Land Bridge Research Articles

A Lankan invasion? An intriguing case of the presence of a Sri Lankan endemic skink on the southwestern Indian Coast

The biota of the Indian subcontinent is a result of Gondwanan vicariance to some extent but largely through multiple faunal exchanges between neighbouring regions. However, in recent times, humans have influenced regional biotas through the human-mediated transport of many generalist species. In this study, we report populations of Lankascincus fallax, a skink species supposedly endemic to Sri Lanka, from the west coast of Kerala in India. We conducted morphological and genetic analysis to ascertain the identity of this species and to check whether the Indian population is monophyletic. We then performed a divergence dating analysis to test whether the presence of this population is a result of ancient dispersal into India or a result of more recent events. Additionally, we used species distribution modelling to test whether the Indian L. fallax is a result of natural dispersal into India during the past (mid-Pliocene to the last glacial maximum) when there were possible land bridges between India and Sri Lanka. We find that the Indian population is nested within the Sri Lankan L. fallax and that this population diverged from the Sri Lankan population very recently, during the Pleistocene. We do not find climatic suitability between the Indian west coast and Sri Lanka under current climatic conditions, or during the past suggesting no suitable dispersal corridors between India and Sri Lanka. Overall, we hypothesize that the Indian populations of L. fallax are likely a result of human-mediated transport into India and subsequent dispersal across the west coast of Kerala.

Multiple glacial refugia during Pleistocene climatic oscillations shape the genetic pattern of Machilus thunbergii across East Asia

Abstract Pleistocene climatic oscillations caused periodic decline and rise of sea levels, leading to dispersion and retraction cycles of island flora. Yet, the role of island refugia in the current Sino-Japanese Floristic Region remains poorly understood. In this study, we investigated the population genetic structure of the widespread Sino-Japanese Floristic Region tree Machilus thunbergii to infer the potential impact of island refugia. We collected 1378 samples from 64 locations across the distribution ranges. Using chloroplast DNA and microsatellite markers, we found a pronounced genetic differentiation between mainland and island populations, which can be divided further into two and three groups, respectively. Furthermore, comparable numbers of private alleles and haplotypes are present in both mainland and island populations. No essential current gene flow was detected between mainland and island populations after their separation 14 000 years ago. Such patterns are hypothesized to result from the influence of multiple glacial island refugia during Pleistocene climatic oscillations, with limited pollen and seed dispersal of the species. Our findings underscore that the islands and submerged land bridge can act as refugia for plants during glacial periods and have essentially shaped the genetic structure of M. thunbergii populations.

The Central Paratethys Sea – Part of the tropical eastern Atlantic rather than gate into the Indian Ocean

The Miocene Paratethys Sea is frequently depicted as junction between the Proto-Mediterranean Sea and the Indian Ocean. Herein, we elucidate the biogeographic character of this large epicontinental Miocene sea based on its speciose gastropod fauna. We debunk the persistent myth that there was a connection between these marine realms during Langhian times via the Tethys Seaway. Throughout most of the Early and Middle Miocene the connectivity of the Central Paratethys was via the Rhône Strait and the Slovenian Strait as supported by up to ~22 % of species shared with the Proto-Mediterranean Sea. The faunistic similarity decreased successively at higher latitudes towards the northeastern Atlantic and dropped to low values towards the North Sea. Therefore, a connection with the North Sea can be excluded throughout the Early and Middle Miocene. Faunistic relations of the Central Paratethys Sea with the Eastern Paratethys Sea were surprisingly low until the late Middle Miocene, when endemic species from the Eastern Paratethys ‘flooded’ the Central Paratethys. Therefore, the effectiveness in species transfer or presence of the Carasu and Barlad straits, hypothetically connecting both seas, must be questioned for most of the Middle Miocene.The present-day gastropod faunas of the tropical eastern Atlantic (TEA) and the Indo-West Pacific Region (IWP) can be distinguished clearly by their differing faunal structure (different relative abundance of certain families). The faunas of the Paratethyan and the Proto-Mediterranean Sea follow more closely the type nowadays represented in the tropical eastern Atlantic, suggesting a common origin. The faunistic connectivity with the Indian Ocean, via the Tethys Seaway ceased very early during the Early Miocene, predating the formation of the Gomphotherium land bridge by several million years. Consequently, we reject a re-activation of the Tethys Seaway during the Langhian as providing an effective oceanographic gateway. This is an important observation for climate models, linking the closure of the Tethys Seaway to Miocene climate change.

