Studies of Costa Rican Gelidiales (Florideophyceae). II. Two Pacific Taxa Including Gelidium microglossum, n. sp.
Studies of Costa Rican Gelidiales (Florideophyceae). II. Two Pacific Taxa Including Gelidium microglossum, n. sp.
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DOI：
10.2984/68.1.9
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发表时间：
2014-01-01
期刊：
影响因子：
0.7
通讯作者：
Freshwater, D. Wilson
中科院分区：
文献类型：
--
作者：
Grusz, Amanda L.;Freshwater, D. Wilson
对沿哥斯达黎加太平洋海岸采集的两种石花菜进行了详细的形态学和 rbcL 序列分析。尽管在热带东太平洋地区相对知名，但硬叶石花菜此前仅在哥斯达黎加采集过一次。目前发现的四个硬叶 G. sclerophyllum 收藏品具有相同的 rbcL 序列，并且与同种型标本的部分序列仅在一个碱基对上有所不同。系统发育分析表明，G. sclerophyllum 和 G. floridanum W. R. Taylor 是孪生姐妹种。观察到雌性生殖系统和囊果的发育遵循石花菜属物种描述的通常模式。还首次观察到硬叶G. spermatangial 的发育，并揭示了精子细胞通过横向分裂而被切断，这是石花菜目的特征。新物种Gelidium microglossum Grusz & Freshwater也被收集和描述。这是一种具有匍匐习性的小型物种，通常具有不同宽度的压缩轴，并且最终枝条呈棒状。独特的特征包括匙形四孢子囊小枝、通常形成网状网络的髓质细胞、方向可变的根茎和不寻常的附着半翅结构。系统发育分析确定了 G. microglossum 属于石花菜属，但在属内的定位仍不确定。
Detailed morphological and rbcL sequence analyses are presented for two species of Gelidium collected along the Pacific coast of Costa Rica. Although relatively well known in the tropical eastern Pacific, Gelidium sclerophyllum W. R. Taylor had previously been collected only once in Costa Rica. Four current G. sclerophyllum collections were found to have identical rbcL sequences and differed from a partial sequence for an isotype specimen at only one base pair. Phylogenetic analyses revealed that G. sclerophyllum and G. floridanum W. R. Taylor are geminate sister species. Development of the female reproductive system and cystocarps were observed to follow the usual patterns described for Gelidium species. Spermatangial development in G. sclerophyllum was also observed for the first time and revealed the cutting off of spermatia by transverse divisions as is characteristic of Gelidiales. The new species, Gelidium microglossum Grusz & Freshwater, was also collected and described. This is a small species with a prostrate habit, generally compressed axes of variable width, and clavate to obphyriform ultimate branches. Distinctive characteristics include spatulate tetrasporangial branchlets, medullary cells often forming a meshlike network, variably oriented rhizines, and an unusual attachment haptera structure. Phylogenetic analyses resolve G. microglossum within Gelidium, but placement within the genus remains uncertain.