Independent Transitions Research Articles

Retention, mobility, and successful transition to independence of health sciences postdocs.

Obtaining a tenure track faculty position (TTFP) after postdoctoral appointment (PDA) completion is considered an indicator of successful transition to independence (TTI). Whether cross-institutional mobility (CIM)-moving to a different institution from that of the PDA-contributes to TTI is unclear, as data evaluating retention and mobility is lacking. We tested the hypothesis that, for postdocs (PDs) at R1 institutions, CIM is a significant predictor of successful TTI defined as TTFP-status 3 years post-PDA. Using University of Pittsburgh data for health sciences PDs we tested the association of CIM at PDA completion (moved to a different institution (CIM = 1) or retained at Pitt (CIM = 0)) with TTFP-status 3 years post-PDA (TTFP, non-TTFP, or left faculty position) using multinomial logistic regression models. Among all 622 Pitt PDs, 3-year retention in a faculty position at Pitt was 21%, while 14% had a faculty position outside of Pitt. Among the analytic sample of PDs with an academic career outcome during the study period (N = 238; 50% women, 8% underrepresented minorities (URM)), at baseline PDA completion 39% moved to a different institution (CIM = 1), and 61% remained at Pitt (CIM = 0) in any job type. Those with CIM = 1 had greater odds of having a TTFP at follow-up than those with CIM = 0 [adjusted OR (95% CI): 4.4 (2.1, 9.2)]. One fifth of Pitt PDs were retained by Pitt as faculty. While Pitt PDs were equally likely to get a faculty position whether they were retained at Pitt or left, those who left had greater odds of obtaining a TTFP. Future work with longer follow-up times, expanded markers of TTI, and samples from other R1 institutions is needed to better understand the reason for these results. This knowledge can lead to better support for the next generation of PDs as they successfully transition to faculty.

Chemical, structural and electronic properties of ultrathin V2O3 films on Al2O3 substrate: Implications in Mott-like transitions

V2O3 presents a complex interrelationship between the metal–insulator transition and the structural rhombohedral-monoclinic one in temperature, as a function of sample thickness. Whilst in bulk V2O3 the two transitions coincide on the temperature scale, at 15 nm thickness a fully independent Mott-like transition occurs at lower temperature, with no corresponding structural changes perhaps related to epitaxial strain. It is therefore of relevance to investigate the thin and ultrathin film growth to pinpoint the chemical, electronic and structural phase phenomenology and the role of the interface with the substrate. Here we present results on the thickness dependent properties of V2O3 from 1 nm up to 40 nm thick as grown on c-plane Al2O3 substrates by exploiting variable sampling depth probes. The surface morphology of stoichiometric ultra-thin V2O3 layers evolves from islands-like to continuous flat film with thickness, with implications on the overall properties.

How broad is the selfing syndrome? Insights from convergent evolution of gene expression across species and tissues in the Capsella genus.

The shift from outcrossing to selfing is one of the main evolutionary transitions in plants. It is accompanied by profound effects on reproductive traits, the so-called selfing syndrome. Because the transition to selfing also implies deep genomic and ecological changes, one also expects to observe a genomic selfing syndrome. We took advantage of the three independent transitions from outcrossing to selfing in the Capsella genus to characterize the overall impact of mating system change on RNA expression, in flowers but also in leaves and roots. We quantified the extent of both selfing and genomic syndromes, and tested whether changes in expression corresponded to adaptation to selfing or to relaxed selection on traits that were constrained in outcrossers. Mating system change affected gene expression in all three tissues but more so in flowers than in roots and leaves. Gene expression in selfing species tended to converge in flowers but diverged in the two other tissues. Hence, convergent adaptation to selfing dominates in flowers, whereas genetic drift plays a more important role in leaves and roots. The effect of mating system transition is not limited to reproductive tissues and corresponds to both adaptation to selfing and relaxed selection on previously constrained traits.

