Increasing Information Content and Diagnosability in Family-Level Classifications.

Higher-level classifications often must account for monotypic taxa representing depauperate evolutionary lineages and lacking synapomorphies of their better-known, well-defined sister clades. In a ranked (Linnean) or unranked (phylogenetic) classification system, discovering such a depauperate taxon does not necessarily invalidate the rank classification of sister clades. Named higher taxa must be monophyletic to be phylogenetically valid. Ranked taxa above the species level should also maximize information content, diagnosability, and utility (e.g., in biodiversity conservation). In spider classification, families are the highest rank that is systematically catalogued, and incertae sedis is not allowed. Consequently, it is important that family-level taxa be well defined and informative. We revisit the classification problem of Orbipurae, an unranked suprafamilial clade containing the spider families Nephilidae, Phonognathidae, and Araneidae sensu stricto. We argue that, to maximize diagnosability, information content, conservation utility, and practical taxonomic considerations, this "splitting" scheme is superior to its recently proposed alternative, which lumps these families together as Araneidae sensu lato. We propose to redefine Araneidae and recognize a monogeneric spider family, Paraplectanoididae fam. nov. to accommodate the depauperate lineage Paraplectanoides. We present new subgenomic data to stabilize Orbipurae topology which also supports our proposed family-level classification. Our example from spiders demonstrates why classifications must be able to accommodate depauperate evolutionary lineages, for example, Paraplectanoides. Finally, although clade age should not be a criterion to determine rank, other things being equal, comparable ages of similarly ranked taxa do benefit comparative biology. [Classification, family rank, phylogenomics, systematics, monophyly, spider phylogeny.].

A diversification relay race from Caribbean-Mesoamerica to the Andes: historical biogeography of Xylophanes hawkmoths.

The regions of the Andes and Caribbean-Mesoamerica are both hypothesized to be the cradle for many Neotropical lineages, but few studies have fully investigated the dynamics and interactions between Neotropical bioregions. The New World hawkmoth genus Xylophanes is the most taxonomically diverse genus in the Sphingidae, with the highest endemism and richness in the Andes and Caribbean-Mesoamerica. We integrated phylogenomic and DNA barcode data and generated the first time-calibrated tree for this genus, covering 93.8% of the species diversity. We used event-based likelihood ancestral area estimation and biogeographic stochastic mapping to examine the speciation and dispersal dynamics of Xylophanes across bioregions. We also used trait-dependent diversification models to compare speciation and extinction rates of lineages associated with different bioregions. Our results indicate that Xylophanes originated in Caribbean-Mesoamerica in the Late Miocene, and immediately diverged into five major clades. The current species diversity and distribution of Xylophanes can be explained by two consecutive phases. In the first phase, the highest Xylophanes speciation and emigration rates occurred in the Caribbean-Mesoamerica, and the highest immigration rates occurred in the Andes, whereas in the second phase the highest immigration rates were found in Amazonia, and the Andes had the highest speciation and emigration rates.

Hidden Phylogenomic Signal Helps Elucidate Arsenurine Silkmoth Phylogeny and the Evolution of Body Size and Wing Shape Trade-Offs.

One of the key objectives in biological research is understanding how evolutionary processes have produced Earth's diversity. A critical step toward revealing these processes is an investigation of evolutionary tradeoffs-that is, the opposing pressures of multiple selective forces. For millennia, nocturnal moths have had to balance successful flight, as they search for mates or host plants, with evading bat predators. However, the potential for evolutionary trade-offs between wing shape and body size are poorly understood. In this study, we used phylogenomics and geometric morphometrics to examine the evolution of wing shape in the wild silkmoth subfamily Arsenurinae (Saturniidae) and evaluate potential evolutionary relationships between body size and wing shape. The phylogeny was inferred based on 782 loci from target capture data of 42 arsenurine species representing all 10 recognized genera. After detecting in our data one of the most vexing problems in phylogenetic inference-a region of a tree that possesses short branches and no "support" for relationships (i.e., a polytomy), we looked for hidden phylogenomic signal (i.e., inspecting differing phylogenetic inferences, alternative support values, quartets, and phylogenetic networks) to better illuminate the most probable generic relationships within the subfamily. We found there are putative evolutionary trade-offs between wing shape, body size, and the interaction of fore- and hindwing (HW) shape. Namely, body size tends to decrease with increasing HW length but increases as forewing (FW) shape becomes more complex. Additionally, the type of HW (i.e., tail or no tail) a lineage possesses has a significant effect on the complexity of FW shape. We outline possible selective forces driving the complex HW shapes that make Arsenurinae, and silkmoths as a whole, so charismatic. [Anchored hybrid enrichment; Arsenurinae; geometric morphometrics; Lepidoptera; phylogenomics; Saturniidae.].

