Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

Early Cretaceous Freshwater Fish Fauna in Kyushu,Japan
123
Table 1.
Japan.
Comparison ofcharacters in three genera ofthe family Amiidae from China and
Nipponamia gen. nov. Sinamia Ikechaoamia
TL 301.0 mm 120-270 mm 94 mm
counts
Premaxillary teeth
Vertebrae
other characters
4
74
6-11
7
5 or more
Gular plate rhombic triangle
p
45-50
Largest teeth on premaxilla almost similar in size on dentary
Hyomandibular*
Ventral end of
hyomandibular
Length of vertebral
centrum
deeply concave in
V-shape
two parts
shorter than the depth
wide and shallow
one part
longer than the depth
p
p
longer than the depth
Ural centrum slightly curved curved curved
Ganoine scale absent present present
* The part between the condyles of hyomandibular for the neurocranium and the opercular
process. TL, total length.
amia, a generic name of the family Amiidae.
Nipponamia satoi sp. nov.
(Figs. 8-11, PL 37-38)
Diagnosis.
As for the genus, monotypic species.
Holotype. KMNH VP 100,147, the dorsal surface of the head region and the lateral
side of the body are exposed, but most of the dorsal fin, pelvic fin and anal fin are
missing. The total length is 298.0 mm.
Locality. Tokuriki (TO-1), Kokura-minami-ku (Kokura Southern Ward), Kitakyu
shu City, Fukuoka Prefecture, Japan.
Horizon. The First Formation (the lower formation, W,, correlated to the Sengoku
Formation) of the Wakino Subgroup in the Kwanmon Group, the LowerCretaceous.
Etymology. The species is named for Mr. Masahiro Sato who collected and donated
the specimen to the Kitakyushu Museum and Institute of Natural History.
Description of the holotype.
The body and the head region appear to be cylindrical, assuming from the