A new neoceratopsian (Ornithischia, Ceratopsia) from the Lower Cretaceous Ohyamashimo Formation (Albian), southwestern Japan

AbstractThe herbivorous dinosaur clade Ceratopsia flourished in the northern hemisphere during the Late Jurassic to Late Cretaceous. Previous palaeobiogeographic studies have suggested that their initial diversification occurred in Asia, with early‐branching neoceratopsians extending their geographical range to North America sometime during the Barremian to Albian. However, the specific timing and mode of their dispersal from Asia to North America remains unknown. Here we describe a new, early‐branching neoceratopsian, Sasayamagnomus saegusai gen. et sp. nov., from the Albian Ohyamashimo Formation in southwestern Japan, representing the easternmost fossil record of ceratopsians in Asia. Sasayamagnomus exhibits three diagnostic features in the jugal, squamosal and coracoid, respectively, and also has a unique combination of characters in the lacrimal. Our phylogenetic analysis indicates that Sasayamagnomus forms a clade with Aquilops americanus, one of the earliest neoceratopsians from North America, followed by the sister taxon Auroraceratops rugosus from China. The present time‐calibrated phylogenetic tree indicates that the immigration of neoceratopsians from Asia to North America occurred during the latest Aptian or early Albian, refining the previously suggested timeframe. This aligns with fragmentary neoceratopsian fossil records from the Lower Cretaceous of North America and the initial formation of the Bering land bridge. Furthermore, the simultaneous occurrence of global warming (which enabled the development of extensive forests in the Arctic region) and the emergence of the Bering land bridge during the Aptian–Albian, probably played a crucial role in facilitating the immigration of neoceratopsians from Asia to North America.

A molecular phylogeny of the Petaluridae (Odonata: Anisoptera): A 160-Million-Year-Old story of drift and extinction

Petaluridae (Odonata: Anisoptera) is a relict dragonfly family, having diverged from its sister family in the Jurassic, of eleven species that are notable among odonates (dragonflies and damselflies) for their exclusive use of fen and bog habitats, their burrowing behavior as nymphs, large body size as adults, and extended lifespans. To date, several nodes within this family remain unresolved, limiting the study of the evolution of this peculiar family. Using an anchored hybrid enrichment dataset of over 900 loci we reconstructed the species tree of Petaluridae. To estimate the temporal origin of the genera within this family, we used a set of well-vetted fossils and a relaxed molecular clock model in a divergence time estimation analysis. We estimate that Petaluridae originated in the early Cretaceous and confirm the existence of monophyletic Gondwanan and Laurasian clades within the family. Our relaxed molecular clock analysis estimated that these clades diverged from their MRCA approximately 160 mya. Extant lineages within this family were identified to have persisted from 6 (Uropetala) to 120 million years (Phenes). Our biogeographical analyses focusing on a set of key regions suggest that divergence within Petaluridae is largely correlated with continental drift, the exposure of land bridges, and the development of mountain ranges. Our results support the hypothesis that species within Petaluridae have persisted for tens of millions of years, with little fossil evidence to suggest widespread extinction in the family, despite optimal conditions for the fossilization of nymphs. Petaluridae appear to be a rare example of habitat specialists that have persisted for tens of millions of years.

Out of and in East Asia: Phylogeny, biogeography and diversification of Thalictroideae (Ranunculaceae) in the Northern Hemisphere.

