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1. Oceanic islands of Wallacea as a source for dispersal and diversification of murine rodents

   https://doi.org/10.1111/jbi.13720  

   Rowe, Kevin C. ; Achmadi, Anang S. ; Fabre, Pierre‐Henri ; Schenk, John J. ; Steppan, Scott J. ; Esselstyn, Jacob A. ( October 2019 , Journal of Biogeography)

   To determine the historical dynamics of colonization and whether the relative timing of colonization predicts diversification rate in the species‐rich, murine rodent communities of Indo‐Australia.

   Indo‐Australian Archipelago including the Sunda shelf of continental Asia, Sahul shelf of continental Australia, the Philippines and Wallacea of Indonesia.

   Order Rodentia, Family Muridae.

   We used a fossil‐calibrated molecular phylogeny and Bayesian biogeographical modelling to infer the frequency and temporal sequence of biogeographical transitions among Sunda, Sahul, the Philippines and Wallacea. We estimated diversification rates for each colonizing lineage using a method‐of‐moments estimator of net diversification and Bayesian mixture model estimates of diversification rate shifts.

   We identified 17 biogeographical transitions, including nine originating from Sunda, seven originating from Sulawesi and broader Wallacea and one originating from Sahul. Wallacea was colonized eight times, the Phillipines five times, Sunda twice and Sahul twice. Net diversification rates ranged from 0.2 to 2.12 species/lineage/My with higher rates in secondary and later colonizers than primary colonizers. The highest rates were in the genusRattusand their closest relatives, irrespective of colonization history.

   Our inferences from murines demonstrate once again the substantial role of islands as sources of species diversity in terrestrial vertebrates of the IAA with most speciation events occurring on islands. Sulawesi and broader Wallacea have been a major source of colonists for both island and continental systems. Crossings of Wallace's Line were more common than subsequent transitions across Lydekker's Line to the east. While speciation following colonization of oceanic archipelagos and large islands is consistent with adaptive radiation theory and ideas regarding ecological opportunity, we did not observe a strong signal of incumbency effects. Rather, subsequent colonists of landmasses radiated unhindered by previous radiations.

    

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2. Dispersal out of Wallacea spurs diversification of Pteropus flying foxes, the world’s largest bats (Mammalia: Chiroptera)

   https://doi.org/10.1111/jbi.13750  

   Tsang, Susan M. ; Wiantoro, Sigit ; Veluz, Maria Josefa ; Sugita, Norimasa ; Nguyen, Y‐Lan ; Simmons, Nancy B. ; Lohman, David J. ( November 2019 , Journal of Biogeography)

   Islands provide opportunities for isolation and speciation. Many landmasses in the Indo‐Australian Archipelago (IAA) are oceanic islands, and founder‐event speciation is expected to be the predominant form of speciation of volant taxa on these islands. We studied the biogeographic history of flying foxes, a group with many endemic species and a predilection for islands, to test this hypothesis and infer the biogeographic origin of the group.

   Australasia, Indo‐Australian Archipelago, Madagascar, Pacific Islands.

   Pteropus(Pteropodidae).

   To infer the biogeographic history ofPteropus, we sequenced up to 6,169 bp of genetic data from 10 markers and reconstructed a multilocus species tree of 34 currently recognizedPteropusspecies and subspecies with threeAcerodonoutgroups usingBEASTand subsequently estimated ancestral areas using models implemented inBioGeoBEARS.

   Species‐level resolution was occasionally low because of slow rates of molecular evolution and/or recent divergences. Older divergences, however, were more strongly supported and allow the evolutionary history of the group to be inferred. The genus diverged in Wallacea from its common ancestor withAcerodon; founder‐event speciation out of Wallacea was a common inference.Pteropusspecies in Micronesia and the western Indian Ocean were also inferred to result from founder‐event speciation.

   Dispersal between regions of the IAA and the islands found therein fostered diversification ofPteropusthroughout the IAA and beyond. Dispersal inPteropusis far higher than in most other volant taxa studied to date, highlighting the importance of inter‐island movement in the biogeographic history of this large clade of large bats.

    

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3. Biogeography and evolution of social parasitism in Australian Myrmecia bulldog ants revealed by phylogenomics

   Mera-Rodríguez LD, Jourdan H ( May 2023 , Molecular phylogenetics and evolution)

   Studying the historical biogeography and life history transitions from eusocial colony life to social parasitism contributes to our understanding of the evolutionary mechanisms generating biodiversity in eusocial insects. The ants in the genus Myrmecia are a well-suited system for testing evolutionary hypotheses about how their species diversity was assembled through time because the genus is endemic to Australia with the single exception of the species M. apicalis inhabiting the Pacific Island of New Caledonia, and because at least one social parasite species exists in the genus. However, the evolutionary mechanisms underlying the disjunct biogeographic distribution of M. apicalis and the life history transition(s) to social parasitism remain unexplored. To study the biogeographic origin of the isolated, oceanic species M. apicalis and to reveal the origin and evolution of social parasitism in the genus, we reconstructed a comprehensive phylogeny of the ant subfamily Myrmeciinae. We utilized Ultra Conserved Elements (UCEs) as molecular markers to generate a molecular genetic dataset consisting of 2,287 loci per taxon on average for 66 out of the 93 known Myrmecia species as well as for the sister lineage Nothomyrmecia macrops and selected outgroups. Our time-calibrated phylogeny inferred that: (i) stem Myrmeciinae originated during the Paleocene ~ 58 Ma ago; (ii) the current disjunct biogeographic distribution of M. apicalis was driven by long-distance dispersal from Australia to New Caledonia during the Miocene ~ 14 Ma ago; (iii) the single social parasite species, M. inquilina, evolved directly from one of the two known host species, M. nigriceps, in sympatry via the intraspecific route of social parasite evolution; and (iv) 5 of the 9 previously established taxonomic species groups are non-monophyletic. We suggest minor changes to reconcile the molecular phylogenetic results with the taxonomic classification. Our study enhances our understanding of the evolution and biogeography of Australian bulldog ants, contributes to our knowledge about the evolution of social parasitism in ants, and provides a solid phylogenetic foundation for future inquiries into the biology, taxonomy, and classification of Myrmeciinae. 

