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.

Cerotegument microstructure of whip spiders (Amblypygi: Euamblypygi Weygoldt, 1996) reveals characters for systematics from family to species level.

Like other arthropods, whip spiders of the arachnid order Amblypygi Thorell, 1883 protect themselves against external environmental influences. In this taxon, in addition to the epicuticle, the outermost layer of the exoskeleton, a cement layer (cerotegument) with superhydrophobic properties is deposited over certain body parts. Due to the high level of interspecific variation, the cerotegument structure and the morphology of its associated gland openings have been suggested to be informative for whip spider systematics. The first comparative study of the cerotegument is presented herein, based on a survey across 4 families, 16 genera, and 62 species of Euamblypygi Weygoldt, 1996, the suborder comprising all extant whip spiders except the rare monotypic family Paracharontidae Weygoldt, 1996. Results confirmed that the morphology of the colloidal particles and their assembly on cement globules differ considerably among taxa, but that the level of variation differs among lineages. Interspecific variation in cerotegument ultrastructure was highest among species of Neoamblypygi Weygoldt, 1996, making it an informative character in this clade. Evolutionary trends and intraspecific variation in the structure of the amblypygid cerotegument are briefly discussed.

Burrowing into the forest: Phylogeny of the Asian forest scorpions (Scorpionidae: Heterometrinae) and the evolution of ecomorphotypes.

Asian forest scorpions (Scorpionidae Latreille, 1802: Heterometrinae Simon, 1879) are distributed across South and Southeast Asia. All are fossorial, constructing burrows under stones or in open ground, in habitats differing in precipitation and vegetation cover, from rainforests and tropical deciduous forests to savanna and scrubland. The systematics of these scorpions has long been confused due to bad taxonomy and the absence of a phylogenetic framework. Although the monophyly of the group was previously confirmed as part of broader phylogenetic analyses based on exemplar species, the only quantitative analysis of species-level variation to date was based on overall similarity. This contribution presents the first species-level phylogenetic analysis of Asian Scorpionidae, based on 186 morphological characters and 4188 aligned base-pairs of DNA sequence data from two nuclear and three mitochondrial loci for 132 terminals including all 41 ingroup species and four outgroup species. Simultaneous analyses of the morphological and molecular datasets with parsimony, Maximum Likelihood and Bayesian Inference provided the framework for a revised classification presented elsewhere. In order to understand how adaptation following dispersal into new habitats has driven the morphological diversification of Asian forest scorpions, species were scored for 10 characters concerning morphology and burrow architecture, which contributed to an ensemble index of adaptation to habitat aridity. Species were classified into three ecomorphotypes based on the index, and ancestral state reconstruction of ecomorphotypes performed on the phylogeny. A pattern was recovered in which lineages and species occurring in different habitats on a continuum from wet (evergreen forest) to dry (savanna, scrubland) exhibited characters presumed to be adaptive and hence responsible for driving scorpion diversification.

Dated phylogeny and ancestral range estimation of sand scorpions (Buthidae: Buthacus) reveal Early Miocene divergence across land bridges connecting Africa and Asia.

Sand scorpions of the genus Buthacus Birula, 1908 (Buthidae C.L. Koch, 1837) are widespread in the sandy deserts of the Palearctic region, occurring from the Atlantic coast of West Africa across the Sahara, and throughout the Middle East to Central Asia. The limits of Buthacus, its two species groups, and many of its species remain unclear, and in need of revision using modern systematic methods. The study presented here set out to investigate the phylogeny and biogeography of the Buthacus species occurring in the Levant, last studied in 1980. A phylogenetic analysis was performed on 104 terminals, including six species collected from more than thirty localities in Israel and other countries in the region. Three mitochondrial and two nuclear gene loci were sequenced for a total of 2218 aligned base-pairs. Morphological datasets comprising 22 qualitative and 48 quantitative morphological characters were compiled. Molecular and morphological datasets were analyzed separately and simultaneously with Bayesian Inference, Maximum Likelihood, and parsimony. Divergence time and ancestral range estimation analyses were performed, to understand dispersal and diversification. The results support a revised classification of Levantine Buthacus, and invalidate the traditional species groups of Buthacus, instead recovering two geographically-delimited clades, an African clade and an Asian clade, approximately separated by the Jordan Valley (the Jordan Rift Valley or Syro-African Depression), the northernmost part of the Great Rift Valley. The divergence between these clades occurred in the Early Miocene (ca. 19 Ma) in the Levant, coinciding temporally with the existence of two land bridges, which allowed faunal exchange between Africa and Asia.

Volcanism and palaeoclimate change drive diversification of the world's largest whip spider (Amblypygi).

