New Guinean orogenic dynamics and biota evolution revealed using a custom geospatial analysis pipeline

Abstract

Background The New Guinean archipelago has been shaped by millions of years of plate tectonic activity combined with long-term fluctuations in climate and sea level. These processes combined with New Guinea’s location at the tectonic junction between the Australian and Pacific plates are inherently linked to the evolution of its rich endemic biota. With the advent of molecular phylogenetics and an increasing amount of geological data, the field of New Guinean biogeography begins to be reinvigorated. Results We inferred a comprehensive dated molecular phylogeny of endemic diving beetles to test historical hypotheses pertaining to the evolution of the New Guinean biota. We used geospatial analysis techniques to compare our phylogenetic results with a newly developed geological terrane map of New Guinea as well as the altitudinal and geographic range of species (https://arcg.is/189zmz). Our divergence time estimations indicate a crown age (early diversification) for New Guinea Exocelina beetles in the mid-Miocene ca. 17 Ma, when the New Guinean orogeny was at an early stage. Geographic and geological ancestral state reconstructions suggest an origin of Exocelina ancestors on the eastern part of the New Guinean central range on basement rocks (with a shared affinity with the Australian Plate). Our results do not support the hypothesis of ancestors migrating to the northern margin of the Australian Plate from Pacific terranes that incrementally accreted to New Guinea over time. However, our analyses support to some extent a scenario in which Exocelina ancestors would have been able to colonize back and forth between the amalgamated Australian and Pacific terranes from the Miocene onwards. Our reconstructions also do not support an origin on ultramafic or ophiolite rocks that have been colonized much later in the evolution of the radiation. Macroevolutionary analyses do not support the hypothesis of heterogeneous diversification rates throughout the evolution of this radiation, suggesting instead a continuous slowdown in speciation. Conclusions Overall, our geospatial analysis approach to investigate the links between the location and evolution of New Guinea’s biota with the underlying geology sheds a new light on the patterns and processes of lineage diversification in this exceedingly diverse region of the planet.

A species-group key and notes on phylogeny and character evolution in New Guinean Exocelina Broun, 1886 diving beetles (Coleoptera, Dytiscidae, Copelatinae)

“…Earlier phylogenetic analyses based on molecular data substantiated the lotic New Guinean Exocelina as a monophyletic group, which emerged from a single colonization event by an Australian lineage and led to a rich species radiation on the island ( Balke et al 2004 , 2007 ). More recent investigations suggested an origin of New Guinean Exocelina during the late Miocene, ca 5 or 9 million years ago ( Toussaint et al 2014 , 2015 ), or even in the mid-Miocene, ca 17 Ma, when the New Guinean orogeny was at an early stage ( Toussaint et al 2021 ) and inferred a constant process of lineage diversification with a continuous slowdown in speciation.…”

Diversification and community assembly of the world’s largest tropical island

“…However, these same trends could also result if long‐term climatic stability in montane forests lowers extinction rates at higher elevations (Fjeldså, et al, 2012). Clearly pertinent to understanding these patterns is that the montane areas where these species are currently distributed were largely absent until the last 5 Myr (Baldwin et al, 2012; Schodde & Christidis, 2014; van Ufford & Cloos, 2005), although the south‐east Peninsula Ranges might be older (Toussaint et al, 2021). Coupled with significant uncertainty surrounding the tectonic history of New Guinea, it remains an open question how lineages that seemingly pre‐date the age of the central range are currently endemic to these areas (Schodde & Christidis, 2014).…”

“…However, these same trends could also result if long-term climatic stability in montane forests lowers extinction rates at higher elevations (Fjeldså, et al, 2012). Clearly pertinent to understanding these patterns is that the montane areas where these species are currently distributed were largely absent until the last 5 Myr (Baldwin et al, 2012;Schodde & Christidis, 2014;van Ufford & Cloos, 2005), although the south-east Peninsula Ranges might be older (Toussaint et al, 2021).…”

Biogeographic–tectonic calibration of 14 nodes in a butterfly timetree

“…The endemism is often thought to result from the unusual soil chemistry, but it is more likely to reflect the tectonic history of ophiolites (Heads, 2014). Toussaint et al (2021c) played down the significance of this history for terrestrial biogeography. They wrote: "ophiolites by definition are sections of the seafloor and the upper mantle that have been thrust on to continental crustthis means that ophiolites found on landmasses today, were covered by >1000 m of seawater prior to their obduction, and could not harbor terrestrial life".…”