The evolution of two distinct strategies of moth flight.

Across insects, wing shape and size have undergone dramatic divergence even in closely related sister groups. However, we do not know how morphology changes in tandem with kinematics to support body weight within available power and how the specific force production patterns are linked to differences in behaviour. Hawkmoths and wild silkmoths are diverse sister families with divergent wing morphology. Using three-dimensional kinematics and quasi-steady aerodynamic modelling, we compare the aerodynamics and the contributions of wing shape, size and kinematics in 10 moth species. We find that wing movement also diverges between the clades and underlies two distinct strategies for flight. Hawkmoths use wing kinematics, especially high frequencies, to enhance force and wing morphologies that reduce power. Silkmoths use wing morphology to enhance force, and slow, high-amplitude wingstrokes to reduce power. Both strategies converge on similar aerodynamic power and can support similar body weight ranges. However, inter-clade within-wingstroke force profiles are quite different and linked to the hovering flight of hawkmoths and the bobbing flight of silkmoths. These two moth groups fly more like other, distantly related insects than they do each other, demonstrating the diversity of flapping flight evolution and a rich bioinspired design space for robotic flappers.

Adaptive shifts underlie the divergence in wing morphology in bombycoid moths.

The evolution of flapping flight is linked to the prolific success of insects. Across Insecta, wing morphology diversified, strongly impacting aerodynamic performance. In the presence of ecological opportunity, discrete adaptive shifts and early bursts are two processes hypothesized to give rise to exceptional morphological diversification. Here, we use the sister-families Sphingidae and Saturniidae to answer how the evolution of aerodynamically important traits is linked to clade divergence and through what process(es) these traits evolve. Many agile Sphingidae evolved hover feeding behaviours, while adult Saturniidae lack functional mouth parts and rely on a fixed energy budget as adults. We find that Sphingidae underwent an adaptive shift in wing morphology coincident with life history and behaviour divergence, evolving small high aspect ratio wings advantageous for power reduction that can be moved at high frequencies, beneficial for flight control. By contrast, Saturniidae, which do not feed as adults, evolved large wings and morphology which surprisingly does not reduce aerodynamic power, but could contribute to their erratic flight behaviour, aiding in predator avoidance. We suggest that after the evolution of flapping flight, diversification of wing morphology can be potentiated by adaptative shifts, shaping the diversity of wing morphology across insects.

Phylogenetic Systematics and Evolution of the Spider Infraorder Mygalomorphae Using Genomic Scale Data.

The infraorder Mygalomorphae is one of the three main lineages of spiders comprising over 3000 nominal species. This ancient group has a worldwide distribution that includes among its ranks large and charismatic taxa such as tarantulas, trapdoor spiders, and highly venomous funnel-web spiders. Based on past molecular studies using Sanger-sequencing approaches, numerous mygalomorph families (e.g., Hexathelidae, Ctenizidae, Cyrtaucheniidae, Dipluridae, and Nemesiidae) have been identified as non-monophyletic. However, these data were unable to sufficiently resolve the higher-level (intra- and interfamilial) relationships such that the necessary changes in classification could be made with confidence. Here, we present a comprehensive phylogenomic treatment of the spider infraorder Mygalomorphae. We employ 472 loci obtained through anchored hybrid enrichment to reconstruct relationships among all the mygalomorph spider families and estimate the timeframe of their diversification. We sampled nearly all currently recognized families, which has allowed us to assess their status, and as a result, propose a new classification scheme. Our generic-level sampling has also provided an evolutionary framework for revisiting questions regarding silk use in mygalomorph spiders. The first such analysis for the group within a strict phylogenetic framework shows that a sheet web is likely the plesiomorphic condition for mygalomorphs, as well as providing insights to the ancestral foraging behavior for all spiders. Our divergence time estimates, concomitant with detailed biogeographic analysis, suggest that both ancient continental-level vicariance and more recent dispersal events have played an important role in shaping modern day distributional patterns. Based on our results, we relimit the generic composition of the Ctenizidae, Cyrtaucheniidae, Dipluridae, and Nemesiidae. We also elevate five subfamilies to family rank: Anamidae (NEW RANK), Euagridae (NEW RANK), Ischnothelidae (NEW RANK), Pycnothelidae (NEW RANK), and Bemmeridae (NEW RANK). Three families Entypesidae (NEW FAMILY), Microhexuridae (NEW FAMILY), and Stasimopidae (NEW FAMILY), and one subfamily Australothelinae (NEW SUBFAMILY) are newly proposed. Such a major rearrangement in classification, recognizing nine newly established family-level rank taxa, is the largest the group has seen in over three decades. [Biogeography; molecular clocks; phylogenomics; spider web foraging; taxonomy.].

