Multiple lineages of hyper‐diverse Zopheridae beetles survived the New Zealand Oligocene Drowning

Abstract

Aim During the late Oligocene (23 mya) the New Zealand landmass was reduced to approximately 18% of its current area. It has been hypothesized that this event, known as the Oligocene Drowning, caused population bottlenecking and mass extinction. Using phylogenetic methods, we examine the effect of this and other environmental events on the hyper‐diverse Zopheridae beetles (162 morphospecies), which largely inhabit leaf litter and dead wood. Location New Zealand. Taxon Zopheridae, Coleoptera. Methods Here we use a fossil‐calibrated phylogenetic tree estimated from mitochondrial cytochrome c oxidase subunit I and nuclear large subunit rRNA genes to identify monophyletic New Zealand zopherid lineages and date the age of these lineages. We used Bayesian diversification models (compound Poisson process on mass extinction times) to test the hypothesis that the New Zealand zopherids underwent a mass extinction in the late Oligocene followed by an increase in speciation rate in the Miocene. We also used these data to estimate the age of these lineages in New Zealand. Results We demonstrate that 15–20 zopherid lineages survived the Oligocene Drowning depending on the calibration scheme. Of these lineages from 3 to 11 have posterior intervals that encompass the rifting of New Zealand from Gondwana in the late Cretaceous, again depending on the calibration scheme. The diversification model shows no evidence of an increase in extinction rate during the Oligocene Drowning or during any other period since the Cretaceous. Furthermore, rather than recovering an increase in speciation rate during the Miocene and Pliocene, due to environmental changes, we instead recovered a large drop in the speciation rate during this time. Main conclusions The New Zealand zopherid fauna is a combination of lineages, some of which may have existed on New Zealand since the rifting from Gondwana and other more recent arrivals. The late Oligocene reduction in land area was insufficient to cause a mass extinction in the Zopheridae. This suggests the amount of emergent land was great enough to support a diverse invertebrate fauna. Our study demonstrates the different biogeographic patterns evident in cryptic, hyper‐diverse, and poorly dispersing invertebrate species relative to more mobile plants and animals.

Complex patterns of Gondwanan biogeography revealed in a dispersal‐limited arachnid

“…Our results agree with studies of other low dispersal organisms concluding that lineages persisted on these highly reduced New Zealand terranes during the proposed drowning (e.g. Allwood et al, 2010; Boyer & Giribet, 2009; Buckley et al, 2020; Giribet & Boyer, 2010).…”

“…Our results agree with studies of other low dispersal organisms concluding that lineages persisted on these highly reduced New Zealand terranes during the proposed drowning (e.g. Allwood et al, 2010;Boyer & Giribet, 2009;Buckley et al, 2020;Giribet & Boyer, 2010 Antarctica and eastern Australia persisted until 35.5 Ma (Brown et al, 2006;Lawver & Gahagan, 1998;McLoughlin, 2001), and thus all these divergences could be explained by vicariance. While the physical connections among West Antarctic terranes are less resolved, these patterns seen here in the Calliuncus group corroborate some continuous (likely) terrestrial connectivity through this region.…”

Evolutionary history and eco‐climatic diversification in southern African dung beetle Sisyphus

“…Sisyphus , like many Scarabaeinae, are fossorial beetles, but they have also dispersed quickly and widely across continents and marine barriers (Sole & Scholtz, 2010; Sole, Wirta, Forgie, & Scholtz, 2011). The CoMET analysis suggests that sisyphines could have survived the late Cenozoic environmental crises in southern Africa, possibly, migrating to new habitats with favourable conditions, as observed in the New Zealand Zopheridae beetles, which survived the Oligocene drowning (Buckley, Lord, Ramón‐Laca, Allwood, & Leschen, 2020). However, undetected extinction events in Sisyphus cannot be ruled out due to the vagaries of the fossil record.…”

Structural Design Variations in Beetle Elytra

“…Insect cuticles have been widely studied because of their unique and elegant architectures that fulfill the organism's numerous needs for survival. [1,2] In Coleoptera, a transformation of their delicate forewings into protective stiff wings (elytra), which engineering structures, we must understand and compare both the structural and mechanical deviations of elytra from flight capable or incapable beetles.…”

“…Here, we investigate two species of beetles from different habitats and describe how variations in their exoskeletal architecture and composition allow them to thrive in their respective environments. We focus on the elytra from two species of beetles that branched ≈250 million years ago: [1,3] Trypoxylus dichotomus (known as the rhinoceros beetle), a tree-dwelling and thus flight capable beetle inhabiting East Asia, and Phloeodes diabolicus (deemed the diabolical ironclad beetle), a terrestrial fungivore incapable of flight residing on the western coast of North America. [16,19,23,24] P. diabolicus belongs to a group of flightless beetle species (i.e., Zopheridae) that separated from other terrestrial (flight-capable species) beetles ≈150 million years ago.…”