Micragnostus, Howell, 1935

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 : 53

Micragnostus cf. M. intermedius

( Plate 7.17–7.18 )

Discussion. This single pygidium in collection 5/22/08B from Ninemile Canyon strongly resembles the holotype of Micragnostus intermedius ( Palmer, 1968) in its transverse F2, parallel trend of the axial furrows from F1 to slightly posterior to F2 posteroaxis, wide and deep border furrow and narrow border. It does, however, display a slightly less inflated, nearly semi-circular posteroaxis. Whether that difference is merely intraspecific variation is undeterminable with the limited material available for comparison.

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.