1. Phylogenetic relationships and historical biogeography of silkmoths (Lepidoptera: Bombycidae) suggest an origin in Southern Gondwana.
- Author
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Lin, Rung-Juen, Lin, Yu-Chi, Braby, Michael F., Zwick, Andreas, and Hsu, Yu-Feng
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CURRENT distribution , *PALEOCENE Epoch , *BASE pairs , *VICARIANCE , *EOCENE Epoch - Abstract
[Display omitted] • Biogeographic hypothesis testing and ancestral area reconstruction supports an origin of Bombycidae in Southern Gondwana during the Paleocene (c. 64 Mya). • Bombycidae differentiated into two subfamilies by vicariance between South America (Epiinae) and Australia (Bombycinae) during the Eocene (c. 56 Mya). • Although most species of Bombycinae are distributed in South-East Asia, they did not originate in the Oriental Region. Rather, the ancestor dispersed out of Australia to South-East Asia during the Eocene (c. 53 Mya) or possibly later. • A second dispersal event occurred from Asia to Africa during the Miocene (c. 16 Mya), most likely facilitated by the Gomphotherium land bridge. • Our study provides an explanation for the group's disjunct distribution in the Southern Hemsiphere and Asia, which, interestingly, does not involve dispersal across Beringia. Silkmoths (Bombycidae) have a disjunct distribution predominantly in the Southern Hemisphere and Asia. Here we reconstruct the phylogenetic history of the family to test competing hypotheses on their origin and assess how vicariance and long-distance dispersal shaped their current distribution. We sequenced up to 5,074 base pairs from six loci (COI, EF1-α, wgl, CAD, GAPDH, and RpS5) to infer the historical biogeography of Bombycidae. The multilocus dataset covering 20 genera (80 %) of the family, including 17 genera (94 %) of Bombycinae and 3 genera (43 %) of Epiinae, was used to estimate phylogenetic patterns, divergence times and biogeographic reconstruction. Dating estimates extrapolated from secondary calibration sources indicate the Bombycidae stem-group originated approximately 64 Mya. The subfamilies Epiinae (South America) and Bombycinae (Australia, Asia, East Palaearctic, and Africa) were reciprocally monophyletic, diverging at c. 56 Mya (95 % credibility interval: 66–46 Mya). The 'basal' lineage of Bombycinae — Gastridiota + Elachyophtalma — split from the rest of Bombycinae c. 53 Mya (95 % credibility interval: 63–43 Mya). Gastridiota is a monobasic genus with a relictual distribution in subtropical forests of eastern Australia. The Oriental and African genera comprised a monophyletic group: the Oriental region was inferred to have been colonized from a long-distance dispersal event from Australia to South-East Asia c. 53 Mya or possibly later (c. 36–26 Mya); Africa was subsequently colonized by dispersal from Asia c. 16 Mya (95 % credibility interval: 21–12 Mya). Based on the strongly supported phylogenetic relationships and estimates of divergence times, we conclude that Bombycidae had its origin in the fragment of Southern Gondwana consisting of Australia, Antarctica and South America during the Paleocene. The disjunction between South America (Epiinae) and Australia (Bombycinae) is best explained by vicariance in the Eocene, whereas the disjunct distribution in Asia and Africa is best explained by more recent dispersal events. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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