Heterosignum bicornis sp. nov. is described from the deep water near the mouth of Suruga Bay, central Japan. The new species differs from its congeners in having two remarkable frontal processes on the head.
In part 2, morphological characteristics, early stages, and group division are discussed. Nine new taxa, i.e., kuriyamai sp. nov., monastyrskiyi sp. nov., pseudomeia sp. nov., pseudonara sp. nov., dongvanensis ssp. nov., huangi ssp. nov., dalatensis ssp. nov., vietnamica ssp. nov., and xamneuana ssp. nov., are described.
The Lower Cretaceous Crato and Santana formations have provided one of the richest Mesozoic fish faunas from South America. An updated review of this ichthyofauna, comprising, 28 nominal species, is presented here. Contrary to the previous idea that the Araripe Basin had an endemic fauna related to the opening of the South Atlantic Ocean, it is now accepted that this fauna is instead related to that of the Tethys. A marine connection with the Araripe Basin is indicated by the presence of species closely related to those of other assemblages occurring in the western part of the Tethys. However, the absence of marine invertebrates suggests non-marine conditions for this basin, with only intermittent connections to the epicontinental seaway. Some of the fishes found in the Crato Formation are juveniles of the species found in the Santana Formation, suggesting several important paleoecological implications related to the reproduction of these fishes and using there as a nursery.
The osteological description and illustrations of the cyprinid fish Zacco platypus (Temminck and Schlegel, 1846) from Oita Prefecture, Japan are provided for studies on fossil cyprinid fishes found in East Asia and Japan. As a result of this study, it was found that the parietal, supraobital, dentary, opercle and urohyal of Z. platypus differ from those of Nipponocypris sieboldii and N. temminckii, which were considered as a member of the genus Zacco.
The gap disturbance regimes and gap regeneration behaviour were investigated in secondary deciduous broad-leaved forests in a lower-altitude stand and a higher-altitude stand, on a forest floor covered with dense dwarf bamboo on Mt. Jiri, South Korea. The species compositions of the canopy trees, suppressed saplings, and gap successors differed between stands. Gap disturbance regimes, such as the total gap area in the total survey area, and the density of the gaps also differed across stands. The densities of the canopy gaps in both stands were basically similar to those reported in other old-growth forests, although the percentage gap area and the size of each gap were smaller in these stands than those in old-growth forests. Different types of gap regeneration behaviour were identified among the major canopy and sub-canopy tree species. Quercus mongolica occurred in all regeneration categories (canopy trees, gap makers, suppressed saplings, and gap successors), indicating that this species can regenerate in gaps from saplings recruited before gap formation. Lindera erythrocarpa and Acer pseudo-sieboldianum lacked canopy trees and gap makers, suggesting that these species might not yet be large enough to reach the canopy layer, but could have sapling banks beneath the closed canopy. The gap regeneration behaviour observed on Mt. Jiri differed markedly from that in various old-growth forests in Japan. These differences might be attributable to differences in the natural disturbance regimes as well as to differences in the successional stages among the forests. There were also very few canopy and/or sub-canopy species with gap successors, suggesting that the canopy gaps in both stands do not play important roles in the gap regeneration of the component species of the stands. The dense cover of dwarf bamboo on the forest floor may explain why the gaps have little effect on the regeneration of many tree species.