More Like this

1. First global molecular phylogeny and biogeographical analysis of two arachnid orders (Schizomida and Uropygi) supports a tropical Pangean origin and mid‐Cretaceous diversification

   https://doi.org/10.1111/jbi.13076  

   Clouse, Ronald M. ; Branstetter, Michael G. ; Buenavente, Perry ; Crowley, Louise M. ; Czekanski‐Moir, Jesse ; General, David Emmanuel M. ; Giribet, Gonzalo ; Harvey, Mark S. ; Janies, Daniel A. ; Mohagan, Alma B. ; et al ( August 2017 , Journal of Biogeography)

   We sought to illuminate the history of the arachnid orders Schizomida and Uropygi, neither of which have previously been subjected to global molecular phylogenetic and biogeographical analyses.

   Specimens used in this study were collected in all major tropical and subtropical areas where they are presently found, including the Americas, Africa, Australia and the Indo‐Pacific region.

   From field‐collected specimens, we sequenced two nuclear and two mitochondrial markers, combined these with publicly available data, and conducted multi‐gene phylogenetic analyses on 240 Schizomida, 24 Uropygi and 12 other arachnid outgroups. Schizomid specimens included one specimen from the small family Protoschizomidae; other schizomid specimens were in Hubbardiidae, subfamily Hubbardiinae, which holds 289 of the order's 305 named species. We inferred ancestral areas using the Dispersal‐Extinction‐Cladogenesis model of range evolution, and we used fossil calibrations to estimate divergence times.

   We recovered monophyletic Schizomida and Uropygi as each other's sister group, forming the clade Thelyphonida, and terminals from the New World were usually positioned as the earliest diverging lineages. The ancestral area for schizomids reconstructed unambiguously to the region comprised of Mexico, Southern California and Florida (the xeric New World subtropics). Optimal trees suggested a single colonization of the Indo‐Pacific in both orders, although this did not receive bootstrap support. Molecular dating gave an Upper Carboniferous origin for each order, and a mid‐Cretaceous expansion of Schizomida, including the origin and initial diversification of those in the Indo‐Pacific.

   Ancestral area reconstructions, molecular dating and fossil evidence all support an Upper Carboniferous, tropical Pangean origin for Thelyphonida, Schizomida and perhaps Uropygi. Much of this region became unsuitable habitat for these arachnids during the breakup of Pangea, but they persisted in the area that is now Meso‐ and South America. From there they then expanded to the Indo‐Pacific, where schizomids today display an idiosyncratic combination of microendemism and long‐range dispersal.

    

   more » « less
2. Out of the Orient: Post‐Tethyan transoceanic and trans‐Arabian routes fostered the spread of Baorini skippers in the Afrotropics

   https://doi.org/10.1111/syen.12365  

   Toussaint, Emmanuel F. A. ; Vila, Roger ; Yago, Masaya ; Chiba, Hideyuki ; Warren, Andrew D. ; Aduse‐Poku, Kwaku ; Storer, Caroline ; Dexter, Kelly M. ; Maruyama, Kiyoshi ; Lohman, David J. ; et al ( May 2019 , Systematic Entomology)

   The origin of taxa presenting a disjunct distribution between Africa and Asia has puzzled biogeographers for more than a century. This biogeographic pattern has been hypothesized to be the result of transoceanic long‐distance dispersal, Oligocene dispersal through forested corridors, Miocene dispersal through the Arabian Peninsula or passive dispersal on the rifting Indian plate. However, it has often been difficult to pinpoint the mechanisms at play. We investigate biotic exchange between the Afrotropics and the Oriental region during the Cenozoic, a period in which geological changes altered landmass connectivity. We use Baorini skippers (Lepidoptera, Hesperiidae) as a model, a widespread clade of butterflies in the Old World tropics with a disjunct distribution between the Afrotropics and the Oriental region. We use anchored phylogenomics to infer a robust evolutionary tree for Baorini skippers and estimate divergence times and ancestral ranges to test biogeographic hypotheses. Our phylogenomic tree recovers strongly supported relationships for Baorini skippers and clarifies the systematics of the tribe. Dating analyses suggest that these butterflies originated in the Oriental region, Greater Sunda Islands, and the Philippines in the early Miocenec. 23 Ma. Baorini skippers dispersed from the Oriental region towards Africa at least five times in the past 20 Ma. These butterflies colonized the Afrotropics primarily through trans‐Arabian geodispersal after the closure of the Tethyan seaway in the mid‐Miocene. Range expansion from the Oriental region towards the African continent probably occurred via theGomphotheriumland bridge through the Arabian Peninsula. Alternative scenarios invoking long‐distance dispersal and vicariance are not supported. The Miocene climate change and biome shift from forested areas to grasslands possibly facilitated geodispersal in this clade of butterflies.

    

   more » « less
3. The phylogeographic history of a range disjunction in eastern North America: the role of post‐glacial expansion into newly suitable habitat

   https://doi.org/10.1002/ajb2.1686  

   Mohn, Rebekah A. ; Oleas, Nora H. ; Smith, Adam B. ; Swift, Joel F. ; Yatskievych, George A. ; Edwards, Christine E. ( June 2021 , American Journal of Botany)

   A disjunct distribution, where a species’ geographic range is discontinuous, can occur through vicariance or long‐distance dispersal. Approximately 75 North American plant species exhibit a ~650 km disjunction between the Ozark and Appalachian regions. This disjunction is attributed to biogeographic forces including: (1) Eocene–Oligocene vicariance by the formation of the Mississippi embayment; (2) Pleistocene vicariance from interglacial flooding; (3) post‐Pleistocene northward colonization from separate glacial refugia; (4) Hypsithermal vicariance due to climate fluctuations; and (5) recent long‐distance dispersal. We investigated which of these pathways most likely gave rise to the Appalachian‐Ozark disjunction inDelphinium exaltatum.