The tropics contain many of the most biodiverse regions on Earth but the processes responsible for generating this diversity remain poorly understood. This study investigated the drivers of diversification in arthropods with stenotopic ecological requirements and limited dispersal capability using as a model the monotypic whip spider (Amblypygi) genus Acanthophrynus, widespread in the tropical deciduous forests of Mexico. We hypothesized that for these organisms, the tropical deciduous forests serve as a conduit for dispersal, with their disappearance imposing barriers. Given that these forests are located in a region of complex geological history and that they fluctuated in extent during the Pliocene-Pleistocene glacial/interglacial cycles we combine molecular divergence dating, palaeoclimatic niche modelling and ancestral area reconstruction to test if and when habitat fragmentation promoted diversification in Acanthophrynus. Concomitant with the expected role of landscape change, we demonstrate that orogeny of the Trans-Mexican Volcanic Belt, in the Late Miocene or Early Pliocene (6.95-5.21 million years ago), drove the earliest divergence of Acanthophrynus by vicariance. Similarly, as expected, the later onset of glaciations strongly impacted diversification. Whereas a more stable climate in the southern part of the distribution enabled further diversification, a marked loss of suitable habitat during the glaciations only allowed dispersal and diversification in the north to occur later, resulting in a lower overall diversity in this region. Barriers and diversification patterns identified in Acanthophrynus are reflected in the phylogeography of codistributed vertebrates and arthropods, emphasizing the profound impact of Trans-Mexican Volcanic Belt orogeny and glacial/interglacial cycles as drivers of diversification in the Mexican Neotropics.

Fine structure of the epicuticular secretion coat and associated glands of Pedipalpi and Palpigradi (Arachnida).

Pedipalpi Latreille, 1810 is a poorly studied clade of arachnids comprising the whip spiders (Amblypygi Thorell, 1883), short-tailed whip scorpions (Schizomida Petrunkevitch, 1945) and whip scorpions (Thelyphonida Cambridge, 1872). It has recently been shown that whip spiders coat their exoskeleton with a solid cement layer (cerotegument) that forms elaborate microstructures and turns the cuticle into a super-hydrophobic state. The amblypygid cerotegument provides taxonomic information due to its fine structural diversity, but its presence and variation in the sister groups was previously unknown. The present contribution reports the surface structure of the cuticle in species of Palpigradi, Thelyphonida, and Schizomida to determine if these taxa possess a solid epicuticular secretion coat. Scanning electron microscopy revealed that in addition to Amblypygi only species of Thelyphonida possess solid epicuticular secretion layers. Unlike in Amblypygi, in the Thelyphonida this layer does not usually form microstructures and is less rigidly attached to the underlying cuticle. A species of Typopeltis Pocock, 1894, which exhibited globular structures analogous to the amblypygid cerotegument, was an exception. Glandular structures associated with cement secretions in Amblypygi and Thelyphonida were considered homologous due to similar structure. Solid epicuticular secretion coats were absent from Schizomida, which is interpreted as a secondary loss despite the presence of slit-like glandular openings that appear to produce such epicuticular secretions. The micro-whip scorpion order Palpigradi Thorell, 1900 exhibited markedly different cuticular surface structures and lacked solid epicuticular secretions, consistent with the hypothesis that this order is not closely related to Pedipalpi. These results enhance the knowledge of the small, enigmatic orders of Arachnida.

Out of India, thrice: diversification of Asian forest scorpions reveals three colonizations of Southeast Asia.

The 'Out of India' hypothesis is often invoked to explain patterns of distribution among Southeast Asian taxa. According to this hypothesis, Southeast Asian taxa originated in Gondwana, diverged from their Gondwanan relatives when the Indian subcontinent rifted from Gondwana in the Late Jurassic, and colonized Southeast Asia when it collided with Eurasia in the early Cenozoic. A growing body of evidence suggests these events were far more complex than previously understood, however. The first quantitative reconstruction of the biogeography of Asian forest scorpions (Scorpionidae Latreille, 1802: Heterometrinae Simon, 1879) is presented here. Divergence time estimation, ancestral range estimation, and diversification analyses are used to determine the origins, dispersal and diversification patterns of these scorpions, providing a timeline for their biogeographical history that can be summarized into four major events. (1) Heterometrinae diverged from other Scorpionidae on the African continent after the Indian subcontinent became separated in the Cretaceous. (2) Environmental stresses during the Cretaceous-Tertiary (KT) mass extinction caused range contraction, restricting one clade of Heterometrinae to refugia in southern India (the Western Ghats) and Sri Lanka (the Central Highlands). (3) Heterometrinae dispersed to Southeast Asia three times during India's collision with Eurasia, the first dispersal event occurring as the Indian subcontinent brushed up against the western side of Sumatra, and the other two events occurring as India moved closer to Eurasia. (4) Indian Heterometrinae, confined to southern India and Sri Lanka during the KT mass extinction, recolonized the Deccan Plateau and northern India, diversifying into new, more arid habitats after environmental conditions stabilized. These hypotheses, which are congruent with the geological literature and biogeographical analyses of other taxa from South and Southeast Asia, contribute to an improved understanding of the dispersal and diversification patterns of taxa in this biodiverse and geologically complex region.

Publisher Correction: Island Ancestors and New World Biogeography: A Case Study from the Scorpions (Buthidae: Centruroidinae).

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Island Ancestors and New World Biogeography: A Case Study from the Scorpions (Buthidae: Centruroidinae).

