The porcellanid crab Porcellana sayana is, for the first time, reported to have a symbiotic association with the crab Stratiolibinia bellicosa. This is also the first record on the association between the porcelain crab P. sayana and a brachyuran crab on the Brazilian coastline. In addition, this is the second record of association of P. sayana with a Majoidea crab.

The larval development of the hermit crab Areopaguristes nigroapiculus (Komai, 2009) (Decapoda: Anomura: Diogenidae) is described and illustrated from the material reared in the laboratory. The development included three zoeal and a single megalopal stages. At 22–25°C, megalop of A. nigroapiculus was attained 6–9 days after hatching. The present paper is the first description of the complete larval development in the genus Areopaguristes. Morphological characters of zoeas and megalop of A. nigroapiculus are compared with those described for the closely related Paguristes species. The comparison on the zoeal characters revealed that A. nigroapiculus is distinguished from Paguristes species by the absence of anterolateral carapace spines and by the fused fourth telson process in zoea III. These two features are possible generic characters of Areopaguristes. In the rest of larval characters, A. nigroapiculus agree well with Paguristes species having three zoeal stages. In the plankton of Peter the Great Bay, the larvae of A. nigroapiculus sporadically occurred only in July and August, at depths of 3–45 m and surface water temperatures of 18–22°C.

In the present paper the authors record the occurrence of two hermit crabs, Coenobita brevimanus Dana and C. rugosus H. Milne-Edwards, for the first time from the Indian coast. The records show the extended distribution of both the species of hermit crabs and suggest their possible continuous distribution from the east coast of Africa to the south-west Pacific Ocean.

An unidentified species of hermit crab from the Maldives was photographed using a plastic box as shelter instead of a natural shell. This could be a result of increased pollution and shell collection disrupting the natural processes in coral reefs.

Two new species of Munidopsis from the hydrothermal vent area, Kairei Field, Central Indian Ridge in the Indian Ocean and Forecast Vent Field, Mariana Back Arc Basin in the west Pacific are described and illustrated. Their affinities to closely related species are discussed. The number of Munidopsis species associated to hydrothermal vents in the world oceans has increased to 16. The habitat of new species is briefly described and the pattern of abundance of vent associated Munidopsis is briefly discussed.

The fossil record of unquestionable decapod remains dates back to Permo Triassic times. Evaluation of all available data from the fossil record, trace fossils and facies reveals various trends within the evolution of Mesozoic decapods, and its relation to their ecology. One of these trends is the protection of the long vulnerable abdomen. The most successful method, gradual reduction and inflection of the abdomen against the ventral cephalothorax, led to the Brachyura. Brachyurans exhibit the broadest spectrum of habitat adaptions.