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Hi everyone. I would expose a paleontological ID question that intrigues me. Let me do it in a storytelling style. Prologue Last November I found this beautiful bug in a limestone Upper Campanian /Lower Maastrichtian strata in the SE of Pyrenees, Catalonia (Spain). So, I start a little detective process... which turned not to be so little. This cidaroid specimen is almost complete, retaining even its plates, which is rather rare. In fact, its plates are of most importance in this story. Chapter 1 In 1933 French paleontologist Jules Lambert found some cidaroid specimens in the Pyrenees, in a place not far from I live, called Falgars (a Holy Mary sanctuary surrounded by meadows and woods, a very nice place). He described the species as Typocidaris falgarsensis, designing a holotype. He donated –among others- the holotype to the Museu Geologic del Seminari de Barcelona (Seminary’s –catholic- of Barcelona Geological Museum). But during the turmoil of revolutionary events of Spanish Civil War the Seminary’s was sacked in 1936 and the holotype was lost. In 1997 paleontologist J.J.Carrasco did a revision of the species and fixed a neotype, a specimen found some 4 km west of Falgars, in strata continuity, near the little village of Sant Julià de Cerdanyola. He reclassified it as Temnocidaris (Stereocidaris) falgarsensis (Lambert 1933). He did it in this paper (in Spanish) (The exact site where the original holotype was found is now forgotten) Sant Julià de Cerdanyola village I went to the MGSB museum, where director Dr. Calzada kindly allowed me to compare my specimen with the neotype, and as far as I know they are the same. ID solved? Not entirely In 1991 North-American paleontologists D.B.Blake and W.J.Zinsmeister described a new genus and new species of cidaroid echinoid from the Maastrichtian of Seymour Island, Antarctic Peninsula: Almucidaris durhami. As they said here The species is unique in that the plates of the female expanded and hollowed to form marsupia. Maybe not so unique, though, as during the last 90’s (I don’t know when exactly) some specimens of cidaroid echinoids forming marsupia were found around... Sant Julià de Cerdanyola. You can see them in this thread of the Spanish Foro Nautilus (my specimen is the last one, and was found some 15 km. west of Sant Julià, not far from the town of Berga. Note that it has no marsupia, so it is arguably male). Andrew B. Smith took the view that Pyrenean Upper Cretaceous cidaroids showing marsupia should be classed in the genus Almucidaris, as he stated in The Echinoid Directory. In fact A.B.Smith made for the first time this statement in: Smith, A.B. & Jeffery, C.H. 2000. Maastrichtian and Palaeocene echinoids: a key to world faunas. Special Papers in Palaentology 63, 1-406. Unfortunately, I have no access to this paper. I have sent some messages to TED, with no answer. Unsolved enigmas So, we Spanish amateur or professional paleontologists have assumed Andrew B. Smith’s view, calling our specimens Almucidaris falgarsensis. But some questions remain unresolved. a) If specimens with marsupia are females, what about the male ones (as mine)? The belonging of arguably male specimens of Temnocidaris (Stereocidaris) falgarsensis to the genus Almucidaris can’t be stated? This would lead to a very paradoxical situation, with females of one species belonging to a genus and male ones remaining in another (a bizarre sort of sexual discrimination ). b- Are Almucidaris durhami and Almucidaris falgarsensis the same species or only belong to the same genus? c) Have been found specimens in other places, apart from Antarctica and Pyrenees, of cidaroid echinoids having developed large brood chambers in the plates? I highly appreciate any information and suggestions, and I hope I have not bored you.