Scorpions are an excellent system for understanding biogeographical patterns. Most major scorpion lineages predate modern landforms, making them suitable for testing hypotheses of vicariance and dispersal. The Caribbean islands are endowed with a rich and largely endemic scorpion fauna, the origins of which have not been previously investigated with modern biogeographical methods. Three sets of hypotheses have been proposed to explain present patterns of diversity in the Caribbean: (1) connections via land bridges, (2) vicariance events, and (3) overwater dispersal from continents and among islands. The present study investigates the biogeographical diversification of the New World buthid scorpion subfamily Centruroidinae Kraus, 1955, a clade of seven genera and more than 110 species; infers the ancestral distributions of these scorpions; and tests the relative roles of vicariance and dispersal in the formation of their present distributions. A fossil-calibrated molecular phylogeny was estimated with a Bayesian criterion to infer the dates of diversification events from which ancestral distributions were reconstructed, and the relative likelihood of models of vicariance vs. dispersal, calculated. Although both the timing of diversification and the ancestral distributions were congruent with the GAARlandia land-bridge hypothesis, there was no significant difference between distance-dependent models with or without the land-bridge. Heteroctenus Pocock, 1893, the Caribbean-endemic sister taxon of Centruroides Marx, 1890 provides evidence for a Caribbean ancestor, which subsequently colonized Central America and North America, and eventually re-colonized the Greater Antilles. This 'reverse colonization' event of a continent from an island demonstrates the importance of islands as a potential source of biodiversity.

Intraspecific venom variation in southern African scorpion species of the genera Parabuthus, Uroplectes and Opistophthalmus (Scorpiones: Buthidae, Scorpionidae).

Scorpion venoms comprise cocktails of proteins, peptides, and other molecules used for immobilizing prey and deterring predators. The composition and efficacy of scorpion venoms appears to be taxon-specific due to a coevolutionary arms race with prey and predators that adapt at the molecular level. The taxon-specific components of scorpion venoms can be used as barcodes for species identification if the amount of intraspecific variation is low and the analytical method is fast, inexpensive and reliable. The present study assessed the extent of intraspecific variation in newly regenerated venom collected in the field from geographically separated populations of four southern African scorpion species: three buthids, Parabuthus granulatus (Ehrenberg, 1831), Uroplectes otjimbinguensis (Karsch, 1879), and Uroplectes planimanus (Karsch, 1879), and one scorpionid, Opistophthalmus carinatus (Peters, 1861). Although ion signal patterns were generally similar among venom samples of conspecific individuals from different populations, MALDI-TOF mass spectra in the mass range m/z 700-10,000 revealed only a few ion signals that were identical suggesting that species identification based on simple venom mass fingerprints (MFPs) will be more reliable if databases contain data from multiple populations. In general, hierarchical cluster analysis (HCA) of the ion signals in mass spectra was more reliable for species identification than counts of mass-identical substances in MFPs. The statistical approach revealed conclusive information about intraspecific diversity. In combination with a comprehensive database of MALDI-TOF mass spectra in reflectron mode, HCA may offer a method for rapid species identification based on venom MFPs.

The spider tree of life: phylogeny of Araneae based on target-gene analyses from an extensive taxon sampling.

