Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

EarlyCretaceous Freshwater Fish Fauna in Kyushu, Japan
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length. The head length is contained 3.8 times in the standard length. The
number of dorsal fin rays is over 9. Four predorsal scutes are visible. The ventral
scutes are total 16, with 9 scutes between the pectoral and pelvic fins, and 7 scutes
between the pelvic and anal fins. The total number of vertebrae is 35, with 17
caudal vertebrae. The number of ribs is 16. The depth between the dorsal margin
of the body and the abdominal vertebral column at the maximum depth of the body
is contained 2.1 times in the depth between the abdominal vertebral column and the
ventral margin of the body.
In KMNH VP 100,201, the body depth is contained 4.3 times in the standard
length. The head length is contained 4.3 times in the standard length. The
number of dorsal fin rays is 10. The number of dorsal fin pterygiophores is 10. Six
predorsal scutes are visible. The ventral scutes are total 17, with 9 scutes between
the pectoral and pelvic fins, and 8 scutes between the pelvic and anal fins. The total
number of vertebrae is 35, with 17 caudal vertebrae. The number of ribs is 16.
Seven supraneurals are visible. The depth between the dorsal margin of the body
and the abdominal vertebral column at the maximum depth of the body is contained
2.0 times in the depth between the abdominal vertebral column and the ventral
margin of the body.
In KMNH VP 100,202, the number of dorsal fin rays is 11. The number of
dorsal fin pterygiophores is 11. The number of anal fin pterygiophores is 22. Five
predorsal scutes are visible. The ventral scutes are total 18, with 10 scutes between
the pectoral and pelvic fins, and 8 scutes between the pelvic and anal fins. The total
number of vertebrae is 35, with 16 caudal vertebrae. The number of ribs is 17.
Seven supraneurals are visible. The depth between the dorsal margin of the body
and the abdominal vertebral column at the maximum depth of the body is contained
1.9 times in the depth between the abdominal vertebral column and the ventral
margin of the body.
Remarks. Diplomystus primotinus is closest to Diplomystus sp. in having almost same
meristic characters and the proportion, but D. primotinus differs from D. sp. in the
form of the preopercle. The angle between the upper and the lower limbs of the
preopercle is an right-angled in D. primotinus, an obtuse in D. sp. The body depth of
D. sp. is slightly deeper than that of D. primotinus. D. primotinus has the most
elongate body in this genus (Tab. 5).
Diplomystus kokuraensis Uyeno, 1979.
(Figs. 68-72, PI. 54)
Holotype. KMNH VP 100,031, an almost complete specimen, with its left side
exposed, but a part of the body behind the dorsal fin is missing. The standard
length is 35.8 mm.