Fossil evidence indicates that millipedes were the first animals adapted to life on land about 425 million years ago, becoming the very first land animals and beating vertebrates by a staggering 50 million years.1,2 These multi-legged arthropods provide a vital ecological role in forests by decomposing coarse organic matter and contributing to the formation of nutrient-rich soils.3,4 To date, 14,232 species have been described, with at least as many still awaiting discovery.5 Despite their ecological significance and ancient origins in the Ordovician, the evolutionary relationships among millipedes have remained unresolved, and a synthesis of the 16 orders that comprise the class Diplopoda had never been attempted. In this study, we analyzed the last two remaining unsampled orders, Siphonocryptida and Siphoniulida, two rare paleoendemics whose placement had been unresolved until now. Our results show that all extant diplopod orders except one were present by the end of the Jurassic, that millipedes evolved potent terpenoid alkaloid chemical defenses 261 million years ago, and that Siphonocryptida is a derived lineage of Polyzoniida. Early millipede lineages possessed sophisticated sensory structures, including compound eyes and Tömösváry organs, which were repeatedly lost over 459 million years of diversification. These findings provide a robust framework for understanding the evolution of the earliest fully terrestrial animals and support ongoing efforts to discover and describe thousands of new millipede species.

We describe Bollmanella amorensis sp. nov. from Labor of Love Cave, White Pine County, Nevada, United States. From cave explorations in Great Basin National Park and Humboldt-Toiyabe National Forest in White Pine Co., Nevada, we provide new records of Idagona lehmanensis Shear, 2007, and Nevadesmus ophimontis Shear, 2009, and ecological notes on Labor of Love Cave, a list of species encountered, and remarks on the distinctiveness of caves in the Great Basin Desert.

Brachycybe is a genus of the millipede subterclass Colobognatha, a group which exhibits rare social characteristics, including species aggregations and male brood care. Although it has been hypothesized that alkaloid-based defensive secretions may also serve as pheromones, no studies have focused on these traits. Here, we evaluated the chemical secretions of six species, two of which were previously unstudied, and conducted Y-tube pheromone assays. Chemical investigations led to the structure elucidation of three new metabolites, each containing a carboxylic acid. Y-tube pheromone assays revealed that Brachycybe producta is significantly attracted to conspecifics (p = 0.0428), and is deterred by a different species of alkaloid-producing millipede (p = 0.0161). The former assay was repeated using a mixture of the crude (p = 0.0428) and purified (p = 0.0433) chemical defense secretion from B. producta. This study provides the first evidence that colobognath millipede’s chemical secretions serve both a defensive and as pheromone role.

Brachycybe is a genus of the millipede subterclass Colobognatha, a group that exhibits rare social characteristics, including species aggregations and male brood care. Although it has been hypothesized that alkaloid-based defensive secretions may also function as pheromones, no studies have examined these traits. Here, we evaluated the chemical secretions of six species, two of which had not been previously studied, and conducted Y-tube pheromone assays. Chemical investigations elucidated the structures of three new metabolites: hydrogosodesmine acid (6), homo-hydrogosodesmine acid (7), and buzonamine acid (8). Y-tube pheromone assays revealed that Brachycybe producta is significantly attracted to conspecifics (p = 0.0428) and is deterred by a different species of alkaloid-producing millipede (p = 0.0161). The former assay was repeated using a mixture of the crude (p = 0.0428) and purified (p = 0.0433) chemical defense secretion fromB. producta. This study provides the first evidence that colobognath millipede chemical secretions serve both defensive and pheromone roles.

