Sm-Nd whole rock isochron ages have been determined for metadiabase and gabbro of the Ikoma Mass in the Kinki Ryoke Belt of the Southwest Japan Arc. The ages and initial 143Nd/144Nd ratios are as follows: hornblende gabbro-norite, 180 ± 23 Ma, 0.512180 ± 0.000024; metadiabase, 197 ± 31 Ma, 0.512166 ± 0.000035; anorthositic gabbro, 169 ± 29 Ma, 0.512148 ± 0.000027. The combined age, using hornblende gabbro-norite and metadiabase, is 192 ± 19 Ma (0.512169 ± 0.000021). Similar rock types collected from other masses plot around the isochrons defined by their counterparts from the Ikoma Mass. These age data indicate that the mafic igneous activity took place in the Ryoke Belt (a late Cretaceous granitic terrane) during the middle to early Jurassic. Sm-Nd and Rb-Sr whole rock and mineral isochron ages of hornblende gabbro are 97.7 ± 5.5 Ma and 71.8 ± 9.5 Ma, respectively, which indicate thermal resetting of the gabbro by intrusion of granitic plutons. Cortlanditic gabbros from the Ikoma Mass and other masses do not plot on the Sm-Nd whole rock isochrons for hornblende gabbro-norite, metadiabase and anorthositic gabbro. This suggests that cortlanditic gabbros evolved independently from other gabbros.

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The squirrel Callosciurus erythraeus (Pallas) (Rodentia: Sciuridae) was intentionally introduced to Japan in 1935 and has become established throughout much of the country. Although they live mainly in forests, Pallas squirrels come into gardens and are frequently fed by people or kept as pets, so their ectoparasites could be of potential medical as well as veterinary importance. During 2001-2003 we conducted the first ectoparasite survey of Pallas squirrels in Japan. From 105 C. erythraeus captured in Kamakura District of Kanagawa Prefecture on Honshu Island, three types of ectoparasite were found: 52 specimens of the sucking louse Neohaematopinus callosciuri Johnson (Anoplura: Haematopinidae), 26 fleas Ceratophyllus (Monopsyllus) anisus Rothschild (Siphonaptera: Ceratophyllidae) and four nymphs of the tick Haemaphysalis flava Neumann (Acari: Ixodidae) on 22, 13 and one squirrels, respectively. Evidently in Japan C. erythraeus carries relatively few ectoparasite species; this may be a contributory factor to their invasive success. Further investigations are needed to assess risks of zoonotic transmission of plague or murine typhus by C. anisus, of louse-borne typhus by N. callosciuri and of tularaemia and especially Japanese spotted fever (Rickettsia japonica) by H. flava.

Rb and Sr contents and Sr-isotopic ratios as well as Si02 and K20 contents were determined for basic rocks (gabbro, cortlandite, anorthosite and metadiabase) from the Ryoke Belt in the Kinki and Setouchi Inland Sea districts, Southwest Japan. The basic rocks are characterized by lower K20 and Rb contents and by higher initial Sr-isotopic ratios than the mantle-derived igneous rocks in the oceanic region. The high initial Sr-isotopic ratios of the basic rocks are explained by the high isotopic ratios of their source materials.