Understanding the biogeographical patterns and processes underlying the distribution of diversity within the Northern Hemisphere has fascinated botanists and biogeographers for over a century. However, as a well-known centre of species diversity in the Northern Hemisphere, whether East Asia acted as a source and/or a sink of plant diversity of the Northern Hemisphere remains unclear. Here, we used Thalictroideae, a subfamily widely distributed in the Northern Hemisphere with the majority of species in East Asia, to investigate the role of East Asia in shaping the biogeographical patterns of the Northern Hemisphere and to test whether East Asia acted as a museum or a cradle for herbaceous taxa. Based on six plastid and one nuclear DNA regions, we generated the most comprehensive phylogeny for Thalictroideae including 217 taxa (ca. 66% species) from all ten of the currently recognized genera. Within this phylogenetic framework, we then estimated divergence times, ancestral ranges, and diversification rates. The monophyletic Thalictroideae contains three major clades. All genera with more than one species are strongly supported as monophyletic except for Isopyrum, which is nested in Enemion. The most recent common ancestor of Thalictroideae occurred in East Asia in the late Eocene (ca. 36 Ma). From the Miocene onwards, at least 46 dispersal events were inferred to be responsible for the current distribution of this subfamily. East Asian Thalictroideae lineages experienced a rapid accumulation at ca. 10 Ma. The biogeographical patterns of Thalictroideae support the "out of and in East Asia" hypothesis, i.e., East Asia is both a source and a sink of biodiversity of the Northern Hemisphere. The global cooling after the middle Miocene Climatic Optimum, combined with the exposed land bridges due to sea-level decline, might have jointly caused the bidirectional plant exchanges between East Asia and other Northern Hemisphere regions. East Asia serves as evolutionary museums and cradles for the diversity of Thalictroideae and likely for other herbaceous lineages.

RAD-seq data for Engelhardia roxburghiana provide insights into the palaeogeography of Hainan Island and its relationship to mainland China since the late Eocene

Hainan Island in southern China is situated within the Indo-Burma biodiversity hotspot, and has attracted the attention of evolutionary biologists, geologists, and biogeographers. However, the palaeogeography of Hainan Island and its relationship with mainland China remains contested. In this paper, we report RAD-seq data for Engelhardia roxburghiana populations from Hainan Island and adjacent mainland areas to identify genetic diversity, structure, divergence time, and demographic dynamics over geologic time. Findings were assessed using climate model data to constrain suitable distribution areas. Results indicate that E. roxburghiana dispersed from the Chinese mainland to Hainan Island via a hypothetical land bridge during the late Eocene so that the drift of Hainan Island was impossible. We cast doubt on the hypothesis that Hainan Island was connected to Vietnam and Guangxi at this time. We emphasize that higher genetic diversity in the Yunnan-Guizhou Plateau and Chiang-nan regions is the result of mixed populations or the existence of refugia, and lower genetic diversity in the Indochina Peninsula is due to a historical bottleneck. From the late Eocene to Oligocene, the arid belt that dominated East Asia retreated, facilitating the expansion of E. roxburghiana from the Indochina Peninsula to southern China. The main diversification of E. roxburghiana occurred in the Miocene following the strengthening precipitation within the East Asian Summer Monsoon. Climatic oscillations during the Quaternary led to the contraction of E. roxburghiana in the Indochina Peninsula, with expansion after Last Glacial Period (LGP; 119 to 11.7 ka). Southern China has served as a refugium and continues to do so in the future. In summary, our study elucidates the evolutionary trajectory of E. roxburghiana through large-scale sampling, providing insights into the palaeogeography of Hainan Island and itsbiogeographic relationships with adjacent mainlands.

