Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

EarlyCretaceous Freshwater Fish Fauna in Kyushu, Japan 145
Fig. 28. Yungkangichthys macrodon sp. nov., head region of the holotype, KMNH VP 100,183.
Horizon. The Fourth Formation (the uppermost formation, W4, correlated to the
Upper Wakamiya Formation) of the Wakino Subgroup in the Kwanmon Group, the
Lower Cretaceous.
Etymology. The species name, macrodon, means large teeth, which refers to the fact
that this species has the large teeth on the parasphenoid.
Description of the holotype.
The body is deep. The body depth is contained 1.7 times in the standard
length in estimation. The head length is contained 3.8 times in the standard length
in estimation. The outline of the head dorsal margin is slightly convex. The
restored outline from the occipital region to the dorsal origin is slightly convex. The
restored outline of the abdomen is slightly convex and rapidly ascends in front of the
anal origin (Figs. 26 and 27). The dorsal fin is missing. The anal fin is large and
each fin ray is long and is not slender. The anal fin pterygiophores are slender and
long. The pectoral fin is situated near the ventral edge of the body at the
postero-ventral corner of the head. The pelvic fin is situated at the middle ofventral
edge of abdomen. The number of principal anal fin rays is over 11. The number of
anal fin pterygiophores is over 10. The principal anal fin rays are preceded by two