The water scavenger beetle subfamily Acidocerinae is a cosmopolitan, ecologically diverse lineage with more than 500 described species whose morphology and classification are poorly understood. We present the first phylogenetic analyses of the subfamily inferred from five loci (18S, 28S, H3, CAD, COI). We used secondary calibrations to estimate divergence times and employ this phylogeny to revise the classification and examine the historical biogeography of this lineage. Most genera are resolved as reciprocally monophyletic, with several exceptions:
A late Mesoproterozoic detrital zircon (DZ) age population, which was previously considered diagnostic of a link between the Lhasa terrane and northwest Australia, occurs in other Gondwanan components, thus obscuring the paleogeographic position of the Lhasa terrane in Gondwana. Here we compiled large‐
- NSF-PAR ID:
- 10379400
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 49
- Issue:
- 21
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract Horelophopsis syn. n. is recovered as a derived lineage of and placed in synonymy withAgraphydrus . The large genusHelochares , as well as its primary constituent subgeneraHelochares (s. str.) andHydrobaticus are found to be polyphyletic.Batochares stat. n. andSindolus stat. rev. are elevated from subgenera ofHelochares to generic rank.Crephelochares stat. rev. is removed from synonymy withChasmogenus . We found that the crown Acidocerinae date to the mid‐Jurassic in South America + Africa (West Gondwana). South America and Africa remain important areas of endemism throughout the evolution of the lineage and are resolved either individually or in combination as the ancestral area for all but one clade that is older than 90 million years ago. Six of the seven lineages occurring in South America diverged more than 100 million years ago and are endemic to the region, suggesting the Neotropical acidocerine fauna became isolated following the breakup of West Gondwana. Conversely, lineages found on other Gondwanan fragments (India, Madagascar, Australia) are comparatively young and derived, with all being Cenozoic in age. The few taxa that occur in North America today are all the result of recent Cenozoic dispersal from South America, although North America may have played an important role as an ancestral area in the Mesozoic. -
The Bengal Fan is the world’s largest submarine fan deposit by area, and fan sediments preserve a faithful record of Tibetan-Himalayan orogenesis since Early Miocene time. This study uses detrital zircon (U-Th)/He (ZHe) thermochronology, U-Pb and ZHe double-dating, and sediment mixing models to characterize shifts in provenance and erosional history of the Himalaya and Tibet recorded by Bengal Fan sediments from Late Miocene to Late Pleistocene time, with emphasis on the Pliocene-Pleistocene interglacial transition. Zircon grains are collected from sediment cores acquired during IODP Expedition 354 (2015). A total of 157 single zircon grains from 25 samples of sandy and silty turbidites will be analyzed for single ZHe analyses (an average of 8 grains per sample), and ~50 zircon grains will be chosen for double-dating with U-Pb geochronology. In turn, all ZHe results will be compared with large-n (n=300-600) U-Pb age distributions from the same samples. Sediment mixing models will determine potential source regions for individual samples by “unmixing” crystallization and cooling age populations present in each sample. Preliminary results (n=84) show shifts in the range of cooling ages from ~5.9-45 Ma in the Late Miocene, with a single grain at ~233 Ma, to ~2.5-410 Ma in the Late Pliocene, and finally ~0.5-20 Ma in the Early-Middle Pleistocene, with a single grain at ~492 Ma. These results indicate shifts in source contributions from central-East Himalaya in the Late Miocene, to a Lesser and Tethyan Himalaya source in the Late Pliocene, to a predominantly Eastern Tibet and Lhasa terrane source in the Late Pleistocene in tandem with a broad increase in exhumation rates. We attribute these variations in cooling age ranges to change in sediment source terrains for the Ganges and Brahmaputra River system. Ongoing work seeks to further refine sediment mixing models for the Ganges-Brahmaputra-Bengal Fan system in tandem with large-n U-Pb geochronologic efforts.more » « less
-
more » « less
Abstract The tectonic assembly of the Northern Cordillera is currently disputed and directly impacts Paleozoic‐to‐recent paleogeographic and plate tectonic reconstructions of North America. In this study, we present new U‐Pb zircon geochronology from the allochthonous Yukon‐Tanana terrane and the parautochthonous Cassiar terrane of the Northern Cordillera from south‐central Yukon, Canada. Our data provide new constraints for the assembly of the Northern Cordillera in this region. Metasedimentary samples from the Ingenika Group (Cassiar terrane) and the Snowcap and Finlayson assemblages (Yukon‐Tanana terrane) yielded detrital zircon age spectra that are comparable to known northwest Laurentia age spectra. One of our samples from the Snowcap assemblage yields a detrital zircon age spectrum that is anomalous for northwest Laurentia, but comparable to Early Paleozoic strata deposited in the Nevada‐Idaho‐Utah region. Zircon rim growth and Pb‐loss recorded by detrital zircon in the Snowcap assemblage and Ingenika Group samples record metamorphism at 370 ± 4 Ma and between 171 ± 5 and 135 ± 3 Ma. Late Devonian metamorphism and magmatism possibly corresponds to rifting of the Snowcap assemblage from the Laurentian margin. Middle Jurassic‐Early Cretaceous metamorphic zircon rim ages from the Cassiar terrane record metamorphism during collisions between the Intermontane superterrane (including the Yukon‐Tanana terrane) and Laurentia (Early to Middle Jurassic), and between the Insular superterrane and Laurentia (Middle to Late Jurassic). Our study suggests that collision between the Yukon‐Tanana terrane and the Laurentian margin began no earlier than ∼205 Ma.
