Continent-island boundary and environment-shaped evolution in the marine amphipod Ampithoe marcuzzii complex (Crustacea: Eumalacostraca: Ampithoidae)

Author(s)

Iwasa-Arai, Tammy ; Siqueira, Silvana G. L. ; Sobral-Souza, Thadeu ; Leite, Fosca P. P. ; Andrade, Sonia C. S.

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 14, n. 1, p. 18-pg., 2024-01-05.

Abstract

Marine amphipods are crustaceans that lack a larval phase and consequently have low dispersion rates. Despite that, these crustaceans present a remarkable ability to be transported by rafting on natural floating substrata, especially macroalgae, where they find shelter, food and a mating ground. The species Ampithoe marcuzzii is widely distributed throughout the western Atlantic Ocean. Here, it was used as a model to study seascape genomics and phylogeography in invertebrates with low dispersion capacities. We anticipated that the lineages would present isolation-by-distance patterns. However, surface currents and other abiotic variables could facilitate connectivity among distant sites. Based on mitochondrial and nuclear genes, SNPs, and environmental associations, we observed the presence of a species complex within A. marcuzzii, separating mainland and insular populations. Each species showed an independent evolutionary history, with a strong latitudinal population structure and evidence of isolation-by-distance and isolation-by-environment, characterizing the 'continent' species. Historical expansion and environmental variables were observed associated with the southeastern population, and ecological niche modeling corroborated the region as a paleorefuge. Conversely, populations from 'islands' presented complicated evolutionary histories, with closer localities genetically isolated and distant localities connected. These findings indicate that insular populations with low dispersion capacity might be more susceptible to spatial connectivity by floating substrata and to changes in surface currents. In contrast, mainland populations might be more vulnerable to local climate changes due to lack of gene flow. (AU)

• FAPESP's process: 18/00488-7 - Species delimitation, comparative phylogeography and conectivity of Peracarida (Crustacea: Eumalacostraca) associated with Sargassum in Brazil with emphasis on insular populations
• Grantee: Tammy Iwasa Arai
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/10313-0 - Build-up of scientific collections of marine invertebrates: strategies for biodiversity conservation
• Grantee: Antonia Cecília Zacagnini Amaral
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 15/20139-9 - Seascape genetics and evaluation of expression profiles on marine invertebrates on Brazilian Southeast coast
• Grantee: Sónia Cristina da Silva Andrade
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 17/16837-8 - Protection efficiency in coastal habitats: an integrated approach in the study of macrophyte and associated invertebrates diversity at areas under different conservation status
• Grantee: Fosca Pedini Pereira Leite
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants