The redescription of the holotype and only known specimen of Psilotrachelosaurus toeplitschi Nopcsa, 1928, from the northern Alps of Austria, and its comparison with other pachypleurosauroids show the specimen to represent a distinct genus and species. It is the sister-taxon of the Serpianosaurus-Neusticosaurus clade from the Middle Triassic of Central and Southern Europe (German Lettenkeuper as well as Grenzbitumenzone and Meridekalke of the southern Alps in southern Switzerland and Italy). Psilotrachelosaurus is represented by a subadult (sex y) or a small but already sexually mature (sex x) individual. Diagnostic features of the specimen include body proportions (relatively short humerus as compared to standard length), ossified distal carpal and tarsal 4, and a relatively broad pubis Includes bibliographical references (p. 15-17) The redescription of the holotype and only known specimen of Psilotrachelosaurus toeplitschi Nopcsa, 1928, from the northern Alps of Austria, and its comparison with other pachypleurosauroids show the specimen to represent a distinct genus and species. It is the sister-taxon of the Serpianosaurus-Neusticosaurus clade from the Middle Triassic of Central and Southern Europe (German Lettenkeuper as well as Grenzbitumenzone and Meridekalke of the southern Alps in southern Switzerland and Italy). Psilotrachelosaurus is represented by a subadult (sex y) or a small but already sexually mature (sex x) individual. Diagnostic features of the specimen include body proportions (relatively short humerus as compared to standard length), ossified distal carpal and tarsal 4, and a relatively broad pubis Fieldiana series has been published as Geological Series by Field Columbian Museum (1895-1909) and Field Museum of Natural History (1909-1943), and as Fieldiana: Geology by Chicago Natural History Museum (1945-1966) and Field Museum of Natural History (1966-1978). Fieldiana Geology New Series No. 1 began June 29, 1979