-
more » « less
Abstract Aim We explored the extent to which Gondwanan vicariance contributed to the circum‐Antarctic distribution of the mite harvestman family Pettalidae, a group of small, dispersal‐limited arachnids whose phylogeny has been poorly resolved, precluding rigorous biogeographic hypothesis testing.
Location Continental landmasses of former temperate Gondwana (Chile, South Africa, Sri Lanka, Australia and New Zealand).
Taxon Pettalidae, Opiliones.
Methods We generated transcriptomes for a phylogeny of 16 pettalids, spanning 9 genera. Data were analysed using maximum likelihood, Bayesian inference and coalescence methods. The phylogenetic position of the Sri Lankan genus
Pettalus was further explored using quartet likelihood mapping and changes in gene likelihood scores. We also estimated divergence times and looked for signatures of extinction across Antarctica and central Australia using previously published phylogenies with near‐complete species sampling constrained to match our transcriptomic results. Finally, we estimated ancestral ranges and inferred instances of vicariance.Results We recovered a well‐supported topology with a division between taxa from landmasses that made up East Gondwana, and a grade of taxa from West Gondwana.
Pettalus was resolved either as the sister group of the Queensland‐endemicAustropurcellia , or as the sister group to a larger clade from East Gondwana, though favouringPettalus +Austropurcellia . Divergence times for multiple vicariance events coincided with Gondwana's breakup. Speciation–extinction analysis found one diversification process for the family: an initial burst of cladogenesis that slowed down through time.Main Conclusions Given that the order of cladogenesis corresponds to the order in which Gondwana fragmented, and the concurrent timing of vicariance and rifting, Gondwanan breakup explains major biogeographic patterns in Pettalidae. Some divergences predate initial rifting, but there is no evidence of
trans ‐oceanic dispersal. The Sri Lanka–eastern Australia relationship makes sense in the light of large‐scale extinction across Antarctica and central Australia; however, we find no clear signatures of mass extinction. -
more » « less
Abstract Detrital zircon (DZ) U‐Pb geochronology is a widely used provenance tool that leverages bedrock age signatures of hinterland source terranes. However, complex sediment recycling of multicycle zircon and hinterland provinces with nondiagnostic U‐Pb ages represent possible pitfalls for provenance reconstructions. Additional biases pertain to source rock zircon fertilities and insensitivity to low‐ and medium‐grade tectonothermal events that do not result in zircon generation. To bridge these inherent biases and gaps in DZ U‐Pb provenance data sets and derive more comprehensive tectonic reconstruction, this study combined U‐Pb and trace element analyses on DZ, apatite, and rutile as well as zircon (U‐Th)/He analyses from the Proto‐Zagros foreland basin in western Iran to shed light on Late Cretaceous tectonic accretion along Arabia. Integrated multimineral, multimethod data sets record formation of a 110‐ to 85‐Ma island arc within Triassic mid‐oceanic ridge crust of the Neotethys ocean, simultaneous obduction starting in Santonian‐Early Campanian times, and inversion of the Arabian rift margin. Overall, integration of these techniques constrains provenance based on multiple independent criteria including crystallization age, cooling history, and petrogenic‐geodynamic environment. This approach not only more completely described provenance signatures but also helped avoid significant pitfalls. For example, while Triassic DZ U‐Pb ages might be mistaken as input from Eurasia, zircon trace element analysis reveals a MORB signature and attributes these DZ to Neotethyan oceanic rather than Eurasian continental origin, having fundamentally different paleogeographic/tectonic implications for the Arabia‐Eurasia collision. Moreover, detrital rutile and apatite resolve and characterize multiple Paleozoic‐Mesozoic thermotectonic events not recorded by DZ U‐Pb due to their largely amagmatic nature.
