FIGURE 4 in Revision of the Early Ordovician (late Tremadocian; Stairsian) cheirurid trilobite Tesselacauda Ross, with species from the Great Basin, western USA

FIGURE 4. Hypostomes of various species of Cheiruridae. 1, 2. Tesselacauda kriegerae n. sp. (upper Tremadocian; Stairsian; Bearriverops alsacharovi Zone). 1. SUI 147614 (see also Pl. 15, figs 1, 5, 9, 13, 17), Section G 26.6 m, x12. 2. SUI 147639 (see also Pl. 18, figs 11, 12, 14, 16), Section HC6 124.0 m, x12. 3, 4. Tesselacauda depressa Ross, 1951 (upper Tremadocian; Stairsian; Bearriverops loganensis Zone). 3. SUI 147516 (see also Pl. 2, figs 13–16), Section HC5 106.7 m, x9. 4. SUI 147539 (see also Pl. 5, figs 3, 7, 11, 15, 19), Section MME 75.5 m, x10. 5. Cydonocephalus n. sp. 1, SUI 147657, Antelope Valley For- mation (probably Dapingian), Funeral Mountains, Death Valley National Park, California, x12. 6. Cydonocephalus n. sp. 2, GSC 135352, Table Cove Formation (Darriwilian), near Main Brook, northwestern Newfoundland, Canada, x12. 7. Heliomerinae n. gen. n. sp. 1, SUI 147658, Section H 127.1 m (Floian; Tulean; Heckethornia bowiei Zone), x15. 8. Heliomerinae n. gen. n. sp. 2, SUI 147659, Section H 191.7 m (Floian; Blackhillsian; Bathyurina plicolabeona Zone), x15. 9. Kawina n. sp. 1, SUI 147660, Section K 1.5T m (Dapingian; Pseudoolenoides dilectus Zone), x10. 10. Sycophantia polydora (Billings, 1865), GSC 135353, Table Cove Formation (Darriwilian), near Main Brook, northwestern Newfoundland, Canada, x15. 11. Sphaerexochus n. sp. 1, GSC 135354, Table Cove Formation (Darriwilian), near Main Brook, northwestern Newfoundland, Canada, x20. 12. Kawina n. sp. 2, GSC 135355, Table Cove Formation (Darriwilian), near Main Brook, northwestern Newfoundland, Canada, x12. 13. Forteyops n. sp. 1, SUI 147661, Section H 222.1 m (Floian; Blackhillsian; Carolinites nevadensis Zone), x25. 14. Acanthoparyphinae n. gen. n. sp. 1, SUI 147662, Section J 40.0 m (Floian; Blackhillsian; "Pseudocybele nasuta Zone"), x20.