Revision of F. R. C. Reed’s Ordovician trilobite types from Myanmar (Burma) and western Yunnan Province, China Author Fortey, Richard A. Department of Earth Sciences, Museum of Natural History, Cromwell Road, London, SW 7 5 BD, UK. Author Wernette, Shelly J. Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA. & Department of Geography and Environmental Studies, Texas State University, San Marcos, TX 78666, USA Author Hughes, Nigel C. text Zootaxa 2022 2022-07-08 5162 4 301 356 journal article 93239 10.11646/zootaxa.5162.4.1 7d343017-483e-43be-9439-d06e748fc54e 1175-5326 6810290 DD2279FA-E8F1-4951-A5CA-91082E875580 Prionocheilus Rouault, 1847 Type species . Prionocheilus verneuli Rouault, 1847 , by monotypy. Discussion . We accept the priority of the generic name Prionocheilus over Pharostoma (see Dean 1971 ). Reed (1915 , p. 46) erected a species based on a cranidium, Calymene ( Pharostoma ) liluensis , which might be regarded as a Prionocheilus species. Zhou et al. (1977) erected the genus Xuanenia , type species X . pustulosus Zhou, 1977 , from central South China , based on an imperfectly preserved cranidium. The same genus and species were subsequently described by Tripp et al. (1989) for material from the Upper Ordovican Tangtou Formation, Jiangsu Province . The similarity of some of this material to ‘ Pharostoma ’ liluensis was noted already by Fortey & Cocks (1998) , and is confirmed by the present study. Tripp et al. (1989) remarked that “ Xuanenia is extremely close to Prionocheilus Roualt, 1847 (sic)[and] differs only in the effaced lateral glabellar lobes and furrows and smaller pygidium with fewer segments.” There is little difference with regard to glabellar lobes and furrows between the cranidium figured by Tripp et al. (1989 , fig. 17k) and the type specimen of ‘ Pharostoma ’ liluensis , which in turn is not significantly different from cranidia of Prionocheilus spp. ; we prefer to use that generic name pending further clarification of Xuanenia . It is possible that P. liluensis has priority over subsequently named species in this group, but a comparative study of adjacent species is needed to clarify this.