The caseyid millipede genus Opiona Chamberlin, 1951 contains 15 species distributed from southern Alaska and the Canadian province of British Columbia south to Santa Cruz County, California. We provide new records and range extensions of five previously described species and describe five new species: Opiona arcata sp. nov., O. johnsoni sp. nov., O. alsea sp. nov., O. triangalensis sp. nov., and O. laquesis sp. nov.. The following new synonym and combination are proposed: Opiona Chamberlin, 1951 = Speoseya Causey, 1963, syn. nov. and Opiona grahami (Causey, 1963) = Speoseya grahami Causey, 1963, comb. nov.-the valid names being the former. We propose a new subfamily Opioninae, subfam. nov., to include Opiona; Metopiona Gardner & Shelley, 1989; Opionoides Shear & Marek, 2025; Paropiona Shear & Marek 2025; and Benlomondia Shear & Marek, 2025.

The recent explosion in the described chemistry from Colobognatha, a millipede subterclass, has rekindled interest in the defensive secretions from these ancient animals. Colobognatha are the only millipedes that produce terpenoid alkaloids, and prior to 2020, studies into these defensive secretions were limited to a single order, Polyzoniida. However, it has become clear that numerous species of the order Platydesmida also produce structurally diverse terpenoid alkaloids with potent biological activity. Platydesmida defensive secretions encompass multiple natural product scaffolds with greater chemical complexity compared to previously reported millipede-derived alkaloids. Here we report the analysis of the defensive secretions of Andrognathus corticarius, a millipede found across the Appalachian region. A. corticarius is evolutionary sister to all other Platydesmida and is the presumed oldest genus within the order. Analysis of the defensive secretions revealed that A. corticarius produces an arsenal of alkaloids that are dissimilar to all previously reported metabolites. Complete structural elucidation was accomplished using 2D NMR, HRMS, chemical derivatization, DFT and ECD, which revealed the presence of two distinct scaffolds: a 5,6-fused heterocycle named the andrognathines and a 6,6,6,5-bridged heterocycle containing seven continuous stereogenic centers named the andrognathanols. Each scaffold is decorated with diverse fatty acids, which leads to the extraordinary number of unique metabolites detected within the secretions. The alkaloids likely serve to defend the millipedes from predation as they are actively secreted upon physical disturbance. This discovery also provides support for a plausible biosynthetic pathway that appears to be evolving simplicity across the evolutionary history of the Platydesmida.

A third species of the macrosternodesmid millipede genus Nevadesmus Shear, 2009 is described from a cave in Tonto National Forest, Pinal Co., southern Arizona, USA. This new species, Nevadesmus superstitiona Shear, Pape & Marek, sp. nov. occurs significantly distant from the localities of the two other species, which occur in Nevada. The epigean and hypogean settings of the cave site and remarks on its natural history are provided. Thirty-two animal taxa are present in the cave, including the new millipede. Four other endemic troglobiotic species are present: a scorpion (Pseudouroctonus sp.: Vaejovidae), a terrestrial isopod (Brackenridgia sp.: Trichoniscidae), a silverfish (Speleonycta sp.: Nicoletiidae) and a thread-legged bug (Gardena cf. elkinsi: Reduviidae). A resident population of the tailless whip scorpion (Paraphrynus tokdod: Amblypygi: Phrynidae) is the first record of this family in an Arizona Cave. Tonto National Forest Cave #34 is the second most species diverse cave currently known in Arizona.

In poison frogs (Dendrobatidae), conspicuous colors have evolved repeatedly in tandem with high numbers and quantities of skin toxins (alkaloids). Here, we focus on an inconspicuously-colored species—Silverstoneia flotator—which has long been deemed toxin-free and thought to forage opportunistically on mites and ants. Both assumptions have received some empirical support, but there is also evidence that predators avoid S. flotator. In a Panamanian S. flotator population, we sampled invertebrates in frog diets and the surrounding environment (using Berlese and pitfall traps) and screened for skin, dietary, and environmental alkaloids using untargeted metabolomics. We found that while the frogs are opportunistic consumers of mites and ants, they display preferences at finer taxonomic scales (for symphypleonan springtails and Pheidole ants). We also annotated 64 skin compounds as alkaloids, 38 of which were present in the environment. One alkaloid present in the skin and environment is likely the highly potent epibatidine. While the average biosynthetic (class and superclass) diversity of alkaloids in a dorsal skin sample is higher than that of a ventral skin and environmental—but not dietary—sample, environmental samples diverge more in their alkaloids’ biosynthetic diversities than do dietary or skin samples. The frogs consume a consistent set of alkaloids, forage in a variable chemical space, and possess diverse dorsal skin alkaloids. They might use finer-scale diet specialization to modulate the types, quantities, and numbers of alkaloids they ingest. We encourage further examination of inconspicuously-colored taxa to better understand the ecological importance of diet-acquired toxins and specialized diets in these organisms.

