Autonomous reef monitoring structures (ARMS) have been proposed as a standardized, passive, nondestructive sampling tool. This study assessed the ability of ARMS to capture the cryptic species diversity of two coral reefs by recording species richness and taxonomic representativeness using conventional taxonomy. The capacity of ARMS, as artificial substrates, to favor the establishment of nonindigenous species over native species was also evaluated. The use of ARMS allowed the detection of 370 species morphotypes from nine phyla, yielding 13 new records of geographic distribution expansion, one exotic species for the Gulf of México and the Caribbean Sea, and six newly described species. It was also possible to make spatial comparisons of species richness between both reefs. ARMS captured cryptic diversity exceptionally well, with the exception of echinoderms. Furthermore, these artificial structures did not hinder the colonization ability of native species; in fact, the colonization patterns on the structures themselves represented the spatial differences in the structure of benthic assemblages. This study represents the first effort to make a conventional taxonomic description of the cryptic fauna of the Yucatan Peninsula using ARMS. It is recommended to assess coral reef species diversity, but more taxonomists specialized in marine invertebrates are needed.

The coastal habitats in the southern Gulf of Mexico face multiple threats, such as rising water temperatures, acidification, increased turbidity, invasive species and pollutants. This imperils the biodiversity of beaches, wetlands and coral reefs. To address this, there is a need for comprehensive baseline information on marine biodiversity. Several reefs in the Gulf of Mexico have been extensively studied, yet smaller reefs on the Yucatan continental shelf lack thorough exploration despite their ecological significance. These reefs serve as crucial biodiversity hotspots influenced by environmental characteristics, receiving diverse taxa from the Gulf of Mexico. The macroalgae study at the Bank of Campeche dates back to the 1950s, but comprehensive investigations have been sporadic. The recent study aims to fill this gap, contributing to the taxonomic inventory of the area's benthic macroflora. Methodologically, extensive sampling across eight reefs was conducted, collecting and preserving macroalgae samples for identification in the laboratory. The study documented 90 infrageneric taxa across the reefs, with Cayo Arenas exhibiting the highest species count. Additionally, three new distribution reports for Mexico were identified in the region. The distribution of species varied amongst locations, with few species in common even amongst geographically proximate reefs. The diversity found in these reefs slightly trails behind other studied regions, but surpasses previous reports for the Campeche Bank. It is important to emphasise that the significance of this study lies in its focus on remote reefs with complicated and costly access logistics. Additionally, it is one of the first publicly available datasets published for this region. The study aligns with existing literature on prevalent families in reef environments and highlights differences in species distribution, based on depth variations amongst reefs. The findings of new distribution records in the region and the distinctiveness of localities despite their proximity underscore the unique ecological dynamics of these reefs. These reefs are located in remote and difficult-to-access areas, highlighting the importance of the data obtained on their biodiversity and conservation status. This work presents for the first time a list of macroalgae for the reefs of Banco Nuevo, Banco Obispo, Banco Pera and Serpientes Reef. Three new distribution reports for Yucatan were identified at the Banco Obispo reef: Botryocladia shanksii E. Y. Dawson, Ceratodictyon scoparium (Montagne & Millardet) R. E. Norris and Asteromenia peltata (W. R. Taylor) Huisman & Millar and a new report for the Mexican Atlantic, Herposiphonia parca Setchell at the Triángulo Oeste reef. This results in distinct algal communities compared to other reefs in the region, emphasising their ecological significance and the need for continued research and conservation efforts. To our knowledge, this is one of the first interoperable datasets being published on the marine algae of the southern Gulf of Mexico reef ecosystems.