Ghost shrimps of Callianassidae and Ctenochelidae are soft-bodied, usually heterochelous decapods representing major bioturbators of muddy and sandy (sub)marine substrates. Ghost shrimps have a robust fossil record spanning from the Early Cretaceous (~ 133 Ma) to the Holocene and their remains are present in most assemblages of Cenozoic decapod crustaceans. Their taxonomic interpretation is in flux, mainly because the generic assignment is hindered by their insufficient preservation and disagreement in the biological classification. Furthermore, numerous taxa are incorrectly classified within the catch-all taxon . To show the historical patterns in describing fossil ghost shrimps and to evaluate taphonomic aspects influencing the attribution of ghost shrimp remains to higher level taxa, a database of all fossil species treated at some time as belonging to the group has been compiled: 250 / 274 species are considered valid ghost shrimp taxa herein. More than half of these taxa (160 species, 58.4%) are known only from distal cheliped elements, i.e., dactylus and / or propodus, due to the more calcified cuticle locally. Rarely, ghost shrimps are preserved in burrows or in direct association with them, and several previously unpublished occurrences are reported herein. For generic assignment, fossil material should be compared to living species because many of them have modern relatives. Heterochely, intraspecific variation, ontogenetic changes and sexual dimorphism are all factors that have to be taken into account when working with fossil ghost shrimps. Distal elements are usually more variable than proximal ones. Preliminary results suggest that the ghost shrimp clade emerged not before the Hauterivian (~ 133 Ma). The divergence of Ctenochelidae and Paracalliacinae is estimated to occur within the interval of Hauterivian to Albian (133-100 Ma). Callichirinae and Eucalliacinae likely diverged later during the Late Cretaceous (100-66 Ma), whereas Callianassinae did not appear before the Eocene (56 Ma).

Adults and larvae of two new cryptic, endemic caddisflies, sp.n. and sp.n., are described and illustrated from the Western Balkans. Phylogenetic analysis (Bayesian MCMCMC) and association of different life history stages in both cryptic species were achieved through comparison of morphological characters and mitochondrial (mtCOI and mtLSU) and nuclear (nuWG) gene sequence data. The new species form a sister clade to the widely distributed and , with which they were formerly misidentified. Adults differ from each other and other species in the genus by the uniquely shaped inferior appendages in males and segment X in females. The larvae differ from each other and their congeners in the shape of the pronotum, and presence and constitution of additional spines on the parietalia. Larvae of both species are grazers and prefer stony substrate. sp.n. has a wide distribution in the Western Balkans, while sp.n. is endemic to Dalmatia. Our findings demonstrate the significance of the Western Balkans as a freshwater biodiversity hotspot, and accentuate the importance of research focused on freshwater biodiversity and biogeography in southern Europe.