Wotte and Sundberg—Small shelly fossils from the Great Basin
Groom Range (GR 8), Log Cabin Mine (LC 1), and Oak Spring Summit (OS 11) sections; Delamaran Stage.
Description.—Straight (Fig. 6.24, 6.25, 6,27, 6.28) to gently curved (Fig. 6.26) fragments with circular cross-section. Tube fragments slightly expanding. Length and width of tube frag- ments up to 2.4mm and 200 μm, respectively. Internal molds smooth.
Remarks.—Classification of hyolithelminthids is primarily based on cross-section, ornamentation, and degree of tapering of the phosphatic tubes, which has resulted in a large variety of generic and specific names of often unclear differences (Landing, 1988; Bengtson et al., 1990; Skovsted, 2006b; Paterson et al., 2007; Topper et al., 2009; Skovsted and Peel, 2011; Smith et al., 2015). Following Bengtson in Gravestock et al. (2001) and Elicki (2011), we use the formal classification into hyolithellid and torellellid hyolithelminths. Internal molds described have a circular cross-section and are thus referred with some uncertainty to the hyolithellid genus Hyolithellus Billings, 1872 (1871).
Phylum uncertain
Class Coeloscleritomorpha Bengtson and Missarzhevsky, 1981 Order Chancelloriida Walcott, 1920 Family Chancelloriidae Walcott, 1920
Remarks.—Several samples have produced isolated rays that cannot be assigned to a particular genus within this family. These are listed as chancelloriid spicules even though they may belong to co-occurring taxa listed below.
Genus Allonnia Doré and Reid, 1965
Type species.—Allonnia tripodophora Doré and Reid, 1965 (p. 20, fig. 1); Carteret Formation (lower Cambrian; correlated with the Cambrian Series 2); Carteret, Cotentin Peninsula, Normandy, France.
Allonnia sp. Figure 8.9–8.11
Occurrence.—Several spicules from the Antelope Canyon (AC 0, AC 2, AC 4, AC 5), Echo Canyon (E 6, E 10, E 12, E 16), Grassy Spring (GS 1, GS 2, GS 8, GS 13, GS 16, GS 17, GS K), Groom Range (GR 4, GR 5, GR 8, GR 11), Indian Springs Canyon (I 12), Log Cabin Mine (LC 1, LC 2, LC 3, LC 5, LC 6, LC 7), Montezuma Range (M 5), Oak Spring Summit (OS 1, OS 2, OS 4, OS 5, OS 6, OS 6/2, OS 7, OS 7.0, OS 11, OS 12), and Split Mountain (SM 14, SM 15) sections; Montezuman–Dela- maran stages.
893
Description.—Poorly preserved spicules with 4+0 rays slightly diverge from the basal plane.
Remarks.—Chancelloriids with 2+0, 3+0, and 4+0 rays are referred to the genus Allonnia (see Qian and Bengtson, 1989; Moore et al., 2013). Orientation and arrangement of our four- rayed spicules indicate a systematic affiliation to A. tetrathallis (Jiang in Luo et al., 1982).
Genus Chancelloria Walcott, 1920
Type species.—Chancelloria eros Walcott, 1920 (p. 329–331, pl. 86, figs. 2, 2a–c; pl. 88, figs. 1, 1a–f); Ogygopsis Zone, Burgess Shale Member, Stephen Formation (middle Cambrian; correlated with the Cambrian Series 3); northeast of Burgess Pass, British Columbia, Canada.
Chancelloria sp. 1 Figure 8.12–8.15
Occurrence.—Hundreds of spicules from the Log Cabin Mine (LC 6) and Oak Spring Summit (OS 4) sections; Dyeran Stage.
Description.—Poorly preserved spicules with 6+0 rays. Rays slightly bent upwards from the basal plane. Foramen on the lower side rounded to oval (Fig. 8.14).
Remarks.—Detailed systematic affiliation is difficult due to poor preservation. Shape and organization of spicules suggest an affiliation to Chancelloria. However, an affiliation to Archiasterella Sdzuy, 1969 (e.g., A. elegans Demidenko in Gravestock et al., 2001) could not be excluded.
Chancelloria sp. 2 Figure 8.16–8.22
Occurrence.—Thousands of spicules and large number of isolated rays from the Antelope Canyon (AC 0, AC 2, AC 4, AC 5), Echo Canyon (E 6, E 10, E 12, E 16), Grassy Spring (GS 1, GS 2, GS 8, GS 13, GS 16, GS 17, GS K), Groom Range (GR 4, GR 5, GR 8, GR 11), Indian Springs Canyon (I 12), Log Cabin Mine (LC 1, LC 2, LC 3, LC 5, LC 6, LC 7), Montezuma Range (M 5,M6), Oak Spring Summit (OS 1, OS 2,OS 4,OS 5, OS 6, OS 6/2, OS 7, OS 7.0,OS 11, OS 12), and Split Mountain sections (SM 14, SM 15); Montezuman–Delamaran stages.
Description.—Spicules with 5 +1 broken rays. The vertical ray is more robust and shorter than the lateral rays. Rays slightly bent upwards from the basal plane.
Figure 6. Small shelly fossils from the Campito, Delamar, Echo Shale, Combined Metals members of Montezuma Range, Echo Canyon, Grassy Spring, Oak Spring Summit, Log Cabin Mine sections as well as from the basal Emigrant Formation of Split Mountain; Montezuman–Dyeran stages; all scale bars 200 μm: (1–23) Pelagiella aff. P. subangulata (Tate, 1892): (1–3) FG 544/GB/LC/6/A9-12, (1, 2) lateral view, (3) oblique apertural view; (4–6) FG 544/GB/LC/6/A9-19, (4, 5) lateral view, (6) oblique apertural view; (7–9) FG 544/GB/LC/6/A9-33, (7, 8) lateral view, (9) oblique apertural view; (10–12) FG 544/GB/SM/14/A1-13, (10, 11) lateral view, colonization of endolithic cyanobacteria on the internal mold, (12) oblique apertural view; (13, 14) FG 544/GB/OS/5/A12-13, lateral view; (15) FG 544/GB/GR/11/A10-11, lateral view; (16) FG 544/GB/GR/11/A10-22, lateral view; (17–19) FG 544/GB/GR/11/A10-6, (17, 18) lateral view, (19) oblique apertural view; (20–22) FG 544/GB/GR/11/A10-31, (20, 21) lateral view, (22) oblique apertural view; (23) FG 544/GB/GS/13/A6-14, oblique lateral view. (24–28) Hyolithellus? sp.: (24) FG 544/GB/M/5/C8-2; (25) FG 544/GB/LC/6/A8-1; (26) FG 544/GB/M/5/C8-1; (27) FG 544/GB/M/5/C8-3; (28) FG 544/GB/GS/17/A5-11.
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