Yokosuka City Museum

A new species of leucothoid amphipod, Leucothoe limidicola sp. nov. was collected from the mantle cavity and tentacles of the file clam, Limaria hirasei (Limidae). Commensalism associated with bivalves has been relatively rare in the genus Leucothoe and the present new species represents the sixth species of bivalve-associated commensal in the genus. According to the molecular phylogenetic analyses based on the partial sequence of the 18S gene, this new species was recovered as sister to Leucothoe akaisen. There were ~1.5% and ~9.4% differences between these two species in the 18S and COI sequences, respectively, and seven species-specific indels in the former. Morphologically, the new species can be distinguished from Le. akaisen by the distally dentate lateral surface of male gnathopod 2 carpus and straight or weakly concave, oblique posterodistal margin of pereopods 6, 7 bases.

SummaryHibiscus glaber is a symbolically significant endemic species found exclusively on the Ogasawara (Bonin) Islands. It is one of the main tree species in the natural forests of the island. This species is illustrated here, and its natural history, ecology, pollination, and cultivation are described.

Lepadichthys coccinotaenia Regan 1921 (Gobiesocidae: Diademichthyinae) is redescribed on the basis of 60 specimens, including the holotype, and a new species of Lepadichthys, previously misidentified as L. coccinotaenia, described from Japan. Lepadichthys trishula sp. nov. is characterized by the following combination of characters: 10–12 (modally 11) dorsal-fin rays; 9–11 (10) anal-fin rays; 23–26 (23) pectoral-fin rays; upper end of gill membrane level with base of 8th to 10th (usually 10th) pectoral-fin ray in lateral view; 6–8 (7) gill rakers on each arch; 32 or 33 (32) vertebrae; snout somewhat short and slender, its length and depth 7.4–9.4 (mean 8.4) and 4.0–6.5 (5.1) % SL, respectively; upper jaw not sharply pointed or projected, its length 5.5–7.7 (6.5) % SL; side of lower-jaw teeth with hook-like tips; head depth 7.2–10.4 (8.5) % SL; disc size moderate, its length 14.0–18.2 (16.8) % SL; dorsal and anal fins with weak membranous connections to caudal fin; head sensory canal pores well developed, including 2 nasal, lacrimal and postorbital, and 3 preopercular pores; and three narrow white stripes from snout to vertical through posterior margin of disc, including two lateral and one on the dorsal midline. The new species is currently known only from Japan, whereas L. coccinotaenia occurs only in the southwestern Indian Ocean.

Abstract Rhagophthalmus fugongensisLi & Liang andRhagophthalmus lufengensisLi & Ohba are introduced as new to science. The first record ofR. tonkineusin China is provided. The male genitalia ofR. gibbosulusandR. giganteusare described and illustrated. The female and larva ofR. giganteusand the female ofR. semisulcatusare illustrated. The distribution ofRhagophthalmusis discussed and a rectification of the relative arrangement of different parts of the male genitalia is provided (the base‐piece is on the ventral side of the male genitalia, and the parameres on the dorsal side).