Twenty-seven individuals of Batrachospermum helminthosum Bory were collected from various sites in Japan, from temperate Iwate Prefecture to subtropical Okinawa Prefecture. The chloroplast-encoded rbcL gene was sequenced from each sample. Phylogenetic analyses were performed using these and previously published sequences of 12 samples from North America. There were five haplotypes among the Japanese samples. Haplotype 1 was collected throughout a large geographical area corresponding to most of the sampling range in this study and was represented by most individuals (21 individuals). The other haplotypes were represented by one to three individuals, respectively. These distributions of haplotypes suggest the occurrence of one large metapopulation and/or recent colonization over a wide geographical area in Japan. Phylogenetic analysis showed two well-supported clades within B. helminthosum, one clade containing four haplotypes (1-4) from Japan and the other clade comprising five North American haplotypes. Such differences between Japanese and North American haplotypes might be a result of continental drift and subsequent isolation in the Mesozoic era. The position of haplotype 5 from Okinawa in Japan is poorly resolved, but it is not closely related to the other four Japanese haplotypes. It is suggested that several taxonomic characteristics (sexuality, point of origin of carpogonium-bearing branches, and trichogynes with or without basal knobs or branching) is not fixed genetically but is affected by environmental conditions. Based on the results of the present study, B. coerulescens Sirodot and B. elegans Sirodot should be placed in synonymy with B. helminthosum.

The bangiophycean filamentous red alga Bangia atropurpurea is distributed in freshwater habitats such as littoral and splash zones of lakes or rapid currents distant from the sea. In these habitats, the distribution and growth of this alga appear to be related to hard water rich in calcium ions. To characterize the eco-physiological properties of this calciphilic red alga, we examined the effects of long-term and short-term Ca(2+) depletion on photosynthetic growth of the thallus and on the phycobilisome. Long-term culture experiments suggested that higher Ca(2+) concentrations (>50mgL(-1)) were required to sustain thallus growth and pigmentation of cells. In short-term Ca(2+)-depletion treatments, fluorescence derived from phycoerythrin (PE) fluctuated, although the absorption spectra of the thalli did not change. After 30 min of Ca(2+) depletion, the fluorescence lifetime of PE became markedly longer, indicating that the energy transfer from PE to phycocyanin (PC) was suppressed. The fluorescence lifetime of PE returned to its original value within a short time after 4h of Ca(2+) depletion, however, energy transfer from PE to PC was still suppressed. This suggested that the excitation energy absorbed by PE was quenched during prolonged Ca(2+) depletion. The efficient energy transfer from PC and allophycocyanin were unchanged during these treatments.

Phylogenetic relationships of the Chugoku-Kyushu and Shikoku groups of the Japanese spinous loach, Cobitis takatsuensis, among the diploid congeners in Japan, C. biwae and Cobitis sp. complex with Niwaella delicata as an outgroup, were investigated by analyzing 20 protein-coding loci. The two groups of C. takatsuensis are clearly diverged genetically, with the genetic distance corresponding to the species level (average D ϭ 0.27). The two groups form a monophyletic cluster (bootstrap probability, P ϭ 94.9%) that is a sister cluster of C. biwae (P ϭ 63.1%). The monophyletic cluster of the Cobitis sp. complex (P ϭ 93.2%) is the most distantly related in the genus. The present results differ mostly from the mitochondrial phylogeny previously known in which the Chugoku-Kyushu group of C. takatsuensis is connected to the eastern group of C. biwae and the Shikoku group is connected to the Cobitis sp. complex with the western group of C. biwae. The contradiction between the allozymic and mitochondrial phylogenies suggests that the Shikoku group of C. takatsuensis and the western group of C. biwae received mitochondrial introgression from the Cobitis sp. complex.

A new species of spinous loach, Cobitis shikokuensis, is described based on 297 specimens from Shikoku Island, Japan. The new species was formerly known as the Shikoku group of Cobitis takatsuensis. It can be distinguished from other species of Cobitis and closely related genera by a combination of the following characters: dorsal fin with 6 branched soft rays; anal fin with 5 branched soft rays; one brownish streak across eye from the tip of nose, no streak on cheek; a black spot smaller than eye diameter near the dorsal corner of the caudal fin base; 3-5 small brownish speckles on ventral side of caudal peduncle; high caudal peduncle with well-developed fleshy keels on dorsal and ventral side; a lamina circularis at base of dorsal part of pectoral fin absent; first branched soft ray of pectoral fin broad in males; pectoral soft rays widely branched from the approximate midpoint; last anal fin ray with 2 elements; interorbital width 11.2-17.1% of head length.

We describe a new species of spined loach, Cobitis sakahoko, based on the holotype and nine paratypes collected from the Oyodo River system in the southern region of Kyushu Island, Japan. This species is distinguished from its congeners by the following combination of characteristics: lamina circularis at the base of the pectoral fin in adult males, a rectangular plate with a neck in the midlower part; the upper segments of the first branched soft ray of the pectoral fin broad; snout relatively short, length 32.1-38.2% of head length; long maxillary barbel, longer than the eye diameter; prepelvic myotome number 14; and line L5 organised in 8-13 oblong or ovoid blotches.