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4. Unexpectedly high levels of lineage diversity in Sundaland Puddle Frogs (Dicroglossidae: Occidozyga Kuhl and Van Hasselt, 1822).

   Flury, J. ( January 2021 , Molecular phylogenetics and evolution)

   null (Ed.)

   One of the most urgent contemporary tasks for taxonomists and evolutionary biologists is to estimate the number of species on earth. Recording alpha diversity is crucial for protecting biodiversity, especially in areas of elevated species richness, which coincide geographically with increased anthropogenic environmental pressures - the world’s so-called biodiversity hotspots. Although the distribution of Puddle frogs of the genus Occidozyga in South and Southeast Asia includes five biodiversity hotspots, the available data on phylogeny, species diversity, and biogeography are surprisingly patchy. Samples analyzed in this study were collected throughout Southeast Asia, with a primary focus on Sundaland and the Philippines. A mitochondrial gene region comprising ~ 2000 bp of 12S and 16S rRNA with intervening tRNA Valine and three nuclear loci (BDNF, NTF3, POMC) were analyzed to obtain a robust, time-calibrated phylogenetic hypothesis. We found a surprisingly high level of genetic diversity within Occidozyga, based on uncorrected p-distance values corroborated by species delimitation analyses. This extensive genetic diversity revealed 29 evolutionary lineages, defined by the > 5% uncorrected p-distance criterion for the 16S rRNA gene, suggesting that species diversity in this clade of phenotypically homogeneous forms probably has been underestimated. The comparison with results of other anuran groups leads to the assumption that anuran species diversity could still be substantially underestimated in Southeast Asia in general. Many genetically divergent lineages of frogs are phenotypically similar, indicating a tendency towards extensive morphological conservatism. We present a biogeographic reconstruction of the colonization of Sundaland and nearby islands which, together with our temporal framework, suggests that lineage diversification centered on the landmasses of the northern Sunda Shelf. This remarkably genetically structured group of amphibians could represent an exceptional case for future studies of geographical structure and diversification in a widespread anuran clade spanning some of the most pronounced geographical barriers on the planet (e.g., Wallace’s Line). Studies considering gene flow, morphology, ecological and bioacoustic data are needed to answer these questions and to test whether observed diversity of Puddle frog lineages warrants taxonomic recognition. 

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5. Around the world in 10 million years: Rapid dispersal of a kleptoparasitoid spider wasp (Pompilidae: Ceropales )

   https://doi.org/10.1111/jbi.14103  

   Rodriguez, Juanita ; Bank, Sarah ; Waichert, Cecilia ; von Dohlen, Carol D. ; Pitts, James P. ( April 2021 , Journal of Biogeography)

   Cosmopolitan distributions have classically been explained by Pangaean vicariance. However, evidence of recently diverged cosmopolitan groups has re‐opened consideration on the processes involved. Our aim is to estimate the processes leading to the worldwide distribution of the kleptoparasitoid genusCeropales.

   Worldwide.

   Ceropalesspider wasps (Pompilidae).

   Data from three molecular markers for 52 specimens ofCeropalesand two calibration points from previous analyses were used to reconstruct a dated phylogeny under a relaxed molecular clock. We compared the fit of 12 models using BioGeoBEARS: DEC (subset sympatry, narrow vicariance), DIVALIKE (narrow and wide vicariance), BAYAREALIKE (widespread sympatry), and these same models with an added jump dispersal parameter and constraining dispersal rates among areas. Using the AIC best‐fit model (DEC+J), we performed Biogeographic Stochastic Mapping (BSM) to infer biogeographic processes by simulating 200 BSM on the BEAST chronogram.

   The origin of crown‐groupCeropaleswas ca. 10.6 Ma (15.7–6.5 95% HPD), and 11 jump‐dispersal events explain its distribution. A constrained DEC+J model, allowing adjacent area dispersal was the best‐fit AIC model. Dispersals across the Bering land bridge, Isthmus of Panama, Mediterranean Sea, and Sunda Plains took place from the late Miocene to present times.

   Ceropalesis a recently diverged group that originated in Eurasia in the Miocene and dispersed to occupy the Americas, Africa, and Australia. Colonization was probably favored by the already diversified hosts (Pompilinae and Pepsinae), which reduced limiting factors such as food resource and nest construction. The evolution of a generalist parasitic lifestyle could facilitate long‐distance dispersal. This is the first study addressing the global historical biogeography of a cosmopolitan spider wasp.

    

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