LAUSR

Abstract. Kazacharthrans are exclusively fossil crustaceans restricted to the Triassic and possibly Jurassic period and were first described by Tchernyshev in 1940. Kazachartha is supposed to represent the sister group to Notostraca (tadpole shrimps). Little is known about the morphology of most kazacharthrans, and in general only few publications are available. We present here a specimen with kazacharthan-related traits, which we compare to the co-occurring species Notostraca minor (formerly Triops cancriformis minor), a notostracan representative. Both specimens come from the Museum Terra Triassica in Euerdorf, Lower Franconia, southern Germany and were documented using cross-polarized light and autofluorescence settings to achieve well contrasted, high-resolution images. Key morphological features of the kazacharthran-like specimen are the very broad shield without a dorsal midline and spines, a broad and elongated posterior trunk and a square-shaped telson with lateral bulges. Also some details, like different eye structures, mandibular and cervical groove, intestine, and the paired shell glands are visible. Comparison to Notostraca minor revealed differences in these morphological features between the two specimens. We suggest an interpretation of the presented specimen near Kazacharthra due to the described features and discuss the importance of the specimen for branchiopodan phylogeny and biogeography.