| Literature DB >> 27833425 |
Ingi Agnarsson1, Stephanie M LeQuier2, Matjaž Kuntner3, Ren-Chung Cheng4, Jonathan A Coddington5, Greta Binford6.
Abstract
The Caribbean islands harbor rich biodiversity with high levels of single island endemism. Stretches of ocean between islands represent significant barriers to gene-flow. Yet some native species are widespread, indicating dispersal across oceans, even in wingless organisms like spiders. Argiope argentata (Fabricius, 1775) is a large, charismatic, and widespread species of orb-weaving spider ranging from the United States to Argentina and is well known to balloon. Here we explore the phylogeography of Argiope argentata in the Caribbean as a part of the multi-lineage CarBio project, through mtDNA haplotype and multi-locus phylogenetic analyses. The history of the Argiope argentata lineage in the Caribbean goes back 3-5 million years and is characterized by multiple dispersal events and isolation-by-distance. We find a highly genetically distinct lineage on Cuba which we describe as Argiope butchkosp. n. While the argentata lineage seems to readily balloon shorter distances, stretches of ocean still act as filters for among-island gene-flow as evidenced by distinct haplotypes on the more isolated islands, high FST values, and strong correlation between intraspecific (but not interspecific) genetic and geographic distances. The new species described here is clearly genetically diagnosable, but morphologically cryptic, at least with reference to the genitalia that typically diagnose spider species. Our results are consistent with the intermediate dispersal model suggesting that good dispersers, such as our study species, limit the effect of oceanic barriers and thus diversification and endemism.Entities:
Keywords: Biogeography; CarBio; GAARlandia; Intermediate dispersal model; Isolation by distance model; dispersal; diversification
Year: 2016 PMID: 27833425 PMCID: PMC5096361 DOI: 10.3897/zookeys.625.8729
Source DB: PubMed Journal: Zookeys ISSN: 1313-2970 Impact factor: 1.546
Figure 1.A dated phylogeny of in the Caribbean, and other relatives. Shown are the results of tree based species delimitation analyses (GMYC method) on a BEAST phylogeny (node ages in million years) and the location of spiders used in this study (inset picture). Asterisk denotes posterior probability support >95%. The OTUs (operational taxonomic units) correspond to a cryptic species, sp. n., from Cuba (argentataCU) and populations from other Caribbean islands (argentataCAR) plus mainland (argentataUS) treated as conspecific ().
Descriptive statistics for K2P distances within and between the molecular , which were identified by molecular species delimitation methods.
(Kimura 2-parameter)
operational taxonomic units
| Within | |||
|---|---|---|---|
| OTU | N |
| |
| Mean | Std. Err | ||
| argentataCAR | 74 | 0.009 | 0.002 |
| argentataUS | 3 | 0.018 | 0.004 |
| argentataCU | 10 | 0.006 | 0.001 |
| Between OUTs | |||
| OTU 1 | OTU 2 |
| |
| Mean | Std. Err | ||
| argentataCAR | argentataUS | 0.029 | 0.006 |
| argentataCAR | argentataCU | 0.061 | 0.010 |
| argentataUS | argentataCU | 0.064 | 0.010 |
Figure 2.Regression analysis between geographic and genetic distances among all specimens of s.l. included here. Blue dots and line represent within species comparisons and red dots and line those among the two species as here defined. Black line is regression across all data. Geographical distances well explain genetic distances within species, but not between the species, as expected.
Figure 3.A haplotype network of Caribbean and sp. n. Haplotypes are colored by locality as indicated, circle size reflects number of individuals carrying that haplotype from 1-7 in total, open circles represent unobserved haplotypes. Hash marks indicate mutational differences among haplotypes. Inset photograph is of a female .
Figure 4.Female holotype sp. n. a dorsal b lateral c ventral; Male paratype sp. n. d dorsal e lateral f ventral g external epigynum h external epigynum illustration showing spermatheca and spiraling ducts i internal epigynum illustration dorsal m palp lateral n palp ventral; j external epigynum k external epigynum illustration showing spermatheca and spiraling ducts l internal epigynum illustration dorsal o palp lateral p palp ventral.
Figure 5.Comparative morphology of the male palpal organ of the widespread and the new . No clearly diagnostic features were identified in the new species, though slight differences in the terminal parts of the median apophysis and the embolus are observed and merit further comparative investigation.