Gómez-Zurita J, Juan C, Petitpierre E
Lab. Genètica, Universitat de les Illes Balears, Palma de Mallorca, Balearic Islands, E-07071, Spain.
Mol Phylogenet Evol. 2000 Feb;14(2):304-17. doi: 10.1006/mpev.1999.0712.
The apterous genus Timarcha consists of three subgenera and more than 100 species in its Palearctic distribution, with specialized feeding on few plant families. Fifty-four sequences sampled from 31 taxa of the genus plus three outgroup leaf beetles were studied for their complete cytochrome oxidase II (COII) and a fragment of 16S rDNA mitochondrial genes, representing a total of about 1200 bp. Phylogenetic analyses using maximum-parsimony and distance methods for each gene separately and for the combined data set gave compatible topologies. The subgenus Metallotimarcha consistently appears in a basal position and is well differentiated from the remaining Timarcha, but no clear monophyletic grouping of Timarchostoma and Timarcha s. str. subgenera can be deduced from our analysis. Calibration of the molecular clock has been done using the opening of the Gibraltar Strait after the Messinian salinity crisis (about 5.5 MYA) as the biogeographic event causing disjunction of two particular taxa. Accordingly, the COII evolutionary rate has been estimated to be of 0.76 x 10(-8) substitution/site/year in Timarcha. Relation between phylogeny and host-plant use indicates widening of trophic regime as a derived character in Timarcha.
无翅叶甲属（Timarcha）在古北区分布有三个亚属和100多个物种，其取食高度特化，仅以少数几个植物科为食。从该属的31个分类单元以及三种外群叶甲中采集了54个序列，对其完整的细胞色素氧化酶II（COII）和一段16S rDNA线粒体基因进行了研究，总共约1200个碱基对。分别对每个基因以及合并数据集使用最大简约法和距离法进行系统发育分析，得到了一致的拓扑结构。金属无翅叶甲亚属（Metallotimarcha）始终处于基部位置，与其余的无翅叶甲属有明显分化，但从我们的分析中无法推断出无翅叶甲亚属（Timarchostoma）和狭义无翅叶甲亚属（Timarcha s. str.）有明确的单系类群。分子钟的校准以墨西拿盐度危机（约550万年前）后直布罗陀海峡的开通作为导致两个特定分类单元间断分布的生物地理事件。据此，估计无翅叶甲属中COII的进化速率为0.76×10⁻⁸替换/位点/年。系统发育与寄主植物利用之间的关系表明，食性范围的扩大是无翅叶甲属的一个衍生特征。
