Research Article Morphological Diversity of Gracilaria blodgettii Harvey 1853 (Gracilariaceae, Rhodophyta) from Sarawak, Malaysian Borneo Ruhana Hassan , 1,2 Muhammad Nur Arif Othman , 1 Mohd Nasarudin Harith , 1 and Amir Shah Ruddin Md Sah 3 1 Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia 2 Centre for Pre University Studies, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia 3 School of Biological Sciences, Universiti Sains Malaysia, Gelugor, 11800 Penang, Malaysia Correspondence should be addressed to Ruhana Hassan; hruhana@unimas.my Received 28 December 2018; Revised 19 April 2019; Accepted 11 June 2019; Published 2 July 2019 Academic Editor: Fernando Rosado Spilki Copyright © 2019 Ruhana Hassan et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Gracilaria red algae are notable for their economic importance as agrophytes, sold as salad vegetable, and used as the base for selected food and nonalcoholic beverages. A wild population of Gracilaria exists in coastal areas of Sarawak, Malaysian Borneo, but there is only limited knowledge on species diversity and its abundance leaving the untapped economic potential of this resource. is study was carried out to determine diversity of wild Gracilaria populations in Lawas, Santubong, and Asajaya, Sarawak, using the combination of morphological character examination and 5′ region of the mitochondrial cytochrome c oxidase 1 (CO1-5P) gene analysis. Identification of the species using morphological characters revealed three species, namely, Gracilaria changii, G. blodgettii, and G. arcuata, had been collected from the sampling sites. However, based on 672 bp CO1-5P gene sequence analysis, all the three species were identified as G. blodgettii; besides, low genetic divergence values (0.17%–0.34%) were scored between samples in this study with the same species in GenBank. In the phylogenetic trees, all samples in this study group together with other G. blodgettii have high bootstrap values; thus, this species is monophyletic. is study implies that species identification of Gracilaria and other seagrass taxa which have a phenotypic plasticity problem should include the CO1-5P gene analysis as it is a reliable gene marker for species diversity assessment. 1. Introduction Genus Gracilaria Greville consists of more than 170 species worldwide, distributed from tropical to temperate waters, covering from intertidal to subtidal zones [1–3]. It can be found from Arctic Ocean to tropical seas of the northern hemisphere and countries of Southeast Asian regions such as Malaysia, Indonesia, ailand, Vietnam, Singapore, and Philippines [4, 5]. Gracilaria is important in production of agar in food industry [6] and culture medium in research industry [7], and it serves as a habitat for various aquatic organisms [8, 9], besides becoming food for the local people. Up to now, 20 species of Gracilaria had been identified in Malaysia [10], where half of them were found in Sarawak, namely, G. arcuata Zanardini, G. articulata Chang & Xia, G. changii Xia & Abbott, G. coronopifolia J. Agardh, G. blodgettii Harvey, G. Salicornia (Agardh) Dawson, G. edulis (Gmelin) Silva, and G. textorii (Suringar) Hariot and the remaining identified as Gracilaria sp. 1 and Gracilaria sp. 2 [11]. ey could be found in Kuching, Bintulu, and Miri, growing in the intertidal area or attached to the man-made structures [12]. In another report, in Asajaya, Sarawak, Gracilaria thalli were found attached on the roots of mangrove trees [13]. Molecular studies have shown positive results in solving the identification and taxonomy of seaweeds worldwide. Gracilaria is known as seaweeds with high plasticity char- acteristics and simple morphologies with very minor vari- ations among them and sometimes have different structures throughout its life cycles [14, 15]. Various gene markers had Hindawi Scientifica Volume 2019, Article ID 3430968, 9 pages https://doi.org/10.1155/2019/3430968