The Echinoid Directory

• Test subpentagonal in outline; depressed in profile with rounded ambitus; weakly concave on oral surface.
• Apical disc large, pentagonal, extending posterior to ambitus and forming a U-shaped notch to the posterior. Plates loosely connected to corona and always lost; presumed monocyclic.
• Ambulacra simple and non-petaloid aborally; plates narrow and tall with pore-pairs small and oblique. Continues as simple plating to the peristome and with pores becoming biserial in adults (uniserial throughout in smaller individuals).
• Peristome small, central and circular; feeble buccal notches.
• Tuberculation fine and uniform; interambulacral plates with a single large primary tubercle that is perforate and non-crenulate with a large circular areole; primary tubercles displaced adradially at ambitus and adapically.
• Traces of perignathic girdle (auricles) in juveniles.
• Spines unknown (spine reported by Smith & Anzalone is strongly crenulate and unlikely to come from this taxon).

Lower Jurassic (Pliensbachian), Italy, Iraq.

Cidarites ludovicii Meneghini, 1867, p. 17 [=Hemipedina marconissae Desor, 1856, p. 59], by original designation.

• Only the type species.

Euechinoidea; stem group Irregularia.

Monotypic; subjective junior synonym of Mesodiadema Neumayr, 1889.

As discussed in Smith & Anzalone (2000), Desor's (1858) Hemipedina marcconissae comes from the same horizon and general area. Having now studied this species, there is little doubt that it is synonymous with Cidarites ludovicii Meneghini, 1867. Because H. marconissae was made the type species of Mesodiadema by Neumayr (1889), Fucini\'s Loriolella becomes a junior synonym.

Hawkin's (1922) Pseuopygaster is also indistinguishable and falls into synonymy.

Fucini, A. 1904. Loriolella ludovicii Meneghini. Nuovo genere di Echino irregulare. Annali delle Universita Toscane, 24, 3–9, 1 pl.

Smith, A. B. & Anzalone, L. 2000. Loriolella, a key taxon for understanding the early evolution of irregular echinoids. Palaeontology 43, 303-324.