Flores B S, Siddall M E, Burreson E M
School of Marine Science, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point 23062, USA.
J Parasitol. 1996 Aug;82(4):616-23.
The phylogenetic position of the phylum Haplosporidia was investigated with the complete small subunit rRNA gene sequences from 5 species in the phylum: Haplosporidium nelsoni and Haplosporidium costale, parasites of the eastern oyster Crassostrea virginica; Haplosporidium louisiana, a parasite of the mudcrab Panopeus herbstii; Minchinia teredinis, a parasite of shipworms (Teredo spp.) and Urosporidium crescens, a hyperparasite found in metacercariae of the trematode Megalophallus sp. in the blue crab, Callinectes sapidus. Multiple alignments of small subunit rRNA gene sequences included the 5 haplosporidian taxa and 14 taxa in the alveolate phyla Ciliophora, Dinoflagellida, and Apicomplexa. Maximum parsimony analysis placed the phylum Haplosporidia as a monophyletic group within the alveolate clade, as a taxon of equal rank with the other 3 alveolate phyla, and as a sister taxon to the clade composed of the phyla Dinoflagellida and Apicomplexa. Transversionally weighted parsimony placed the haplosporidians as a sister taxon to the ciliates. A separate analysis focused on the relationships of species in the genus Haplosporidium. Analyses were conducted with the haplosporidians as a functional ingroup, using each of the alveolate phyla individually as functional outgroups. The results indicated that species in the genus Haplosporidium do not form a monophyletic assemblage. As such, the present morphological criteria for distinguishing the genera Haplosporidium and Minchinia are insufficient.
利用单孢子虫门5个物种的完整小亚基rRNA基因序列，对单孢子虫门的系统发育位置进行了研究：纳尔逊单孢子虫和科斯特单孢子虫，它们是美国东海岸牡蛎的寄生虫；路易斯安那单孢子虫，是泥蟹的寄生虫；船蛆单孢子虫，是船蛆的寄生虫；新月尿孢子虫，是在蓝蟹体内的吸虫巨睾属尾蚴中发现的一种超寄生虫。小亚基rRNA基因序列多序列比对包括5个单孢子虫类群以及纤毛虫门、甲藻纲和顶复门这3个有泡虫门中的14个类群。最大简约法分析将单孢子虫门置于有泡虫进化枝内的一个单系类群中，作为与其他3个有泡虫门等级相同的一个分类单元，并且作为由甲藻纲和顶复门组成的进化枝的姐妹分类单元。颠换加权简约法将单孢子虫类作为纤毛虫的姐妹分类单元。一项单独的分析聚焦于单孢子虫属内物种的关系。以单孢子虫类作为一个功能内群进行分析，分别将每个有泡虫门作为功能外群。结果表明，单孢子虫属中的物种并未形成一个单系类群。因此，目前用于区分单孢子虫属和明钦属的形态学标准并不充分。