Paropiona Shear & Marek, gen. nov. is described from northwestern and central Washington State, USA. It includes two new species, Paropiona gardneri Shear & Marek, sp. nov. from Pacific and Cowlitz Counties, and Paropiona aenigma Shear & Marek, sp. nov. from Clallam, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Thurston and Wahakiakum Counties. Opionoides Shear & Marek, gen. nov. is monotypic with only Opionoides cataracta Shear & Marek, sp. nov. from Coos Co. Oregon. The new genera are related to, but distinct from the genus Opiona Chamberlin, 1951.

The recent explosion in documented chemistry from Colobognatha, a millipede subterclass with more than 240 species, has rekindled interest in the defensive secretions from these ancient animals. Prior to 2020, studies on defensive secretions by Colobognatha─the only millipedes that produce terpenoid alkaloids─were limited to a single order, Polyzoniida. However, numerous species of the order Platydesmida have recently been shown to produce structurally diverse terpenoid alkaloids with potent biological activities. Platydesmidan defensive secretions encompass multiple natural product scaffolds with greater chemical complexity compared to previously reported millipede-derived alkaloids. Here, we report an analysis of the defensive secretions of Andrognathus corticarius, an evolutionary sister to all other Platydesmida. Analyzing defensive secretions revealed that A. corticarius produces an arsenal of alkaloids dissimilar to all previously reported metabolites. Using various analytical techniques, we accomplished complete structural assignment of two distinct scaffolds: a 5,6-fused heterocycle named the andrognathines and a 6,6,6,5-bridged heterocycle containing seven continuous stereogenic centers named the andrognathanols. Each scaffold contains diverse fatty acids; this leads to an extraordinary number of unique metabolites. These described alkaloids are actively secreted upon physical disturbance and change the behavior of ants that reside in the same environment.

The genus Benlomondia Shear & Marek, gen. nov., and two new species, Benlomondia benlomondensis Shear & Marek, sp. nov., and Benlomondia mateo Shear & Marek, sp. nov., are described from Santa Cruz and San Mateo Counties, California, respectively. The new genus is similar to, but distinct from, Opiona Chamberlin, 1951.

We revise the millipede genus Apheloria Chamberlin, 1921a colorful and often encountered group of millipedes in eastern North America. With molecular phylogenetics, we estimate the evolutionary history of the genus, and use it in combination with morphology to understand species diversity. We describe a new species, Apheloria uwharrie sp. nov. from North and South Carolina, synonymize Apheloria tigana Chamberlin, 1939 syn. nov. with Apheloria virginiensis (Drury, 1770), and remove Apheloria luminosa (Kenyon, 1893) syn. nov. from the genus and place it in synonymy with Pleuroloma flavipes Rafinesque, 1820. Currently there are six species of Apheloria: Apheloria corrugata (Wood, 1864) stat. nov.; Apheloria montana (Bollman, 1887); Apheloria polychroma Marek, Means & Hennen, 2018; Apheloria uwharrie sp. nov.; Apheloria virginiensis (Drury, 1770); and Apheloria whiteheadi (Shelley, 1986).