We present a phylogenetic analysis of spiders using a dataset of 932 spider species, representing 115 families (only the family Synaphridae is unrepresented), 700 known genera, and additional representatives of 26 unidentified or undescribed genera. Eleven genera of the orders Amblypygi, Palpigradi, Schizomida and Uropygi are included as outgroups. The dataset includes six markers from the mitochondrial (12S, 16S, COI) and nuclear (histone H3, 18S, 28S) genomes, and was analysed by multiple methods, including constrained analyses using a highly supported backbone tree from transcriptomic data. We recover most of the higher-level structure of the spider tree with good support, including Mesothelae, Opisthothelae, Mygalomorphae and Araneomorphae. Several of our analyses recover Hypochilidae and Filistatidae as sister groups, as suggested by previous transcriptomic analyses. The Synspermiata are robustly supported, and the families Trogloraptoridae and Caponiidae are found as sister to the Dysderoidea. Our results support the Lost Tracheae clade, including Pholcidae, Tetrablemmidae, Diguetidae, Plectreuridae and the family Pacullidae (restored status) separate from Tetrablemmidae. The Scytodoidea include Ochyroceratidae along with Sicariidae, Scytodidae, Drymusidae and Periegopidae; our results are inconclusive about the separation of these last two families. We did not recover monophyletic Austrochiloidea and Leptonetidae, but our data suggest that both groups are more closely related to the Cylindrical Gland Spigot clade rather than to Synspermiata. Palpimanoidea is not recovered by our analyses, but also not strongly contradicted. We find support for Entelegynae and Oecobioidea (Oecobiidae plus Hersiliidae), and ambiguous placement of cribellate orb-weavers, compatible with their non-monophyly. Nicodamoidea (Nicodamidae plus Megadictynidae) and Araneoidea composition and relationships are consistent with recent analyses. We did not obtain resolution for the titanoecoids (Titanoecidae and Phyxelididae), but the Retrolateral Tibial Apophysis clade is well supported. Penestomidae, and probably Homalonychidae, are part of Zodarioidea, although the latter family was set apart by recent transcriptomic analyses. Our data support a large group that we call the marronoid clade (including the families Amaurobiidae, Desidae, Dictynidae, Hahniidae, Stiphidiidae, Agelenidae and Toxopidae). The circumscription of most marronoid families is redefined here. Amaurobiidae include the Amaurobiinae and provisionally Macrobuninae. We transfer Malenellinae (Malenella, from Anyphaenidae), Chummidae (Chumma) (new syn.) and Tasmarubriinae (Tasmarubrius, Tasmabrochus and Teeatta, from Amphinectidae) to Macrobuninae. Cybaeidae are redefined to include Calymmaria, Cryphoeca, Ethobuella and Willisius (transferred from Hahniidae), and Blabomma and Yorima (transferred from Dictynidae). Cycloctenidae are redefined to include Orepukia (transferred from Agelenidae) and Pakeha and Paravoca (transferred from Amaurobiidae). Desidae are redefined to include five subfamilies: Amphinectinae, with Amphinecta, Mamoea, Maniho, Paramamoea and Rangitata (transferred from Amphinectidae); Ischaleinae, with Bakala and Manjala (transferred from Amaurobiidae) and Ischalea (transferred from Stiphidiidae); Metaltellinae, with Austmusia, Buyina, Calacadia, Cunnawarra, Jalkaraburra, Keera, Magua, Metaltella, Penaoola and Quemusia; Porteriinae (new rank), with Baiami, Cambridgea, Corasoides and Nanocambridgea (transferred from Stiphidiidae); and Desinae, with Desis, and provisionally Poaka (transferred from Amaurobiidae) and Barahna (transferred from Stiphidiidae). Argyroneta is transferred from Cybaeidae to Dictynidae. Cicurina is transferred from Dictynidae to Hahniidae. The genera Neoramia (from Agelenidae) and Aorangia, Marplesia and Neolana (from Amphinectidae) are transferred to Stiphidiidae. The family Toxopidae (restored status) includes two subfamilies: Myroinae, with Gasparia, Gohia, Hulua, Neomyro, Myro, Ommatauxesis and Otagoa (transferred from Desidae); and Toxopinae, with Midgee and Jamara, formerly Midgeeinae, new syn. (transferred from Amaurobiidae) and Hapona, Laestrygones, Lamina, Toxops and Toxopsoides (transferred from Desidae). We obtain a monophyletic Oval Calamistrum clade and Dionycha; Sparassidae, however, are not dionychans, but probably the sister group of those two clades. The composition of the Oval Calamistrum clade is confirmed (including Zoropsidae, Udubidae, Ctenidae, Oxyopidae, Senoculidae, Pisauridae, Trechaleidae, Lycosidae, Psechridae and Thomisidae), affirming previous findings on the uncertain relationships of the "ctenids" Ancylometes and Cupiennius, although a core group of Ctenidae are well supported. Our data were ambiguous as to the monophyly of Oxyopidae. In Dionycha, we found a first split of core Prodidomidae, excluding the Australian Molycriinae, which fall distantly from core prodidomids, among gnaphosoids. The rest of the dionychans form two main groups, Dionycha part A and part B. The former includes much of the Oblique Median Tapetum clade (Trochanteriidae, Gnaphosidae, Gallieniellidae, Phrurolithidae, Trachelidae, Gnaphosidae, Ammoxenidae, Lamponidae and the Molycriinae), and also Anyphaenidae and Clubionidae. Orthobula is transferred from Phrurolithidae to Trachelidae. Our data did not allow for complete resolution for the gnaphosoid families. Dionycha part B includes the families Salticidae, Eutichuridae, Miturgidae, Philodromidae, Viridasiidae, Selenopidae, Corinnidae and Xenoctenidae (new fam., including Xenoctenus, Paravulsor and Odo, transferred from Miturgidae, as well as Incasoctenus from Ctenidae). We confirm the inclusion of Zora (formerly Zoridae) within Miturgidae.

Systematic revision of the neotropical club-tailed scorpions, Physoctonus, Rhopalurus, and Troglorhopalurus, revalidation of Heteroctenus, and descriptions of two new genera and three new species (Buthidae, Rhopalurusinae)

