Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

220 Yoshitaka Yabumoto
In KMNH VP 100,216, the body depth is contained 2.0 times in the standard
length. The head length is contained 3.7 times in the standard length. There are
11 dorsal fin pterygiophores. The number of ventral scutes is 20, with 14 scutes
between the pectoral and pelvic fins, and 6 scutes between the pelvic and anal fins.
The total number of vertebrae is 35, with 16 caudal vertebrae. The number of ribs
is 17. Six median supraneurals are present.
In KMNH VP 100,234, the body depth is contained 3.6 times in the standard
length. The head length is contained 3.4 times in the standard length. There are
12 dorsal fin pterygiophores. There are 28 anal fin pterygiophores. The number of
ventral scutes is 17, with 10 scutes between the pectoral and pelvic fins, and 7 scutes
between the pelvic and anal fins. The number of dorsal scutes is 11. The total
number of vertebrae is 35, with 16 caudal vertebrae. The number of ribs is 17.
Remarks. This species, Diplomyslus sp., is middle between D. primotinus and D.
kokuraensis in the body depth (Tab. 5). It is closest to D. primotinus in having the
almost same proportion, but D. sp. slightly differs from D. primotinus in the form of
the preopercle and the body depth. The angle between the upper and lower limbs of
the preopercle is an obtuse in D. sp., an right-angled in D. primotinus. The body
depth of D. sp. is slightly deeper than that of D. primotinus. But these differences are
considered to be small to recognize it as a new species in the present study.
Order and Family incertae sedis
Genus Paraleptolepis gen. nov.
Diagnosis. The first preural centrum has a rudimentary neural arch. Three
epurals are present just behind the neural arch of the first preural centrum. Three
uroneurals are present. The first uroneural extends forward beyond the first preural
centrum and reaches the anterior end of the second preural centrum. The number
of branched caudal fin rays is 17. Teeth are absent on the parasphenoid, endoptery
goid and maxilla. The supramaxilla is present. Small canine like teeth are present
on the premaxilla and dentary. The frontal is short. Median fins are posterior.
The origin of the dorsal fin is just before the anal origin. The dorsal fin base is
shorter than the anal fin base. The number of dorsal fin rays is 11 to 12. The
number of anal fin rays is 17 to 19. The number of vertebrae is 40 to 42, with 19 to
20 caudal vertebrae.
Type species.
Paraleptolepis kikuchii sp. nov.
Etymology. The generic name, Paraleptolepis consists of para, a Greek word meaning
beside or near, and leptolepis, a generic name of the "Leptolepiformes".