Comparative anatomy of the copulatory organs of Batoidea (Chondrichthyes: Elasmobranchii)

• Grant number: 15/10942-9
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: August 03, 2015
• End date: November 02, 2015
• Field of knowledge: Biological Sciences - Zoology - Applied Zoology
• Principal Investigator: Marcelo Rodrigues de Carvalho
• Grantee: Renan Andrade Moreira
• Supervisor: Lynne R. Parenti
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Smithsonian National Museum of Natural History, United States
• Associated to the scholarship: 13/12434-5 - Comparative morphology and importance systematic of the mixopterigium of Batoidea (Chondrichthyes: Elasmobranchii), BP.DR

Abstract

Batoidea is a monophyletic group and is the most diverse superorder within Chondrichthyes with about 640 valid species. Endoskeletal copulatory organs in males (claspers) are a synapomorphy of Chondrichthyes. The classification as well as interrelationships within elasmobranchs has been influenced by characteristics found in the copulatory organs. In Rajiformes (skates), for example, the claspers are very important in phylogenic and taxonomic studies, with most genera and species defined based on the anatomy of clasper elements, especially those of the terminal group (dorsal and ventral terminal cartilages). However in other batoids the anatomy and morphology of the claspers are still precariously known, highlighting the necessity of a thorough morphological analysis of the copulatory organs of Batoidea. The present PhD project, therefore, is a thorough, detailed morphological and systematic analysis of the variation observed in claspers among all batoid groups. The main objective of the present project is to describe and compare the external and internal (muscle and skeleton) components of the clasper, clarifying relationships of homology of its components among batoids, and discovering systematic patterns that are plylogenetically informative that may aid in resolving problematic relationships within batoids (such as which batoid group is most basal, elucidate the doubtful monophyletic status of guitarfishes and the phylogenetic position of problematic taxa, such as Zanobatus, Platyrhinidae and electric rays).