''Stigmadiscus'' Rasetti, 1966, is a genus of Lower Cambrian Eodiscinid trilobite belonging to the family

Weymouthiidae The Weymouthiidae Kobayashi 1943 are an extinct family of eodiscinid agnostid trilobites. They lived during the late Lower Cambrian and earliest Middle Cambrian (Botomian to Delamaran) in the so-called ''Olenellus''- and ''Eokochaspis''-zon ...

Kobayashi (1943) Order Agnostida (Salter 1864) It lived during the Botomian stage, = late Lower Cambrian Stage 4 (upper of two stages subdividing the un-named Series 2); the upper Botomian Stage boundary corresponds to base of both the Middle Cambrian Wuliuan stage and Miaolingian Series. ''Stigmadiscus'' resembles ''Acidiscus'' in having a relatively short glabella, distinct S1 and S2 lateral furrows, and a slender occipital spine. In fact, according to Cotton & Fortey (2005, fig. 3) COTTON, T. J. and FORTEY, R. A. (2005). "5. Comparative morphology and relationships of the Agnostida". In Koenemann, S.; Jenner, R. (eds.). ''Crustacean Issues 16, Crustacea and Arthropod Relationships''. Boca Raton: CRC Press. consensus is that ''Stigmadiscus'' and ''Bolboparia'' Rasetti, 1966, are sister taxa of ''Acidiscus''.

References

Cambrian trilobites Weymouthiidae Agnostida genera Cambrian trilobites of North America {{agnostida-stub Cambrian genus extinctions