Jurodidae

Abstract: Ocelli and ocellus-like structures on the vertex of the adult head were examined in different representatives of Coleoptera and the presence of these was confirmed for the suborder Polyphaga. The presence of structures, which are likely homologous with ocelli of other insects were confirmed by semi-thin sectioning in Hydraenidae, Staphylinidae, Derodontidae and Dermestidae. The presence of ocelli is newly recorded for a representative of Scydmaenidae (Nesuthia fijii Franz). The weakly pigmented areas on the vertex of Neopelatops (Leiodidae) lack a lens and associated nervous tissue and are referred to as pseudocelli, which may be present in other groups. The internal structure of Coleopteran ocelli is strongly simplified compared with other groups of Insecta where longitudinal retinula cells are arranged at a right angle to the cuticular surface and enclosed by a sheath of pigment cells. Such a regular arrangement is absent from all beetles examined histologically. A flattened group of cells without a rhabdom and without an enclosing layer of pigment cells is present underneath the cuticular lens. While, the infrastructure of the ocelli is more or less reduced in Coleoptera, the presence of these features in the ground-plan of Coleoptera is dependent on the confirmation of the presence of ocelli in Archostemata (Jurodidae?) and a robust phylogenetic hypothesis for the order.

Abstract: This study gives an overview of recent developments and results in the morphological and phylogenetic study of Archostemata, and a short account of innovative morphological techniques such as for instance micro computer tomography (μ-CT) and computer based 3-dimensional reconstructions. Archostemata are a small relict group of beetles. They display a mosaic pattern of highly derived characters, mainly of the head, and of plesiomorphic features, mainly of the thorax. The results of recent cladistic analyses suggest that Ommatidae, Cupedidae, Micromalthidae, Crowsoniellidae and Jurodidae (Sikhotealinia and †Jurodes), and the extinct families †Schizophoridae, †Catiniidae, and tAdemosynidae form a clade Archostemata. However, the placement of Jurodidae and the three fossil groups remains ambiguous, mainly due to lack of reliable morphological data. Within Archostemata, Ommatidae are probably the most basal group and recent cladistic analyses suggest that Jurodidae may form the sistergroup of a clade comprising Micromalthidae, Crowsoniellidae, †Schizophoridae, tCatiniidae, and †Ademosynidae. Archostemata is the sistergroup of the remaining three beetle suborders. All Permian fossil lineages traditionally assigned to Archostemata belong to the stem group of Coleoptera, with a branching pattern (†Tshekardocoleidae + (†Permocupedidae + (†Rhombocoleidae + (tTriadocupedinae + (Coleoptera s.str. [=crown group]))))). The reconstruction of the phylogeny of Archostemata is still impeded by a severe lack of material and morphological data. Intensive collecting activities should have high priority, combined with the application of traditional and modem morphological methods. Innovative techniques have given new and strong impulses to insect morphology in the last years.