Comparisons of endocranial casts of the subfamily Hydrodamalinae (Mammalia; Sirenia) reveal some interesting evolutionary trends, especially in the changes to the shape of the cerebrum and olfactory bulbs, and the position of the optic nerve. Endocranial casts of both Hydrodamalis spissa Furusawa, 1988 and H. gigas (Zimmermann, 1780) reveal several synapomorphies (spherical olfactory bulbs, the optic nerve separate from the trigeminal nerve, and diminished fissura longitudinalis cerebri and transverse sulcus). A revised phylogeny of North Pacific Sirenia based in part on endocranial casts demonstrates that H. spissa and H. gigas are very closely related within the Hydrodamalinae. On the other hand, although they contemporaneously inhabited the North Pacific Ocean, the eastern Pacific H. cuestae differs clearly from the western Pacific H. spissa.

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We propose two new methods, an “endobiont method” and a “model method,” to quantitatively evaluate shell-peeling predation against snails and hermit crabs in fossil gastropod assemblages. The endobiont method, based on the frequency of peeled and pagurized shells, provides the minimum and maximum estimates of predation against hermit crabs. The model method, based on the frequency distribution of shell repairs per shell in peeled and unpeeled shells, estimates directly the frequencies of predation against hermit crabs and snails. Our two methods were applied to a deep-water gastropod assemblage from the Pliocene Shinzato Formation, Okinawa, Japan. Results show that peeling predation, irrespective of the high frequency of repaired breaks (though to be an indication of high predatory attacks on snails in previous studies), is mostly attributable to hermit crabs rather than to snails in elongate shells, whereas it is the reverse in spherical shells. The results suggest that the frequency of repaired breaks is strongly controlled by the abundance of elongate shells in fossil gastropod assemblages, and that the increasing evidence of peeling predation, irrespective of predation pressure, is also caused by the increase of elongate shells (e.g., caenogastropods) in gastropod assemblages since the mid-Mesozoic. The new methods could be used for the real understanding of the history of this unique biological interaction through geologic times.

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An unusual new palaeoniscoid, Senekichthys hirundo gen. et sp. nov., is described from the Lower Carboniferous of the Tuva Republic (Southwestern Siberia) of Russia. In the shape of its anal and caudal fins this new taxon resembles the peculiar palaeoniscoid Dwykia analensis Gardiner, 1969 from the Lower Carboniferous of South Africa, but the very incomplete record of the latter gives no possibility to place both forms in a single family. In general view Senekichthys seems to be most similar to the family Elonichthyidae, but many derived characters occurring in the new taxon (e.g., long and pointed snout, large orbit with regard to the postorbital head length, very long and slim caudal lobe, very long and short-based anal fin, fulcral scales on the upper caudal lobe ending well before its distal tip, absence of ridge scutes, etc.) support its classification outside of the elonichthyids. Therefore Senekichthys is considered as a Palaeoniscimorpha incertae sedis. The Lower Carboniferous fish faunas of Western Siberia are briefly discussedand compared.

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New materials of Hesperornis rossicus Nessov et Yarkov, 1993 (one complete and one fragmentary tarsometatarsus) from the lower Campanian Karyakino locality in Saratov Province, Russia, show for the first time distal tarsometatarsal morphology for this species and allow reconsideration of its diagnosis. H. rossicus is the most derived species of the genus, having the greatest size for the genus and strongly reduced inner fingers, with undivided trochlea on tarsometatarsus for digits II and III and condyle for digit II completely behind that of digit III. Previous records of Hesperornis sp. from Rychkovo and Hesperornithidae indet. from Bereslavka (both Volgograd Province, Russia) are referred here to H. rosslcus.

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Haugia cf. variabitis (d’Orbigny) has been found in the upper part of the Idenohana Formation in the Uminoura area, Kumamoto Prefecture. This species is originally known from the Upper Toarcian H. variabilis Subzone of the Lytoceras jurense Zone in western Europe. This occurrence combined with our analyses of the lithofacies and sequence stratigraphy suggests that the Idenohana Formation is conformably overlain by the Kyodomari Formation.

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Two conodont apparatuses, Neospathodus symmetricus Orchard, 1995 and N. chionensis (Bender, 1967) are reconstructed on the basis of the material from the Spathian (Lower Triassic) limestone in the Taho Formation of Ehime Prefecture, southwest Japan. The Neospathodus apparatuses are composed of eight types of elements: digyrate (cypridodelliform) M, alate S₀, digyrate (enantiognathiform) S₁, di gyrate (grodelliform) S₂, bipennate S_3/4, angulate P₂, and segminate P₁ elements. This apparatus structure is the same as that for Neogondolella and is comparable to the standard 15-element plan of the Carboniferous ozarkodinids.

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