Spiders did not repeatedly gain, but repeatedly lost, foraging webs.

Much genomic-scale, especially transcriptomic, data on spider phylogeny has accumulated in the last few years. These data have recently been used to investigate the diverse architectures and the origin of spider webs, concluding that the ancestral spider spun no foraging web, that spider webs evolved de novo 10-14 times, and that the orb web evolved at least three times. These findings in fact result from a particular phylogenetic character coding strategy, specifically coding the absence of webs as logically equivalent, and homologous to, 10 other observable (i.e., not absent) web architectures. "Absence" of webs should be regarded as inapplicable data. To be analyzed properly by character optimization algorithms, it should be coded as "?" because these codes-or their equivalent-are handled differently by such algorithms. Additional problems include critical misspellings of taxon names from one analysis to the next (misspellings cause some optimization algorithms to drop terminals, which affects taxon sampling and results), and mistakes in spider natural history. In sum, the method causes character optimization algorithms to produce counter-intuitive results, and does not distinguish absence from secondary loss. Proper treatment of missing entries and corrected data instead imply that foraging webs are primitive for spiders and that webs have been lost ∼5-7 times, not gained 10-14 times. The orb web, specifically, may be homologous (originated only once) although lost 2-6 times.

Golden Orbweavers Ignore Biological Rules: Phylogenomic and Comparative Analyses Unravel a Complex Evolution of Sexual Size Dimorphism.

Instances of sexual size dimorphism (SSD) provide the context for rigorous tests of biological rules of size evolution, such as Cope's rule (phyletic size increase), Rensch's rule (allometric patterns of male and female size), as well as male and female body size optima. In certain spider groups, such as the golden orbweavers (Nephilidae), extreme female-biased SSD (eSSD, female:male body length $\ge$2) is the norm. Nephilid genera construct webs of exaggerated proportions, which can be aerial, arboricolous, or intermediate (hybrid). First, we established the backbone phylogeny of Nephilidae using 367 anchored hybrid enrichment markers, then combined these data with classical markers for a reference species-level phylogeny. Second, we used the phylogeny to test Cope and Rensch's rules, sex specific size optima, and the coevolution of web size, type, and features with female and male body size and their ratio, SSD. Male, but not female, size increases significantly over time, and refutes Cope's rule. Allometric analyses reject the converse, Rensch's rule. Male and female body sizes are uncorrelated. Female size evolution is random, but males evolve toward an optimum size (3.2-4.9 mm). Overall, female body size correlates positively with absolute web size. However, intermediate sized females build the largest webs (of the hybrid type), giant female Nephila and Trichonephila build smaller webs (of the aerial type), and the smallest females build the smallest webs (of the arboricolous type). We propose taxonomic changes based on the criteria of clade age, monophyly and exclusivity, classification information content, and diagnosability. Spider families, as currently defined, tend to be between 37 million years old and 98 million years old, and Nephilidae is estimated at 133 Ma (97-146), thus deserving family status. We, therefore, resurrect the family Nephilidae Simon 1894 that contains Clitaetra Simon 1889, the Cretaceous GeratonephilaPoinar and Buckley (2012), Herennia Thorell 1877, IndoetraKuntner 2006, new rank, Nephila Leach 1815, Nephilengys L. Koch 1872, Nephilingis Kuntner 2013, Palaeonephila Wunderlich 2004 from Tertiary Baltic amber, and TrichonephilaDahl 1911, new rank. We propose the new clade Orbipurae to contain Araneidae Clerck 1757, Phonognathidae Simon 1894, new rank, and Nephilidae. Nephilid female gigantism is a phylogenetically ancient phenotype (over 100 Ma), as is eSSD, though their magnitudes vary by lineage.