The Neotropical "club-tailed" scorpions of the genus Rhopalurus Thorell, 1876, and two related genera in family Buthidae C.L. Koch, 1837, i.e., Physoctonus Mello-Leitão, 1934, and Troglorhopalurus Lourenço et al., 2004, are revised, based on a simultaneous phylogenetic analysis of 90 morphological characters and 4260 aligned DNA nucleotides from three mitochondrial and two nuclear gene loci. The monophyletic New World buthid subfamily Rhopalurusinae Bucherl, 1971, to which these scorpions were originally assigned, is redefined, revised diagnoses and a key to identification of its genera and species (except for Centruroides Marx, 1890) provided, and their distributions mapped. The paraphyly of Rhopalurus Thorell, 1876, which comprises several monophyletic groups congruent with its disjunct distribution, justifies its relimitation and that of Troglorhopalurus Lourenço et al., 2004, the revalidation of Heteroctenus Pocock, 1893, and creation of Ischnotelson, gen. nov. (type species: Rhopalurus guanambiensis Lenarducci, Pinto-da-Rocha and Lucas, 2005) and Jaguajir, gen. nov. (type species: Rhopalurus agamemnon C.L. Koch, 1839). Ten new combinations are proposed: Heteroctenus abudi (Armas and Marcano Fondeur, 1987), comb. nov.; Heteroctenus bonettii (Armas, 1999), comb. nov.; Heteroctenus garridoi (Armas, 1974), comb. nov.; Heteroctenus gibarae (Teruel, 2006), comb. nov.; Heteroctenus princeps (Karsch, 1879), comb. nov.; Ischnotelson guanambiensis (Lenarducci, Pinto-da-Rocha and Lucas, 2005), comb. nov.; Jaguajir agamemnon (C.L. Koch, 1839), comb. nov.; Jaguajir pintoi (Mello-Leitão, 1932), comb. nov.; Jaguajir rochae (Borelli, 1910), comb. nov.; Troglorhopalurus lacrau (Lourenço and Pinto-da-Rocha, 1997), comb. nov. Three new species are described: Ischnotelson peruassu, sp. nov. (type locality: Parque Estadual do Peruassu, Minas Gerias, Brazil); Physoctonus striatus, sp. nov. (type locality: Castelo do Piauí, Piauí, Brazil); Rhopalurus ochoai, sp. nov. (type locality: San Agustín, Edo. Zulia, Venezuela). Fifteen new junior subjective synonyms are proposed: Rhopalurus acromelas Lutz and Mello, 1922, Rhopalurus melleipalpus Lutz and Mello, 1922, Rhopalurus iglesiasi Werner, 1927, Rhopalurus lambdophorus Mello-Leitão, 1932, Rhopalurus dorsomaculatus Prado, 1938, and Rhopalurus goiasensis Prado, 1940 = Jaguajir agamemnon (C.L. Koch, 1839); Rhopalurus pintoi kourouensis Lourenço, 2008 = Jaguajir pintoi (Mello-Leitão, 1932); Rhopalurus crassicauda Caporiacco, 1947, Rhopalurus amazonicus Lourenço, 1986, and Rhopalurus crassicauda paruensis Lourenço, 2008 = Rhopalurus laticauda Thorell, 1876; Rhopalurus melloleitaoi Teruel and Armas, 2006, and Rhopalurus aridicola (Teruel and Armas, 2012) = Heteroctenus junceus (Herbst, 1800); Rhopalurus granulimanus Teruel, 2006 = Heteroctenus gibarae (Teruel, 2006); Rhopalurus virkii Santiago-Blay, 2009 = Heteroctenus abudi (Armas and Marcano Fondeur, 1987); Rhopalurus brejo Lourenço, 2014 = Troglorhopalurus lacrau (Lourenço and Pinto-da-Rocha, 1997).

The spider tree of life: phylogeny of Araneae based on target-gene analyses from an extensive taxon sampling

