Sponges and cnidarians (Hydrozoa and Anthozoa) from Oro Verde reef; benthic coverage and faunal affinity with the reef systems of Veracruz, Mexico.

Sampling was conducted in twelve geographical points of the Oro Verde reef during the June-August 2015 period, in-order-to record species of sponges, hydrocorals and anthozoans, and to estimate the coverage of algae, sponges, corals, sea fans and abiotic components (e.g., sand and pavement) using 50 m long photo transects. We explored the northern, southern, central, eastern and western section of the reef. Analysis of non-metric multidimensional scaling (NMDS) was performed to explain similarities of the sampling units based on the information obtained. In addition, the  composition of sponges and coral reefs from Oro Verde reef was compared with the other reef systems of Veracruz to determine affinities using the NMDS method. The similarity test ANOSIMwas used to explain significant differences among dissimilar groups. A total of 35 species of Phylum Porifera and 29 species of Phylum Cnidaria were recorded. The most common species in the reef were the sponges Callyspongia armigera, Niphates erecta, and Amphimedon compressa, and the corals Montastraea cavernosa, Porites astreoides, Siderastrea siderea, Colpophyllia natans. Filamentous and frondose algae were the most abundant in coverage (49.4 ± 7.7% and 20 ± 9.7%, respectively), compared to reef corals that showed low coverage (9.5 ± 6.1%), which consisted mainly of M. cavernosa, C. natans and S. siderea. The faunal richness and the benthic coverage are distributed in a homogeneous way in the reef as sampling sites revealed similarities in these community attributes. The composition of sponges from Oro Verde reef presented higher affinity with the adjacent reefs and with the submerged reefs of southern of Veracruz. However, Oro Verde reef is more similar with neighboring reefs in species richness of corals. Discrepancies with the other reefs are attributed to the lack of complete inventories (e. g., Tuxpan) and / or by presenting species with limited distribution.