   We genotyped populations ofD. exaltatumfrom five Ozark and seven Appalachian localities, analyzed genetic structure, tested the order and timing of divergences usingDIYABC, and conducted niche reconstructions up to 21,000 years before present (YBP).

   Populations fell into five main genetic clusters, i.e., a group in the central Appalachians, and four “lowland” groups. DIYABC analyses showed the central Appalachian and lowland lineages diverging 11,300 to17,000 YBP, and the lowland groups diverging 6800 to 10,900 YBP. Niche reconstructions showed that suitable climate for the central Appalachian lineage experienced large spatial discontinuity starting 14,000 YBP, such that divergence and persistence before this period is less plausible than divergence thereafter.

   Our results did not fully support any of the original hypotheses. Rather, the oldest divergence likely occurred after 13,500 YBP through expansion into newly opened habitat in the Appalachians. The Appalachian‐Ozark disjunction likely resulted from northward dispersal of the lowland lineage as climate warmed during the Holocene.

    

   more » « less
4. Complex patterns of Gondwanan biogeography revealed in a dispersal‐limited arachnid

   https://doi.org/10.1111/jbi.14080  

   Derkarabetian, Shahan ; Baker, Caitlin M. ; Giribet, Gonzalo ( March 2021 , Journal of Biogeography)

   We explore the biogeographic history of the Gondwanan lineage Triaenonychidae, a dispersal‐limited arachnid taxon that underwent a recent taxonomic revision based on phylogenomic data. We explicitly test hypotheses related to a biogeographical pattern of ‘common vicariance, rare dispersal’, predicted for dispersal‐limited taxa.

   Continental landmasses of former temperate Gondwanan terranes (southern South America, southern Africa, Madagascar, Australia, New Zealand, and New Caledonia).

   Triaenonychidae, Opiliones, Arachnida.

   Utilizing a recently published phylogenomic data set based on ultra‐conserved elements, we conduct Bayesian divergence dating analyses, ancestral area estimation in a likelihood model testing framework, and analyses of macroevolutionary dynamics. Results are correlated with geological history and palaeoclimate reconstructions to infer biogeographic history and distribution.

   We find that divergence dates of ancestral Triaenonychidae pre‐date continental breakup of Gondwana and could be attributed to palaeoclimatic differentiation across Gondwana. There is evidence for two separate expansion routes that span eastern and western Gondwana corresponding to northern warmer climate and southern cooler climate lineages. Many divergences across intercontinental lineages coincide with the timing of continental fragmentation, supporting vicariance as a dominant force. However, some lineages are supported as obvious examples of rare long‐distance dispersal. Biogeographic results support the predicted pattern of common vicariance and rare dispersal for these dispersal‐limited organisms.

   Vicariance due to continental fragmentation was important in the early diversification of Triaenonychidae. Their unique combination and degrees of dispersal ability and microhabitat preference resulted in complex phylogenetic patterns of geographic distribution not typically seen in other animal taxa. Examining biogeographic patterns across recent studies of arachnid taxa with varying dispersal ability, it is clear that biological characteristics play an important role in the relative importance of dispersal and vicariance (dispersal–vicariance continuum) for any given taxon and can be useful in forming testable a priori hypotheses.

    

   more » « less
5. A fully resolved backbone phylogeny reveals numerous dispersals and explosive diversifications throughout the history of Asteraceae

   https://doi.org/10.1073/pnas.1903871116  

   Mandel, Jennifer R. ; Dikow, Rebecca B. ; Siniscalchi, Carolina M. ; Thapa, Ramhari ; Watson, Linda E. ; Funk, Vicki A. ( June 2019 , Proceedings of the National Academy of Sciences)

   The sunflower family, Asteraceae, comprises 10% of all flowering plant species and displays an incredible diversity of form. Asteraceae are clearly monophyletic, yet resolving phylogenetic relationships within the family has proven difficult, hindering our ability to understand its origin and diversification. Recent molecular clock dating has suggested a Cretaceous origin, but the lack of deep sampling of many genes and representative taxa from across the family has impeded the resolution of migration routes and diversifications that led to its global distribution and tremendous diversity. Here we use genomic data from 256 terminals to estimate evolutionary relationships, timing of diversification(s), and biogeographic patterns. Our study places the origin of Asteraceae at ∼83 MYA in the late Cretaceous and reveals that the family underwent a series of explosive radiations during the Eocene which were accompanied by accelerations in diversification rates. The lineages that gave rise to nearly 95% of extant species originated and began diversifying during the middle Eocene, coincident with the ensuing marked cooling during this period. Phylogenetic and biogeographic analyses support a South American origin of the family with subsequent dispersals into North America and then to Asia and Africa, later followed by multiple worldwide dispersals in many directions. The rapid mid-Eocene diversification is aligned with the biogeographic range shift to Africa where many of the modern-day tribes appear to have originated. Our robust phylogeny provides a framework for future studies aimed at understanding the role of the macroevolutionary patterns and processes that generated the enormous species diversity of Asteraceae. 

   more » « less