Differs from Micraster in having pore-pairs in the frontal ambulacrum subpetaloid, a more inflated shape, and a non-labiate peristome. Differs from Plesiaster in having shorter and narrower petals and a more inflated outline. However, differences are minor and there are no structural plating differences between these taxa. Closest to Gibbaster in appearance differing only in minor details (Pseudogibbaster has a more downward-facing peristome and less projecting labral plate, and its periproct opens higher on the posterior surface). Possibly only a subgenus of Gibbaster.
Smith, A. B. & Jeffery, C. H. 2000. Maastrichtian and Palaeocene echinoids: a key to world faunas. Special Papers in Palaeontology 63, 1-404.
Smith, A. B., Gallemi, J., Jeffery, C. H., Ernst, G. & Ward, P. D. 1999. Late Cretaceous-Early Tertiary echinoids from northern Spain: implications for the Cretaceous-Tertiary extinction event. Bulletin of the Natural History Museum, London, Geology Series 55, 81-137.