Evolutionary convergence on hummingbird pollination in Neotropical Costus provides insight into the causes of pollinator shifts.

The evolution of hummingbird pollination is common across angiosperms throughout the Americas, presenting an opportunity to examine convergence in both traits and environments to better understand how complex phenotypes arise. Here we examine independent shifts from bee to hummingbird pollination in the Neotropical spiral gingers (Costus) and address common explanations for the prevalence of transitions from bee to hummingbird pollination. We use floral traits of species with observed pollinators to predict pollinators of unobserved species and reconstruct ancestral pollination states on a well-resolved phylogeny. We examine whether independent transitions evolve towards the same phenotypic optimum and whether shifts to hummingbird pollination correlate with elevation or climate. Traits predicting hummingbird pollination include small flower size, brightly colored floral bracts and the absence of nectar guides. We find many shifts to hummingbird pollination and no reversals, a single shared phenotypic optimum across hummingbird flowers, and no association between pollination and elevation or climate. Evolutionary shifts to hummingbird pollination in Costus are highly convergent and directional, involve a surprising set of traits when compared with other plants with analogous transitions and refute the generality of several common explanations for the prevalence of transitions from bee to hummingbird pollination.

Complex developmental and transcriptional dynamics underlie pollinator-driven evolutionary transitions in nectar spur morphology in Aquilegia (columbine).

Determining the developmental programs underlying morphological variation is key to elucidating the evolutionary processes that generated the stunning biodiversity of the angiosperms. Here, we characterized the developmental and transcriptional dynamics of the elaborate petal nectar spur of Aquilegia (columbine) in species with contrasting pollination syndromes and spur morphologies. We collected petal epidermal cell number and length data across four Aquilegia species, two with short, curved nectar spurs of the bee-pollination syndrome and two with long, straight spurs of the hummingbird-pollination syndrome. We also performed RNA-seq on A. brevistyla (bee) and A. canadensis (hummingbird) distal and proximal spur compartments at multiple developmental stages. Finally, we intersected these data sets with a previous QTL mapping study on spur length and shape to identify new candidate loci. The differential growth between the proximal and distal surfaces of curved spurs is primarily driven by differential cell division. However, independent transitions to straight spurs in the hummingbird syndrome have evolved by increasing differential cell elongation between spur surfaces. The RNA-seq data reveal these tissues to be transcriptionally distinct and point to auxin signaling as being involved with the differential cell elongation responsible for the evolution of straight spurs. We identify several promising candidate genes for future study. Our study, taken together with previous work in Aquilegia, reveals the complexity of the developmental mechanisms underlying trait variation in this system. The framework we established here will lead to exciting future work examining candidate genes and processes involved in the rapid radiation of the genus.

Becoming urban: How city life shapes the social structure and genetics of ants.

Cities and urban environments can do peculiar things to biodiversity that shares them with us. How cities affect their invited and uninvited inhabitants has become an increasingly important question. More than half of the world's population dwells in urban areas, and these environments will keep expanding considerably. Understanding how this relatively recent, rapid, and pervasive form of landscape modification influences the ecology and evolution of organisms that cannot escape, or may benefit from it, is an emerging field of biology. Although we are aware of how some birds, mammals or plants respond to urban environments, less is known about insects and invertebrates in general. In this issue of Molecular Ecology, Blumenfeld et al. (2022) bring new remarkable insights into how a common ant species adjusts to urban settings across the United States by changing its social structure and behaviour. Using a large‐scale molecular, chemical and behavioural dataset, they document how the odorous house ant Tapinoma sessile differs in its colony organisation and dispersal strategy between rural and urban habitats. In each of the study regions and continent‐wide, rural and urban colonies are genetically and chemically differentiated, suggesting that urban settings act as potent agents of selection and isolation. The novelty and importance of this study are that it documents multiple independent transitions toward the same social organisation and the apparent effect of habitat on the life history of a eusocial insect species.

