Panderodus equicostatus ( Rhodes, 1953 )

Waid, Christopher B. T. & Cramer, Bradley D., 2017, Telychian (Llandovery, Silurian) conodonts from the LaPorte City Formation of eastern Iowa, USA (East-Central Iowa Basin) and their implications for global Telychian conodont biostratigraphic correlation, Palaeontologia Electronica 42 (6), pp. 1-37 : 24

Panderodus equicostatus ( Rhodes, 1953)

Figure 7.1-2

*1953 Paltodus equicostatus ; Rhodes, pl. 21, figs. 106-109.

2005 Panderodus equicostatus Rhodes ; Sansom and Smith, pl. 1, figs. 26-28 (synonymy through 1994).

2008 Panderodus equicostatus Rhodes ; Calner, Eriksson, Clarkson, and Jeppsson, fig. 4A.

2008 Panderodus equicostatus Rhodes ; Männik, fig. 10X-Z, BB, CC.

2015 Panderodus equicostatus Rhodes ; Jarochowska and Munnecke, fig. 7M, N; fig. 8I-L.

Description. Elements are long, slender, and fairly straight for 2/3 to 3/4 of the length of the element. White matter restricted to the tips of the cusps, where the most curvature occurs. Cusps are very short on most specimens, with the exception of truncatiform elements, where the cusp about 1/4 of the total length of the element. Furrows are very narrow, and extend most of the length of the element. See Sansom and Smith (2005) for detailed species diagnosis, and Sansom et al. (1994) for illustration of apparatus (figured as Panderodus acostatus ).

Remarks. This species can be differentiated from Panderodus unicostatus by the distribution of white matter and the overall curvature of the elements. The white matter in P. equicostatus elements is restricted to the tips, and the anterior margin of the element is less rounded in lateral view than most specimens of P. unicostatus .

Material examined. One aequaliform, eleven tortiform, eleven falciform, seventry-four graciliform, six truncatiform, and eighteen arcuatiform elements.

Figures

FIGURE 7. Simple cone elements from Garrison Core. All specimens in lateral view except for 6. 1-2, Panderodus equicostatus, graciliform, GC 124.66–124.93 m, SUI 142251 (1) and graciliform, GC 121.92-121.88 m, SUI 142253 (2). 3-5, Panderodus panderi, graciliform, GC 124.66–124.93 m, SUI 142252 (3); arcuatiform, GC 131.95–132.23 m, SUI 142254 (4); and graciliform, GC 111.38–111.63 m, SUI 142255 (5). 6, Psuedooneotodus beckmanni, oral view, GC 135.65–136.10 m, SUI 142256. 7, Panderodus cf. P. unicostatus, falciform, GC 135.65–136.10 m, SUI 142257. 8- 11, Panderodus unicostatus, falciform, GC 131.95–132.23 m, SUI 142258 (8); fused cluster of 8 elements, GC 130.20–130.48 m, specimen destroyed processing for SEM (9); fused cluster of 6 elements, GC 131.95–132.23 m, SUI 142260 (10); and tortiform element, GC 131.95–132.23 m, SUI 142261 (11); 12-13, Walliserodus curvatus, dyscritiform, GC 134.06–134.31 m, SUI 142262 (12) and curvatiform, GC 128.85–129.11 m, SUI 142263 (13). 14-15, Panderodus greenlandensis, arcuatiform GC 118.20–118.41 m, SUI 142264 (14) and graciliform, GC 134.06–134.31 m, SUI 142265 (15). White scale bar represents 0.5 mm.