We report for first time the species Laurencia natalensis for the Atlantic Ocean based on collections made in Venezuela. Once thought to be restricted to the Indian Ocean, the presence of this species is confirmed in this study by phylogenetic analyses using the plastid-encoded large subunit ribulose-bisphosphate carboxylase/oxygenase gene (rbcL). Sequences of the cytochrome C oxidase subunit I (COI) barcode region were obtained for additional support of taxonomic placement. In the rbcL phylogenetic analyses, a well-supported clade was recovered unequivocally placing our specimen as conspecific to L. natalensis from the east coast of South Africa. The barcode region (COI) sequences from Venezuela also clustered with the one obtained from L. natalensis from KwaZulu-Natal. In pairwise comparison of both markers, African and Venezuelan species diverged within the intraspecific variation recorded for Laurencia sensu stricto species. The Venezuelan specimens showed a distinctive combination of anatomical features shared with African specimens that aided in the species determination. However, sterile and immature sporophytic plants of Laurencia natalensis from Venezuela are morphologically variable; particularly sterile plants showed overall anatomical differences in habit when compared with African species. This finding raises the possibility that L. natalensis have been overlooked and probably confused in the field with other species of the Laurencia sensu stricto group.

中文翻译：

---

Laurencia natalensis（Ceramiales，Rhodophyta）：大西洋的新纪录

我们首次报告委内瑞拉采集的大西洋大西洋物种Laurencia natalensis。曾经被认为仅限于印度洋，通过使用质体编码的大亚基核糖二磷酸羧化酶/加氧酶基因（rbcL）进行系统发育分析，证实了该物种的存在。获得细胞色素C氧化酶亚基I（COI）条形码区域的序列，以进一步支持分类学定位。在rbcL的系统发育分析中，一个明确支持的进化枝被明确地回收，使我们的标本与南非东海岸的纳塔氏菌同种。委内瑞拉的条形码区域（COI）序列也与从夸祖鲁-纳塔尔省的纳塔尔氏酵母获得的条形码区域聚在一起。在两个标记的成对比较中，非洲和委内瑞拉物种在Laurencia sensu stricto物种的种内变异内发生分歧。委内瑞拉标本显示出与非洲标本共享的独特解剖特征，有助于物种确定。然而，委内瑞拉劳伦西亚纳塔尔松的不育和不成熟的孢子体在形态上是可变的。与非洲物种相比，特别是不育植物在习性上表现出整体解剖学差异。这一发现增加了田纳西杆菌被忽视的可能性，并可能在田间与劳伦西亚·森苏·克雷索的其他物种混淆。委内瑞拉标本显示出与非洲标本共享的独特解剖特征，有助于物种确定。然而，委内瑞拉劳伦西亚纳塔尔松的不育和不成熟的孢子体在形态上是可变的。与非洲物种相比，特别是不育植物在习性上表现出整体解剖学差异。这一发现增加了田纳西杆菌被忽视的可能性，并可能在田间与劳伦西亚·森苏·克雷索的其他物种混淆。委内瑞拉标本显示出与非洲标本共享的独特解剖特征，有助于物种确定。然而，委内瑞拉劳伦西亚纳塔尔松的不育和不成熟的孢子体在形态上是可变的。与非洲物种相比，特别是不育植物在习性上表现出整体解剖学差异。这一发现增加了田纳西杆菌被忽视的可能性，并可能在田间与劳伦西亚·森苏·克雷索的其他物种混淆。