Population genetic and phylogeographic insights into the phyllosomal odyssey

Matthew Iacchei

doi:10.21425/f5fbg19453

Abstract

The majority of marine species maintain genetic connectivity through pelagic propagules, with pelagic duration hypothesized to limit dispersal potential. This dissertation investigates the geographic scale of genetic connectivity when pelagic duration is likely not limiting. I analyzed mtDNA sequences and microsatellites to determine patterns of genetic structure across the geographic distributions of three lobster species: Panulirus penicillatus (Red Sea to the East Pacific Ocean), P. interruptus (sub- tropical East Pacific), and P. marginatus (Hawaiian endemic). At the broadest spatial scale, significant genetic discontinuities for P. penicillatus correspond to provincial biogeographic boundaries, including putative species-level disjunction across the East Pacific Barrier. On a smaller scale, novel kinship analy- ses combined with traditional F-statistics indicate that larval behavior and oceanographic processes re- sult in localized recruitment for P. interruptus. Geographic scales of connectivity differ by location and species, even in Hawai'i, where P. marginatus and P. penicillatus co-occur. These findings indicate the combined effects of geography, ocean currents, and biology overcome extremely long pelagic periods and result in variable degrees of genetic connectivity.

Highlights

Identifying the drivers of larval dispersal patterns and connectivity in marine populations is essential both to understand marine metapopulation dynamics and to successfully manage marine species and populations (Palumbi 2004, Kritzer and Sale 2006, Fogarty and Botsford 2007)
I use a combination of mitochondrial DNA sequence data and nuclear microsatellite markers to assess the scales of population genetic connectivity in three different Panulirus lobster species using standard genetic analysis techniques
Panulirus marginatus is sympatric with P. penicillatus over this geographic extent, but is endemic to Hawai‘i. I conduct a deeper investigation into the genetic structuring of a third species, Panulirus interruptus (Randall, 1840), across the majority of its species distribution along the West Coast of North America from Monterey Bay, CA to Bahía Magdalena, Mexico (17 sites, 1102 samples)

Summary

Introduction

Identifying the drivers of larval dispersal patterns and connectivity in marine populations is essential both to understand marine metapopulation dynamics and to successfully manage marine species and populations (Palumbi 2004, Kritzer and Sale 2006, Fogarty and Botsford 2007). I use genetic data from three species of spiny lobsters within the genus Panulirus, each of which has a PLD exceeding 180 days (Phillips et al 2006), to gain a more fundamental understanding of the role of the teleplanic larval phase in maintaining population connectivity and geographic range sizes in marine species: do teleplanic larvae sustain effectively panmictic populations across broad geographic expanses?

Results

Conclusion