The fossil record and macroevolutionary history of the beetles

Abstract

Coleoptera (beetles) is the most species-rich metazoan order, with approximately 380 000 species. To understand how they came to be such a diverse group, we compile a database of global fossil beetle occurrences to study their macroevolutionary history. Our database includes 5553 beetle occurrences from 221 fossil localities. Amber and lacustrine deposits preserve most of the beetle diversity and abundance. All four extant suborders are found in the fossil record, with 69% of all beetle families and 63% of extant beetle families preserved. Considerable focus has been placed on beetle diversification overall, however, for much of their evolutionary history it is the clade Polyphaga that is most responsible for their taxonomic richness. Polyphaga had an increase in diversification rate in the Early Cretaceous, but instead of being due to the radiation of the angiosperms, this was probably due to the first occurrences of beetle-bearing amber deposits in the record. Perhaps, most significant is that polyphagan beetles had a family-level extinction rate of zero for most of their evolutionary history, including across the Cretaceous-Palaeogene boundary. Therefore, focusing on the factors that have inhibited beetle extinction, as opposed to solely studying mechanisms that may promote speciation, should be examined as important determinants of their great diversity today.

Biotic and environmental dynamics through theLateJurassic–EarlyCretaceous transition: evidence for protracted faunal and ecological turnover

“…Increased origination rates of major Coleoptera groups (e.g. Polyphaga) in the Early Cretaceous support this hypothesis (Smith & Marcot, 2015).…”

“…Major groups of Lepidoptera might have emerged in the Late Jurassic-Early Cretaceous interval, paving the way for them to become one of the most diverse insect groups today (Connor & Taverner, 1997;Kristensen & Skalski, 1998;Sohn et al, 2015). Overall coleopteran diversity appeared to increase through the J/K boundary (Smith & Marcot, 2015), and there is some evidence that the fragmentation of Gondwana led to the diversification of major lineages in the earliest Cretaceous (Kim & Farrell, 2015).…”

Evolutionary and paleobiological implications of Coleoptera (Insecta) from Tethyan-influenced Cretaceous ambers

“…3), are distributed in both public and private collections, and consequently the real proportions of their paleobiological content is difficult to establish. Coleoptera have been recorded in all Cretaceous ambers with bioinclusions (e.g., Poinar, 1992;Rasnitsyn and Ross, 2000;Grimaldi et al, 2000Grimaldi et al, , 2002Poinar and Milki, 2001;Penney, 2010;Schmidt et al, 2010); but the information that could be extracted after analysis of these collection has only recently begun to be exploited and it is still not included in recent compiling work (e.g., Smith and Marcot, 2015).…”

“…The fauna clearly differs between the early and late Cretaceous, with the former being more similar to the Jurassic than the latter, and shows a divergence in some of the major polyphagan lineages present today (Ponomarenko, 2002;Grimaldi and Engel, 2005). Speculation as to whether flowering plants had any influence or coevolved with pollinators (including beetles) during the Cretaceous (Crowson, 1981;Farrell, 1998;Grimaldi, 1999;Grimaldi and Engel, 2005;Hunt et al, 2007;Friis et al, 2011) or they were already present when angiosperms appeared (Labandeira and Currano, 2013;Wang et al, 2013;Smith and Marcot, 2015) is still debated.…”

Making the Most of Clade Selection

“…Sexually reproducing organisms necessarily need conspecific mates. But a beetle species does not similarly need any of the other 380,000 species in the clade Coleoptera; Smith and Marcot 2015). The causal arrow goes only one way.…”