Common evolutionary origin of aquareoviruses and orthoreoviruses revealed by genome characterization of Golden shiner reovirus, Grass carp reovirus, Striped bass reovirus and golden ide reovirus (genus Aquareovirus, family Reoviridae)

Full-length and partial genome sequences of four members of the genus Aquareovirus, family Reoviridae (Golden shiner reovirus, Grass carp reovirus, Striped bass reovirus and golden ide reovirus) were characterized. Based on sequence comparison, the unclassified Grass carp reovirus was shown to be a member of the species Aquareovirus C The status of golden ide reovirus, another unclassified aquareovirus, was also examined. Sequence analysis showed that it did not belong to the species Aquareovirus A or C, but assessment of its relationship to the species Aquareovirus B, D, E and F was hampered by the absence of genetic data from these species. In agreement with previous reports of ultrastructural resemblance between aquareoviruses and orthoreoviruses, genetic analysis revealed homology in the genes of the two groups. This homology concerned eight of the 11 segments of the aquareovirus genome (amino acid identity 17-42%), and similar genetic organization was observed in two other segments. The conserved terminal sequences in the genomes of members of the two groups were also similar. These data are undoubtedly an indication of the common evolutionary origin of these viruses. This clear genetic relatedness between members of distinct genera is unique within the family Reoviridae. Such a genetic relationship is usually observed between members of a single genus. However, the current taxonomic classification of aquareoviruses and orthoreoviruses in two different genera is supported by a number of characteristics, including their distinct G+C contents, unequal numbers of genome segments, absence of an antigenic relationship, different cytopathic effects and specific econiches.

Suckers (Fish, Catostomidae) from the Eocene of China account for the family's current disjunct distributions

Unequivocal Eocene suckers from China are for the first time reported here. This discovery demonstrates that catostomids of the Eocene Epoch (some 55-35 Ma ago) are scattered widely on mainland Asia as well as western North America. The present day disjunct distribution pattern of catostomids, with 68 extant species widespread in North America and the northern part of Middle America and only two in the restricted areas of Asia, is the result of their post-Eocene decline in Asia due to the competitive pressure from cyprinids, their Late Cenozoic radiation in North America, and the vicariant and dispersal events triggered by the changed biogeographic landscape. All of these prove to be a historical product of the geological, biological, and climatic changes throughout the Cenozoic.

中国海蓝子鱼科Family Siganidae分类和动物地理学特点

蓝子鱼科鱼类隶属于鲈形目、刺尾鱼亚目，广泛分布于我国东海、南海及台湾海域。本文根据中国科学院海洋研究所多年来在我国海域采集并收藏的以及部分补充采集的蓝子鱼标本，参考国际最新研究资料，对我国海域蓝子鱼科鱼类进行分类和动物地理学研究，共记录中国海域蓝子鱼科鱼类1属2亚属11种。经研究分析，得到如下结论： 1.中国沿海蓝子鱼科鱼类的多样性问题。国内曾有13种蓝子鱼的分布记录，其中蠕纹蓝子鱼Siganus vermiculatus和暗体蓝子鱼S. punctatissimus仅以前的学者做过名录形式的记载，并无标本收藏，本文中不做介绍。此外尖嘴蓝子鱼Siganus unimaculatus也可能存在于中国海域，有待于进一步研究。目前确定在中国海域有分布的蓝子鱼为11种，约占世界总种数（27）的40％多，种的多样性较高。 2. 形态学比较研究说明，蓝子鱼在体形、体色、牙齿、头骨、椎骨、耳石等特征方面存在种间差异，可作为蓝子鱼科鱼类分类的有效鉴别特征。对于外部形态极其相似的种，可借助内部解剖特征相辅助予以区分。 3．对蓝子鱼动物地理学特点研究分析结论如下：a.中国海域存在的11种蓝子鱼在印度－太平洋海域均有分布，没有地方特有种。b.长鳍蓝子鱼和褐蓝子鱼在我国东海、台湾海域和南海均有分布，褐蓝子鱼在黄海北部亦有分布，种群数量较大；其它9种，除凹吻蓝子鱼仅分布于南海外，均分布于南海及台湾海域，种群数量较小。c.中国海域蓝子鱼种类组成与邻近的菲律宾、马来西亚、印度尼西亚海域比较相似，中国分布的种类在这些海域均有分布，且分布于这一区域而中国没有记录的有5种。与日本相比，种类组成也比较相似，中日共有种达9种，仅分布于中国海域2种，仅分布于日本海域1种。 4. 作者参照国际最新研究结果和较为公认的分类系统Nelson（1994），将蓝子鱼科置于刺尾鱼亚目，而不再使用国内学者长期惯用的蓝子鱼亚目。蓝子鱼科包括一属蓝子鱼属Siganus Forsskål, 1775，两亚属：蓝子鱼亚属Siganus Forsskål, 1775 和罗蓝子鱼亚属 Lo Seale, 1906，同时使全部种名的变动和确定与国际最新研究结果(Woodland, 1990; 2001）取得一致。

中国海豆蟹科Family Pinnotheridae分类学研究

本文根据中国科学院海洋研究所收藏的豆蟹科标本和国内外相关文献，进行了中国海域豆蟹科的分类学研究。作者克服了豆蟹科分类难度大，研究积累较少，种的界限不清等困难，在短期内初步查清了中国海域豆蟹科种类及分布情况，共记述5亚科12属 40种。发现4新记录属，9新记录种，和豆蟹属1未定种Pinnotheres sp.，丰富了中国海豆蟹科区系内容，列出了共栖种中国海域全部记录过的宿主。 作者对鉴定过程中出现的疑难问题：“中型三强蟹Tritodynamia intermedia Shen, 1935是否为霍氏三强蟹 Tritodynamia horvathi Nobili, 1905的同物异名” 进行了细致比较、研究，否定了通行多年的Sakai（1976）的“T. intermedia Shen为T. horvathi Nobili的次异名”的结论，肯定了二者均为有效种。 对中国海域豆蟹科种类地理分布初步研究表明其分布与日本海域和东南亚海域都有相似之处，但有显著不同：仅发现于中国海域而未见于日本海域的豆蟹属Pinnotheres多达8种：涨腹豆蟹Pinnotheres excussus Dai et al., 1980，球豆蟹Pinnotheres pilulus Dai et al., 1980，锯颚豆蟹Pinnotheres serrignathus Shen, 1932，宽豆蟹Pinnotheres dilatatus Shen, 1932，青岛豆蟹Pinnotheres tsingtaoensis Shen, 1932，海阳豆蟹Pinnotheres haiyangensis Shen, 1932，钝颚豆蟹Pinnotheres obtusidentata（Dai et al., 1980），光豆蟹Pinnotheres luminatus Dai et al., 1980）；仅发现于中国海域的三强蟹属Tritodynamia有4种：福建三强蟹Tritodynamia fujianensis Chen, 1979，长腿三强蟹Tritodynamia longipropodum Dai et al., 1980，宽身三强蟹 Tritodynamia dilatatum Yang et Sun,1996和海南三强蟹 Tritodynamia hainanensis Dai et al.g, 1980；而未发现于中国海域的日本特有种多达13种。结果表明这一类群由于共栖和地域分化程度较高乃至地区性特有种数显著较多。 论文通过对豆蟹科系统分类和初步的动物地理学研究，搞清了中国海豆蟹科的种和分布、多样性及其宿主等基本情况。为今后研究豆蟹科种类生物学、生态学特性提供了基础资料。