 ).

Figures

FIGURE 47. Shells of Metalycaeus species. A. Metalycaeus (?) awalycaeoides Páll-Gergely & Hunyadi, n. sp., holotype (HNHM 99730). B. Metalycaeus latecostatus (Möllendorff, 1882) (lectotype, SMF 39215). C. Metalycaeus laosensis Páll- Gergely n. sp. (holotype, MNHN IM- 2012 - 27172). Scale represents 5 mm. All photos: B. Páll-Gergely.

FIGURE 57. Distribution of Metalycaeus species. Empty diamond. Metalycaeus zayuensis (Zhang, Chen & Zhou, 2008). Filled triangle. Metalycaeus oharai Páll-Gergely & Hunyadi n. sp. Filled square. Metalycaeus (?) awalycaeoides Páll- Gergely & Hunyadi, n. sp. Circles. Metalycaeus muciferus (Heude, 1885). Empty triangle, top down. Metalycaeus laosensis n. sp. Empty circles indicate figured populations of Metalycaeus muciferus. 1. Tchen K’eou (Chengkou), the type locality of Alycaeus muciferus Heude, 1885. 2. Changyang (SMF 39254). 3. 2015 / 48. 4. 20070714 B. 5. Pe-shang (type locality of Alycaeus helicodes Gredler, 1887). 6. 2013 / 7. 7. 2011 / 15.