Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

Early Cretaceous Freshwater Fish Fauna in Kyushu,Japan 153
Fig. 34. Aokiichthys toriyamai gen. et sp. nov., caudal region of the holotype, KMNH VP
100,160.
pectoral fin elongates and reaches the pelvic insertion. The caudal fin is emarginate.
The number of principal dorsal fin rays is 12. There are 12 dorsal fin ptery
giophores. The number of principal anal fin rays is 20. There are 20 anal fin
pterygiophores. The principal dorsal and anal fin rays are preceded by two small
unbranched accessory rays respectively. Ten pectoral fin rays are visible. There
are 17 principal caudal fin rays (1,7,8,1).
The gape of the mouth is large. The lower jaw is long and narrow. The
dentary bears small canine like teeth on its oral margin. The suture between the
dentary and the anglo-articular is not visible. The premaxilla also bears small
canine like teeth. The premaxillary teeth are larger than the dentary teeth. The
posterior end of the lower jaw is placed below the posterior margin of the orbit.
Seven large canine like teeth are preserved almost at center of the orbit on the
parasphenoid. These teeth are larger than those of the premaxilla and the dentary.
There are villiform teeth on the endopterygoid. Seven branchiostegal rays are
visible. The frontal is long and carries a superficial long canal. The canal has a
lateral branch at the middle of the frontal. The canal is not separated at the
posterior end (Fig. 33).
The total number of vertebrae is 35, with 18 caudal vertebrae. The anterior
end of the vertebral column is not visible. The number of abdominal vertebrae is
estimated on the basis of the ribs. The number of ribs is 15. There is a series of
median supraneurals beginning behind the head and ending above the second caudal
vertebra. Each supraneural is cylindrical. The scale are visible at the dorsal part.