The “sexy shrimp”
Coral reefs in all tropical oceans.
Specimens of
We found evidence for at least five cryptic lineages (9%–22%
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.
- NSF-PAR ID:
- 10038599
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of Biogeography
- Volume:
- 44
- Issue:
- 11
- ISSN:
- 0305-0270
- Page Range / eLocation ID:
- p. 2660-2672
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract Aim Thor amboinensis is currently considered a single circumtropical species. However, the tropical oceans are partitioned by hard and soft barriers to dispersal, providing ample opportunity for allopatric speciation. Herein, we test the null hypothesis thatT. amboinensis is a single global species, reconstruct its global biogeographical history, and comment on population‐level patterns throughout the Tropical Western Atlantic.Location Methods Thor amboinensis were obtained through field collection and museum holdings. We used one mitochondrial (COI ) and two nuclear (NaK, enolase) gene fragments for global species delimitation and phylogenetic analyses (n = 83 individuals, 30 sample localities), while phylogeographical reconstruction in theTWA was based onCOI only (n = 303 individuals, 10 sample localities).Results COI pairwise sequence divergence): four in the Indo‐West Pacific and one in the Tropical Western Atlantic. Phylogenetic reconstruction revealed that endemic lineages from Japan and the South Central Pacific are more closely related to the Tropical Western Atlantic lineage than to a co‐occurring lineage that is widespread throughout the Indo‐West Pacific. Concatenated and species tree phylogenetic analyses differ in the placement of an endemic Red Sea lineage and suggest alternate dispersal pathways into the Atlantic. Phylogeographical reconstruction throughout the Tropical Western Atlantic reveals little genetic structure over more than 3,000 km.Main conclusions Thor amboinensis is a species complex that has undergone a series of allopatric speciation events and whose members are in secondary contact in the Indo‐West Pacific. Nuclear‐ and mitochondrial‐ gene phylogenies show evidence of introgression between lineages inferred to have been separated more than 20 Ma. Phylogenetic discordance between multi‐locus analyses suggest thatT. amboinensis originated in the Tethys sea and dispersed into the Atlantic and Indo‐West Pacific through the Tethys seaway or, alternatively, originated in the Indo‐West Pacific and dispersed into the Atlantic around South Africa. Population‐level patterns in the Caribbean indicate extensive gene flow across the region. -
more » « less
Abstract Aim Fossil data may be crucial to infer biogeographical history, especially in taxa with tropical trans‐Pacific distributions. Here, we use extinct and extant trochanteriid flattened spiders to test hypotheses that could explain its trans‐Pacific disjunct distribution, including a Boreotropical origin with a North Atlantic dispersal, an African origin with South Atlantic dispersal and an Eurasian origin with Bering Bridge route.
Location World‐wide.
Taxon Trochanteriidae,
Plator ‐Doliomalus ‐Vectius (PDV) clade.Methods MicroCT was used to collect morphological data from an undescribed Baltic amber fossil. These data were used with additional fossils and extant species in a total‐evidence, tip‐dated phylogenetic analysis. We tested different scenarios using constrained dispersal matrices in a Bayesian approach. An analysis with fossils pruned was also performed to explore how lack of fossil data might impact inferences of biogeographical process.
Results The phylogenetic analyses allowed us to place the new fossil in the genus
Plator . Analyses without fossils suggest an African origin with a dispersal to Asia from India and a South Atlantic dispersal to South America. When fossils are included, hypothesis‐testing rejects this scenario and equally supports a Boreotropical and an Afro‐European origin with a South Atlantic route and a dispersal to Asia from Europe.Main conclusions Biogeographical inferences of disjunctly distributed taxa should be interpreted with caution when fossils are not included. Although one alternative hypothesis was not completely rejected, results show that the Boreotropical hypothesis for the PDV clade could be a robust explanation for its actual distribution. This hypothesis is mostly overlooked in animal taxa and rigorous tests with other taxa with similar distributions may reveal that a Boreotropical origin is common. We discuss methodological approaches that could improve biogeographical tests using fossils as terminals.
-
more » « less
Abstract Aim 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.
Location Continental landmasses of former temperate Gondwanan terranes (southern South America, southern Africa, Madagascar, Australia, New Zealand, and New Caledonia).
Taxon Triaenonychidae, Opiliones, Arachnida.
Methods 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.
Results 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.
Main conclusions 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
Abstract The northern temperate genus
Dracocephalum consists of approximately 70 species mainly distributed in the steppe‐desert biomes of Central and West Asia and the alpine region of the Qinghai‐Tibetan Plateau (QTP). Previous work has shown thatDracocephalum is not monophyletic and might includeHyssopus andLallemantia . This study attempts to clarify the phylogenetic relationships, diversification patterns, and the biogeographical history of the three genera (defined asDracocephalum s.l.). Based on a sampling of 66 taxa comprising more than 80% from extant species ofDracocephalum s.l., morphological, phylogenetic (maximum parsimony, likelihood, and Bayesian inference based on nuclear ITS and ETS, plastidrpl32‐trnL ,trnL‐trnF ,ycf1 , andycf1‐rps15 , and two low‐copy nuclear markersAT3G09060 andAT1G09680 ), molecular dating, diversification, and ancestral range estimation analyses were carried out. Our results demonstrate that bothHyssopus andLallemantia are embedded withinDracocephalum and nine well‐supported clades can be recognized withinDracocephalum s.l. Analyses of divergence times suggest that the genus experienced an early rapid radiation during the middle to late Miocene with major lineages diversifying within a relatively narrow timescale. Ancestral area reconstruction analyses indicate thatDracocephalum s.l. originated in Central and West Asia and southern Siberia, and dispersed from Central and West Asia into the QTP and adjacent areas twice independently during the Pliocene. The aridification of the Asian interior possibly promoted the rapid radiation ofDracocephalum within this region, and the uplift of the QTP appears to have triggered the dispersal and recent rapid diversification of the genus in the QTP and adjacent regions. Combining molecular phylogenetic and morphological evidence, a revised infrageneric classification ofDracocephalum s.l. is proposed, which recognizes nine sections within the genus. -
more » « less
Abstract Aim 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.
Location Australasia, Indo‐Australian Archipelago, Madagascar, Pacific Islands.
Taxon Pteropus (Pteropodidae).Methods To infer the biogeographic history of
Pteropus , we sequenced up to 6,169 bp of genetic data from 10 markers and reconstructed a multilocus species tree of 34 currently recognizedPteropus species and subspecies with threeAcerodon outgroups usingBEAST and subsequently estimated ancestral areas using models implemented inBioGeoBEARS .Results 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 with
Acerodon ; founder‐event speciation out of Wallacea was a common inference.Pteropus species in Micronesia and the western Indian Ocean were also inferred to result from founder‐event speciation.Main conclusions Dispersal between regions of the IAA and the islands found therein fostered diversification of
Pteropus throughout the IAA and beyond. Dispersal inPteropus is 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.
