Transoceanic Dispersal and Plate Tectonics Shaped Global Cockroach Distributions: Evidence from Mitochondrial Phylogenomics

Abstract

Following the acceptance of plate tectonics theory in the latter half of the 20th century, vicariance became the dominant explanation for the distributions of many plant and animal groups. In recent years, however, molecular-clock analyses have challenged a number of well-accepted hypotheses of vicariance. As a widespread group of insects with a fossil record dating back 300 My, cockroaches provide an ideal model for testing hypotheses of vicariance through plate tectonics versus transoceanic dispersal. However, their evolutionary history remains poorly understood, in part due to unresolved relationships among the nine recognized families. Here, we present a phylogenetic estimate of all extant cockroach families, as well as a timescale for their evolution, based on the complete mitochondrial genomes of 119 cockroach species. Divergence dating analyses indicated that the last common ancestor of all extant cockroaches appeared ∼235 Ma, ∼95 My prior to the appearance of fossils that can be assigned to extant families, and before the breakup of Pangaea began. We reconstructed the geographic ranges of ancestral cockroaches and found tentative support for vicariance through plate tectonics within and between several major lineages. We also found evidence of transoceanic dispersal in lineages found across the Australian, Indo-Malayan, African, and Madagascan regions. Our analyses provide evidence that both vicariance and dispersal have played important roles in shaping the distribution and diversity of these insects.

A Proposed Timescale for the Evolution of Armophorean Ciliates: Clevelandellids Diversify More Rapidly Than Metopids

“…) and the upper bound on the earliest insect fossils (Bourguignon et al. ). The node uniting clevelandellids from anurans, was assigned a lower bound of 65 Ma and an upper bound of 275 Ma.…”

“…The node uniting clevelandellids occurring in blaberiid and blattid cockroaches, was assigned a lower bound of 61 Ma and an upper bound of 407 Ma. The minimum calibration date was based on the oldest known, blaberiid cockroach Gyna obesa (Evangelista et al 2017) and the upper bound on the earliest insect fossils (Bourguignon et al 2018). The node uniting clevelandellids from anurans, was assigned a lower bound of 65 Ma and an upper bound of 275 Ma.…”

Testing Darwin's transoceanic dispersal hypothesis for the inland nettle family (Urticaceae)

“…; Bourguignon et al . ; Guo et al . ), forcing the scientific community to accept other explanations for disjunctions, leading to increasing acceptance of the role of LDD in shaping the present distributions of organisms (Raxworthy et al .…”

“…The advent of molecular dating, however, repeatedly revealed cases of transoceanic disjunctions that were too young to result from tectonic vicariance (Popp et al 2011;Bourguignon et al 2018;Guo et al 2018), forcing the scientific community to accept other explanations for disjunctions, leading to increasing acceptance of the role of LDD in shaping the present distributions of organisms (Raxworthy et al 2002;Pyron 2014;Rota et al 2016;Carlton et al 2017;Luebert et al 2017).…”

First records of the parthenogenetic Surinam cockroach Pycnoscelus surinamensis (Insecta: Blattodea: Blaberidae) for Central Europe

“…A neighbour‐joining tree (Saitou & Nei, ) applying the K2P model (Kimura, )—the model typically employed in DNA barcoding studies—and 1,000 bootstrap replicates for statistical node support (Felsenstein, ) was inferred using MEGA6. Following Bourguignon et al (), the tree was rooted with P. femapterus . MEGA6 was also used for calculating K2P‐distances among species and within P. surinamensis .…”