Molecular Phylogenetics Reveals Multiple Transitions to Self-Compatibility in a Primary Subclade of Oenothera (Onagraceae)

Evolutionary shifts in breeding system are thought to have played key roles in the diversification of many lineages of plants, including the evening primrose family (Onagraceae), which includes the genus Oenothera L. Diversification in Oenothera has been accompanied by frequent breeding system shifts, but it is not clear whether these differences are due to shared evolutionary history or reflect repeated independent adaptations to varying ecological conditions. In this study, we focus on “Subclade B,” one of two primary clades within Oenothera, and combine phylogenetic reconstructions and breeding system data to evaluate evidence for multiple transitions to self-compatibility. This study includes 46 of the 58 named taxa (species and subspecies) of Oenothera Subclade B. Some taxa were sequenced in earlier analyses, available from GenBank, one was resampled here to add new sequences, and 28 taxa are newly sequenced here. We base our phylogeny on sequencing of portions of four chloroplast markers (rps16, ndhF, trnL-F, and rbcL) and two nuclear genes (ITS and ETS). We used pollination tests to verify or determine the breeding system of these taxa.
 Our phylogeny supports the current classification of Oenothera with minor changes and provides greater insight and clarity to the relationships of these species. Our results provide support for the monophyly of most of the sections in Oenothera Subclade B, as well as greater resolution for topology within sections Gaura (L.) W. L. Wagner & Hoch, Hartmannia (Spach) Walpers, Kneiffia (Spach) Walpers, and Megapterium (Spach) Walpers. Relationships among these monophyletic lineages, and the placement of sections Paradoxus W. L. Wagner and Peniophyllum (Pennell) Munz, and of the allopolypoid O. hispida (Benth.) W. L. Wagner, Hoch & Zarucchi, are not uniformly well-supported and need further clarification, but these phylogenetic uncertainties had minimal impact on the inference of transitions in self-compatibility in Subclade B.
 We use maximum likelihood, Bayesian inference and stochastic character mapping to estimate the minimum and maximum number of transitions necessary to explain the phylogenetic distribution of self-compatible lineages. Our results confirm at least 12 and possibly up to 15 independent transitions from self-incompatibility to self-compatibility in Oenothera Subclade B. This lability in breeding system, which is also seen broadly across Oenothera, lends strong support to the hypothesis that this trait plays a key role in the diversification of the genus.

Maritime midge radiations in the Pacific Ocean (Diptera: Chironomidae)

AbstractMaritime chironomid midges (Diptera) are diverse, yet these ‘pearls of the ocean’ are little known. Emphasizing Pacific Ocean taxa, we used six genetic markers (18S, 28S, CAD1, CAD4, FolCOI and COI) and fossil calibrations to produce Bayesian time‐calibrated phylogenies to date eight independent marine transitions in three subfamilies. Deep nodes involve subfamily Telmatogetoninae (originating mid‐Cretaceous, 101–128, 114 Ma), with sister genera Telmatogeton Schiner and Thalassomya Schiner splitting later in the Cretaceous (56–82, 69 Ma). Two transitions in Orthocladiinae involve Clunio Haliday and Pseudosmittia Edwards, dating from the upper Cretaceous, both with Eocene crown groups. In subfamily Chironominae, transitions to marine occur in two tribes. Four transitions occur within the otherwise nonmarine crown groups Kiefferulus Goetghebuer, Dicrotendipes Kieffer, Polypedilum Kieffer and Ainuyusurika Sasa & Shirasaka. Two separate robust clades in tribe Tanytarsini involve: (1) a minor radiation within Paratanytarsus dated to the mid‐Eocene around 43 Ma; and (2) an unexpected but fully supported diversification in Pontomyia Edwards plus Yaetanytarsus Sasa dated to around 47 Ma, with separation of Pontomyia from Yaetanytarsus around 40 Ma. Crown Pontomyia, represented by three species, was estimated to have diverged around 19 Ma, whereas the crown radiation of Yaetanytarsus, with 12 sampled species, dates to the mid‐Eocene. In a comprehensive global review we concisely document new synonymies and new combinations revealed by the study. The evolutionary timing estimate provides insights into the frequency of marine transitions and diversifications in the Chironomidae in association with dynamic oceanic changes during the Oligocene and Miocene.

