RESEARCH PAPER Family Dibrachicystidae (Echinodermata: Rhombifera) from the ‘‘Middle’’ Cambrian of the Barrandian area, Czech Republic Oldr ˇich Fatka • Michal Szabad Received: 18 June 2013 / Accepted: 26 June 2013 / Published online: 30 July 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract A slightly crushed but otherwise nearly com- plete specimen of the recently described rhombiferan echinoderm genus Vizcainoia Zamora and Smith, 2012 is documented from the ‘‘Middle’’ Cambrian Jince Formation of the Prˇı ´bram–Jince Basin of the Czech Republic. Isolated thecal plates, earlier determined as calyx plates of the eocrinoid Acanthocystites briareus Barrande, 1887 and/or as eocrinoid sp., occurring in diverse levels of the Jince Formation are reassigned to Dibrachicystidae gen. et sp. indet. Similarly, isolated thecal plates collected from the Buchava Formation of the Skryje–Ty ´r ˇovice Basin could be classified as Dibrachicystidae gen. et sp. indet. Specimens from the Barrandian area are the first records of the family Dibrachicystidae outside of southwestern Europe, of the family otherwise known only from the Languedocian of Montagne Noire of France and from the Caesaraugustian and Languedocian of Iberian Chains of northern Spain. Keywords Vizcainoia Á Barrandian area Á ‘‘Middle’’ Cambrian Kurzfassung Ein leicht angebrochenes, sonst aber fast vollsta ¨ndiges Exemplar der Stachelha ¨uter-Gattung Vizcai- noia Zamora and Smith, 2012, wurde in der mittel- kambrischen Jince-Formation des Prˇı ´bram–Jince Beckens in der Tschechischen Republik gefunden. Isolierte Kelchplatten aus verschiedenen Lagen der Jince-Forma- tion, welche fru ¨her als dem Eocrinoiden Acanthocystites briareus Barrande, 1887 zugeho ¨rig klassifiziert wurden, werden nun Dibrachicystidae gen. et sp. indet. zugeordnet. Vergleichbare isolierte Platten aus der Buchava-Formation des Skryje–Ty ´r ˇovice Beckens geho ¨ren ho ¨chstwahrschein- lich ebenfalls zu Dibrachicystidae gen. et sp. indet. Die vorliegenden Exemplare aus dem Barrandium sind die ersten Funde dieser Familie außerhalb SW Europas. Bisher war die Familie Dibrachicystidae nur aus dem Languedo- cian der Montagne Noire in Frankreich und aus dem Caesaraugustian und Languedocian der Iberischen Ketten Nordspaniens bekannt. Schlu ¨ sselwo ¨rter Vizcainoia Á Barrandium Á Mittleres Kambrium Introduction Our knowledge of Cambrian echinoderm Lagersta ¨tten has greatly improved in the last two decades. The record of Cambrian echinoderms comprises nearly 200 species classified within eight major groups: (1) helicoplacoids, (2) eocrinoids, (3) edrioasteroids, (4) rhombiferans, (5) cinc- tans, (6) ctenocystoids, (7) solutes, and (8) stylophorans (Zamora et al. 2013). Recently, the surprising discovery of two-armed echinoderms from the early ‘‘Middle’’ Cam- brian of Spain and France supplemented this record (Zamora 2010; Zamora and Smith 2012). The two genera, Dibrachicystis Zamora and Smith, 2012 and Vizcainoia Zamora and Smith, 2012, were assigned to the newly established family Dibrachicystidae. The aim of this contribution is to document the presence of the rhombiferan family Dibrachicystidae from the early O. Fatka (&) Faculty of Science, Institute of Geology and Palaeontology, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic e-mail: fatka@natur.cuni.cz M. Szabad Obra ´ncu ˚ Mı ´ru 75, 261 02 Prˇı ´bram VII, Czech Republic 123 Pala ¨ontol Z (2014) 88:159–166 DOI 10.1007/s12542-013-0193-1