Impacts of trade facilitation on greenhouse gas emissions in the Belt and Road Initiative countries

The Belt and Road Initiative (BRI) trade facilitation could generate both economic and environmental impacts. Nevertheless, the resulting impacts on greenhouse gas (GHG) emissions remain unclear. Here we apply a global computable general equilibrium model to simulate the economic changes induced by BRI trade facilitation and thereby assess the GHG emissions burdens within China and the main economic corridors. We show that trade facilitation results in economic improvement at the expense of emissions for most BRI countries. Yet economic growth in these countries has outstripped emissions growth. Especially for countries within the New Eurasian Land Bridge (ELB), most of them even have achieved decoupling of economic growth from emissions under trade facilitation, which is mainly benefited from the decrease of non-CO2 GHG emissions. We stress that non-CO2 GHGs mitigation in more developing regions is essential to achieve an economic-environmental win-win state, in the context of future global trade liberalization.

The Function of Inland Shipping on Economic Supporting Activities of the South Kalimantan Community 1980-2000

The main problem examined in this research is how the function of inland shipping is to support the economic activities of the people of South Kalimantan in 1950-1970 The results of the research show that the river network has become the economic lifeblood of the population where most of their economic activities are carried out through and on rivers due to shipping activities. Rivers cannot be separated from their role as trade routes. River shipping has an important role in transporting trade goods. Agricultural products and forest products are one of the main commodities transported via river shipping. As a means of traffic, rivers play a role in opening up the isolation of inland areas that cannot be passed by land. The method used in this research uses the historical method through the Heuristic stage (data collection), internal and external criticism of the data obtained, interpretation and historiography of historical writing based on the data that has been obtained according to the researcher's objectives. The novelty of this research is that previous research only revealed the phenomenon of river shipping broadly, then this research focuses on the economic sector. It can be concluded that with the times and the rapid development of technology, the transportation sector has developed. The widespread development of land transportation facilities by creating land roads and bridges to connect between regions can shorten distances and travel times. However, it even has an impact on the economic sector through water transportation routes.

Complete phylogeny of Micrathena spiders suggests multiple dispersal events among Neotropical rainforests, islands and landmasses, and indicates that Andean orogeny promotes speciation.

The Neotropical region is the most diverse on the planet, largely owing to its mosaic of tropical rainforests. Multiple tectonic and climatic processes have been hypothesized to contribute to generating this diversity, including Andean orogeny, the closure of the Isthmus of Panama, the GAARlandia land bridge and historical connections among currently isolated forests. Micrathena spiders are diverse and widespread in the region, and thus a complete phylogeny of this genus allows the testing of hypotheses at multiple scales. We estimated a complete, dated phylogeny using morphological data for 117 Micrathena species and molecular data of up to five genes for a subset of 79 species. Employing event-based approaches and biogeographic stochastic mapping while considering phylogenetic uncertainty, we estimated ancestral distributions, the timing and direction of dispersal events and diversification rates among areas. The phylogeny is generally robust, with uncertainty in the position of some of the species lacking sequences. Micrathena started diversifying around 25 Ma. Andean cloud forests show the highest in-situ speciation, while the Amazon is the major dispersal source for adjacent areas. The Dry Diagonal generated few species and is a sink of diversity. Species exchange between Central and South America involved approximately 23 dispersal events and started ~20 Ma, which is consistent with a Miocene age for the Isthmus of Panama closure. We inferred four dispersal events from Central America to the Antilles in the last 20 Myr, indicating the spiders did not reach the islands through the GAARlandia land bridge. We identified important species exchange routes among the Amazon, Andean cloud forests and Atlantic forests during the Plio-Pleistocene. Sampling all species of the genus was fundamental to the conclusions above, especially in identifying the Andean forests as the area that generated the majority of species. This highlights the importance of complete taxonomic sampling in biogeographic studies.

Extended haplotype with rs41524547-G defines the ancestral origin of SCA10.

