Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

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154 Yoshitaka Yabumoto The estimated number of scales is 17 or 18from the posterior end of the head to the dorsal origin. The first preural centrum bears the cylindrical parhypural. Five hypurals are visible. The first hypural is the largest. The second hypural is about three-fifths of the first one in width. There is a space between the second and the third hypurals. The third to fifth hypurals are slender. There are two ural centra. The epural is not visible (Fig. 34). Description of the paratypes. In KMNH VP 100,161, the body depth is contained 3.1 times in the standard length. The head length is contained 3.1 times in the standard length. The dorsal fin base is contained 1.6 times in the anal fin base. The number of principal anal fin rays is 18. There are 18 anal fin pterygiophores. The number of ribs is 14. In KMNH VP 100,162, the body depth is contained 3.3 times in the standard length. The head length is contained 3.5 times in the standard length. The first dorsal fin pterygiophore is above the first caudal vertebra. The dorsal fin base is contained 2.1 times in the anal fin base. The number of principal dorsal fin rays is 11. There are 11 dorsal fin pterygiophores. The number of principal anal fin rays is 18. There are 18 anal fin pterygiophores. The total number of vertebrae is 34, with 17 caudal vertebrae. In KMNH VP 100,163, the body depth is contained 3.1 times in the standard length. The head length is contained 3.0 times in the standard length. The first dorsal fin pterygiophore is above the second caudal vertebra. There are 9 dorsal fin pterygiophores. The numberof principal anal fin rays is 18. There are 18 anal fin pterygiophores. There are villiform teeth on the endopterygoid. Five large canine like teeth are visible on the parasphenoid at the posterior part of orbit. In KMNH VP 100,164, the body depth is contained 3.7 times in the standard length. The head length is contained 3.5 times in the standard length. The first dorsal fin pterygiophore is above the second caudal vertebra. The dorsal fin base is contained 1.6 times in the anal fin base. The number of principal dorsal fin rays is 11. The number of principal anal fin rays is 19. There are 19 anal fin pteryg iophores. In KMNH VP 100,165, the body depth is contained 3.0 times in the standard length. The head length is contained 3.9 times in the standard length. The dorsal fin base is contained 1.7 times in the anal fin base. The number of principal dorsal fin rays is 9. There are 9 dorsal fin pterygiophores. The number of principal anal fin rays is 19. Six pelvic fin rays are present. The total number of vertebrae is 36, with 19 caudal vertebrae. The number of ribs is 15. Remarks. This new species, Aokiichthys toriyamai, resemble Paralycoptera wui Chang & Chou, 1974 (Fig. 30) in having almost same number of dorsal and anal fin rays,
Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan 155 OPE 5mm Fig. 35. The opercle ofAokiichthys sp., KMNH VP 100,172. the almost same proportion and the size (Tab. 3). But it differs from P. wui in having the smaller number of vertebrae and ribs. The number of vertebrae is 35 to 36 with 17 to 19 caudal vertebrae in A. toriyamai, 40 to 42 with 20 caudal vertebrae in P. wui. The number of ribs is 14 to 15 in A. toriyamai, 20 to 22 in P. wui (Tab. 3). A. toriyamai is closest to Aokiichthys changae (Figs. 36-39) in having almost same meristic characters and almost same proportion in the genus Aokiichthys, with the exception of the relative position of median fins. The origin of the dorsal fin is vertical with the anal origin in A. toriyamai. The origin of the dorsal fin is behind of the anal origin in A. changae. Aokiichthys changae sp. nov. (Figs. 36-39, PI. 45) Diagnosis. It differs from other species of the genus Aokiichthys in having the combination of following characters. Large teeth are present on the parasphenoid. The body is moderate and the body depth is contained 3.2 to 3.7 times in the standard length. The median fins are relatively posterior in position. The dorsal origin is behind the anal origin and vertical with the fifth anal fin pterygiophore (about anterior one third of the anal fin base). The number of principal dorsal fin rays is 9 to 11. The number of principal anal fin rays is 17 to 19. The range of size is 62.5 to 83.1 mm in standard length. The number of vertebrae is 35 to 36, with 18 to 19 caudal vertebrae. The number of ribs is 14 to 15. Holotype. exposed. Paratypes. KMNH VP 100,166, an almost complete specimen with its right side The standard length is 67.3 mm. KMNH VP 100,167, an almost complete specimen with its left side
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Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

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