A new species of the processid shrimp genus Nikoides Paulson, 1875 (Decapoda: Caridea) from Japan.

A new species of the processid shrimp genus Nikoides Paulson, 1875, N. subdistalis, is described and illustrated on the basis of five specimens collected from Kushimoto, Wakayama Prefecture, Japan, at depths of 712 m. The new species appears most similar to N. maldivensis Borradaile, 1915 among the 10 known congeners, but is notable in the unique dentition of the rostrum and the characteristic shape of the antennular stylocerite. A partial segment of the mitochondrial 16S rRNA gene was sequenced from one of the paratypes of the new species, and genetic divergence among four congeneric taxa, of which three was downloaded from the GenBank database, is shown. An identification key to 11 species of Nikoides, including the new species, is given.

A new species of the laomediid mud shrimp genus Naushonia Kingsley, 1897 (Decapoda: Gebiidea) from Japan.

A new species of the laomediid mud shrimp genus Naushonia Kingsley, 1897, N. kiiensis, is described and illustrated on the basis of a single male specimen from Kii Peninsula, central Japan, at a sublittoral depth of 14 m. The new species is morphologically closest to N. serratipalma Komai Anker, 2010, known from French Polynesia and the Red Sea coast of Saudi Arabia, among the 15 known congeners, but is distinguished from the latter by the spinulose middorsal and submedian gastric carinae on the carapace, the rugose posterior dorsum of the carapace, stronger but fewer spines on the distomesial lobe of the pereopod 1 merus and fewer spinules consisting of the serration of the palm lateral margin. From Japanese waters three species have been recorded, of which only N. japonica Komai, 2004 is known from the temperate mainland. The new species is the second occurring in the Japanese mainland.

Remarkably loud snaps during mouth-fighting by a sponge-dwelling worm.

Many aquatic animals, including mammals, fishes, crustaceans and insects, produce loud sounds underwater [1-6]. Soft-bodied worms would seem unlikely to produce a loud snap or pop because such brief, intense sounds normally require extreme movements and sophisticated energy storage and release mechanisms [5]. Surprisingly, we discovered a segmented marine worm that makes loud popping sounds during a highly stereotyped intraspecific agonistic behavior we call 'mouth fighting'. These sounds - sound pressures up to 157 dB re 1 µPa at 1 m, with frequencies in the 1-100 kHz range and a strong signal at ∼6.9 kHz - are comparable to those made by snapping shrimps, which are among the most intense biological sounds that have been measured in the sea [6]. We suggest a novel mechanism for generating ultrafast movements and loud sounds in a soft-bodied animal: thick, muscular pharyngeal walls appear to allow energy storage and cocking; this permits extremely rapid expansion of the pharynx within the worm's body during the strike, which yields an intense popping sound (likely via cavitation) and a rapid influx of water. Clearly, even soft-bodied marine invertebrates can produce remarkably loud sounds underwater. How they do so remains an intriguing biomechanical puzzle that hints at a new type of extreme biology.

Species-diverse coral communities on an artificial substrate at a tuna farm in Amami, Japan.

Tuna-farming is expanding worldwide, necessitating the monitoring/managing of its effects on the natural environment. In Japan, tuna-farming is conducted on coral reefs that have been damaged by mass-bleaching events and crown-of-thorns starfish (COTS) outbreaks. This study focused on the coral community on an artificial substrate of tuna-farm to reveal the possible effects of tuna-farming on the natural environment. Corals flourished on ropes suspended in the farm in the Amami Islands, southern Japan. These were moored 3 m below the sea-surface in 50-m-deep water. The coral community on the rope was analyzed and compared with those on natural substrata on two adjacent COTS-damaged reefs and with that in a protected reef. Corals were monitored throughout a year. Sixty coral species grew on the ropes, that corresponds to 27.3% of the 220 species known from Amami. The coral community was unique, dominated by massive faviid corals. On the ropes, the water temperature rarely exceeded 30.0 °C and no corals on the rope were severely bleached or covered by sedimentation during the observations. The tuna-farm infrastructure provided corals with a suitable habitat, and species-rich coral communities were established. These coral communities are an important node connecting tuna-farms and the natural environment.