Introduction Patient-reported outcome measurements (PROMs) are gaining considerable popularity as tools to assess the effectiveness of the treatment in plastic surgery, being a complement to surgical outcomes. The SCAR-Q questionnaire has been recently developed for patients with surgical, traumatic, and burn scars. Aim The study aims to describe the process of translation and linguistic validation of the scar questionnaire (SCAR-Q) for use in Polish patients undergoing scar treatment. Material and methods An official Polish translation and language validation of the SCAR-Q were done in adherence to International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines. The process consisted of four steps: two independent forward translations, a back translation, a review of the back translation, and cognitive participant interviews. Results The field-tested version of the SCAR-Q consisted of 29 items across three scales measuring appearance concerns, symptoms, and the psychosocial impact of the scar. The forward translation was done by two independent translators and revealed specific difficulties in translation to the Polish language (4/29 items). The back translation showed no significant differences compared to the original English version. Cognitive debriefing interviews involved nine Polish patients with postraumatic scars, burn scars, and scars after skin tumor resection. Participants have not reported any major difficulties in understanding the content of the questionnaire. Conclusions The ISPOR provides a straightforward and thorough guideline for the PROMs translation process. The new SCAR-Q is an accessible and efficient PROM that can be implemented in Polish patients to assess the effectiveness of scar treatment.

Millipedes have long been known to produce a diverse array of chemical defense agents that deter predation. These compounds, or their precursors, are stored in high concentration within glands (ozadenes) and are released upon disturbance. The subterclass Colobognatha contains four orders of millipedes, all of which are known to produce terpenoid alkaloids-spare the Siphonophorida that produce terpenes. Although these compounds represent some of the most structurally-intriguing millipede-derived natural products, they are the least studied class of millipede defensive secretions. Here, we describe the chemistry of millipede defensive secretions from three species of Brachycybe: Brachycybe producta, Brachycybe petasata, and Brachycybe rosea. Chemical investigations using mass spectrometry-based metabolomics, chemical synthesis, and 2D NMR led to the identification of five alkaloids, three of which are new to the literature. All identified compounds are monoterpene alkaloids with the new compounds representing indolizidine (i.e. hydrogosodesmine) and quinolizidine alkaloids (i.e. homogosodesmine and homo-hydrogosodesmine). The chemical diversity of these compounds tracks the known species phylogeny of this genus, rather than the geographical proximity of the species. The indolizidines and quinolizidines are produced by non-sympatric sister species, B. producta and B. petasata, while deoxybuzonamine is produced by another set of non-sympatric sister species, B. rosea and Brachycybe lecontii. The fidelity between the chemical diversity and phylogeny strongly suggests that millipedes generate these complex defensive agents de novo and begins to provide insights into the evolution of their biochemical pathways.

Millipedes have long been known to produce structurally diverse chemical defenses, including hydrogen cyanide, terpenoid alkaloids, and oxidized aromatics. Although the hydrogen cyanide and oxidized aromatic producing millipedes have been well studied, less than 10% of the terpenoid alkaloid producers have been chemically investigated. Several previous studies have shown that alkaloids disorient predators, but their biochemical target is currently unknown. Herein, we investigated the defensive secretions of a colobognath millipede, Ischnocybe plicata, and elucidated the constitution, absolute configuration, and conformation of four new highly oxidized terpenoid alkaloids, termed ischnocybines, using a range of analytical techniques. The ischnocybines are actively secreted from the defensive glands and were shown to disorient ants, a likely common predator. Evaluation of the ischnocybines in a panel of neuroreceptors revealed that ischnocybine A possesses potent (Ki 13.6 nM) and selective (100-fold) binding affinity for sigma-1, an orphan neuroreceptor, over sigma-2. These molecules represent the most complex alkaloids to be discovered from millipedes and provide the first potential insights into a biochemical target responsible for their defensive properties.