Spinocerebellar ataxia type 10 (SCA10) is a rare autosomal dominant ataxia caused by a large expansion of the (ATTCT)n repeat in ATXN10. SCA10 was described in Native American and Asian individuals which prompted a search for an expanded haplotype to confirm a common ancestral origin for the expansion event. All patients with SCA10 expansions in our cohort share a single haplotype defined at the 5'-end by the minor allele of rs41524547, located ~35kb upstream of the SCA10 expansion. Intriguingly, rs41524547 is located within the miRNA gene, MIR4762, within its DROSHA cleavage site and just outside the seed sequence for mir4792-5p. The world-wide frequency of rs41524547-G is less than 5% and found almost exclusively in the Americas and East Asia-a geographic distribution that mirrors reported SCA10 cases. We identified rs41524547-G(+) DNA from the 1000 Genomes/International Genome Sample Resource and our own general population samples and identified SCA10 repeat expansions in up to 25% of these samples. The reduced penetrance of these SCA10 expansions may be explained by a young (pre-onset) age at sample collection, a small repeat size, purity of repeat units, or the disruption of miR4762-5p function. We conclude that rs41524547-G is the most robust at-risk SNP allele for SCA10, is useful for screening of SCA10 expansions in population genetics studies and provides the most compelling evidence to date for a single, prehistoric origin of SCA10 expansions sometime prior to or during the migration of individuals across the Bering Land Bridge into the Americas.

From Shaheen-II to China-Pakistan Economic Corridor: Pakistan-China Military and Economic Relations (2013-2023) At A Glance

For decades, Pakistan and China enjoyed cordial diplomatic relations, which have now been transformed into a long-standing strategic and economic partnership. The historic silk trade route, development of the Gwadar port, Chashma nuclear power plant, and manufacturing of JF-17 thunder fighter jets were some of the instances of this partnership from the past. In recent years, the China-Pakistan Economic Corridor (CPEC), formally agreed upon in 2013, represents a joint commitment to cooperation and development by both states. Following China's "Belt and Road Initiative" (BRI), this project aims to utilize the Eurasian land bridge to connect Pakistan with Central Asia. Despite enormous challenges and threats to Pakistan-China relations posed by Pakistan's border issues, the CPEC is now partially functional, and both states are working on expanding it. With a particular emphasis on strategic and economic aspects, the current study analytically explores the nature of the Pakistan-China relationship. The qualitative approach is applied to identify the relationship changes between countries during 2013 and 2023. Primary and secondary data types will be relied on and utilized to explore the study's findings.

Landscape evolution during Holocene transgression of a mid‐latitude low‐relief coastal plain: The southern North Sea

AbstractLow‐relief coastal landscapes are at major risk of rising sea levels, as vertical changes in relative sea level have far‐reaching lateral effects. Integration of a dense 2D grid of seismic reflection data with sedimentological and geotechnical data obtained in two offshore wind farm zones allows detailed documentation of postglacial landforms and environmental change over a 1,021 km2 area in the western sector of the southern North Sea. Following the retreat of Last Glacial Maximum ice sheets from the southern North Sea, the resulting postglacial terrestrial landscape provided a surface for peatland formation as climate started to warm and the water table rose in response to relative sea‐level rise. Southward‐draining fluvial networks formed contemporaneously with the peatlands, and remnants of this terrestrial wetland landscape are buried beneath Holocene marine sediments. Distinctive isolated incisional features and discrete widening of fluvial channels that cut through the peats are interpreted as either tidal ponds or relict tidal channels. These features record the evolution of this landscape through the Early Holocene as marine transgression inundated a low‐relief coastal plain. The erosion of the peatlands observed in the cores, the patchy preservation of the organic wetland landscape, and the lack of preserved barrier systems recorded by the seismic reflection data suggest that the rate of relative sea‐level rise outpaced sediment supply during the Late Postglacial and Early Holocene in this area of the southern North Sea. In a regional context, the southward draining river channels contrast to northward fluvial drainage to the North Sea, pointing to a subtle drainage divide in the palaeolandscape and the presence of a low‐relief land bridge separating the North Sea and the English‐Channel/La Manche during the Early Holocene. The documented scenario of rising sea levels combined with decreasing sediment supply in a low‐relief setting is a situation faced by many global deltas and coastlines, which makes the southern North Sea a crucial archive of coastal landscape change.