Improvement and comparison the performance of fuzzing testing algorithms for applications in Google Thread Sanitizer

It is difficult to imagine modern information systems without the use of multithreading. The use of multithreading can both improve the performance of the system as in whole so as slow down the execution of multithreaded applications due to the occurrence of multithreaded programming errors. To find such errors in C/C++ languages, there exists a Google Thread Sanitizer compiler module. The order of execution of threads can change every time the program is started for execution and can affect the appearance of such errors. To repeatedly change the order of execution of threads during the execution of the program, Google Thread Sanitizer has a fuzzing testing module that allows you to increase the probability of finding errors. But all the thread scheduling algorithms in this module are presented in the form of sequential execution of threads which can lead to a significant slowdown in Google Thread Sanitizer as well as can affect the testing of applications that depends on timers (waiting for network events, deadline for operations, ...). To speed up the work of fuzzing schedulers, a method for parallelizing independent transitions is proposed. From the point of view of multithreaded programming errors, it is only important to change the shared state between threads, and local calculations do not affect the reproduction of multithreaded errors. The changes of shared states themselves occur at synchronization points (places in the code where threads are switched according to the principle of cooperative multitasking). The method suggests ordering only the change of shared states at synchronization points, and performing local calculations in parallel, due to which parallelization is achieved. For the analysis of theoretical complexity of the algorithm, the method of combinatorial counting is used. A new approach to the organization of fuzzing testing based on the method of parallelization of independent transitions is proposed the implementation of which, according to theoretical and practical estimates, shows a noticeable acceleration of the work of fuzzing schedulers. According to the results of the experiment, it was revealed that for the algorithm of iterating through all execution variants, the acceleration of execution reaches 1.25 times for two threads. For an arbitrary number of threads, an estimate is presented in the form of a formula. The proposed approach allows fuzzing tests to cover multithreaded applications for which execution time is important — applications with reference to timers which improve the quality of the software.

Evidence for additional third-order transitions in the two-dimensional Ising model.

We employ the microcanonical inflection-point analysis method, developed for the systematic identification and classification of phase transitions in systems of any size, to study the two-dimensional Ising model at various lattice sizes and in the thermodynamic limit. Exact results for the density of states, which were obtained by exact algorithmic computation, provide evidence for higher-order transitions in addition to the well-studied second-order ferromagnetic-paramagnetic phase transition. An independent third-order phase transition is identified in the ferromagnetic phase, whereas another third-order transition resides in the paramagnetic phase. The latter is a dependent transition, i.e., it is inevitably associated with the critical transition, but it remains separate from the critical point in the thermodynamic limit. For a deeper insight into the nature of these additional transitions, a detailed analysis of spin clusters is performed.

Comparative wood anatomy and origin of woodiness in subfamilies Secamonoideae and Asclepiadoideae (Apocynaceae)

AbstractThe Apocynaceae subfamilies Secamonoideae and Asclepiadoideae have undergone several transitions during their evolution with regard to growth form and degree of woodiness. In this study, we present a wood anatomical overview of both subfamilies that complements previous work on the remaining Apocynaceae. Detailed microscopic wood descriptions using light and scanning electron microscopy were performed on 60 species that cover most Secamonoideae genera and all major woody Asclepiadoideae lineages. Our observations are in line with subfamilial and (sometimes sub)tribal delimitations. Furthermore, we present for the first time an overview of the estimated number of shifts from herbaceousness to (phylogenetically) derived woodiness in Asclepiadoideae, along with a derived woody species list with distribution and habitat information. In total, at least 168 derived woody species resulting from at least 28 independent woodiness transitions were found, with drought possibly being one of the main drivers of most of these transitions.

