Out of Africa: Biogeography and diversification of the pantropical pond skater genusLimnogonusStål, 1868 (Hemiptera: Gerridae).
Gondwanan vicariance, long-distance dispersal (LDD), and boreotropical migration have been proposed as alternative hypotheses explaining the pantropical distribution pattern of organisms. In this study, the historical biogeography of the pond skater genusLimnogonuswas reconstructed to evaluate the impact of biogeographical scenarios in shaping their modern transoceanic disjunction. We sampled almost 65% of recognizedLimnogonusspecies. Four DNA fragments including 69 sequences were used to reconstruct a phylogram. Divergence time was estimated using a Bayesian relaxed clock method and three fossil calibrations. Diversification dynamics and ancestral area reconstruction were investigated by using maximum likelihood and Bayesian approaches. Our results showed the crown group ofLimnogonusoriginated and diversified in Africa in the early Eocene (49 Ma, HPD: 38-60 Ma), subsequently expanding into other regionsviadispersal. The colonization of the New World originated from the Oriental Region probablyviathe Bering Land Bridge in the late Eocene. Two split events between the Old World and New World were identified: one between Neotropics and Oriental region around the middle Oligocene (30 Ma, HPD: 22-38 Ma), and the other between Neotropics and Africa during the middle Miocene (14 Ma, HPD: 8-21 Ma). The evolutionary history ofLimnogonusinvolved two biogeographical processes. Gondwanan vicariance was not supported in our analyses. The diversification ofLimnogonusamong Africa, Oriental, and Neotropical regions corresponded with the age of land bridge connection and dispersed as a member associated with the broad boreotropical belt before local cooling (34 Ma). The current transoceanic disjunctions inLimnogonuscould be better explained by the disruption of "mixed-mesophytic" forest belt; however, the direct transoceanic LDD between the Neotropics and Africa could not be ruled out. In addition, the "LDD" model coupled with island hopping could be a reasonable explanation for the diversification of the Oriental and Australian regions during the Oligocene.
College of Environmental Science and Engineering Nankai University Tianjin China; College of Life Sciences Institute of Entomology Nankai University Tianjin China.
Zhen
Z
Ye
College of Life Sciences Institute of Entomology Nankai University Tianjin China.
Yahui
Y
Zhen
College of Life Sciences Institute of Entomology Nankai University Tianjin China.
Yanyan
Y
Zhou
College of Life Sciences Institute of Entomology Nankai University Tianjin China.
Wenjun
W
Bu
Gondwanan vicariance; Limnogonus; boreotropical migration; long‐distance dispersal; pantropical distribution