Diving in the Mesozoic Marine Revolution from the perspective of benthic and nektonic mollusks

• Grant number: 22/02746-9
• Support Opportunities: Research Grants - Initial Project
• Start date: February 01, 2023
• End date: January 31, 2028
• Field of knowledge: Biological Sciences - Zoology - Morphology of Recent Groups
• Principal Investigator: José Eduardo Amoroso Rodriguez Marian
• Grantee: José Eduardo Amoroso Rodriguez Marian
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Alvaro Esteves Migotto ; Frank Edward Anderson ; Jeanne Marie Serb ; Jorge Alves Audino ; Noritaka Hirohashi
• Associated scholarship(s): 25/01246-0 - Evolution of sperm storage mechanisms in Coleoidea, BP.MS; 24/05327-2 - Comparative anatomy of eyes in deep-sea bivalves (Propeamussiidae), BP.IC; 23/09834-3 - Evolution of spermatophore transfer mechanisms in Decapodiformes (Mollusca: Cephalopoda), BP.MS; + associated scholarships 23/07751-3 - Spawning pattern of the squid Doryteuthis pleii (Blainville, 1823) (Mollusca: Cephalopoda), as a basis for understanding the species' mating system, BP.MS; 23/09622-6 - Evolution of egg-laying strategies in Decapodiformes (Cephalopoda): how a nektonic clade became completely independent from the ocean floor, BP.MS; 19/18834-1 - Diversity and evolution of Bivalve sensory systems: a unifying approach based on comparative transcriptomics and integrative microscopy, BP.PD - associated scholarships

Abstract

The 'Mesozoic Marine Revolution' (MMR) refers to the dramatic reorganization of marine ecosystems that occurred during the Mesozoic and gave rise to the modern structure of our oceans. Increased primary productivity during the MMR permitted the diversification of predatory lineages, which in turn exerted strong selective pressures on their prey, promoting increasingly defensive adaptations (e.g., infaunalization, thicker shells, increased mobility) in a coevolutionary arms race. As expected, most of the MMR's theoretical framework relies on the fossil record. However, several hypotheses underlying the MMR cannot be tested based solely on fossil data. For instance, a thorough understanding of the evolution of defensive strategies in benthic lineages during the MMR is severely hindered by the rare fossilization of relevant organs, such as photoreceptors. In the case of some nektonic lineages, such as coleoid cephalopods, the situation is even worse, as the MMR's selective pressures promoted adaptations (i.e., shell reduction/loss) that almost completely prevented their preservation in the fossil record. It remains unclear, for example, the processes underlying colonization of distinct pelagic zones, supposedly driven by the increased swimming agility achieved during the MMR. The present research proposal aims at broadening our understanding of the MMR by integrating complementary approaches (i.e., phylogeny, transcriptomics, integrative microscopy, experimentation and natural history) to investigate the macroevolution of benthic (Bivalvia: Pteriomorphia) and nektonic (Cephalopoda: Coleoidea) molluscan lineages with increased taxonomic and ecological diversification during the MMR. The diversification of pteriomorphian sensory organs -potentially associated with predator-prey interactions and with the occupation of novel niches- will be used to test if the MMR's coevolutionary arms race included the evolution of active defense strategies in benthic lineages. The diversification of coleoid reproductive strategies -potentially influenced by habitat shifts in the marine environment- will be used to unravel the pelagic perspective of the MMR, i.e., adaptations associated with the colonization of distinct pelagic zones. In addition to training human resources at different levels (from undergraduate to postdoctoral researchers), the proposal includes an integrated teaching and research initiative that will involve undergraduate and graduate students in the development of outreach activities. (AU)