Historical biogeography of the Neotropical noctilionoid bats (Chiroptera: Noctilionoidea), revisited through a geographically explicit analysis.

Biogeographic studies have generally relied on methods that use a few, large predefined areas, which may overlook fine-scale patterns. Here we test previous hypotheses about the biogeographic history of a diverse bat clade regarding its association with major Neotropical geological formations, particularly the Antilles, the South American Dry Diagonal, the Andes and the Panamanian land bridge, by applying a recently available method that uses actual distributions instead of predefined areas. We compiled and curated spatially explicit, georeferenced data of 173 bat species (Mammalia: Chiroptera: Noctilionoidea) from the online database Global Biodiversity Information Facility. By taking a previous comprehensive phylogeny as an evolutionary framework, we performed computationally intensive analyses using the Geographically-explicit Event Model. This method uses the observed species distributions to reconstruct the ancestral areas and biogeographic events at each phylogeny node. We found that sympatric speciation was the most frequently reconstructed event, and involved mainly the Panamanian Isthmus and northern South America (SA), but all sympatry reconstructions were different and specific to each node. Allopatric events were important in the Andes; vicariance caused both west/east and north/south disjunctions that went unnoticed previously. Founder events indicated bidirectional dispersal between the mainland and the Antilles since the Miocene, and across the incomplete Panamanian bridge and the SA Dry Diagonal since the early Pliocene. Overall, we found support for previous hypotheses on the influence of major Neotropical paleogeographic events in the diversification of the group, but additionally revealed multi-scale patterns that are embedded within the mainland and were previously overlooked. Our results highlight a trans-isthmian centre of diversification in the biogeographic history of Noctilionoidea including the Panamanian Isthmus and Northern SA.

Miocene vanishing of the Central American Seaway between the Panamá Arc and the South American Plate

A controversy has developed in recent years regarding the timing of the closure of the Central American Seaway. This tectonic event significantly impacted oceanic circulation between the tropical Pacific and Atlantic oceans and resulted in the formation of a land bridge connecting the South and North American continents. The long-held view of a Pliocene age (ca. 3 Ma) for the closure of the Central American Seaway has been challenged by the proposal that the Panamá Arc collided with South America during the Middle Miocene (15−13 Ma) as a deep oceanic gap between them closed along the Uramita suture zone. However, direct geologic evidence from this suture zone to support either interpretation has been lacking. Here, we report on a comprehensive study of three stratigraphic transects across the Uramita suture zone, using a host of methodologies including sedimentological, ichnological, micropaleontological, U-Pb detrital geochronological, and provenance analyses. Our data reveal that lower offshore to slope conditions prevailed in the Central American Seaway along the suture zone during the latest Early to earliest Middle Miocene (16.4−15.1 Ma) and that oceanic conditions there ceased to exist between the Middle and Late Miocene. These results agree with the Middle Miocene age proposed for the Central American Seaway closure along the tectonic boundary. However, other deeper portions of the Central American Seaway persisted in western Colombia, which challenges the notion of a Central American Seaway confined to the suture zone between the Panamá Arc and South American Plate during the Middle Miocene.

