No abstract

The Black Sea fauna has been studied for a long time, whence the adult crabs of this region are rather well known. However, not enough attention has been paid to their larval development. Despite the extensive literature concerning the order Decapoda pertaining to the Black Sea, there is no key for the identi cation of the brachyuran larvae. This work aims to ll that gap.There are 20 species of crabs in the Black Sea, belonging to 7 families: Cancridae with 1 species: Cancer pagurus L., 1758; Pirimelidae with 2 spp.; Portunidae (6 spp.); Xanthidae (4 spp.); Grapsidae (3 spp.; the presence of Planes minutus (L., 1758) for the Black Sea is not con rmed, therefore this species has not been included in the key); Majidae (3 spp.); and Potamidae (1 sp.).

го, а в соседних районах Юго-восточной Камчатки и северной части Японского моря они не известны. Таким образом, L. uschakovi весьма вероятно является настоящим эндемиком Охотского моря.

In the XIX and XX centuries thickclawed crayfish Astacus pachypus was reported for the Sevastopol area in Crimea. Nowadays significant changes of hydrolological conditions and substrates took place in the only possible locality where a population of this species could exist-inner part of the Sevastopol Bay and the mouth of River Chernaya. Biotopes characteristic for this place in the XIX century were lost. Since the conditions optimal for thick-clawed crayfish in the River Chernaya estuary are currently absent, this species most likely has vanished from the Sevastopol area. РЕЗЮМЕ. В XIX и начале XX веков в Крыму, в районе Севастополя отмечался толстопалый рак Astacus pachypus. К настоящему времени в месте наиболее вероятного обитания этого вида-кутовой части Севастопольской бухты и устья реки Черной произошли значительные изменения гидрологических условий, субстрата и утрата биотопов, характерных для этих мест в прошлом. Поскольку условия, оптимальные для жизни толстопалого рака в эстуарии реки Черной в настоящее время отсутствуют, то с большой долей вероятности можно предположить, что в районе Севастополя этот вид исчез.

Macropodia czernjawskii (Brandt, 1880), described from the Black Sea, was ignored in the regional faunal accounts for more than a century, although it was recognised in the Mediterranean. Instead, M. longirostris (Fabricius, 1775) and M. rostrata (Linnaeus, 1761) were frequently listed for the Black Sea. We selected a lectotype and redescribed the species on the basis of the type series from the Crimean Peninsula and the new material collected in the Black Sea. Historical and new collections, as well as the analysis of publications, indicate that M. czernjawskii is the only Macropodia species occurring in the Black Sea. Molecular barcode (COI gene marker) data show that M. czernjawskii is a species well-diverged from other studied species of the group. Furthermore, M. parva van Noort & Adema, 1985 has very low genetic distances from M. rostrata and M. longipes A. Milne-Edwards & Bouvier, 1899 is indistinguishable from M. tenuirostris (Leach, 1814), using COI sequences. The respective synonimisations, supported by morphological data, are proposed. M. czernjawskii is a Black Sea – Mediterranean endemic occurring also in the neighbouring Atlantic coastal zone of the Iberian Peninsula and occupying shallower depth, compared to other Mediterranean species of Macropodia. As an upper subtidal inshore species, it is particularly specialised in self-decoration and stimulates abundant epibiosis, providing masking and protection. The bulk of epibiosis consists of algae and cyanobacteria. Amongst the 25 autotrophic eukaryote taxa, identified to the lowest possible level, green chlorophytes Cladophora sp. and calcareous rhodophytes Corallinales gen. sp. were most commonly recorded. Non-indigenous red alga Bonnemaisonia hamifera Hariot, first officially recorded at the Caucasian coast of the Black Sea in 2015, was present in the epibiosis of M. czernjawskii in Crimea as early as 2011.