Byttneriophyllum tiliifolium is a leaf fossil-species of the family Malvaceae that was distributed widely throughout Eurasia from the Miocene to the Pliocene. An affinity to some Malvadendrina subfamilies has been suggested for Byttneriophyllum-bearing plants, but remains to be clarified due to insufficient information on other organs. Here, we report an exceptional lower Miocene fossil locality in Japan where a monodominant forest of the wood fossil-species Wataria parvipora flourished. Notably, the forest floor was covered by a bed consisting almost exclusively of B. tiliifolium. We observed occurrence modes of B. tiliifolium in this bed that confirmed that these leaves were deposited parautochthonously. These observations imply a biological connection between B. tiliifolium and W. parvipora. The wood and leaf characters together might narrow the affinity of Byttneriophyllum-bearing plants down to Helicterioideae within the Malvadendrina, although it is also possible that Byttneriophyllum-bearing plants constitutes an extinct lineage which is characterized by a combination of morphological traits found in several extant lineages. Our results suggest that Byttneriophyllum-bearing plants started to inhabit swamps no later than the end of the early Miocene when the global temperature was getting warmer.

The Sinamiidae are a family of halecomorph fishes (Holostei) stratigraphically limited to the Lower Cretaceous and confined to East Asia. The first species of sinamiids were discovered in China, and then new occurrences were recorded in Thailand and Japan. The three recognized genera, Sinamia, Siamamia and Ikechaoamia, are notably characterized by an unpaired parietal. Here, we describe a new genus and species of sinamiid based on material from the Aptian Khok Kruat Formation of Ban Krok Duean Ha, Nakhon Ratchasima, Thailand. The new taxon known from preserved specimens in 3D is characterized by four pairs of extrascapular and tall cylindrical teeth with a conical enamel stalk topped by an arrowhead-shaped acrodine cap, among other characters. A phylogenetic analysis of the halecomorph fishes shows that the new taxon is the sister of the other Thai species, Siamamia naga, and that the two are grouped with two Chinese genera in a strongly supported clade, the Sinamiinae. This subfamily is here grouped with the Amiinae that contained the extant Amia. This new discovery is a clue that Southeast Asia may have been a center of diversification for this fish clade, and the phylogenetic analysis reveals that amiines may have originated somewhere in Asia during the Cretaceous before they spread throughout the northern hemisphere.

Under aquaculture conditions, Japanese eels (Anguilla japonica) produce a high percentage of males. However, females gain higher body weight and have better commercial value than males, and, therefore, a high female ratio is required in eel aquaculture. In this study, we examined the effects of isoflavones, genistein, and daidzein on sex differentiation and sex-specific genes of eels. To investigate the effects of these phytoestrogens on the gonadal sex, we explored the feminizing effects of soy isoflavones, genistein, and daidzein in a dose-dependent manner. The results showed that genistein induced feminization more efficiently than daidzein. To identify the molecular mechanisms of sex-specific genes, we performed a comprehensive expression analysis by quantitative real-time PCR and RNA sequencing. Phenotypic males and females were produced by feeding elvers a normal diet or an estradiol-17β- or genistein-treated diet for 45 days. The results showed that female-specific genes were up-regulated and male-specific genes were down-regulated in the gonads, suggesting that genistein induces feminization by altering the molecular pathways responsible for eel sex differentiation.

The morphology of lizard skulls is highly diverse, and it is crucial to understand the factors that constrain and promote their evolution to understand how lizards thrive. The results of interactions between cranial bones reflecting these factors can be detected as integration and modularity, and the analysis of integration and modularity allows us to explore the underlying factors. In this study, the integration and modularity of the skulls of lizards and the outgroup tuatara are analyzed using a new method, Anatomical Network Analysis (AnNA), and the factors causing lizards morphological diversity are investigated by comparing them. The comparison of modular structures shows that lizard skulls have high integration and anisomerism, some differences but basically common modular patterns. In contrast, the tuatara shows a different modular pattern from lizards. In addition, the presence of the postorbital bar by jugal and postorbital (postorbitofrontal) also reflect various functional factors by maintaining low integration. The maintenance of basic structures due to basic functional requirements and changes in integration within the modules play a significant role in increasing the morphological diversity of the lizard skull and in the prosperity of the lizards.

The class Bivalvia (phylum Mollusca) is one of the most successful at survival groups of animals with diverse color patterns on their shells, and they are occasionally preserved in the fossil record as residual color patterns. However, the fossil record of the residual color patterns in freshwater bivalves could be traced only to the Miocene, greatly limiting color pattern evolution knowledge. We present the color patterns of the Cretaceous freshwater bivalves belonging to three extinct families of the order Trigoniida (hereinafter the Kitadani Freshwater Bivalves) from Japan, which is the oldest and the second fossil record of freshwater molluscan color patterns. The Kitadani Freshwater Bivalves consists of two types of color patterns: stripes along the growth lines and radial rays tapered toward the umbo, which resemble that of the colored bands of extant freshwater bivalves. This resemblance of the color patterns between the Kitadani Freshwater Bivalves and the extant species indicates that the color patterns of the freshwater bivalves represent the convergent evolution between Trigoniida and Unionida. To explain this convergent evolution, we advocate three conceivable factors: the phylogenetic constraints, monotonous habitats typical of freshwater ecosystems, and the predation pressure by visual predators in freshwater sediments.