The evolution of anti-bat sensory illusions in moths.

Prey transmit sensory illusions to redirect predatory strikes, creating a discrepancy between what a predator perceives and reality. We use the acoustic arms race between bats and moths to investigate the evolution and function of a sensory illusion. The spinning hindwing tails of silk moths (Saturniidae) divert bat attack by reflecting sonar to create a misleading echoic target. We characterized geometric morphometrics of moth hindwings across silk moths, mapped these traits onto a new, robust phylogeny, and found that elaborated hindwing structures have converged on four adaptive shape peaks. To test the mechanism underlying these anti-bat traits, we pit bats against three species of silk moths with experimentally altered hindwings that created a representative gradient of ancestral and extant hindwing shapes. High-speed videography of battles reveals that moths with longer hindwings and tails more successfully divert bat attack. We postulate that sensory illusions are widespread and are underappreciated drivers of diversity across systems.

A global checklist of the Bombycoidea (Insecta: Lepidoptera).

BACKGROUND: Bombycoidea is an ecologically diverse and speciose superfamily of Lepidoptera. The superfamily includes many model organisms, but the taxonomy and classification of the superfamily has remained largely in disarray. Here we present a global checklist of Bombycoidea. Following Zwick (2008) and Zwick et al. (2011), ten families are recognized: Anthelidae, Apatelodidae, Bombycidae, Brahmaeidae, Carthaeidae, Endromidae, Eupterotidae, Phiditiidae, Saturniidae and Sphingidae. The former families Lemoniidae and Mirinidae are included within Brahmaeidae and Endromidae respectively. The former bombycid subfamilies Oberthueriinae and Prismostictinae are also treated as synonyms of Endromidae, and the former bombycine subfamilies Apatelodinae and Phitditiinae are treated as families. NEW INFORMATION: This checklist represents the first effort to synthesize the current taxonomic treatment of the entire superfamily. It includes 12,159 names and references to their authors, and it accounts for the recent burst in species and subspecies descriptions within family Saturniidae (ca. 1,500 within the past 10 years) and to a lesser extent in Sphingidae (ca. 250 species over the same period). The changes to the higher classification of Saturniidae proposed by Nässig et al. (2015) are rejected as premature and unnecessary. The new tribes, subtribes and genera described by Cooper (2002) are here treated as junior synonyms. We also present a new higher classification of Sphingidae, based on Kawahara et al. (2009), Barber and Kawahara (2013) and a more recent phylogenomic study by Breinholt et al. (2017), as well as a reviewed genus and species level classification, as documented by Kitching (2018).

Phylogeny of a cosmopolitan family of morphologically conserved trapdoor spiders (Mygalomorphae, Ctenizidae) using Anchored Hybrid Enrichment, with a description of the family, Halonoproctidae Pocock 1901.

The mygalomorph family Ctenizidae has a world-wide distribution and currently contains nine genera and 135 species. However, the monophyly of this group has long been questioned on both morphological and molecular grounds. Here, we use Anchored Hybrid Enrichment (AHE) to gather hundreds of loci from across the genome for reconstructing the phylogenetic relationships among the nine genera and test the monophyly of the family. We also reconstruct the possible ancestral ranges of the most inclusive clade recovered. Using AHE, we generate a supermatrix of 565 loci and 115,209 bp for 27 individuals. For the first time, analyses using all nine genera produce results definitively establishing the non-monophyly of Ctenizidae. A lineage formed exclusively by representatives of South African Stasimopus was placed as the sister group to the remaining taxa in the tree, and the Mediterranean Cteniza and Cyrtocarenum were recovered with high support as sister to exemplars of Euctenizidae, Migidae, and Idiopidae. All the remaining genera-Bothriocyrtum, Conothele, Cyclocosmia, Hebestatis, Latouchia, and Ummidia-share a common ancestor. Based on these results, we formally elevate this clade to the level of family. Our results definitively establish both the non-monophyly of the Ctenizidae and non-validity of the subfamilies Ummidiinae and Ctenizinae. In order to establish the placement of the remaining three ctenizid genera, Cteniza, Cyrtocarenum, and Stasimopus, thorough analyses within the context of a complete mygalomorph phylogenetic framework are needed. We formally describe the family Halonoproctidae Pocock 1901 and infer that the family's most recent common ancestor was likely distributed in western North America and Asia.

