Hedinaspis sp.

Taylor, John F., Loch, James D. & Repetski, John E., 2024, Taxonomy and stratigraphic distribution of Lotagnostus (Agnostida: Agnostidae) and associated trilobites and conodonts in the Upper Cambrian (Furongian) of Laurentia, Zootaxa 5422 (1), pp. 1-66 : 33-34

Hedinaspis sp.

( Plate 7.19 )

Discussion. A single, very fragmentary pygidium was recovered in collection 5/22/08C in the Lotagnostus rushtoni fauna from the Windfall Formation, Ninemile Canyon, Nevada. The distal half to two-thirds of six pleurae with very broad (exsag.) pleural furrows are bounded in front and behind by narrower, strongly convex bands of roughly equal width. Posterior bands of the anteriormost pleurae extend for very short distance posterolaterally as short, blunt terminal spines. The distinctive form of the pleurae allows for certain assignment to Hedinaspis but the specimen is too fragmentary for more precise identification. Uncertainty as to which part(s) of the skeleton the specimen represents is made all the more difficult by the typically obscure boundary between the thorax and pygidium noted in previous studies of Hedinaspis (e.g. Troedsson, 1937; Lu & Lin, 1989).

Ceratopygid indeterminate

( Plate 16 , figs 13, 17)

Discussion. Two relatively large specimens in collection D7129-CO from the Hot Creek section of the Hales Limestone represent a non-spinose ceratopygid species. The flat, semi-elliptical pygidium with a tapering axis that extends nearly to the posterior margin, and long frontal area on the cranidium resemble those of some species of Pseudoyuepingia (e.g. P. elongata Lu & Lin, 1989 ). However, the cranidium is too fragmentary for confident assignment to genus.

Figures

PLATE 7. Miscellaneous Windfall taxa.Each white scale bar represents 2mm. 1-3. Lotagnostus cf. L. obscurus. USMN 775722, cephalon, from D3362-CO, dorsal, anterior, and left lateral views. 4-6. Rhaptagnostus cf. R. convergens. Cephalon, CM 41350, from 5/22/08B, dorsal, anterior, and right lateral views. 7-9. Lotagnostus cf. L. obscurus. Cephalon, CM 41351, from 5/22/08B, dorsal, anterior, and right lateral views. 10-12. Homagnostus?. Pygidium, CM 41356, from 5/22/08B, dorsal, posterior, and left lateral views. 13-15. Lotagnostus cf. L. obscurus. Pygidium, CM 41353, from 5/22/08B, dorsal, posterior, and left lateral views. 16. Homagnostus? sp. Pygidium, CM 41401, from 5/22/08B, dorsal view. 17-18. Micragnostus cf. M. intermedius. Cephalon, CM 41358, from 5/22/08B, left lateral and dorsal views. 19. Hedinaspis sp. Fragmentary thoracic and/or pygidial fragment, CM 41359, from 5/22/08C, dorsal view. 20. Machairagnostus cf. M. corrugatus. Pygidium, CM 41349, from 5/22/08B, dorsal view. 21-22. Homagnostus? sp. Cephalon, CM 41357, from 5/22/08B, dorsal and anterior views.

PLATE 16. Taxa from Hedinaspis-Charchaqia Fauna in the Hales Formation, Hot Creek section. Each white scale bar represents 2mm. 1. Lotagnostus nolani n. sp. Carapace (latex peel of external mold), USMN 775754, with Mendoparabolina nyensis, cephalon (counterpart of holotype), USMN 218571 (= Taylor, 1976, pl. 3, fig. 16), from D7130-CO, dorsal view, x7.8. 2, 3. Lotagnostus nolani n. sp. Cephalon, USMN 775755, from D7133-CO, dorsal and anterior views, x11.0. 4-5. Lotagnostus nolani n. sp. Cephalon, USMN 775756, from D7130-CO, dorsal and lateral views, x9.7. 6. Lotagnostus nolani n. sp. Pygidium, USMN 775757, from D7130-CO, dorsal view, x12.2. 7. Lotagnostus nolani n. sp., pygidium, USMN 775758, from D7130-CO, dorsal view, x10.3. 8. Pseudagnostus? sp., carapace, USMN 775759, from D7130-CO, dorsal view, x8.0. 9. Pseudagnostus? sp., carapace, USMN 775760, from D7133-CO, dorsal view, x8.3. 10. Mendoparabolina nyensis (Taylor, 1976), small cranidium, USMN 775761, from D7133- CO, dorsal, x14.3. 11. Mendoparabolina nyensis (Taylor, 1976), pygidium, USMN 775762, from D7130-CO, dorsal view, x7.5. 12. Lotagnostus sp., cephalon, USMN 775763, from D7130-CO, dorsal view, x16.8. 13. Ceratopygid undet., cranidium, USMN 775764, from D7129-CO, dorsal view, x3.9. 14. Lotagnostus sp., cephalon, USMN 775765, from D7130-CO, dorsal view, x8.6. 15. Lotagnostus sp., pygidium, USMN 775766, from D7131-CO, dorsal view, x4.4. 16. Lotagnostus sp., pygidium, USMN 775767, from D7130-CO, dorsal view, x6.5. 17. Ceratopygid undet., pygidium, USMN 775768, from D7129-CO, dorsal view, x2.6.