TL;DR: The present paper is restricted to the taxonomical description of this new species including its colouration in life and ecological notes of the species, such as habitat and distribution, associated occurrence of the snapping shrimp and gobioid fishes, burrowing behaviour, and interspecific relationships.
Abstract: During the visit of the first author, Y. MIYA, to the Seto Marine Biological Laboratory, Kyoto University in the summer of 1967 he was compelled attention to Dr. Eiji HARADA'S story of an association of a snapping shrimp with gobies, on which Dr. HARADA was then making observations. According to HARADA'S informations, that snapping shrimp occurred commonly associated with some gobies in burrows on the sandy bottom of shallow sublittoral areas near the Laboratory and Ezura about 1 km east from there in Tanabe Bay. MIYA had not enough time to make his own observations on this association and to collect that snapping shrimp, but Dr. HARADA kindly offered him three specimens of the shrimp for identification. On examination of these specimens it was found that the shrimp was a species of the brevirostris group, apparently new to science. Recently another specimen of the same species was found unexpectedly in a small collection of decapod crustaceans from Kagoshima Bay, which was presented to the present authors through the courtesy of Dr. Toshio SAISHO. The specimen was collected by Dr. Kantaro NAKAHARA, who kindly informed the authors on inquiry that the specimen was found living in association with a goby in shallow water of Kaminose in Kagoshima Bay as in the case of HARADA'S observations and submitted them his records of field observations. The present paper is restricted to the taxonomical description of this new species including its colouration in life. The ecological notes of the species, such as habitat and distribution, associated occurrence of the snapping shrimp and gobioid fishes, burrowing behaviour, and interspecific relationships, will be fully discussed upon sufficient data by Dr. HARADA in the next article of this number (Publ. Seto Mar. Biol. Lab., XVI (5) 315-334, 1969). The holotype is deposited at the museum of the Seto Marine Biological Laboratory
TL;DR: A. A. bellulus excavates decimeter-scale craters in the sediment, carrying sediment grains up the steep inner slope of the crater and depositing them on the outside (lee-equivalent side).
Abstract: Study of aquaria containing the shrimp Alpheus bellulus and poorly sorted, coarse-grained sand has revealed the potential for macroorganisms to create structures closely resembling ripple cross-lamination, including climbing-ripple cross-lamination. A. bellulus excavates decimeter-scale craters in the sediment, carrying sediment grains up the steep inner (stoss-equivalent) slope of the crater and depositing them on the outside (lee-equivalent side). The fabrics produced resemble hydrodynamically produced ripple cross-lamination, particularly when observed in the limited cross sections available in core. This biogenic cross-lamination can be distinguished from hydrodynamic cross-lamination in that the biogenic cross-lamination is steeper than is typical for current-generated ripple cross-lamination, the tabular foresets are close to angle of repose, and the structure has a circular ripple crest.
TL;DR: The association in the same nest of three coexisting species, the swimming goby Ptereleotris hanae, snapping shrimp Alpheus bellulus and gobiid fish Amblyeleotris japonica, was investigated in the field by observation of escape responses into the nest, demonstrating social monogamy.
Abstract: The association in the same nest of three coexisting species, the swimming goby Ptereleotris hanae, snapping shrimp Alpheus bellulus and gobiid fish Amblyeleotris japonica, was investigated in the field by observation of escape responses into the nest. Unlike A. japonica, P. hanae did not function as a “guard” for the shrimp due to its escape behavior at no time influencing the other two species. Pairs of P. hanae were individually recognized during the observations, 33 of 63 pairs being maintained after the end of the reproductive season, thereby demonstrating their social monogamy. Fifteen minute observations during the reproductive season indicated 7.4 (mean) acts of male-to-female nuzzling, 1.4 (mean) acts vice versa. A reduced level of the former and the same level of the latter were observed during the non-reproductive season. This behavioral feature was considered functional in both courtship and pair bond confirmation. Nest takeover was relatively common (n =10), indicating the likelihood of strong competition for nests. Because the latter are very important, providing shelter and spawning beds, a territorial defense hypothesis may explain their monogamy.
TL;DR: This study used the large taxon sampling available to date for phylomitogenomic analysis and demonstrated the phylogenetic relationships of six infraorders in Decapoda (Dendrobranchiata, Caridea, (Stenopodidea), (Achelata, (Polychelida, Astacidea)), which resulted in a well-supported topology.
TL;DR: Resin casts of burrows and the data on the daily positional change of the entrance of one burrow indicate that burrows are extensive enough to come close to the adjacent burrows within the sediment, suggesting that a solitary shrimp has a chance to acquire a mate through the connection of its burrovv vvith the adjacentBurro~v.
Abstract: The snapping shrimp Alpheus bellulus and the gobiid fish Amblyeleotris japonica live together in the burrow dug by the shrimp and a tactile alarm communication is developed between them. The association is established at the juvenile stage soon after settlement and maintained throughout their lives. The members of the association are sometimes changed by the movement of the fish between burrows. Pair formation of the shrimp begins at the juvenile stage and the adults usually occur in pairs. Resin casts of burrows and the data on the daily positional change of the entrance of one burrow indicate that burrows are extensive enough to come close to the adjacent burrows within the sediment, suggesting that a solitary shrimp has a chance to acquire a mate through the connection of its burrovv vvith the adjacent burro~v. The early pair formation and the sta!:le pair bond of this species are attributed to the difficulty in obtaining a mate owing to the discreteness of the habitat.