As a continental island, much of the biota of New Zealand was initially thought to have been shaped by vicariance. Recent studies, however, have highlighted the role of dispersal, with some even suggesting that the entire biota is the product of dispersal events following emergence of the islands. This study focuses on the interplay between dispersal and vicariance, specifically asking whether the spider family Orsolobidae has Gondwanan origins on New Zealand.
The spider family Orsolobidae was sampled from all continents where they occur (Africa, Australia, New Zealand and South America), comprising a total of 66 specimens representing the phylogenetic diversity of the family.
The orsolobid fauna of each land mass except Australia forms a monophyletic group in our analyses. The divergence dating analysis suggests that diversification of Orsolobidae started at a minimum of 80 Ma, while the New Zealand clade dates from a minimum of 40 Ma.
Thus, while many taxa have colonized the islands by dispersal, certain lineages, including the Orsolobidae, have clearly been capable of persisting through times of reduced land area.
Cosmopolitan distributions have classically been explained by Pangaean vicariance. However, evidence of recently diverged cosmopolitan groups has re‐opened consideration on the processes involved. Our aim is to estimate the processes leading to the worldwide distribution of the kleptoparasitoid genus
Worldwide.
Data from three molecular markers for 52 specimens of
The origin of crown‐group
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.
Continental landmasses of former temperate Gondwana (Chile, South Africa, Sri Lanka, Australia and New Zealand).
Pettalidae, Opiliones.
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
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.
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
The Lesser Sunda Islands are situated between the Sunda and Sahul Shelves, with a linear arrangement that has functioned as a two‐way filter for taxa dispersing between the Asian and Australo‐Papuan biogeographical realms. Distributional patterns of many terrestrial vertebrates suggest a stepping‐stone model of island colonization. Here we investigate the timing and sequence of island colonization in Asian‐origin fanged frogs from the volcanic Sunda Arc islands with the goal of testing the stepping‐stone model of island colonization.
The Indonesian islands of Java, Lombok, Sumbawa, Flores and Lembata.
Mitochondrial
The mt
These results suggest that the currently accepted stepping‐stone model of island colonization might not best explain the current patterns of diversity in the archipelago. The high degree of genetic structure, large divergence times, and absent or low levels of migration between lineages suggests that
Solanaceae is a scientifically and economically important angiosperm family with a minimal fossil record and an intriguing early evolutionary history. Here, we report a newly discovered fossil lantern fruit with a suite of features characteristic of Physalideae within Solanaceae. The fossil comes from the early Eocene Laguna del Hunco site (ca. 52 Ma) in Chubut, Argentina, which previously yielded the only other physaloid fruit fossil,
The fruit morphology and calyx venation pattern of the new fossil were compared with
Both species of fossil nightshades from Laguna del Hunco represent crown‐group Solanaceae but are older than all prior age estimates of the family. Although at least 20 transoceanic dispersals have been proposed as the driver of range expansion of Solanaceae, the Patagonian fossils push back the diversification of the family to Gondwanan times. Thus, overland dispersal across Gondwana is now a likely scenario for at least some biogeographic patterns, in light of the ancient trans‐Antarctic land connections between South America and Australia.
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.
