Investigating morphological and molecular variation of spider Sickius longibulbi (Mygalomorphae, Theraphosidae)

• Grant number: 22/13892-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2023
• End date: January 31, 2024
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: José Paulo Leite Guadanucci
• Grantee: Beatriz Bachega Groppo
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

The infraorder Mygalomorphae includes mainly the spiders known as tarantulas. The taxonomic history of the group is complex and unstable, mainly due to the morphological uniformity of the group, which makes the tasks of species delimitation and recognition challenging. The exclusive use of morphological characters to distinguish among taxa can result in inaccuracies and divergences. An important tool in modern taxonomy is DNA barcoding, which uses fragments of mitochondrial genes, allowing species-level recognition and often revealing the existence of cryptic species. The use of different data sources for species delimitation and recognition has been named "integrative taxonomy". Sickius is a monotypic genus (Sickius longibulbi) that includes small tarantulas, has a wide geographic distribution and homogeneuos morphology. The objectives of this project are (1) to study the variation and genetic structuring of different populations of Sickius longibulbi spiders through DNA barcoding techniques; (2) to study the morphological variation of these spiders through traditional (linear) and geometric morphometric methods; (3) to integrate morphological and molecular data to test the hypothesis of gene flow discontinuity between populations of Sickius longibulbi and recognition of probable cryptic species. The investigation will be carried out through the integrative analysis of spiders from different populations, searching for discontinuities that indicate the existence of lineages and morphological characters that allow recognition. We hope to contribute to the taxonomy of tarantulas, create precedents for integrative biogeographic and taxonomic studies, and promote the training of the student in the use of advanced methods in taxonomy.