Yoshitaka Yabumoto

A new Mesozoic coelacanth from Brazil (Sarcopterygii, Actinistia)

Abstract A new genus and species of coelacanth, Parnaibaia maranhaoensis gen. et sp. nov. is described on the basis of four specimens from the Pastos Bons Formation in Maranhao, Brazil. This new genus and species differs from other genera of the family Mawsoniidae by having a stout median ridge on the scales, six free extrascapulars, seven elements in the supraorbital-tectal series and absence of large teeth. P. maranhaoensis bridges the gap between the Triassic Chinlea and Cretaceous Mawsonia and Axelrodichthys.

New amiid fish (Halecomorphi: Amiiformes) from the Lower Cretaceous Crato Formation, Araripe Basin, Northeast Brazil

Abstract A new species of Amiidae, †Cratoamia gondwanica gen. et sp. nov., is here described from the Early Cretaceous Crato Formation of the Araripe Basin, northeast Brazil. The new species, based on complete and nearly complete articulated specimens, includes synapomorphies of the subfamily †Vidalamiinae and the tribe †Vidalamiini. The presence of †Cratoamia in Brazil increases the geographical distribution of the tribe †Vidalamiini into the Southern Hemisphere.

Sinamia kukurihime, a New Early Cretaceous Amiiform Fish from Ishikawa, Japan

Abstract. A new species of the genus Sinamia of the family Sinamiidae of the order Amiiformes, S. kukurihime is described on the basis of a hyomandibula and many isolated bones and scales found from the Lower Cretaceous freshwater deposits of the Kuwajima Formation, Itoshiro Subgroup, Tetori Group in Kuwajima, Hakusan City, Ishikawa Prefecture, Japan. The new species is distinguished from other congeners by the forms of the hyomandibular, frontal, dermopterotic, maxilla, gular plate, preopercle, supracleithrum and scales. Among the genus Sinamia, S. kukurihime sp. nov. is considered to be closest to S. liaoningensis. This is the first record of the genus Sinamia from Japan. The presence of a new species of the genus from Japan demonstrates the wide distribution and diversity of the genus during the Cretaceous in East Asia.

A coelacanth scale from the Upper Triassic Pardonet Formation, British Columbia, Canada

A large ichthyosaur specimen was first reported from the Sikanni Chief River (Pink Mountain), British Columbia, Canada by Keary Walde in 1992. It was excavated by the Canada-Japan Project for Triassic Marine Environments in 1998 to 1999 (Nicholls and Manabe, in prep). During the excavation, an isolated scale was found from the same site and stratigraphic level of the ichthyosaur. This is the first vertebrate specimen from the site excepting ichthyosaurs. The characters of the scale indicate it belongs to a coelacanth. This is the first record of a coelacanth from the Upper Triassic in Canada.

A New Miocene Three-Spined Stickleback (Pisces: Gasterosteidae) from Central Japan

Abstract. Gasterosteus kamoensis sp. nov. is described from the Upper Miocene Minamiimogawa Formation in Kamo City, Niigata, Japan. The new species represents the oceanic complete morph. It is characterized by: short and high ectocoracoid; presence of posttemporal bone; fully developed pelvic girdle with convex anterior margin; wide and not tapering posterior process of pelvic bone; four dorsal spines; comparatively long spines in dorsal, pelvic and anal fins; and large body size, apparently exceeding 130 mm in standard length. Gasterosteus kamoensis sp. nov. is the third nominal fossil species of this genus described from East Asia, along with freshwater G. orientalis Sytchevskaya and the marine G. abnormis Gretchina. Together, these discoveries demonstrate the wide distribution and morphological and ecological diversity of this genus during the Miocene in the northwestern Pacific.

A new Miocene amiid fish, Amia godai from Kani, Gifu, Central Japan

Abstract. A new species of the genus Amia of the family Amiidae, A. godai is described based on a parasphenoid and many isolated bones and scales found from the Early Miocene Nakamura Formation of the Mizunami Group along the Kiso River in Kani City, Gifu Prefecture, Central Japan. Amia godai sp. nov. is distinguished by having a V-shaped edentulous area in the posterior part of the tooth patch of the parasphenoid. This is the first record of the genus from the Early Miocene in the world and the first record of the family from the Cenozoic in Japan.

A Revision of the Amiiform Fish Genus Sinamia with Phylogeny of Sinamiidae

Abstract. All species of the genus Sinamia (Sinamiidae, Amiiformes) are reviewed on the basis of the examination of the holotypes, paratypes, other specimens, and original descriptions of each species. Diagnoses are provided for all species. Phylogenetic analysis supports the monophyly of the family Sinamiidae and demonstrates that the long dorsal fin base in Sinamia and Amia is a matter of convergence. It is considered that the species having a long dorsal fin base lived in still water with vegetation, like Amia calva, while the species having a short dorsal fin base probably lived in the open water.

A New Triassic Coelacanth, Whiteia oishii (Sarcopterygii, Actinistia) from West Timor, Indonesia

Abstract. A new species of coelacanth, Whiteia oishii sp. nov. is described on the basis of complete specimens from West Timor in Indonesia. This species differs from other species in the genus Whiteia by the presence of five to ten long ridges on scales, nine rays on the first dorsal fin, pointed denticles on the anterior fin rays of the first dorsal fin, and an operculum ornamented with many tubercles. Whiteia oishii sp. nov. is the first coelacanth occurrence from Southeast Asia and its discovery sheds light on the worldwide distribution of the genus Whiteia in the marine Triassic.

Apsopelix miyazakii, a New Species of Crossognathid Fish (Teleostei) from the Upper Cretaceous of Hokkaido, Japan

Abstract. Apsopelix miyazakii sp. nov. is described on the basis of a single specimen from the Upper Cretaceous (Turonian), Nakagawa Town, Hokkaido, Japan. This new species differs from the other species of the genus Apsopelix by the existence of a median frontal convexity near the posterior end of the frontal bones, the articulation of the lower jaw behind the middle of the orbit and the antorbital contacting with the first infraorbital at the ventral half of its posterior margin. This is the first record of the genus Apsopelix and the family Crossognathidae from the eastern part of the Tethys.

Function of the pseudomaxillary fold in the mouth opening of the coelacanth, Latimeria chalumnae

The oral region of a coelacanth, Latimeria chalumnae, from the Comoro Islands, was examined in fresh condition, and the complex folding of the membrane between the lower jaw and the skull, and a strut-like structure in the membrane were found. When the mouth opened, the pseudomaxillary folds covered the lateral walls of the mouth. The movement of the membrane is inferred from the observation of the specimen. Coelacanths developed a way of covering the lateral sides of mouth that is different from that of other fishes; especially the pseudomaxillary fold above the strut is unique to coelacanths, but the pseudomaxillary fold below the strut is similar to the lower lip fold of the lepidosirenoid lungfish.