Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

Early Cretaceous Freshwater Fish Fauna in Kyushu,Japan 159
Description of the holotype.
The body is moderate. The body depth is contained 3.5 times in the standard
length. The head length is contained 3.8 times in the standard length. The snout
is rounded. The outline of the head dorsal margin is slightly convex. The outline
from the occipital region to the dorsal origin is almost straight (Fig. 36). The
restored outline of the abdomen is almost straight and runs little under the lower end
of each rib (Fig. 37). The median fins are relatively posterior in position.
The dorsal origin is behind the anal origin and vertical with the fifth anal fin
pterygiophore (about anterior one third of the anal base). The first dorsal fin
pterygiophore is above the first and second caudal vertebrae. The dorsal fin base is
contained 2.1 times in the anal fin base. The pectoral fin is moderate and reaches
the pelvic insertion. The caudal fin is emarginate. The number of principal dorsal
fin rays is 11. There are 12 dorsal fin pterygiophores. The number of principal
anal fin rays is 19. There are 19 anal fin pterygiophores. The principal dorsal and
anal fin rays are preceded by two small unbranched accessory rays respectively.
Seven 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 angulo-articular is not visible and the posterior part of the lower jaw is
poor in preservation. The maxilla bears teeth almost entirely on its oral margin.
The maxillary teeth are larger than the dentary teeth. The posterior end of the
:3^
GS3
PARH
5mm
Fig. 39.
100,166.
Aokiichthys changae gen. et sp. nov., caudal region of the holotype, KMNH VP