The identity of Striaria californica Cook, described in 1899 from a single female, is established on the basis of additional specimens collected by Cook in 1929 and determined to be that species by Loomis (1936) as well as specimens from the San Francisco Bay region, likely to be from near the original collection locality. We propose Amplaria californica (Cook, 1899) new combination. A new genus, Bayaria Shear & Marek n. gen., is established for Striaria nana Loomis, 1936 Bayaria nana (Loomis, 1936) new combination. Striaria carmela Chamberlin, 1947, is a junior synonym of Bayaria nana. A key to the 16 genera of Striariidae and an annotated checklist of the 52 species are provided.

Subterranean arthropods are important components of soils and contribute essential food-web functions and other ecosystem services, however, their diversity and community composition has scarcely been assessed. Subterranean pitfall traps are a commonly used method for sampling soil habitats in Europe but have never been widely implemented in the Americas. We used subterranean pitfall traps to sample previously unsurveyed arthropod communities in southwestern Virginia, U.S. Traps were placed in shallow subterranean habitats (SSHs), underground habitats close to the surface where light does not penetrate, and more specifically at the interface between the soil and underlying “milieu souterrain superficiel”—a microhabitat consisting of the air-filled interstitial spaces between rocks (abbreviated MSS). In total, 2,260 arthropod specimens were collected constituting 345 morphospecies from 8 classes, 33 orders, and 94 families. A region of the mitochondrial cytochrome c oxidase subunit I (COI) gene was amplified and sequenced, and objective sequence clustering of 3% was used to establish molecular operational taxonomic units (mOTUs) to infer observed species richness. In all, 272 COI barcodes representing 256 mOTUs were documented for rare soil-dwelling arthropod taxa and are published to build a molecular library for future research in this system. This work is the first taxonomically extensive survey of North American soil-dwelling arthropods greater than 10 cm below the soil surface.

Ormia ochracea is a parasitoid fly notable for its impressive hearing abilities relative to its small size. Here, we use it as a model organism to investigate if minor size differences in paired sensory organs may be beneficial or neutral to an organism's perception abilities. We took high-resolution images of tympanal organs from 21 O. ochracea specimens and found a statistically significant surface area asymmetry (up to 6.88%) between the left and right membranes. Numerical experiments indicated that peak values of key sound localization variables increased with increasing tympanal asymmetry, which may explain features of the limited available physiological data.

Although most binaural organisms locate sound sources using neurological structures to amplify the sounds they hear, some animals use mechanically coupled hearing organs instead. One of these animals, the parasitoid flyOrmia ochracea(O. ochracea), has astoundingly accurate sound localization abilities. It can locate objects in the azimuthal plane with a precision of 2°, equal to that of humans, despite an intertympanal distance of only 0.5 mm, which is less than1/100th of the wavelength of the sound emitted by the crickets that it parasitizes.O. ochraceaaccomplishes this feat via mechanically coupled tympana that interact with incoming acoustic pressure waves to amplify differences in the signals received at the two ears. In 1995, Mileset aldeveloped a model of hearing mechanics inO. ochraceathat represents the tympana as flat, front-facing prosternal membranes, though they lie on a convex surface at an angle from the flies' frontal and transverse planes. The model works well for incoming sound angles less than±30∘but suffers from reduced accuracy (up to 60% error) at higher angles compared to response data acquired fromO. ochraceaspecimens. Despite this limitation, it has been the basis for bio-inspired microphone designs for decades. Here, we present critical improvements to this classic hearing model based on information from three-dimensional reconstructions ofO. ochracea's tympanal organ. We identified the orientation of the tympana with respect to a frontal plane and the azimuthal angle segment between the tympana as morphological features essential to the flies' auditory acuity, and hypothesized a differentiated mechanical response to incoming sound on the ipsi- and contralateral sides that depend on these features. We incorporated spatially-varying model coefficients representing this asymmetric response, making a new quasi-two-dimensional (q2D) model. The q2D model has high accuracy (average errors of under 10%) for all incoming sound angles. This improved biomechanical model may inform the design of new microscale directional microphones and other small-scale acoustic sensor systems.