摘要：We describe a new species of the unusual crinoid Tiaracrinus, T. jeanlemenni sp. nov. from the latest Emsian of the famous mudmound locality Hamar Laghdad, Morocco. It differs from the previously known species in the higher number of ribs and the vaulted rib-fields, which is corroborated by the comparison of simple quantitative characters and ratios as well as by the results of a cluster analysis and a Principal Component Analysis. Based on the new material and the published specimens, we discuss the phylogeny of the genus and suggest that T. oehlerti and T. moravicus represent the ancestral forms of this small clade.