The orogenic bridge theory: towards a predictive tool for past and future plate tectonics

Wegener’s Continental Drift Theory has laid the foundations of modern plate tectonics. However, despite decades of work and studies around the globe, modern plate tectonics still does not explain all the datasets acquired up to now and is well overdue for a major update. We propose a new theory, the orogenic bridge theory, which partly builds on the Continental Drift Theory and modern plate tectonics and reconciles them with the idea put forward by a competing theory, the Land Bridge Theory (or Isthmian Links). The orogenic bridge theory states that the style of continental rifting is directly controlled by preexisting orogenic structures. On the one hand, preexisting orogens trending parallel to an opening rift facilitate breakup and rift propagation and control the strike and geometry of rift-related structures. This endmember has already been broadly studied worldwide. On the other hand, orogens oriented orthogonal (or highly oblique) to the opening rift will act as strong barriers forcing the rift to step, therefore delaying or impeding breakup and rift propagation and localizing the formation of major-offset transform faults. In the present contribution, we review the evidence in favor of a correlation between rift-orthogonal orogens and major transforms and discuss some of the main implications of the orogenic bridge theory.

Molecular phylogeny and biogeography of the dwarf boas of the family Tropidophiidae (Serpentes: Alethinophidia)

Although present in the South American continent, dwarf boas (Tropidophiidae) show their greatest extant diversification in the Caribbean region, reaching their highest diversity in Cuba. Despite their remarkable species richness, phylogenetic affinities among species of Tropidophis and Trachyboa are still poorly known. Here, we provide a multi-locus phylogenetic hypothesis of the family that includes 25 of the 37 known continental and insular species, including most of its highly diverse Cuban endemic radiation (16 out of 17 species sampled). We also provide a time-calibrated tree derived from our molecular data. Our phylogenetic results indicate that the genus Tropidophis and its mainland and Cuban radiations are paraphyletic, while the Caribbean radiation forms a well-supported clade. We therefore synonymize Trachyboa with Tropidophis and provide new definitions for the species groups. Our time-calibrated tree suggests that tropidophiids originated along the northwestern Andean region of continental South America, diverging from its known sister-group genus Anilius during the late Cretaceous. The Atlantic Rainforest radiation diverged from the Andean radiation during the late Eocene. A mainland tropidophiid ancestor subsequently dispersed from northern South America to the Caribbean region in the latest Eocene. Dispersal likely took place through a near-continuous terrestrial land bridge that connected South America to the Greater Antilles during the late Eocene to early Oligocene (35–33 Ma). The existence of this land bridge, whether formed by the Aves Ridge (GAARlandia Hypothesis) or by a more southernly positioned landmass connecting the Greater Antilles and the northern Lesser Antilles Ridge (GRANoLA hypothesis), remains a topic of debate, which we address in this paper. After that main dispersal event, West Indian tropidophiids underwent over ten speciation events, rapidly colonizing the Caribbean islands. We also address the vertebral morphology of fossil and extant Tropidophiidae, with our observations challenging the current classification of several fossil taxa within crown-Tropidophiidae.

Phylogeny and biogeography of the wingless orthopteran family Rhaphidophoridae

Cave crickets (Rhaphidophoridae) are insects of an ancient and wingless lineage within Orthoptera that are distributed worldwide except in Antarctica, and each subfamily has a high level of endemicity. Here, we show the comprehensive phylogeny of cave crickets using multi-gene datasets from mitochondrial and nuclear loci, including all extant subfamilies for the first time. We reveal phylogenetic relationships between subfamilies, including the sister relationship between Anoplophilinae and Gammarotettiginae, based on which we suggest new synapomorphies. Through biogeographic analyses based on divergence time estimations and ancestral range reconstruction, we propose novel hypotheses regarding the biogeographic history of cave crickets. We suggest that Gammarotettiginae in California originated from the Asian lineage when Asia and the Americas were connected by the Bering land bridge, and the opening of the western interior seaway affected the division of Ceuthophilinae from Tropidischiinae in North America. We estimate that Rhaphidophoridae originated at 138 Mya throughout Pangea. We further hypothesize that the loss of wings in Rhaphidophoridae could be the result of their adaptation to low temperatures in the Mesozoic era.

