Organisms Diversity & Evolution

, Volume 16, Issue 1, pp 167–184

Phylogeography of the harvestman genus Metasiro (Arthropoda, Arachnida, Opiliones) reveals a potential solution to the Pangean paradox

  • Ronald M. Clouse
  • Prashant P. Sharma
  • Jessie C. Stuart
  • Lloyd R. Davis
  • Gonzalo Giribet
  • Sarah L. Boyer
  • Ward C. Wheeler
Original Article

DOI: 10.1007/s13127-015-0233-7

Cite this article as:
Clouse, R.M., Sharma, P.P., Stuart, J.C. et al. Org Divers Evol (2016) 16: 167. doi:10.1007/s13127-015-0233-7

Abstract

At both global and local scales, mite harvestmen (Opiliones, Cyphophthalmi) have been shown to have achieved their current global distribution strictly through vicariance. However, the implicit low dispersal capability of this group does not explain how they expand their ranges and come to occupy enormous landmasses prior to rifting. To investigate at the population level the limited vagility that characterizes the suborder generally, and how its dispersal capacity determines diversification dynamics, range expansion, and historical biogeography, we examined as a test case the phylogeography of the genus Metasiro. This genus consists of three widely separated, morphologically cryptic species that inhabit the Southeastern United States. Distances between sampling sites spanned a range of geographic scales, from 4 m to over 500 km. Population structure was inferred from fragments of six loci (three mitochondrial, three nuclear) amplified from 221 specimens. We tested for population structure and gene flow, constructed a dated phylogeny of the genus, and developed a program for estimating the effective population size with confidence intervals. Individuals of Metasiro americanus demonstrate remarkable population structure at scales of less than 25 m, but populations vary in their haplotypic diversity, and some exhibit evidence of historical gene flow. The estimated timing of cladogenesis within the genus accords closely with the geological history of the North American coastline, and the three species are at the endpoints of large watersheds. This suggests that mite harvestman lineages expand their ranges by hydrochory, providing for the first time a plausible mechanism whereby these animals dispersed across Pangea despite their low vagility in stable environments.

Keywords

Apalachicola River Appalachia Cyphophthalmi Hydrochory Pangea Vicariance 

Supplementary material

13127_2015_233_MOESM1_ESM.pdf (78 kb)
Figure S1Complete phylogeny recovered under maximum likelihood using all sequenced markers (12S, 16S, COI, H3, 18S, and 28S). This is the same phylogeny dated using PATHd8 and shown in Fig. 2. (PDF 78 kb)
13127_2015_233_MOESM2_ESM.pdf (102 kb)
Figure S2Summary of dating calibrations in PATHd8, with inputted fixed dates (triangles) or date ranges (rectangle) shown on relevant nodes. With only the root fixed (a, PATHd8 requires one fixed node), dates of all nodes tend to push forward, significantly younger than dates recovered from other Cyphophthalmi. Adding a date range for Sternophthalmi, the infraorder to which Metasiro belongs (b), results in dates that differ little from simply adding a calibration point for the breakup of Pangea (c, 200 Ma). Without the root constrained, the date for it extends back 1 billion years (d), as is common in dating programs. (PDF 102 kb)
13127_2015_233_MOESM3_ESM.docx (30 kb)
ESM 1(DOCX 30 kb)
13127_2015_233_MOESM4_ESM.pdf (93 kb)
ESM 2Ne_CALCULATOR (PDF 93.3 kb)

Copyright information

© Gesellschaft für Biologische Systematik 2015

Authors and Affiliations

  • Ronald M. Clouse
    • 1
    • 2
  • Prashant P. Sharma
    • 1
    • 3
  • Jessie C. Stuart
    • 4
  • Lloyd R. Davis
    • 5
  • Gonzalo Giribet
    • 6
  • Sarah L. Boyer
    • 7
  • Ward C. Wheeler
    • 1
  1. 1.Division of Invertebrate ZoologyAmerican Museum of Natural HistoryNew YorkUSA
  2. 2.Department of Bioinformatics and GenomicsUniversity of North Carolina at CharlotteCharlotteUSA
  3. 3.Department of ZoologyUniversity of Wisconsin–MadisonMadisonUSA
  4. 4.Harvard Medical SchoolBostonUSA
  5. 5.GainesvilleUSA
  6. 6.Museum of Comparative Zoology, Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeUSA
  7. 7.Biology DepartmentMacalester CollegeSaint PaulUSA