A historical biogeography of megadiverse Sericini—another story “out of Africa”?

Abstract

Megadiverse insect groups present special difficulties for biogeographers because poor classification, incomplete knowledge of taxonomy, and many undescribed species can introduce a priori sampling bias to any analysis. The historical biogeography of Sericini, a tribe of melolonthine scarabs comprising about 4000 species, was investigated using the most comprehensive and time-calibrated molecular phylogeny available today. Problems arising through nomenclatural confusion were overcome by extensive sampling (665 species) from all major lineages of the tribe. A West Gondwanan origin of Sericini (c. 112 Ma) was reconstructed using maximum parsimony, maximum-likelihood and model-based ancestral area estimation. Vicariance in the tribe's earliest history separated Neotropical and Old World Sericini, whereas subsequent lower Cretaceous biogeography of the tribe was characterized by repeated migrations out of Africa, resulting in the colonization of Eurasia and Madagascar. North America was colonized from Asia during the Cenozoic and a lineage of "Modern Sericini" reinvaded Africa. Diversification dynamics revealed three independent shifts to increased speciation rates: in African ant-adapted Trochalus, Oriental Tetraserica, and Asian and African Sericina. Southern Africa is proposed as both cradle and refuge of Sericini. This area has retained many old lineages that portray the evolution of the African Sericini fauna as a series of taxon pulses.

Landscape genetics indicate recently increased habitat fragmentation in African forest‐associated chafers

“…The Miocene is known for a general cooling and aridification (Zachos et al ., ) and for the onset of intensified diversification in Pleophylla (Eberle et al ., ) and other forest‐associated organisms (Measey & Tolley, ; Mlambo et al ., ; Menegon et al ., ; Eberle et al ., ). This was argued to be attributable to fragmentation and isolation of previously widespread species in forest remains (Maley, ).…”

“…Reliance on two lines of evidence from independent sources of data strengthened the results, which were further backed up by reflections on past development of forest cover in South Africa. Conclusions are closely linked with the conservational importance of South Africa as a cradle of evolution (Pickford, ; Eberle et al ., ), promoting the persistence of a rich and valuable (phylogenetic) diversity (Sechrest et al ., ; Schnitzler et al ., ; Huntley et al ., ). Frequent natural climate fluctuations that led to repeated forest retreats and expansions in southern Africa (Deacon, ; Eeley et al ., ) might have acted as speciation pump (Terborgh, ; Voelker et al ., ; McDonald & Daniels, ) producing a unique and diverse flora and fauna.…”

“…Congo (Eberle et al ., ), a pattern that is also observed in other forest‐associated species (e.g., Huber, ). It is one of the oldest lineages of the highly diverse tribe of Sericini (Ahrens, ; Eberle et al ., ) that originated ca. 79 Mya and showed a burst of speciation since the Miocene (Eberle et al ., ).…”

Rekindling Jeannel’s Gondwanan vision? Phylogenetics and evolution of Carabinae with a focus on Calosoma caterpillar hunter beetles

“…Although the timing of diversification in some beetle lineages has been shown to concur with that of Gondwanan fragmentation (e.g. Bukontaite, Miller & Bergsten, 2014;Kim & Farrell, 2015;Andújar et al, 2016;Günter et al, 2016;Toussaint et al, 2017c;Toussaint, Fikáček & Short, 2016b;Toussaint, Bloom & Short, 2017b;Eberle et al, 2017), the biogeographical origins of other beetle groups with Gondwana-like distributions have been demonstrated to post-date this major tectonic reassembly (e.g. Toussaint & Short, 2017).…”

Cretaceous West Gondwana vicariance shaped giant water scavenger beetle biogeography

“…Our ancestral range estimation recovers with moderate support a West Gondwana vicariant pattern with a joint ancestral distribution in these two regions. A recent study on Sericini chafers (Coleoptera, Scarabaeidae) recovered a similar pattern with the best biogeographical model estimating a vicariant split consistent with the West Gondwana vicariance hypothesis (WGVH) (Eberle et al ., ; Fig. ).…”