ABSTRACT

Twenty-one samples belonging to species of Spyridia Harvey with uncinate (= hook-shaped) spines on determinate lateral branches were investigated for their morphology with a focus on the structure of determinate branches, and for comparative chloroplast-encoded rbcL and nuclear LSU rDNA sequence analysis to elucidate their taxonomy and phylogeny. Currently, four Spyridia species with uncinate spines are recognized worldwide: S. alternans, S. cupressina, S. horridula and S. hypnoides. Of them, S. hypnoides has been recognized as the most common species with uncinate spines. In this study, we show that S. aculeata needs to be resurrected from S. hypnoides, and recognized as a distinct species based on samples from Israel, Red Sea, near the type locality. Spyridia aculeata is characterized by the spiral arrangement of determinate branches, incompletely corticated determinate branches, naked basal segment of determinate branches, by the presence of only acropetal cortication in the nodes of determinate branches, and by uncinate spines at the terminal node and on the first and second nodes of determinate branches. In our molecular analyses based on rbcL and LSU rDNA, although four Spyridia species with uncinate spines are supported on phylogenetic trees, they are not a monophyletic group. The feature of uncinate spines in Spyridia is recognized as a polyphyletic character. Our phylogenetic analysis using rbcL and LSU rDNA sequences reveals high gene sequence divergence (6.8–7.0% for rbcL and 1.2–1.3% for LSU rDNA) between samples of S. aculeata and S. hypnoides. Therefore, the distribution of S. hypnoides may be restricted to the Indian Ocean, whereas S. aculeata is widely distributed in the Atlantic Ocean including the Mediterranean Sea and the Red Sea. Another Spyridia species with uncinate spines, S. alternans, is recognized as a synonym of S. horridula by our detailed morphological observations of its type specimen.

摘要

研究了 21 个在确定的侧枝上具有钩状（= 钩状）刺的Spyridia Harvey物种的样本，研究了它们的形态，重点是确定分支的结构，以及比较叶绿体编码的rbc L 和核 LSU rDNA序列分析以阐明它们的分类学和系统发育。目前，全世界公认有四种具有钩刺棘刺的Spyridia物种：S. alternans、S. cupressina、S. horridula和S. hypnoides。其中，S. hypnoides已被公认为具有钩刺棘的最常见物种。在这项研究中，我们表明S. aculeata需要从S. hypnoides 中复活，并根据来自以色列红海附近的样本，将其确认为独特的物种。Spyridia aculeata的特点是定枝呈螺旋状排列，定枝皮质不完全，定枝基部裸露，定枝节仅存在顶叶皮质，末节和第一节有钩刺。和确定分支的第二个节点。在我们基于rbc L 和 LSU rDNA 的分子分析中，虽然系统发育树支持四种具有钩刺棘的Spyridia物种，但它们不是单系群。Spyridia钩刺的特征被认为是一个多系特征。我们使用rbc L 和 LSU rDNA 序列的系统发育分析揭示了S. aculeata和S. hypnoides样本之间的高基因序列差异（rbc L为 6.8-7.0 %，LSU rDNA 为 1.2-1.3%）。因此，S. hypnoides的分布可能仅限于印度洋，而S. aculeata则广泛分布于大西洋，包括地中海和红海。通过我们对其模式标本的详细形态观察，另一种具有钩刺棘刺的Spyridia物种S. alternans被认为是S. horridula的同义词。