We present a phylogenetic analysis of spiders using a dataset of 932 spider species, representing 115 families (only the family Synaphridae is unrepresented), 700 known genera, and additional representatives of 26 unidentified or undescribed genera. Eleven genera of the orders Amblypygi, Palpigradi, Schizomida and Uropygi are included as outgroups. The dataset includes six markers from the mitochondrial (12S, 16S, COI) and nuclear (histone H3, 18S, 28S) genomes, and was analysed by multiple methods, including constrained analyses using a highly supported backbone tree from transcriptomic data. We recover most of the higher-level structure of the spider tree with good support, including Mesothelae, Opisthothelae, Mygalomorphae and Araneomorphae. Several of our analyses recover Hypochilidae and Filistatidae as sister groups, as suggested by previous transcriptomic analyses. The Synspermiata are robustly supported, and the families Trogloraptoridae and Caponiidae are found as sister to the Dysderoidea. Our results support the Lost Tracheae clade, including Pholcidae, Tetrablemmidae, Diguetidae, Plectreuridae and the family Pacullidae (restored status) separate from Tetrablemmidae. The Scytodoidea include Ochyroceratidae along with Sicariidae, Scytodidae, Drymusidae and Periegopidae; our results are inconclusive about the separation of these last two families. We did not recover monophyletic Austrochiloidea and Leptonetidae, but our data suggest that both groups are more closely related to the Cylindrical Gland Spigot clade rather than to Synspermiata. Palpimanoidea is not recovered by our analyses, but also not strongly contradicted. We find support for Entelegynae and Oecobioidea (Oecobiidae plus Hersiliidae), and ambiguous placement of cribellate orb-weavers, compatible with their non-monophyly. Nicodamoidea (Nicodamidae plus Megadictynidae) and Araneoidea composition and relationships are consistent with recent analyses. We did not obtain resolution for the titanoecoids (Titanoecidae and Phyxelididae), but the Retrolateral Tibial Apophysis clade is well supported. Penestomidae, and probably Homalonychidae, are part of Zodarioidea, although the latter family was set apart by recent transcriptomic analyses. Our data support a large group that we call the marronoid clade (including the families Amaurobiidae, Desidae, Dictynidae, Hahniidae, Stiphidiidae, Agelenidae and Toxopidae). The circumscription of most marronoid families is redefined here. Amaurobiidae include the Amaurobiinae and provisionally Macrobuninae. We transfer Malenellinae (Malenella, from Anyphaenidae), Chummidae (Chumma) (new syn.) and Tasmarubriinae (Tasmarubrius, Tasmabrochus and Teeatta, from Amphinectidae) to Macrobuninae. Cybaeidae are redefined to include Calymmaria, Cryphoeca, Ethobuella and Willisius (transferred from Hahniidae), and Blabomma and Yorima (transferred from Dictynidae). Cycloctenidae are redefined to include Orepukia (transferred from Agelenidae) and Pakeha and Paravoca (transferred from Amaurobiidae). Desidae are redefined to include five subfamilies: Amphinectinae, with Amphinecta, Mamoea, Maniho, Paramamoea and Rangitata (transferred from Amphinectidae); Ischaleinae, with Bakala and Manjala (transferred from Amaurobiidae) and Ischalea (transferred from Stiphidiidae); Metaltellinae, with Austmusia, Buyina, Calacadia, Cunnawarra, Jalkaraburra, Keera, Magua, Metaltella, Penaoola and Quemusia; Porteriinae (new rank), with Baiami, Cambridgea, Corasoides and Nanocambridgea (transferred from Stiphidiidae); and Desinae, with Desis, and provisionally Poaka (transferred from Amaurobiidae) and Barahna (transferred from Stiphidiidae). Argyroneta is transferred from Cybaeidae to Dictynidae. Cicurina is transferred from Dictynidae to Hahniidae. The genera Neoramia (from Agelenidae) and Aorangia, Marplesia and Neolana (from Amphinectidae) are transferred to Stiphidiidae. The family Toxopidae (restored status) includes two subfamilies: Myroinae, with Gasparia, Gohia, Hulua, Neomyro, Myro, Ommatauxesis and Otagoa (transferred from Desidae); and Toxopinae, with Midgee and Jamara, formerly Midgeeinae, new syn. (transferred from Amaurobiidae) and Hapona, Laestrygones, Lamina, Toxops and Toxopsoides (transferred from Desidae). We obtain a monophyletic Oval Calamistrum clade and Dionycha; Sparassidae, however, are not dionychans, but probably the sister group of those two clades. The composition of the Oval Calamistrum clade is confirmed (including Zoropsidae, Udubidae, Ctenidae, Oxyopidae, Senoculidae, Pisauridae, Trechaleidae, Lycosidae, Psechridae and Thomisidae), affirming previous findings on the uncertain relationships of the "ctenids" Ancylometes and Cupiennius, although a core group of Ctenidae are well supported. Our data were ambiguous as to the monophyly of Oxyopidae. In Dionycha, we found a first split of core Prodidomidae, excluding the Australian Molycriinae, which fall distantly from core prodidomids, among gnaphosoids. The rest of the dionychans form two main groups, Dionycha part A and part B. The former includes much of the Oblique Median Tapetum clade (Trochanteriidae, Gnaphosidae, Gallieniellidae, Phrurolithidae, Trachelidae, Gnaphosidae, Ammoxenidae, Lamponidae and the Molycriinae), and also Anyphaenidae and Clubionidae. Orthobula is transferred from Phrurolithidae to Trachelidae. Our data did not allow for complete resolution for the gnaphosoid families. Dionycha part B includes the families Salticidae, Eutichuridae, Miturgidae, Philodromidae, Viridasiidae, Selenopidae, Corinnidae and Xenoctenidae (new fam., including Xenoctenus, Paravulsor and Odo, transferred from Miturgidae, as well as Incasoctenus from Ctenidae). We confirm the inclusion of Zora (formerly Zoridae) within Miturgidae.

Morphology of the tracheal system of camel spiders (Chelicerata: Solifugae) based on micro-CT and 3D-reconstruction in exemplar species from three families.

We studied the tracheal system of exemplar species representing three families of Solifugae Sundevall, 1833, i.e., Galeodes granti Pocock, 1903, Ammotrechula wasbaueri Muma, 1962 and Eremobates sp., using µCT-imaging and 3D-reconstruction. This is the first comparative study of the tracheal system of Solifugae in 85 years and the first using high-resolution nondestructive methods. The tracheal system was found to be structurally similar in all three species, with broad major tracheae predominantly in the prosoma as well as anastomoses (i.e., connections between tracheal branches from different stigmata) in the prosoma and opisthosoma. Differences among the three species were observed in the presence or absence of cheliceral air sacs, the number of tracheae supplying the heart, and the ramification of major tracheae in the opisthosoma. The structure of the tracheal system with its extensive branches and some anastomoses is assumed to aid rapid and efficient gas exchange in the respiratory tissues of these active predators. The large diameter of cheliceral tracheae (air sacs) of taxa with disproportionally heavier chelicerae suggests a role in weight reduction, enabling solifuges to reach greater speeds during predation. The air sacs may also permit more rapid and efficient gaseous exchange, necessary to operate the musculature of these structures, thereby improving their use for predation in an environment where prey is scarce.

