中国确切报道的古星珊瑚(Palastraea)共15种(不包含比较种、近似种等),包含1个广布种和14个中国地方种。部分学者以间壁形态为依据将其细分为多个属(Acmoheliophyllum,Palaeosmilastraea,Parapalaeosmilia)。通过对这类珊瑚某些种的薄片进行详细观察,发现即使在单个群体中,间壁形态随着切片位置不同也有变化,该性状不宜作为分属标准。为了进一步验证这些属的建立是否合理,本文选取了16个性状,对中国报道的14个地方种中的13个种进行了分支分析,获得两个支序图并生成一个严格合意树。合意树表明,细分出的3个属均不为单系类群,它们仍应归入同一个属;支序图表明,互为姊妹群的Palaeosmilastraea gracilis和P.gyorxtungensis亲缘关系十分接近,有多数性状完全一致,且产于同地点同层位,可能为同一种。
Fifteen species(including 14 endemic and one epidenmic) of Palastraea were recorded in China. Some Chinese researchers subdivided Palastraea into several genera including Palastraea, Acmoheliophyllum, Palaeosmilastraea, and Parapalaeosmilia in light of characteristics of the epithecal wall. Detailed observations and examinations on some thin sections of Palastraea show, however, the morphologic characters of the epithecal wall seem to vary largely even within the same colony. For further understanding the taxonomic classification of Palastraea and its related taxa, 16 characters were chosen in this paper to make a cladistic analysis for 13 endemic species(with one being omitted) from China. The analysis yields two cladogrames, on which one strict consensus tree can be generated. The tree shows that the three genera including Acmoheliophyllum, Palaeosmilastraea, and Parapalaeosmilia are polyphyletic, which indicates the generic subdivision in light of the epithecal wall is not appropriate. Those species included in these three genera by some researchers should belong to one genus, namely Palastraea. The tree also shows that Palaeosmilastraea gracilis and P. gyorxtungensis are closely related and should be a sister group. They are identical in many characters and even occur in the same horizon at the same locality, therefore, could be the synonym.