A genome-wide phylogeny of jumping spiders (Araneae, Salticidae), using anchored hybrid enrichment.

We present the first genome-wide molecular phylogeny of jumping spiders (Araneae: Salticidae), inferred from Anchored Hybrid Enrichment (AHE) sequence data. From 12 outgroups plus 34 salticid taxa representing all but one subfamily and most major groups recognized in previous work, we obtained 447 loci totalling 96,946 aligned nucleotide sites. Our analyses using concatenated likelihood, parsimony, and coalescent methods (ASTRAL and SVDQuartets) strongly confirm most previous results, resolving as monophyletic the Spartaeinae, Salticinae (with the hisponines sister), Salticoida, Amycoida, Saltafresia, and Simonida. The agoriines, previously difficult to place beyond subfamily, are finally placed confidently within the saltafresians as relatives of the chrysillines and hasariines. Relationships among the baviines, astioids, marpissoids, and saltafresians remain uncertain, though our analyses tentatively conclude the first three form a clade together. Deep relationships, among the seven subfamilies, appear to be largely resolved, with spartaeines, lyssomanines, and asemoneines forming a clade. In most analyses, Onomastus (representing the onomastines) is strongly supported as sister to the hisponines plus salticines. Overall, the much-improved resolution of many deep relationships despite a relatively sparse taxon sample suggests AHE is a promising technique for salticid phylogenetics.

Expanding anchored hybrid enrichment to resolve both deep and shallow relationships within the spider tree of life.

BACKGROUND: Despite considerable effort, progress in spider molecular systematics has lagged behind many other comparable arthropod groups, thereby hindering family-level resolution, classification, and testing of important macroevolutionary hypotheses. Recently, alternative targeted sequence capture techniques have provided molecular systematics a powerful tool for resolving relationships across the Tree of Life. One of these approaches, Anchored Hybrid Enrichment (AHE), is designed to recover hundreds of unique orthologous loci from across the genome, for resolving both shallow and deep-scale evolutionary relationships within non-model systems. Herein we present a modification of the AHE approach that expands its use for application in spiders, with a particular emphasis on the infraorder Mygalomorphae. RESULTS: Our aim was to design a set of probes that effectively capture loci informative at a diversity of phylogenetic timescales. Following identification of putative arthropod-wide loci, we utilized homologous transcriptome sequences from 17 species across all spiders to identify exon boundaries. Conserved regions with variable flanking regions were then sought across the tick genome, three published araneomorph spider genomes, and raw genomic reads of two mygalomorph taxa. Following development of the 585 target loci in the Spider Probe Kit, we applied AHE across three taxonomic depths to evaluate performance: deep-level spider family relationships (33 taxa, 327 loci); family and generic relationships within the mygalomorph family Euctenizidae (25 taxa, 403 loci); and species relationships in the North American tarantula genus Aphonopelma (83 taxa, 581 loci). At the deepest level, all three major spider lineages (the Mesothelae, Mygalomorphae, and Araneomorphae) were supported with high bootstrap support. Strong support was also found throughout the Euctenizidae, including generic relationships within the family and species relationships within the genus Aptostichus. As in the Euctenizidae, virtually identical topologies were inferred with high support throughout Aphonopelma. CONCLUSIONS: The Spider Probe Kit, the first implementation of AHE methodology in Class Arachnida, holds great promise for gathering the types and quantities of molecular data needed to accelerate an understanding of the spider Tree of Life by providing a mechanism whereby different researchers can confidently and effectively use the same loci for independent projects, yet allowing synthesis of data across independent research groups.

Preserving and vouchering butterflies and moths for large-scale museum-based molecular research.