Timeless standards for species delimitation.

Recently a new species of bombyliid fly, Marleyimyia xylocopae, was described by Marshall & Evenhuis (2015) based on two photographs taken during fieldwork in the Republic of South Africa. This species has no preserved holotype. The paper generated some buzz, especially among dipterists, because in most cases photographs taken in the field provide insufficient information for properly diagnosing and documenting species of Diptera.

Similar burrow architecture of three arid-zone scorpion species implies similar ecological function.

Many animals reside in burrows that may serve as refuges from predators and adverse environmental conditions. Burrow design varies widely among and within taxa, and these structures are adaptive, fulfilling physiological (and other) functions. We examined the burrow architecture of three scorpion species of the family Scorpionidae: Scorpio palmatus from the Negev desert, Israel; Opistophthalmus setifrons, from the Central Highlands, Namibia; and Opistophthalmus wahlbergii from the Kalahari desert, Namibia. We hypothesized that burrow structure maintains temperature and soil moisture conditions optimal for the behavior and physiology of the scorpion. Casts of burrows, poured in situ with molten aluminum, were scanned in 3D to quantify burrow structure. Three architectural features were common to the burrows of all species: (1) a horizontal platform near the ground surface, long enough to accommodate the scorpion, located just below the entrance, 2-5 cm under the surface, which may provide a safe place where the scorpion can monitor the presence of potential prey, predators, and mates and where the scorpion warms up before foraging; (2) at least two bends that might deter incursion by predators and may reduce convective ventilation, thereby maintaining relatively high humidity and low temperature; and (3) an enlarged terminal chamber to a depth at which temperatures are almost constant (±2-4 °C). These common features among the burrows of three different species suggest that they are important for regulating the physical environment of their inhabitants and that burrows are part of scorpions' "extended physiology" (sensu Turner, Physiol Biochem Zool 74:798-822, 2000).

Phylogeny, species delimitation and convergence in the South American bothriurid scorpion genus Brachistosternus Pocock 1893: Integrating morphology, nuclear and mitochondrial DNA.

A phylogenetic analysis of the scorpion genus Brachistosternus Pocock, 1893 (Bothriuridae Simon, 1880) is presented, based on a dataset including 41 of the 43 described species and five outgroups, 116 morphological characters and more than 4150 base-pairs of DNA sequence from the nuclear 18S rDNA and 28S rDNA gene loci, and the mitochondrial 12S rDNA, 16S rDNA, and Cytochrome c Oxidase Subunit I gene loci. Analyses conducted using parsimony, Maximum Likelihood and Bayesian Inference were largely congruent with high support for most clades. The results confirmed the monophyly of Brachistosternus, the nominal subgenus, and subgenus Ministernus Francke, 1985, as in previous analyses based only on morphology, but differed in several other respects. Species from the plains of the Atacama Desert diverged basally whereas the high altitude Andean species radiated from a more derived ancestor, presumably as a consequence of Andean uplift and associated changes in climate. Species limits were assessed among species that contain intraspecific variation (e.g., different morphs), are difficult to separate morphologically, and/or exhibit widespread or disjunct distributions. The extent of convergence in morphological adaptation to life on sandy substrata (psammophily) and the complexity of the male genitalia, or hemispermatophores, was investigated. Psammophily evolved on at least four independent occasions. The lobe regions of the hemispermatophore increased in complexity on three independent occasions, and decreased in complexity on another three independent occasions.

A multilocus molecular phylogeny of the endemic North American camel spider family Eremobatidae (Arachnida: Solifugae).

Camel spiders (Solifugae) are a diverse but poorly studied order of arachnids. No robust phylogenetic analysis has ever been carried out for the order or for any family within the Solifugae. We present a molecular phylogenetic analysis of the endemic North American family Eremobatidae Kraepelin, 1899, the first such analysis of a family of Solifugae. We use a multi-locus exemplar approach using DNA sequences from partial nuclear (28S rDNA and Histone H3) and mitochondrial (16S rRNA and Cytochrome c Oxidase I) gene loci for 81 ingroup exemplars representing all genera of Eremobatidae and most species groups within the genera Eremobates Banks, 1900, Eremochelis Roewer, 1934, and Hemerotrecha Banks, 1903. Maximum Likelihood and two Bayesian analyses consistently recovered the monophyly of Eremobatidae, Eremorhax Roewer, 1934 and Eremothera Muma, 1951 along with a group comprising all subfamily Eremobatinae Kraepelin, 1901 exemplars except Horribates bantai Muma, 1989 and a group comprising all Eremocosta Roewer, 1934 exemplars except Eremocosta acuitalpanensis (Vasquez and Gavin, 2000). The subfamily Therobatinae Muma, 1951 and the genera Chanbria Muma, 1951, Hemerotrecha, Eremochelis, and Eremobates were polyphyletic or paraphyletic. Only the banksi group of Hemerotrecha was monophyletic; the other species groups recognized within Eremobates, Eremochelis, and Hemerotrecha were paraphyletic or polyphyletic. We found no support for the monophyly of the subfamily Therobatinae. A time-calibrated phylogeny dated the most recent common ancestor of extant eremobatids to the late Eocene to early Miocene, with a mean estimate in the late Oligocene (32.2 Ma).

