Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan 113
Ul
U1 a
U1p
U2
URN
VS
first ural centrum
anterior part of first ural centrum
posterior part of first ural centrum
second ural centrum
uroneural
ventral scute
Locality and Horizon
The Wakino Subgroup is distributed from the northern part of Kyushu Island to
west of Yamaguchi Prefecture. Fish fossil sites of the Wakino Subgroup are res
tricted to Kitakyushu City, Fukuoka Prefecture (Fig. 1). There are 12 localities of
fish fossils.
Two localities belonging to the First Formation (the lower formation, W|) are
found in Kokura-minami-ku (Kokura Southern Ward), Tokuriki and Dobaru. Fish
fossils are more abundant at Tokuriki (130°52'02*'E, 33°49'l15"N; localityno. TO-1).
Some fish fossils are found at Dobaru (130°5l'00"E, 33°46'33"N; locality no. DF-1).
The only locality belonging to the Third Formation (the upper formation, W3) is
at Minamigaoka (130°5l'02"E, 33°50'57*N; locality no. KM-1) in Kokura-kita-ku
(Kokura Northern Ward).
There are 9 localities belonging to the Fourth Formation (the uppermost
formation, W4) which are situated in Yamada Park, a former military arsenal and in
surrounding areas (Figs. 1 and 2). Among the localities, fish fossils are most
abundant on the cliffnear the front gate of Yamada Park (130°5r46*E, 33G5ril"N;
locality no. KA-0 by M. Ota et al., 1979) and on the cliff at the cement plant of
Mitsubishi Material Co. Ltd. (130°5r58"E, 33°5f02'rN; locality no. KD- 34 by M.
Ota et al., 1979). Some fish fossils were found in localities KA-1, KA-2, KA-6,
KA-9, KA-11, KD-22, (M. Ota et al., 1979) and Sanji (130°50'35*E, 33°50'00*N;
locality no. HS-1). Locality KA-0 belongs to the lower part of the Fourth Formation
and the locality of KA-1 belongs to the upper part of the Fourth Formation (M. Ota
et al., 1979).
Y. Ota (1955, 1957) recognized four formations in the Wakino Subgroup in
Kitakyushu City: the lower formation, the middle formation, the upper formation and
the uppermost formation (Fig. 3). These formations were correlated respectively, to
the four formations of the Wakino Subgroup in Wakino: the Sengoku Formation, the
Nyoraida Formation, the Lower Wakamiya Formation and the Upper Wakamiya
Formation (Y. Ota, 1955, 1960b). The age of the Sengoku Formation is considered
to be Hauterivian to Barremian (Y. Ota, 1981). The age of the Wakino Subgroup
is considered to be Late Neocomian (Y. Ota, 1981; Matsumoto et al., 1982).
Four formations in this area are described here on the basis of Y. Ota (1955,
1957), Matsushita (1968), and M. Ota el al. (1979). Several names for each