Revealing neglected groups: integrative taxonomy, phylogeny, and macroevolutionary patterns of Pycnogonida (Arthropoda, Chelicerata) from the Western Atlantic

• Grant number: 24/20899-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2025
• End date: February 28, 2029
• Field of knowledge: Biological Sciences - Zoology
• Principal Investigator: André Rinaldo Senna Garraffoni
• Grantee: Alan Rodrigo Batistão
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 18/10313-0 - Build-up of scientific collections of marine invertebrates: strategies for biodiversity conservation, AP.BTA.TEM

Abstract

The class Pycnogonida consists of exclusively marine, benthic, cosmopolitan chelicerates, occurring from the intertidal zone to great depths. Although they are common in phyto- and encrusting communities, Pycnogonida is considered a neglected taxon worldwide, possibly due to their cryptic habits and small size. In Brazil, studies are limited to records for faunistic inventories and descriptions of new species, always lacking an evolutionary context. Thus, considering the numerous knowledge gaps regarding Pycnogonida, in Brazil and in the world, this PhD project aims to expand the understanding of the taxonomy, evolution, and diversity patterns of these overlooked animals. To achieve these goals, four research fronts have been outlined. The first will consist of the redescriptions of Achelia sawayai, Anoplodactylus evelinae, A. stictus, Callipallene evelinae, Tanystylum evelinae, and T. isabellae through integrative taxonomy, combining anatomical, ecological, and molecular data (12S, 16S, COI, 18S, 28S, and histone H3) to provide a more precise delimitation of these Brazilian species. The second will focus on investigating the morphofunctional patterns of the chelicerae, palps, and ovigers of representatives from the eleven families of Pycnogonida, using histology, histochemistry, scanning electron microscopy, and laser scanning confocal microscopy for a detailed anatomical survey that will be evolutionarily interpreted through character optimization in the group's phylogenies. In the third step, a probe set of ultraconserved elements ("UCEs") for capturing DNA sequences from fresh and historical specimens will be tested for constructing high-resolution phylogenomics. Finally, the last stage will involve identifying the Wallacean shortfall of pycnogonids in the Atlantic Ocean, conducting analyses of endemism, species distribution models, and detecting biogeographical units.