Evolution of Pacific Rim diving beetles sheds light on Amphi‐Pacific biogeography

Abstract

The origin of biodiversity in the Neotropics predominantly stems either from Gondwana breakup or late dispersal events from the Nearctic region. Here, we investigate the biogeography of a diving beetle clade whose distribution encompasses parts of the Oriental region, the Indo‐Australian archipelago (IAA) and the Neotropics. We reconstructed a dated molecular phylogeny, inferred diversification dynamics and estimated ancestral areas under different biogeographic assumptions. For the Oriental region and the IAA, we reveal repeated and complex colonization patterns out of Australia, across the major biogeographic lines in the region (e.g. Wallace's Line). The timing of colonization events across the IAA broadly coincides with the proposed timing of the formation of major geographic features in the region. Our phylogenetic hypothesis recovers Neotropical species nested in two derived clades. We recover an origin of the group in the early Eocene about 55 million yr ago, long after the break‐up of Gondwana initiated, but before a complete separation of Australia, Antarctica and the Neotropics. When allowing an old Gondwanan ancestor, we reconstruct an intricate pattern of Gondwanan vicariance and trans‐Pacific long‐distance dispersal from Australia toward the Neotropics. When restricting the ancestral range to more plausible geological area combinations in the Eocene, we infer an Australian origin with two trans‐Pacific long‐distance dispersal events toward the Neotropics. Our results support on one hand a potential Gondwanan signature associated with regional extinctions in the Cenozoic and with Antarctica serving as a link between Australia and the Neotropics. On the other hand, they also support a trans‐Pacific dispersal of these beetles toward the Andean coast in the Oligocene.

Historical biogeography of the hyperdiverse hidden snout weevils (Coleoptera, Curculionidae, Cryptorhynchinae)

“…() and also younger than in Toussaint et al . (), which focused on higher‐level relationships within beetles. Attelabidae and Belidae c .…”

“…Gustafson & Miller () suggested the colonization of Antarctica by Macrogyrus whirligig beetles in the Palaeocene. A similar pattern was suggested for Platynectes diving beetles in the Eocene (Toussaint et al ., ), and for Hydrobiusini and Oocyclus water scavenger beetles in the Cretaceous (Toussaint & Short, , ). This pattern therefore seems to be much more common than previously thought and is supported by recent palaeoclimatic evidence.…”

“…Primers and PCR conditions principally follow Toussaint et al . (). In total, the dataset consisted of the mitochondrial 16S and the nuclear 18S and 28S ribosomal RNA genes, as well as the protein‐coding genes cytochrome c oxidase subunit 1 (COI), arginine kinase (ArgK), carbamoyl‐phosphate synthetase 2 (CAD), elongation‐factor 1 alpha (EF1α) and enolase (EN).…”

“…Eberle et al ., ; Setliff, ; Tänzler et al ., ; Riedel et al ., , ; Luna‐Cozar et al ., ; Riedel & Narakusumo, ). Recent studies on the Western Palaearctic Cryptorhynchinae of the Acalles group (Astrin & Stüben, ; Astrin et al ., ) and the Indo‐Australian genus Trigonopterus Fauvel (Tänzler et al ., , ; Toussaint et al ., ) provided insights into their evolution, but the systematics and evolution of the highly diverse South American and Indo‐Australian faunas remain largely unexplored. Many species and genera of the litter fauna are still undescribed, while the relationships and composition of major groups are in equal need of study.…”

Cretaceous West Gondwana vicariance shaped giant water scavenger beetle biogeography

“…The dispersal events inferred in clades C4 and C5, respectively from South America toward Africa or Australasia, require a trans‐oceanic dispersal explanation or continental dispersal through Antarctica followed by extinction in the latter case. Trans‐oceanic dispersal events have been suggested on other water beetle clades, for instance in Platynectini diving beetles (Coleoptera, Dytiscidae) from the Oriental region toward South America (Toussaint et al ., ). In clade C5, the dispersal from South America toward the Oriental region (Fig.…”