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 1975 1 32 http://dx.doi.org/10.5070/p940454153 journal article 10.5070/P940454153 0031-0298 10913559 58312615-0833-432E-BF5D-3DFFBF361AAA BARLOWODUS SP. CF. B. FLORALIS ( FIG. 8A–K ; TABLE 1 ; SUPPL. 1, FIGS. 4 , 5 , 7 ) Referred specimens — Circa 20 specimens from BC II level 430.5' ( 131.2 m ); two from level 453' ( 138.1 m ): Roberts Mountains Formation . Description and comparison —Small scales with complex crown sculpture, all with fine ribbed ultrasculpture ( Fig. 8A–K ). One possible head or oral scale has a high multi-ridged crown and high neck with a rounded base and large central pulp opening ( Fig. 8A ). One possible cephalopectoral scale has a flattened rhombic crown which rises only slightly to a posterior point; fine ultrasculpture as well as borings can be seen on the surface ( Fig. 8B ). Most scales are trunk scales. The crowns rise gently posteriad with three flat ridges or a system of bifurcating ridges separated by deep or wide grooves. The posterior or posterolateral crown margin is multi-pointed ( Fig. 8A, C–F, H–K ). Most scales in level 430.5’ seem affected by fungal damage (as noted for other specimens above). Histology was attempted using anise oil but the structure is disrupted and so we cannot verify the apparent “criss-cross aspidine ‘pegs’” noted as characteristic for the genus and separate family by Märss et al. (2006 , p. 121). However, a similar criss-cross pattern of Sharpey’s fiber bundle spaces is found in other deep and swollen old bases of other thelodont scale taxa such as Thelodus laevis (e.g., Bystrow 1957 , Gross 1967 ). Remarks —Most of the scales from Nevada seem closest to B. floralis . The type locality for the latter is at 34.5* m in the same section where it co-occurs with the other two Barlowodus species ( Märss et al. 2006 ).