Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

160 Yoshitaka Yabumoto
lower jaw is placed below almost center ofthe orbit. Fourlarge canine like teeth are
preserved on the parasphenoid at almost center of the orbit. These teeth are larger
than those of the premaxilla, maxilla and dentary. One infraorbital is visible and
have a sensory canal along the orbital margin. The supramaxilla is present and is
leaf-shape (Fig. 38).
The total number of vertebrae is 36, with 19 caudal vertebrae.
end of the vertebral column is not visible.
The anterior
The number of abdominal vertebrae is
estimated on the basis of ribs. The number of ribs is 15. There is a series of
median supraneurals ending above the first caudal vertebra. Each supraneural is
cylindrical.
The first preural centrum bears the narrow parhypural. The neural arch and
spine of the first preural centrum are complete. Six hypurals are visible. The first
hypural is the largest. The third to sixth hypurals are slender. There are two ural
centra. The second ural centrum bears at least three hypurals (HYU3-5). Three
uroneurals are visible. The anterior ends of the uroneurals are not visible. The
epural is not visible (Fig. 39).
Description of the paratypes.
In KMNH VP 100,167, the body depth is contained 3.7 times in the standard
length. The head length is contained 3.8 times in the standard length. The dorsal
fin base is contained 1.6 times in the anal fin base. The number of principal dorsal
fin rays is 11. There are 11 dorsal fin pterygiophores. The number of principal
anal fin rays is 17. There are 18 anal fin pterygiophores. There are 9 pectoral fin
rays. The total number of vertebrae is 36, with 19 caudal vertebrae.
In KMNH VP 100,168, the body depth is contained 3.5 times in the standard
length. The head length is contained 4.0 times in the standard length. The dorsal
fin base is contained 1.9 times in the anal fin base. The number of principal dorsal
fin rays is 11. There are 11 dorsal fin pterygiophores. The number of principal
anal fin rays is 19. The total number of vertebrae is 36, with 19 caudal vertebrae.
In KMNH VP 100,169, the body depth is contained 3.3 times in the standard
length. The head length is contained 3.7 times in the standard length. The first
dorsal fin pterygiophore is above the second caudal vertebra. The dorsal fin base is
contained 2.2 times in the anal fin base. The number of principal dorsal fin rays is
11. There are 11 dorsal fin pterygiophores. The number of principal anal fin rays
is 19. There are 19 anal fin pterygiophores.
In KMNH VP 100,170, the body depth is contained 3.3 times in the standard
length. The head length is contained 4.1 times in the standard length. The first
dorsal fin pterygiophore is above the second caudal vertebra. The dorsal fin base is
contained 1.7 times in the anal fin base. The number of principal dorsal fin rays is 9.
The number of principal anal fin rays is 19. Nine pectoral fin rays are visible. The
total number ofvertebrae is 35, with 18 caudal vertebrae. The number of ribs is 15.