Pterospathodus eopennatus, Waid, Christopher B. T. & Cramer, Bradley D., 2017

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 : 20-21

Pterospathodus eopennatus ssp. n. 2 Männik, 1998

Figures 4.1-4.3, 4.5 , 10.8-10.19

(multi-element; synonymy for Pt. eopennatus through 1998).

2003 Pterospathodus eopennatus ssp. n. 2 Männik; Loydell, Männik, and Nestor, fig. 14o.

2006 Pterospathodus eopennatus ssp. n. 2 Männik; Hints, Killing, Männik, and Nestor, pl. 3, fig. 9.

2007a Pterospathodus eopennatus ssp. n. 2 Männik; Männik, fig. 6G-H.

Description. Sb 2 element tertiopedate. Lateral processes extend from cusp at different angles. Posterior process denticulate. Undenticulated outer lateral process extends down from the bottom of the cusp. Inner lateral process short, with one denticle. Sc 1 element bipennate with a short, denticulate anterior process extending down away from the cusp, and a short, denticulate posterior process extending straight away from the cusp. M element dolabrate with an undenticulated anterior process extending straight down from a robust cusp, and a denticulate posterior process extending straight, and at a slight angle down, from the cusp. Pb 1 elements angulate to slightly anguliscaphate, denticulate anterior process longer than denticulate posterior process. Cusp and posterior denticles angled posteriorly. Denticles on the anterior process are oriented posteriorly close to the cusp and progressively become more anteriorly oriented farther away from the cusp. Pc element pastinate with a prominent cusp. Anterior process short and angled steeply down from cusp. Posterior process extends straight and intersects cusp at an approximately 90 o angle. Basal cavity flares out beneath cusp into primitive outer lateral process. Pa element in Figure 10.17 -18 blade like, with a half-circle profile in lateral view. Denticles are short relative to height of element. Anterior and posterior processes slightly offset in oral view. Pa element shown in Figure 10.15 relatively long, with 14 denticles on the blade. Denticles highest at the anterior end of the blade, and shortest in the middle of the element. Basal cavity is widest under the shortest denticles. Pa elements recovered by Metzger (2005) have 16–18 denticles.

Remarks. Two well-preserved Pa elements were recovered. The one shown in Figure 10.15 most closely resembles morph 1a of Männik (1998), which is characterized by having a long blade with denticles highest on the anterior and posterior portions, and a basal cavity that is widest under the posterior portion of the cusp. The size of the denticles relative to total element height, curvature of the oral surface in lateral view, and geometry of the basal cavity of the specimen shown in Figure 10.16 -17 most closely resembles morph 2b of Männik (1998). Morph 1 is present in both subspecies of Pterospathodus eopennatus , while morph 2 is only present in Pterospathodus eopennatus ssp. n. 2 sensu Männik (1998). The specimen classified as morph 1 as well as Pa fragments recovered are assigned to Pterospathodus eopennatus ssp. n. 2 sensu Männik (1998) because they were recovered from sample intervals overlying the morph 2 specimen. The Pa specimens recovered by Metzger (2005; Figure 4.1-3, 4.5 ) at the DX5 section most closely resemble morphs 1a or 1b from the Upper Pt. eopennatus ssp. n. 2 Zone ( Männik, 1998, text-figure 6).

Material examined. One Sb 1, two Sb 2, three Sc 1, two M, one Pc, seven Pb 1, four Pa elements.

Figures

FIGURE 4. Specimens reported from the DX5 outcrop section in Metzger (2005). All specimens in lateral view. 1-3, 5, Pterospathodus eopennatus ssp. n. 2 sensu Männik (1998), Pa element, DLH 4, SUI 132418 (1); Pa element, DLH 6, SUI 132420 (2); Pb element, DLH 6, SUI 132420 (3); and Pa element, DLH 9, SUI 132423 (5). 4, 6-9, Pterospathodus amorphognathoides angulatus, Pa element, DLH 6, SUI 132420 (4); Pb element, DLH 6, SUI 132420 (6); Pa element, DLH 6, SUI 132420 (7); Pb element, DLH 6, SUI 132420 (8); and Pa element, DLH 11, SUI 132425 (9). 10, Aulacognathus bullatus? Pb element, DLH 11, SUI 132425.

FIGURE 10. Conodonts from the Garrison Core and DX5 outcrop. 1-7, Pterospathodus amorphognathoides angulatus, Sc1 element, posterior view, GC 115.51–115.76 m, SUI 142304 (1); Pb1? element, lateral view, GC 115.51– 115.76 m, SUI 142305 (2); Pb2 element, GC 111.38–111.63 m, SUI 142306 (3); Pb1 element, inner lateral, and oral views, GC 115.51–115.76 m, SUI 132410 (4 and 5); Pa element, oral view, DX5 3.49–3.59 m, SUI 142307 (6); and Pa element, lateral view, DX5 4.59–4.61 m, SUI 142308 (7). 8-19, Pterospathodus eopennatus ssp. n. 2 sensu Männik (1998), Sb2 element, posterior, and lateral views, GC 130.79–131.09 m, SUI 142309 (8 and 9); Sc1 element, lateral view, GC 130.79–131.09 m, SUI 142310 (10); M element, GC 130.79–131.09 m, SUI 142311 (11); Pb1 element, lateral view, GC 128.85–129.11 m, SUI 142312 (12); Pc element, lateral view, GC 130.20–130.48 m, SUI 142313 (13); Pb1 element, lateral view, GC 130.20–130.48 m, SUI 142314 (14); Pa element, lateral view, GC 128.85–129.11 m, SUI 142315 (15); Pb1 element, lateral view, GC 130.20–130.48 m, SUI 142316 (16); Pa element, lateral, and oral views, GC 130.79–131.09 m, SUI 142317 (17 and 18); and Pa element fragment, oral view, GC 130.20–130.48 m, SUI 142318 (19). 20-21, Aulacognathus sp., juvenile P1 element, oral, and lateral-anterior views, GC 135.65–136.10 m, SUI 142319. 22-23, Kockelella cf. K. abrupta, P1 element, oral, and lateral views, DX5 0.67–0.74 m, SUI 142320.