Butterflies and moths (Lepidoptera) comprise significant portions of the world's natural history collections, but a standardized tissue preservation protocol for molecular research is largely lacking. Lepidoptera have traditionally been spread on mounting boards to display wing patterns and colors, which are often important for species identification. Many molecular phylogenetic studies have used legs from pinned specimens as the primary source for DNA in order to preserve a morphological voucher, but the amount of available tissue is often limited. Preserving an entire specimen in a cryogenic freezer is ideal for DNA preservation, but without an easily accessible voucher it can make specimen identification, verification, and morphological work difficult. Here we present a procedure that creates accessible and easily visualized "wing vouchers" of individual Lepidoptera specimens, and preserves the remainder of the insect in a cryogenic freezer for molecular research. Wings are preserved in protective holders so that both dorsal and ventral patterns and colors can be easily viewed without further damage. Our wing vouchering system has been implemented at the University of Maryland (AToL Lep Collection) and the University of Florida (Florida Museum of Natural History, McGuire Center of Lepidoptera and Biodiversity), which are among two of the largest Lepidoptera molecular collections in the world.

Taxonomic revision of the tarantula genus Aphonopelma Pocock, 1901 (Araneae, Mygalomorphae, Theraphosidae) within the United States.

This systematic study documents the taxonomy, diversity, and distribution of the tarantula spider genus Aphonopelma Pocock, 1901 within the United States. By employing phylogenomic, morphological, and geospatial data, we evaluated all 55 nominal species in the United States to examine the evolutionary history of Aphonopelma and the group's taxonomy by implementing an integrative approach to species delimitation. Based on our analyses, we now recognize only 29 distinct species in the United States. We propose 33 new synonymies (Aphonopelma apacheum, Aphonopelma minchi, Aphonopelma rothi, Aphonopelma schmidti, Aphonopelma stahnkei = Aphonopelma chalcodes; Aphonopelma arnoldi = Aphonopelma armada; Aphonopelma behlei, Aphonopelma vogelae = Aphonopelma marxi; Aphonopelma breenei = Aphonopelma anax; Aphonopelma chambersi, Aphonopelma clarum, Aphonopelma cryptethum, Aphonopelma sandersoni, Aphonopelma sullivani = Aphonopelma eutylenum; Aphonopelma clarki, Aphonopelma coloradanum, Aphonopelma echinum, Aphonopelma gurleyi, Aphonopelma harlingenum, Aphonopelma odelli, Aphonopelma waconum, Aphonopelma wichitanum = Aphonopelma hentzi; Aphonopelma heterops = Aphonopelma moderatum; Aphonopelma jungi, Aphonopelma punzoi = Aphonopelma vorhiesi; Aphonopelma brunnius, Aphonopelma chamberlini, Aphonopelma iviei, Aphonopelma lithodomum, Aphonopelma smithi, Aphonopelma zionis = Aphonopelma iodius; Aphonopelma phanum, Aphonopelma reversum = Aphonopelma steindachneri), 14 new species (Aphonopelma atomicum sp. n., Aphonopelma catalina sp. n., Aphonopelma chiricahua sp. n., Aphonopelma icenoglei sp. n., Aphonopelma johnnycashi sp. n., Aphonopelma madera sp. n., Aphonopelma mareki sp. n., Aphonopelma moellendorfi sp. n., Aphonopelma parvum sp. n., Aphonopelma peloncillo sp. n., Aphonopelma prenticei sp. n., Aphonopelma saguaro sp. n., Aphonopelma superstitionense sp. n., and Aphonopelma xwalxwal sp. n.), and seven nomina dubia (Aphonopelma baergi, Aphonopelma cratium, Aphonopelma hollyi, Aphonopelma mordax, Aphonopelma radinum, Aphonopelma rusticum, Aphonopelma texense). Our proposed species tree based on Anchored Enrichment data delimits five major lineages: a monotypic group confined to California, a western group, an eastern group, a group primarily distributed in high-elevation areas, and a group that comprises several miniaturized species. Multiple species are distributed throughout two biodiversity hotspots in the United States (i.e., California Floristic Province and Madrean Pine-Oak Woodlands). Keys are provided for identification of both males and females. By conducting the most comprehensive sampling of a single theraphosid genus to date, this research significantly broadens the scope of prior molecular and morphological investigations, finally bringing a modern understanding of species delimitation in this dynamic and charismatic group of spiders.

Phylogenomics resolves a spider backbone phylogeny and rejects a prevailing paradigm for orb web evolution.

