New data on gastropod genus Hirsuticyclus (Caenogastropoda, Cyclophoridae) from mid-Cretaceous Kachin amber

Abstract

Abstract The genus Hirsuticyclus Neubauer, Xing and Jochum, 2019 was the first record of an exceptionally preserved land snail with dense periostracal hairs from mid-Cretaceous Kachin (Burmese) amber. Here, we document four newly-discovered shells from Kachin amber, one belonging to the type species Hirsuticyclus electrum Neubauer, Xing and Jochum, 2019 and the remaining three shells belonging to a new species, Hirsuticyclus canaliculatus sp. nov. Well-preserved morphological characteristics of these two species could be clearly demonstrated under light microscopy combined with modern micro-CT scans with computer 3D reconstructions. Our new material of the type species amends the generic diagnosis based on a better-preserved shell including the peristome and operculum. The new species shows distinctive shell characteristics such as numerous spiral keels and a flaring, folded peristome interrupted by two canals. These excellently preserved fossils contribute to our understanding of the morphological diversity and evolution of these ancient members of cyclophoroids.