Phenetic Relationships of Red Seaweeds from Gunungkidul Coastal Area Using Morphological, Anatomical, and Biochemical Characters

The coastal region of Gunungkidul is characterized by coral reefs and sandy substrates, creating an ideal habitat for the abundant growth of red seaweeds (Rhodophyceae). This favorable environment supports a high diversity of life forms, necessitating precise taxonomic approaches such as numerical taxonomy. This study aimed to evaluate species diversity and phenetic relationships among red seaweeds based on morphological, anatomical, and biochemical (pigment content) characteristics, and identify the traits that most significantly influence clustering patterns through principal component analysis (PCA). Morphological characterization focused on the thallus structure, encompassing both vegetative and generative organs, while anatomical analysis involved observations of thallus cell arrangement. Pigment content was assessed using thin-layer chromatography. Cluster and PCA analyses were conducted using MVSP version 3.1. Cluster analysis delineated three distinct groups at the 25% phenon line, with PCA indicating that branching type, blade shape, and blade margin were the most influential traits in defining these groupings. The results suggest that morphological and anatomical features play a more critical role in red seaweed clustering than biochemical characteristics.