| the identity of limnoncaea diuncata kokubo, 1914 (copepoda: poecilostomatoida) from hokkaido, japan, with the relegation of diergasilus do, 1981 to a junior synonym of thersitina norman, 1905. | both sexes of an ergasilid copepod, limnoncaea diuncata kokubo, 1914, are redescribed based on planktonic specimens collected from the type-locality in hokkaido, japan. comparison of this species with thersitina gasterostei (pagenstecher, 1861) revealed that they are conspecific. another ergasilid genus with two claws on the antenna, diergasilus do, 1981, is relegated to synonymy with thersitina norman, 1905. the diagnosis of thersitina is amended. | 2004 | 14739673 |
| hybrid male sterility between the fresh- and brackish-water types of ninespine stickleback pungitius pungitius (pisces, gasterosteidae). | two ecologically distinct forms, fresh- and brackish-water types, of ninespine stickleback co-exist in several freshwater systems on the coast of eastern hokkaido. recent genetic analyses of 13 allozyme loci revealed genetic separation between the two types even though their spawning grounds were in close proximity. on the other hand, there is only a small difference in mitochondrial dna (mtdna) sequence between the two types suggesting that they diverged quite recently or that mtdna introgressi ... | 2005 | 15684581 |
| ecological divergence and habitat isolation between two migratory forms of japanese threespine stickleback (gasterosteus aculeatus). | when two closely related species migrate to divergent spawning sites, divergent use of spawning habitats can directly reduce heterospecific mating. furthermore, adaptations to divergent spawning habitats can promote speciation as a by-product of ecological divergence. here, we investigated habitat isolation and ecological divergence between two anadromous forms of threespine stickleback (gasterosteus aculeatus), the japan sea and pacific ocean forms. in several coastal regions of eastern hokkaid ... | 2010 | 20456572 |