Ice ages and butterflyfishes: Phylogenomics elucidates the ecological and evolutionary history of reef fishes in an endemism hotspot

Abstract

For tropical marine species, hotspots of endemism occur in peripheral areas furthest from the center of diversity, but the evolutionary processes that lead to their origin remain elusive. We test several hypotheses related to the evolution of peripheral endemics by sequencing ultraconserved element (UCE) loci to produce a genome‐scale phylogeny of 47 butterflyfish species (family Chaetodontidae) that includes all shallow water butterflyfish from the coastal waters of the Arabian Peninsula (i.e., Red Sea to Arabian Gulf) and their close relatives. Bayesian tree building methods produced a well‐resolved phylogeny that elucidated the origins of butterflyfishes in this hotspots of endemism. We show that UCEs, often used to resolve deep evolutionary relationships, represent an important tool to assess the mechanisms underlying recently diverged taxa. Our analyses indicate that unique environmental conditions in the coastal waters of the Arabian Peninsula probably contributed to the formation of endemic butterflyfishes. Older endemic species are also associated with narrow versus broad depth ranges, suggesting that adaptation to deeper coral reefs in this region occurred only recently (<1.75 Ma). Even though deep reef environments were drastically reduced during the extreme low sea level stands of glacial ages, shallow reefs persisted, and as such there was no evidence supporting mass extirpation of fauna in this region.

Prolonged morphological expansion of spiny-rayed fishes following the end-Cretaceous

“…We retrieved UCE loci from the remaining 456 specimens at NCBI from previous studies of acanthomorph phylogeny 4,29,48,57,58 or from whole genomic data (Supplementary Table 1). We sampled phenotypic data from 680 of the 1,075-acanthomorph species sampled in the UCE inferred phylogeny.…”

Biogeography of the coastal fishes of the Socotra Archipelago: Challenging current ecoregional concepts

“…( 7) While it is beyond the scope of this study to comprehensively review the phylogeographic literature, no available phylogeographic data (i.e. lately [32,34,35,80,81]) contradict the results, to the best of the authors' knowledge.…”

The Habitat Persistence Hypothesis: a new perspective on the distribution of coral-reef organisms

“…Indeed, Velasco-Lozano et al (2020) found that deep-reef fish assemblages in the eastern Pacific were "more ecologically intact than those around the [nearby] continental islands". Exceptions include regions where deep-reef habitat is dramatically reduced or eliminated during low RSL, such as certain regions around the Arabian Peninsula (DiBattista et al 2018) and IAA (Myres 1999). In the majority of locations (especially around oceanic islands), however, we presume that a lowering of RSL by 120 m or more would not fundamentally change the geologic structure or other environmental parameters of these habitats in most cases.…”