Anomalous Ferromagnetic Behavior in Orthorhombic Li3Co2SbO6.

Monoclinic Li3Co2SbO6 has been proposed as a Kitaev spin liquid candidate and investigated intensively, whereas the properties of its polymorph, the orthorhombic phase, are less known. Here we report the magnetic properties of orthorhombic Li3Co2SbO6 as revealed by dc and ac magnetic susceptibility, muon spin relaxation (μSR), and neutron diffraction measurements. Successive magnetic transitions at 115, 89, and 71 K were observed in the low-field dc susceptibility measurements. The transitions below TN (115 K) are suppressed at higher applied fields. However, zero-field ac susceptibility measurements reveal distinct frequency-independent transitions at about 114, 107, 97, 79, and 71 K. A long-range magnetic ordered state was confirmed by specific heat, μSR, and neutron diffraction measurements, all indicating a single transition at about 115 K. The discrepancy between different measurements is attributed to possible stacking faults and/or local disorders of the ferromagnetic zigzag chains, resulting in ferromagnetic boundaries within the overall antiferromagnetic matrix.

Recent speciation and phenotypic plasticity within a parthenogenetic lineage of levantine whip spiders (Chelicerata: Amblypygi: Charinidae)

Caves constitute ideal study systems for investigating adaptation and speciation, as the abiotic conditions shared by aphotic habitats exert a set of environmental filters on their communities. Arachnids constitute an important component of many cave ecosystems worldwide. We investigated the population genomics of two whip spider species: Sarax ioanniticus, a widely distributed parthenogenetic species found across the eastern Mediterranean; and S. israelensis, a recently described troglomorphic species that is endemic to caves in Israel. Here, we show that S. israelensis is completely genetically distinct from S. ioanniticus and most likely also a parthenogen. Counterintuitively, despite the lack of genetic variability within S. ioanniticus and S. israelensis, we discovered considerable variation in the degree of median eye reduction, particularly in the latter species. Natural history data from captive-bred specimens of S. israelensis validated the interpretation of parthenogenesis. Our results are most consistent with a scenario of a sexual ancestral species that underwent speciation, followed by independent transitions to apomictic parthenogenesis in each of the two daughter species. Moreover, the lack of genetic variability suggests that variation in eye morphology in S. israelensis is driven exclusively by epigenetic mechanisms.

Estimation of Atlantic Water transit times in East Greenland fjords using a 233U-236U tracer approach

Water mass composition and transit times of outflowing waters from the Arctic Ocean can reflect changes of polar climate and ocean circulation upstream. In this study we apply a novel approach using anthropogenic uranium tracers (233U and 236U), combined with salinity, and nutrients (nitrate and phosphate) to estimate transit times of waters from the Atlantic passing through the Arctic and into East Greenland fjords. In Polar Surface Water (PSW, typically found in surface ~150 m of the fjords) the dominant source of 236U is European reprocessing plants (63%) while in Arctic Atlantic Water (AAW, typically directly below PSW in these fjords) it is much less (26%) and the 236U signal is dominated by the global fallout contribution. Here we isolate the 236U signal from reprocessing plants using 236U/233U ratios and use the temporal development in 236U discharges to estimate transit times for Atlantic Water entering the Arctic Ocean and exiting as either PSW or AAW on the Greenland Shelf. PSW, which flows into the fjords from the shelf, has a transit time of between 6 and 14 years from the Arctic entrance (Barents Sea Opening, 74°N, 19°E). The transit time of AAW, which is entrained into upwelling subglacial discharge in the inner parts of the fjords, is in the order of 24–25 years since entrance in the Barents Sea. The findings indicate the potential of this novel 233U-236U approach to trace Atlantic Water circulation in the Arctic Ocean. The method offers independent transit time estimates to compare with circulation models and indicates the potential time lag between documented recent change in properties of water leaving the Arctic Ocean and the upstream processes contributing to these changes.

