Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan 179
lower jaw is contained 1.3 times in the head length. The parasphenoid teeth are
almost same with the teeth of jaws in size. The position of pelvic fin indicates the
deep body (Fig. 51). The present author does not describe it as a new species,
because the specimen is too incomplete.
Family Wakinoichthiidae nov.
Diagnosis. This new family differs from other families of the Osteoglossiformes in
the following combination of characters. The body is slender, and the bodydepth is
contained 6 times or more in the standard length. The head length is contained 4
times or more in the standard length. The long pectoral fin extends beyond the
pelvic fin insertion. The gape ofthe mouth is large and the lower jaw is long with
small canine-like teeth on the dentary. Large teeth are absent on the parasphenoid.
The frontals are long and narrow. The number of principal caudal fin rays is 18
(1,8,8,1). The number of hypurals is 7. The first uroneural does not extend to the
second preural centrum. Two parts of the first ural centrum are present. The
neural arch and spine of the first preural centrum are complete. The number of
vertebrae is 48. The median supraneurals are broad. The dorsal origin is behind
the anal origin. The dorsal fin base is about half of the anal fin base. The end of
the dorsal fin base does not reach the end of the anal fin base.
Diagnosis.
Type species.
Genus Wakinoichthys gen. nov.
As for the family, monotypic genus.
Wakinoichthys aokii sp. nov.
Etymology. The generic name, Wakinoichthys consists of Wakino, the name of the
formation in which the type specimen was yielded, and ichthys, a Greek word meaning
fish.
Remarks. The presence ofthe parasphenoid teeth is not clear (at least large teeth
are absent on the parasphenoid), but the following combination of characters indicate
that the Wakinoichthiidae is a member ofthe teleostean fish order Osteoglossiformes:
1) the median fins are relatively posterior in position, 2) the premaxilla and dentary
have canine like teeth, 3) the endopterygoid has villiform teeth, 4)the pectoral fin
elongates, 5) the series ofsupraneurals are present, 6) the anterior and the posterior
parts ofthe first ural centrum are present, 7) the straplike uroneurals are present, 8)
the number of hypural is seven, 9) the neural arch and spine of the first preural
centrum are complete, 10) the number of principal caudal fin rays, is 18.
Seven families and about twenty genera of the Osteoglossomorpha are known