Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

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234 Yoshitaka Yabumoto URN1-4 HYU1 PARH 2mm J Fig. 93. Paraleptolepis elegans gen. et sp. nov., caudal skeleton of the holotype, KMNH VP 100,227. The principal anal fin rays are preceded by two small unbranched accessory rays. There are villiform teeth on the endopterygoid. The total number of vertebrae is 40, with 20 caudal vertebrae. Sixteen ribs can be counted. In KMNH VP 100,231, the body depth is contained 4.7 times in the standard length. The head length is contained 5.1 times in the standard length. The dorsal fin base is contained 1.8 times in the anal fin base. There are 19 anal fin pterygiophores. The principal anal fin rays are preceded by four small unbranched accessory rays. The number of pectoral fin rays is 11. The total number of vertebrae is 42, with 20 caudal vertebrae. The number of ribs is 20. There are two ural centra. There are four uroneurals. The first uroneural extends to the second preural centrum. The second and third uroneurals extend to the first preural centrum. The fourth uroneural extends to the first ural centrum. In KMNH VP 100,232, the body depth is contained 7.2 times in the standard length. The head length is contained 4.1 times in the standard length. The dorsal fin base is contained 2.1 times in the anal fin base. The preopercle is L-shape. 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 19 anal fin pterygiophores. The principal dorsal and anal fin rays are preceded by four small unbranched accessory rays. The totalnumber ofvertebrae is42, with 20caudal vertebrae. The number of ribs is 20. Remarks. This new species, Paraleptolepis elegans, is close to Paraleptolepis kikuchii in
EarlyCretaceous Freshwater Fish Fauna in Kyushu, Japan 235 meristic characters and the characters of the head and caudal regions, but it differs from P. kikuchii in the proportion. The body is slender and the depth is contained 4.7 to 5.5 times in the standard length in P. elegans, 3.2 to 3.7 times in P. kikuchii (Tab. 6). Order Gonorynchiformes ? Family incertae sedis (Figs. 94-95, PI. 59) Specimen. KMNH VP 100,233, a specimen with its left side exposed. The head region is missing. The length from the dorsal origin to the posterior end of the hypural is 16.2 mm. The estimated standard length is 32.5 mm. Locality. Minamigaoka (KM-1), Kokura-kita-ku (Kokura Northern Ward), Kita kyushu City, Fukuoka Prefecture, Japan. Horizon. The Third Formation (the upper formation, W3, correlated to the Lower Wakamiya Formation) of the Wakino Subgroup in the Kwanmon Group, the Lower Cretaceous. Description. The body is slender. The body depth is contained 7.6 times in the estimated standard length. The outline from the occipital region to the dorsal origin is straight. The dorsal fin is situated at about the middle of the body. The pelvic fin is large and is situated below the dorsal fin (Fig. 94, PI. 59). The first dorsal fin pterygiophore is inserted between the neural spines of the eighth and ninth abdomi nal vertebrae. The dorsal fin is large and the base is longer than the anal fin base. The anal fin base is contained 1.6 times in the dorsal fin base. The pectoral fin is large and extends below the dorsal origin. The origin of the anal fin is behind the end of the dorsal fin base. The caudal fin is forked. The number of principal dorsal fin rays is 12. There are 12 dorsal fin pterygiophores. The number of principal anal fin rays is 11. Thereare 11 anal fin pterygiophores. Twelve pectoral fin rays are visible. Seven pelvic fin rays are visible. There are 19 principal caudal fin rays (1,9,8,1). The total number of vertebrae is 35, with 18 caudal vertebrae. There is a series of median supraneurals beginning immediately behind the head and ending before the dorsal origin. Each supraneural is cylindrical. The neural arch and spine of the first preural centrum are complete. There are 6 hypurals. The first hypural is the largest. The second hypural is about half of the first one in width and does not extend to the first ural centrum. There is a space between the second and third hypurals. There are two ural centra. The second ural centrum bears three hypurals (HYU3-5). One uroneural is visible and extends forward to the first
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Fig. 10. Nipponamia satoi gen. et s
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Fig. 19. Chuhsiungichthys yanagidai
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40-42 2.9 Early Cretaceous Freshwat
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Fig. 37. Aokiichthys changae gen. e
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Early Cretaceous Freshwater Fish Fauna in Kyushu, Japan

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