Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A. Author Burrow, Carole Jan Author Murphy, Michael Author Turner, Susan text PaleoBios 2023 2023-06-06 40 4 1 32 http://dx.doi.org/10.5070/p940454153 journal article 10.5070/P940454153 0031-0298 10913559 58312615-0833-432E-BF5D-3DFFBF361AAA POLYMEROLEPIS KARATAJŪTĖ-TALIMAA, 1968 Type species — Polymerolepis whitei Karatajūtė-Talimaa, 1968. POLYMEROLEPIS SP. ( FIG. 6D ; TABLE 1 ; SUPPL. 1, FIGS. 5 , 7 , 11, 14) Referred specimens —Very rare, one scale at level 458.67’ ( 139.8 m ) and possible scale fragments from 430.5’ ( 131.2 m ), 453’ ( 138.1 m ), 492.3’ ( 150.1 m ): Roberts Mountains Formation. Description and comparison —The scales and scale fragments have finely noded ridges. The scale base is always flat or concave. The type material of P.whitei from the Lochkovian of Podolia shows a wide range of scale morphotypes (e.g., Obruchev and Karatajūtė-Talimaa 1967 , pl. 2 figs. 1–4, Karatajūtė-Talimaa 1998 , figs. 6, 7). Hanke et al. (2013 , figs. 1–5) demonstrated in their description of a partial articulated specimen from the Lochkovian MOTH locality in the Northwest Territories , Canada assigned to P. whitei , comprising an anal fin and part of the caudal fin and peduncle, that the scale variation over the body is even greater than seen in the type scales. Specimens referred to P. whitei from the younger Lochkovian ( delta conodont Zone) Windmill Limestone, Simpson Park Range, Nevada include head, fin, and body scales ( Turner and Murphy 1988 , table 1, figs. 2.14, 15, 20, 22–26). The Nevadan scales are the first record in the Silurian for this taxon. Given the morphological variation in scales from the known localities, it seems possible that more than one species is represented, so we only refer the BC II specimens to an open taxon within the genus rather than to the type species.