Scorpion speciation in the Holy Land: Multilocus phylogeography corroborates diagnostic differences in morphology and burrowing behavior among Scorpio subspecies and justifies recognition as phylogenetic, ecological and biological species.

Scorpio Linnaeus, 1758 (family Scorpionidae Latreille, 1802) was considered monotypic for over a century, and comprised a single species, Scorpio maurus Linnaeus, 1758, with 19 subspecies, distributed from West Africa, throughout the Maghreb and the Middle East, to Iran. Two parapatric subspecies, Scorpio maurus fuscus (Ehrenberg, 1829) and Scorpio maurus palmatus (Ehrenberg, 1828), have long been recognized in the eastern Mediterranean region. We examined morphological variation, burrow architecture and genetic divergence among 39 populations across the distribution of the two subspecies to assess whether they are conspecific and, if not, how many species might be involved. Cuticle coloration, pedipalp chela digital carina condition, and selected measurements were recorded. Sixty burrows were excavated and examined for burrow structure and depth. A multilocus dataset comprising concatenated fragments of one nuclear (28S rDNA) and three mitochondrial (12S rDNA, 16S rDNA, Cytochrome c Oxidase Subunit I) loci, totaling ca. 2400 base-pairs, was produced for 41 individuals, and a single-locus dataset comprising 658 base-pairs of the COI locus for 156 individuals. Despite overlapping ranges in morphometric characters of pedipalp chela shape, the putative subspecies were easily distinguished by cuticle coloration and condition of the pedipalp chela digital carina, and were also found to differ significantly in burrow architecture and depth. Phylogeographical analyses of the COI and multilocus datasets recovered seven distinct clades. Separate analyses of mitochondrial sequences, and combined analyses of mitochondrial and nuclear sequences support most clades. The two major clades corresponded with the geographical distributions of S. m. fuscus and S. m. palmatus in the region. Specimens from these clades were genetically distinct, and exhibited different burrow structure in geographically-proximate localities, suggesting reproductive isolation. The palmatus clade included two distinct subclades of specimens from localities adjacent to the Dead Sea. Three other clades, comprising specimens from the most northeastern localities, were tentatively assigned to subspecies previously recorded in neighboring Jordan and Syria. The morphological, behavioral and genetic evidence supports previous suggestions that Scorpio maurus is a species complex and justifies the following taxonomic emendations: Scorpio fuscus (Ehrenberg, 1829), stat. nov.; Scorpio kruglovi Birula, 1910, stat. nov.; Scorpio palmatus (Ehrenberg, 1828), stat. nov.; Scorpio propinquus (Simon, 1872), stat. nov.

Scorpion sheds 'tail' to escape: consequences and implications of autotomy in scorpions (Buthidae: Ananteris).

Autotomy, the voluntary shedding or detachment of a body part at a determined cleavage plane, is a common anti-predation defense mechanism in several animal taxa, including arthropods. Among arachnids, autotomy has been observed in harvestmen, mites, and spiders, always involving the loss of legs. Autotomy of the opisthosoma (abdomen) was recently reported in a single species of the Neotropical buthid scorpion genus Ananteris Thorell, 1891, but few details were revealed. Based on observations in the field and laboratory, examination of material in museum collections, and scanning electron microscopy, we document autotomy of the metasoma (the hind part of the opisthosoma, or 'tail') in fourteen species of Ananteris. Autotomy is more common in males than females, and has not been observed in juveniles. When the scorpion is held by the metasoma, it is voluntarily severed at the joints between metasomal segments I and II, II and III, or III and IV, allowing the scorpion to escape. After detachment, the severed metasoma moves (twitches) automatically, much like the severed tail of a lizard or the severed leg of a spider, and reacts to contact, even attempting to sting. The severed surface heals rapidly, scar tissue forming in five days. The lost metasomal segments and telson cannot be regenerated. Autotomy of the metasoma and telson results in permanent loss of the posterior part of the scorpion's digestive system (the anus is situated posteriorly on metasomal segment V) and the ability to inject venom by stinging. After autotomy, scorpions do not defecate and can only capture small prey items. However, males can survive and mate successfully for up to eight months in the laboratory. In spite of diminished predation ability after autotomy, survival allows males to reproduce. Autotomy in Ananteris therefore appears to be an effective, adaptive, anti-predation escape mechanism.