Patterns of Phenotypic Evolution Associated with Marine/Freshwater Transitions in Fishes.

Evolutionary transitions between marine and freshwater ecosystems have occurred repeatedly throughout the phylogenetic history of fishes. The theory of ecological opportunity predicts that lineages that colonize species-poor regions will have greater potential for phenotypic diversification than lineages invading species-rich regions. Thus, transitions between marine and freshwaters may promote phenotypic diversification in trans-marine/freshwater fish clades. We used phylogenetic comparative methods to analyze body size data in nine major fish clades that have crossed the marine/freshwater boundary. We explored how habitat transitions, ecological opportunity, and community interactions influenced patterns of phenotypic diversity. Our analyses indicated that transitions between marine and freshwater habitats did not drive body size evolution, and there are few differences in body size between marine and freshwater lineages. We found that body size disparity in freshwater lineages is not correlated with the number of independent transitions to freshwaters. We found a positive correlation between body size disparity and overall species richness of a given area, and a negative correlation between body size disparity and diversity of closely related species. Our results indicate that the diversity of incumbent freshwater species does not restrict phenotypic diversification, but the diversity of closely related taxa can limit body size diversification. Ecological opportunity arising from colonization of novel habitats does not seem to have a major effect in the trajectory of body size evolution in trans-marine/freshwater clades. Moreover, competition with closely related taxa in freshwaters has a greater effect than competition with distantly related incumbent species.

A modern approach to the treatment of cancer-associated venous thromboembolic complications: a lecture

Cancer-associated venous thromboembolic complications are one of the main topical problems in the system of practical healthcare. Having overlapping pathogenetic mechanisms of development, thromboembolic complications accompany the oncological process and often act as its manifesting sign. Treatment of onco-associated venous thromboembolic complications is not an easy task, which is determined by the multiplicity of the pathogenetic mechanisms of hemostatic system disorders in the cohort of patients under consideration, who are threatened both in terms of the development of total PE and fatal bleeding. In addition to the features of the treatment phases, their duration, an important point in the treatment of cancer-associated thrombosis is a limited list of recommended drugs, as well as the permitted dosage regimens. The article analyzes the results of research aimed at studying the effectiveness of apixaban in the treatment of cancer-associated thromboembolic complications. Now the gold standard for the treatment of venous thromboembolic complications is dalteparin. However, low compliance in the use of dalteparin leads to premature termination of treatment or the patient's independent transition to alternative drugs. The appearance of direct oral anticoagulants has significantly changed the treatment paradigm in this morbid group of patients, while leaving a number of unresolved issues.

The Effects of Video Priming on Facilitating the Transition of Children with Autism Spectrum Disorder between Activities and Settings

Preschool children with disabilities spend more time when transitioning between activities and settings than their typically developing peers. Extended transition duration leads to reducing the time spent on teaching. Various antecedent-based transition strategies are used to increase independent transition and decrease the transition duration of children with autism spectrum disorder. One of these strategies is video priming. This study aimed to examine the efficacy of video priming, an antecedent-based transition strategy, on increasing independent transitions of children with autism spectrum disorder and decreasing the time these children spent in transitions. Also, identifying opinions of parents of and teaching staff for participating children regarding the acceptability of video priming was aimed. Four children with autism spectrum disorder between the ages of 4 and 6 participated in the study. An ABAB design was used to evaluate the effects of video priming. Results indicated that video priming effectively increased all children’s independent transitions and decreased transition duration. The results also showed that the parents and teaching staff had a highly positive opinion about the video priming and its acceptability. This study provided additional evidence that video priming can facilitate children’s transition with autism spectrum disorder. The implication for future research and practice were discussed.

Coil-to-Bridge Transitions of Self-Assembled Water Chains Observed in a Nanoscopic Meniscus.

