Nineteen new species of Alycaeidae from Myanmar and Thailand (Gastropoda: Caenogastropoda: Cyclophoroidea) Author Páll-Gergely, Barna Author Hunyadi, András 0000-0003-3488-2817 hunand@freemail.hu Author Grego, Jozef 0000-0002-4977-0415 jozef.grego@gmail.com Author Reischütz, Alexander 0000-0002-8844-7004 alexander.reischuetz@gmx.at Author Auffenberg, Kurt 0000-0001-9660-6776 kurtauffenberg@gmail.com text Zootaxa 2021 2021-05-18 4973 1 1 61 journal article 6241 10.11646/zootaxa.4973.1.1 d0967b08-98d1-4ccd-b472-a678e0e57eda 1175-5326 4771958 42EB4BF2-A571-4894-9EEF-783649A27E4F Metalycaeus heudei (Bavay & Dautzenberg, 1900) Fig. 41 Alycaeus ( Charax ) heudei Bavay & Dautzenberg, 1900a: 121–122 . Alycaeus ( Charax ) heudei — Bavay & Dautzenberg 1900b: 458–459 , plate 11, figs 15–18. Alycaeus paviei Bavay & Dautzenberg, 1912: 50–51 , pl. 4, figs 5–8. Alycaeus paviei var. minor Bavay & Dautzenberg, 1912: 51 , pl. 4, fig. 9. Chamalycaeus ( Dicharax ) compressicosta Zilch, 1957: 145–146 , fig. 33. Chamalycaeus ( Dicharax ) fractus Varga, 1974: 165–167 , figs 1–5. Alycaeus zhuangiyucuii Yang, Fan, Qiao & He, 2012: 32 , fig. 2. Metalycaeus heudei — Páll-Gergely et al . 2017: 74–84, figs 49C–D, 50–52, 53C–D. ( paviei Bavay & Dautzenberg, 1912 , paviei var. minor Bavay & Dautzenberg, 1912 , compressicosta Zilch, 1957 , fractus Varga, 1974 and zhuangiyucuii Yang, Fan, Qiao & He, 2012 are synonyms; Inkhavilay et al . 2019: 16 , fig. 6C. Alycaeus kengtungensis Godwin-Austen, 1914: 409 , plate 139, figs 6, 6a. new synonym Material examined. Holotype : Myanmar , Shan State , “Kengtung, Siam Frontier, leg. Woodthorpe ”, NHMUK 1903.7 .1.3037 ( holotype of A. kengtungensis ). For the examined type specimens of other taxa see Páll-Gergely et al . (2017) . Other material: 4 shells, Myanmar , Kayah State , Hpruso Distr. , Maw Thi Do Village , Bo Pha Gu Cave sink, 19°21.121’N , 97°3.759’E (locality code: JG10 ), 10 Feb. 2019 , J. Grego leg., JG ; 2 shells, Myanmar , Kayah State , Hpruso Distr. , Maw Thi Do , road towards Han Li Village , under bridge over Phruno River , 19°22.966’N , 97°02.153’E (locality code: JG100 ), 12 Dec. 2019 , J. Grego leg., JG ; 1 shell, Myanmar , Kayah State , Hpruso Distr. , Maw Thi Do , road towards Han Li Village , rocks above bridge over Phruno River , 19°23.011’N , 97°02.108’E (locality code: JG101 ), 12 Dec. 2019 , J. Grego leg., JG ; 1 shell, Myanmar , Kayah State , Hpruso Distr. , Maw Thi Do Village , Entrance of Phruno River Cave , 19°22.744’N , 97°02.570’E (locality code: JG102 ), 12 Dec. 2019 , J. Grego leg., HNHM 104867 (photographed shell: 4.77 mm , H: 3.66 mm ) ; 17 shells, same data as preceding, JG . Diagnosis of specimens from Myanmar . A medium-sized to large species with very long R2 having typical Metalycaeus - type elevated, thin, widely spaced ribs, a narrow swelling on R3, and a rounded aperture. Measurements. D: 4.65–5.05 mm , H: 3.66–3.71 mm (newly collected specimens). Remarks. Metalycaeus heudei is a widely distributed, variable species reported from China , Vietnam and Laos . Alycaeus kengtungensis ( Fig. 41B ) from the eastern border of Shan State , Myanmar , and the newly collected shells from Kayah State ( Fig. 5 ) fall within the known morphological variation of Metalycaeus heudei . Therefore, we consider A. kengtungensis a new synonym of M. heudei . With this, M. heudei is the most widely distributed alycaeid species known.