Floristic and ecological insights into silica-scaled chrysophytes in southeastern Queensland, Australia

Silica-scaled chrysophytes, including several lineages of the class Chrysophyceae, possess morphologically diverse silica scales. Despite their ecological significance, few data on their distribution are available from this region. In this study, we aimed to explore the diversity and distribution of silica-scaled chrysophytes in southeastern Queensland. Samples were collected from different water bodies, and scale morphology was examined using transmission and scanning electron microscopy. Water chemical analyses were conducted to reveal the ecological requirements of the species. A total of 35 taxa were identified, including species from the orders Synurales, Chromulinales, and Paraphysomonadales. Mallomonas pseudocoronata, originally thought to be an endemic of North America and later recorded from Europe, was found in Queensland. Our findings provide valuable floristic data and contribute to the understanding of silica-scaled chrysophytes distribution in Australia. Molecular characterization of these species is crucial to assess endemism and further advance chrysophyte research in the region.