Phylogenomics of Tetraopes longhorn beetles unravels their evolutionary history and biogeographic origins

Tetraopes longhorn beetles are known for their resistance to milkweed plant toxins and their coevolutionary dynamics with milkweed plants (Asclepias). This association is considered a textbook example of coevolution, in which each species of Tetraopes is specialized to feed on one or a few species of Asclepias. A major challenge to investigating coevolutionary hypotheses and conducting molecular ecology studies lies in the limited understanding of the evolutionary history and biogeographical patterns of Tetraopes. By integrating genomic, morphological, paleontological, and geographical data, we present a robust phylogeny of Tetraopes and their relatives, using three inference methods with varying subsets of data, encompassing 2–12 thousand UCE loci. We elucidate the diversification patterns of Tetraopes species across major biogeographical regions and their colonization of the American continent. Our findings suggest that the genus originated in Central America approximately 21 million years ago during the Miocene and diversified from the Mid-Miocene to the Pleistocene. These events coincided with intense geological activity in Central America. Additionally, independent colonization events in North America occurred from the Late Miocene to the early Pleistocene, potentially contributing to the early diversification of the group. Our data suggest that a common ancestor of Tetraopini migrated into North America, likely facilitated by North Atlantic land bridges, while closely related tribes diverged in Asia and Europe during the Paleocene. Establishing a robust and densely sampled phylogeny of Tetraopes beetles provides a foundation for investigating micro- and macroevolutionary phenomena, including clinal variation, coevolution, and detoxification mechanisms in this ecologically important group.

New insights into the molecular phylogeny, biogeographical history, and diversification of Amblyomma ticks (Acari: Ixodidae) based on mitogenomes and nuclear sequences.

Amblyomma is the third most diversified genus of Ixodidae that is distributed across the Indomalayan, Afrotropical, Australasian (IAA), Nearctic and Neotropical biogeographic ecoregions, reaching in the Neotropic its highest diversity. There have been hints in previously published phylogenetic trees from mitochondrial genome, nuclear rRNA, from combinations of both and morphology that the Australasian Amblyomma or the Australasian Amblyomma plus the Amblyomma species from the southern cone of South America, might be sister-group to the Amblyomma of the rest of the world. However, a stable phylogenetic framework of Amblyomma for a better understanding of the biogeographic patterns underpinning its diversification is lacking. We used genomic techniques to sequence complete and nearly complete mitochondrial genomes -ca. 15 kbp- as well as the nuclear ribosomal cluster -ca. 8 kbp- for 17 Amblyomma ticks in order to study the phylogeny and biogeographic pattern of the genus Amblyomma, with particular emphasis on the Neotropical region. The new genomic information generated here together with genomic information available on 43 ticks (22 other Amblyomma species and 21 other hard ticks-as outgroup-) were used to perform probabilistic methods of phylogenetic and biogeographic inferences and time-tree estimation using biogeographic dates. In the present paper, we present the strongest evidence yet that Australasian Amblyomma may indeed be the sister-group to the Amblyomma of the rest of the world (species that occur mainly in the Neotropical and Afrotropical zoogeographic regions). Our results showed that all Amblyomma subgenera (Cernyomma, Anastosiella, Xiphiastor, Adenopleura, Aponomma and Dermiomma) are not monophyletic, except for Walkeriana and Amblyomma. Likewise, our best biogeographic scenario supports the origin of Amblyomma and its posterior diversification in the southern hemisphere at 47.8 and 36.8 Mya, respectively. This diversification could be associated with the end of the connection of Australasia and Neotropical ecoregions by the Antarctic land bridge. Also, the biogeographic analyses let us see the colonization patterns of some neotropical Amblyomma species to the Nearctic. We found strong evidence that the main theater of diversification of Amblyomma was the southern hemisphere, potentially driven by the Antarctic Bridge's intermittent connection in the late Eocene. In addition, the subgeneric classification of Amblyomma lacks evolutionary support. Future studies using denser taxonomic sampling may lead to new findings on the phylogenetic relationships and biogeographic history of Amblyomma genus.