Diversity revealed: Ophiuroidea (Echinodermata) from reef ecosystems of Tropical Southwest Atlantic with new characters

The class Ophiuroidea, despite having a wide distribution on the coast of Brazil, only 150 species have been described, which highlights the need to increase the number of regions/areas sampled from a more detailed perspective of their morphology. In this context, the present study aimed to investigate the fauna of Ophiuroidea associated with different types of substrates in reef formations in shallow waters off the coast of Paraba. A total of 425 specimens were obtained through sampling carried out between 2019 and 2021, in seven points along the state's coastal zone. The systematic study provides a detailed analysis of the external and internal morphology (microstructures) and morphometry of 12 species, two orders, five families, and seven genera. The intraspecific variations observed between young and adult individuals were described, in which the relationship between the length of the arms and the diameter of the disc and its variations were established by morphometric analysis. This survey of Ophiuroidea species for the coast of Paraba was essential to understanding the morphological variations exhibited by the species in different locations. This study may contribute to the correct management and conservation of the species, besides expanding knowledge on the class Ophiuroidea along a portion of the Brazilian coast.