Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

180 Yoshitaka Yabumoto
from Upper Jurassic to Recent in Africa, America, East Indies, Australia and Asia.
Among them, most of Mesozoic genera (excepting Chandlerichthys from Middle
Cretaceous deposits of North America by Grande, 1986) are known from Upper
Jurassic to Lower Cretaceous time in eastern Asia. These are Lycoptera, Asiatolepis,
Paralycoptera, Yanbiania, Yungkangichthys, Tongxinichthys, Plesiolycoptera, and Kuyangichthys
(Takai, 1943; Liu H.-T. et al., 1963; Chang and Chou, 1974, 1976, 1977, 1986; Ma,
1980; Liu H.-T. etal., 1982; Li, 1987). Among these Mesozoicgenera, Wakinoichthys
is closer to Lycoptera of the family Lycopteridae in having a slender body, the posterior
position of the median fins, a series of leaf-shape supraneurals, and especially its
caudal skeleton with seven hypurals, two parts of the first ural centrum, and the
complete neural arch and spine of the first preural centrum which were described by
Greenwood (1970). But Wakinoichthys differs from Lycoptera in having the following
characters. There are no large teeth on the parasphenoid. The dorsal origin is
behind the anal origin. The dorsal fin base is about half of the long anal fin base.
The pectoral fin elongates. The centra are well ossified. In the caudal skeleton,
Wakinoichthys is similar to the hiodontid genus Eohiodon from Eocene deposits ofNorth
America (Cavender, 1966; Grande, 1979; Wilson, 1978) and Hiodon of Recent in
North America, but differs in having no large teeth on the parasphenoid and the long
pectoral fin.
The long pectoral fin of Wakinoichthys is similar to that oftheosteoglossoid Singida
from ?Paleocene of East Africa (Greenwood and Patterson, 1967), Phareodus from
Eocene of North America (Cope, 1883; Grande, 1980) and the extant genera
(Osteoglossum in South America and Scleropages in northern Australia and Southeast
Asia). But these osteoglossoid genera differ from Wakinoichthys with their caudal
skeleton. There are five hypurals in Singida and six hypurals in Phareodus, Scleropages
and Osteoglossum (hypurals 3 to6 fused in Osteoglossum) and no uroneurals in Phareodus,
Scleropages and Osteoglossum. The first ural centrum is not separated in these osteog
lossoid genera (Greenwood, 1967; Greenwood and Patterson, 1967).
Wakinoichthys is similar to two genera ofthe family Huashiidae, Huashia from Late
Jurassic-Early Cretaceous deposits ofZhejiang Province in China (Chang and Chou,
1974, 1977) and Kuntulunia from Early Cretaceous deposits of Nei Mongol and Nigxia
Province in China (Liu et al, 1982, 1985; Zhang, 1990), in the position ofmedian fins,
having no large teeth on the parasphenoid and wide supraneurals, but differs in
having the slender body, the long pectoral fin, the long and narrow frontals, the large
gape of the mouth, seven hypurals, two parts of the first ural centrum and the
uroneural not reaching to the second preural centrum. Chang and Chou (1977,
1986) considered that Huashia is related to the Chanidae. Liu et al (1985) and
Zhang (1990) referred the Huashiidae to Osteoglossiformes.
The caudal skeleton of Wakinoichthys indicates that the genus is closely related to
those of the hiodontoid families Lycopteridae and Hiodontidae, which are included
within the suborder Notopteroidei, but Wakinoichthys differs from them in having no