Laganidae, Desor, 1858

Ziegler, Alexander, Lenihan, Jennifer, Zachos, Louis G., Faber, Cornelius & Mooi, Rich, 2016, Comparative morphology and phylogenetic significance of Gregory’s diverticulum in sand dollars (Echinoidea: Clypeasteroida), Organisms Diversity & Evolution (New York, N. Y.) 16 (1), pp. 141-166 : 154

Laganidae

Several species pertaining to the laganid genera Jacksonaster ( Fig. 2g, h ), Laganum ( Fig. 2i, j ), and Peronella ( Fig. 2k–m ) were analyzed. Although no comprehensive X-ray imaging series is available for any laganid species, the combined data—including a relatively small specimen of Peronella macroproctes with 10 mm test length—suggest the absence of Gregory’ s diverticulum in all taxa belonging to the Laganidae .

Figures

Fig. 2 Absence of Gregory’s diverticulum in the Clypeasteridae (a–f), Laganidae (g–m), Echinocyamidae (n–p), Fibulariidae (q, r), and the miniaturized rotulid Fibulariella (s, t). This figure shows selected X-ray images, virtual MRI sections at the level of the main digestive tract, as well as a drawing and a photograph of dissected specimens. a, b Clypeaster reticulatus (24 mm test length); c Ammotrophus cyclius (35 mm); d, e Arachnoides placenta (27 mm); f Fellaster zelandiae (47 mm); g, h