Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

194 Yoshitaka Yabumoto
PREM
PREO
V^
"*v_,
5mm
Fig.62.
100,188.
Wakinoichthys robustus gen. et sp. nov., head region of the holotype, KMNH VP
rays are visible. Five pelvic fin rays are visible. There are 18 principal caudal fin
rays (1,8,8,1). The gape of the mouth is large. The anterior part of the lower jaw
is missing. The suture between the dentary and anglo-articular is not visible and
the posterior part of the lower jaw is poorly preserved. The premaxilla bears small
canine like teeth. The posterior end of the lower jaw is placed below almost center
of the orbit. There are villiform teeth on the endopterygoid. The endopterygoid is
large (Fig. 62). The total number of vertebrae is 45, with 22 caudal vertebrae. The
anterior end of the vertebral column is not visible.
vertebrae was estimated on the basis of the number of ribs.
The number of abdominal
The number of ribs is
21.
There is a series of median supraneurals beginning immediately behind the head
and ending above the first caudal vertebra. Each supraneural is wide and leaf-shape
with a ridge running from a dorsal end to a ventral end. The first preural centrum
bears the narrow parhypural (Fig. 63).
Description of the paratypes.
In KMNH VP 100,189, the body depth is contained 3.5 times in the standard
length. The head length is contained 3.2 times in the standard length. The first
dorsal fin pterygiophore is inserted between the fifth and the sixth caudal vertebrae.
The dorsal fin base is contained 2.4 times in the anal fin base. The number of