Species Diversity

A rhacophorid tree frog from Sumatra that was once identified as Polypedates otilophus (Boulenger, 1893) is sufficiently divergent genetically and morphologically from topotypic specimens from Borneo as to be recognized as a distinct species. It is herein described as P. pseudotilophus sp. nov. The Sumatran frogs can be distinguished easily from the Bornean population by the possession of a much more weakly developed supratympanic bony crest, smoother dorsal skin, and a large, hourglass-shaped dark marking, instead of longitudinal stripes on the dorsum.

A new species of acropomatid fish, Acropoma profundum, is described based on a single specimen, 40.1 mm in standard length, from the Solomon Islands (depth 1169–1203 m). It is distinguished from congeneric species by its unique long, U-shaped luminous gland, which extends from the throat to just in front of the anal-fin origin. The new species is further distinguished from its congeners by the following combination of characters: anus situated nearer to the pelvic-fin base origin than to that of the anal fin, proximal radial of first anal-fin pterygiophore with a trough-like recess, body depth 29.1% SL, and pectoral-fin rays 15. Acropoma profundum is the deepest-living species of its genus, and the smallest in size at sexual maturity.

The population structure and demographic history of a zoarcid fish, Davidijordania poecilimon (Jordan and Fowler, 1902), around Japan were investigated on the basis of sequence variations in the cytochrome b gene of mitochondrial DNA (440 base pairs). Among 44 specimens, 18 haplotypes were recognized. Although some were shared among individuals from different localities in the Sea of Japan or in the Pacific Ocean, no haplotypes were shared between the two regions. The haplotype network showed a rough separation of the Sea of Japan and Pacific population haplotypes, forming a dumbbell-like pattern, each half with a major haplotype. In addition, the pairwise Φ_ST between the Sea of Japan and Pacific populations of 0.35 was significant according to the permutation test (p < 0.01). Such evidence indicates that gene flow between the two populations is restricted by the shallow strait (Tsugaru Strait) between the Sea of Japan and the Pacific Ocean. Mismatch distribution analysis suggests that the Pacific population comprises historically older and larger populations than those in the Sea of Japan.

We describe the new sclerodactylid sea cucumber Cladolabes kirara sp. nov. based on 10 specimens collected in the intertidal zone of the west coast of Nagasaki Prefecture, Japan. For comparison, we also examined the neotype specimen of Cladolabes limaconotus Brandt, 1835 (type species of the genus) and provide illustrations of the general appearance of its body and of ossicles from a tentacle, the introvert, and the middle part of the body. The new species is readily distinguishable from its congeners by the shape of the ossicles in the integument of the body wall, which are two-pillared tables with rudimentary discs, distally united pillars, and most frequently two holes and a cross-beam between the pillars.

Sternomoera moneronensis Labay, 1997, a poorly known freshwater amphipod, is redescribed based on newly collected specimens from its type locality, Moneron Island in the northern Sea of Japan. Certain inaccuracies of the original description, viz., the shape of the antennal sinus of the head and the number of sternal gills on the ventral margin of pereonite 7, are corrected.

Twenty-two mite species of four genera belonging to the family Macrochelidae were collected from the body surface of dung beetles (Scarabaeidae) in Sungai Wain, East Kalimantan, Indonesia. Three species, Macrocheles dayaci sp. nov., M. riparius sp. nov., and M. wainensis sp. nov., are described as new to science. Another eight species are recorded from Kalimantan for the first time.

Maculobates bruneiensis Ermilov, Chatterjee and Marshall, 2013, formerly known only from Brunei, was collected from the islands of Okinawa and Iriomote in southern Japan. The described specimens represent the first recorded presence of any species of Maculobates in Japan. A molecular phylogenetic analysis of M. bruneiensis and other oribatid mites based on 18S rRNA does not support the monophyly of Scheloribates, Haplozetidae, or Fortuyniidae, but they do support the monophyly of Oripodoidea.

Three species of Dactylogyrus Diesing, 1850 (D. inversus Goto and Kikuchi, 1917, D. gotoi Gussev, 1967, and D. kikuchii Gussev, 1967) were collected from the gills of Japanese seabass Lateolabrax japonicus (Cuvier, 1828) in two brackish-water lakes (Lake Nakaumi and Lake Shinji) in Shimane Prefecture, Japan. These collections represent the first records of D. gotoi and D. kikuchii from Japan. Although these two dactylogyrids were originally described from a fish reported as “Lateolabrax japonicus” in China, the latter appears to be a different species, L. maculatus (McClelland, 1844), which has been recently recorded as an introduced species in Japan.