Ten downward portions in the large oscillatory force–distance curve reported earlier are analyzed to understand a nanoscale water meniscus confined between a sharp probe and a flat substrate in air. The sigmoidal shape of each portion leads to the assumption that the meniscus is made up of n independent transitions of two states: one for a coil state and the other for a bridge state. The analysis reveals that each downward portion occurs due to a coil-to-bridge transition of n self-assembled water chains whose length ranges between 197 and 383 chain units. The transition provides novel insights into water’s unique properties like high surface tension and the long-range condensation distances.

Cyphoderia ampulla (Cyphoderiidae: Rhizaria), a tale of freshwater sailors: The causes and consequences of ecological transitions through the salinity barrier in a family of benthic protists.

The salinity barrier that separates marine and freshwater biomes is probably the most important division in biodiversity on Earth. Those organisms that successfully performed this transition had access to new ecosystems while undergoing changes in selective pressure, which often led to major shifts in diversification rates. While these transitions have been extensively investigated in animals, the tempo, mode, and outcome of crossing the salinity barrier have been scarcely studied in other eukaryotes. Here, we reconstructed the evolutionary history of the species complex Cyphoderia ampulla (Euglyphida: Cercozoa: Rhizaria) based on DNA sequences from the nuclear SSU rRNA gene and the mitochondrial cytochrome oxidase subunit I gene, obtained from publicly available environmental DNA data (GeneBank, EukBank) and isolated organisms. A tree calibrated with euglyphid fossils showed that four independent transitions towards freshwater systems occurred from the mid‐Miocene onwards, coincident with important fluctuations in sea level. Ancestral trait reconstructions indicated that the whole family Cyphoderiidae had a marine origin and suggest that ancestors of the freshwater forms were euryhaline and lived in environments with fluctuating salinity. Diversification rates did not show any obvious increase concomitant with ecological transitions, but morphometric analyses indicated that species increased in size and homogenized their morphology after colonizing the new environments. This suggests adaptation to changes in selective pressure exerted by life in freshwater sediments.

Phylogenomics of Elongate-Bodied Springtails Reveals Independent Transitions from Aboveground to Belowground Habitats in Deep Time.

Soil has become a major hotspot of biodiversity studies, yet the pattern and timing of the evolution of soil organisms are poorly known because of the scarcity of paleontological data. To overcome this limitation, we conducted a genome-based macroevolutionary study of an ancient, diversified, and widespread lineage of soil fauna, the elongate-bodied springtails (class Collembola, order Entomobryomorpha). To build the first robust backbone phylogeny of this previously refractory group, we sampled representatives of major higher taxa (6 out of 8 families, 11 out of 16 subfamilies) of the order with an emphasis on the most problematic superfamily Tomoceroidea, applied whole-genome sequencing methods, and compared the performance of different combinations of data sets (universal single-copy orthologs [USCO] vs. ultraconserved elements]) and modeling schemes. The fossil-calibrated timetree was used to reconstruct the evolution of body size, sensory organs, and pigmentation to establish a time frame of the ecomorphological divergences. The resultant trees based on different analyses were congruent in most nodes. Several discordant nodes were carefully evaluated by considering method fitness, morphological information, and topology test. The evaluation favored the well-resolved topology from analyses using USCO amino acid matrices and complex site-heterogeneous models (CATn}{}+GTR and LGn}{}+PMSF (C60)). The preferred topology supports the monophyletic superfamily Tomoceroidea as an early-diverging lineage and a sister relationship between Entomobryoidea and Isotomoidea. The family Tomoceridae was recovered as monophyletic, whereas Oncopoduridae was recovered as paraphyletic, with Harlomillsia as a sister to Tomoceridae and hence deserving a separate family status as Harlomillsiidae Yu and Zhang fam. n. Ancestral Entomobryomorpha were reconstructed as surface-living, supporting independent origins of soil-living groups across the Paleozoic–Mesozoic, and highlighting the ancient evolutionary interaction between aboveground and belowground fauna. [Collembola; phylogenomics; soil-living adaptation; whole-genome sequencing.]