Spiders represent an ancient predatory lineage known for their extraordinary biomaterials, including venoms and silks. These adaptations make spiders key arthropod predators in most terrestrial ecosystems. Despite ecological, biomedical, and biomaterial importance, relationships among major spider lineages remain unresolved or poorly supported. Current working hypotheses for a spider "backbone" phylogeny are largely based on morphological evidence, as most molecular markers currently employed are generally inadequate for resolving deeper-level relationships. We present here a phylogenomic analysis of spiders including taxa representing all major spider lineages. Our robust phylogenetic hypothesis recovers some fundamental and uncontroversial spider clades, but rejects the prevailing paradigm of a monophyletic Orbiculariae, the most diverse lineage, containing orb-weaving spiders. Based on our results, the orb web either evolved much earlier than previously hypothesized and is ancestral for a majority of spiders or else it has multiple independent origins, as hypothesized by precladistic authors. Cribellate deinopoid orb weavers that use mechanically adhesive silk are more closely related to a diverse clade of mostly webless spiders than to the araneoid orb-weaving spiders that use adhesive droplet silks. The fundamental shift in our understanding of spider phylogeny proposed here has broad implications for interpreting the evolution of spiders, their remarkable biomaterials, and a key extended phenotype--the spider web.

An evaluation of sampling effects on multiple DNA barcoding methods leads to an integrative approach for delimiting species: a case study of the North American tarantula genus Aphonopelma (Araneae, Mygalomorphae, Theraphosidae).

The North American tarantula genus Aphonopelma provides one of the greatest challenges to species delimitation and downstream identification in spiders because traditional morphological characters appear ineffective for evaluating limits of intra- and interspecific variation in the group. We evaluated the efficacy of numerous molecular-based approaches to species delimitation within Aphonopelma based upon the most extensive sampling of theraphosids to date, while also investigating the sensitivity of randomized taxon sampling on the reproducibility of species boundaries. Mitochondrial DNA (cytochrome c oxidase subunit I) sequences were sampled from 682 specimens spanning the genetic, taxonomic, and geographic breadth of the genus within the United States. The effects of random taxon sampling compared traditional Neighbor-Joining with three modern quantitative species delimitation approaches (ABGD, P ID(Liberal), and GMYC). Our findings reveal remarkable consistency and congruence across various approaches and sampling regimes, while highlighting highly divergent outcomes in GMYC. Our investigation allowed us to integrate methodologies into an efficient, consistent, and more effective general methodological workflow for estimating species boundaries within the mygalomorph spider genus Aphonopelma. Taken alone, these approaches are not particularly useful - especially in the absence of prior knowledge of the focal taxa. Only through the incorporation of multiple lines of evidence, employed in a hypothesis-testing framework, can the identification and delimitation of confident species boundaries be determined. A key point in studying closely related species, and perhaps one of the most important aspects of DNA barcoding, is to combine a sampling strategy that broadly identifies the extent of genetic diversity across the distributions of the species of interest and incorporates previous knowledge into the "species equation" (morphology, molecules, and natural history).

An exploration of species boundaries in turret-building tarantulas of the Mojave Desert (Araneae, Mygalomorphae, Theraphosidae, Aphonopelma).

Tarantulas in the North American genus Aphonopelma are poorly known due to their challenging patterns of morphological variation and questionable taxonomy; few specimens can be confidently identified using existing keys or comparisons to original descriptions. In an effort to identify new strategies for resolving what has been characterized as a "taxonomic and nomenclatural nightmare", we employed five different approaches for delimiting species in a group of closely related tarantulas from the Mojave Desert in the southwestern United States. These methods included the application of single techniques (morphology, DNA barcoding, shared genealogical exclusivity among independent loci, and generalized mixed Yule coalescent) and an integrative approach that incorporates genealogical and ecological information. Results demonstrate that the taxonomy of these spiders as presently defined underestimates actual species-level diversity and the group is in need of revision. The number of species delimited by each approach, however, was variable and we argue that it is this discordance that emphasizes the importance of incorporating multiple lines of evidence into an integrative taxonomic framework that can be used for constructing robust taxonomic hypotheses for Aphonopelma species.

A reconsideration of the classification of the spider infraorder Mygalomorphae (Arachnida: Araneae) based on three nuclear genes and morphology.

BACKGROUND: The infraorder Mygalomorphae (i.e., trapdoor spiders, tarantulas, funnel web spiders, etc.) is one of three main lineages of spiders. Comprising 15 families, 325 genera, and over 2,600 species, the group is a diverse assemblage that has retained a number of features considered primitive for spiders. Despite an evolutionary history dating back to the lower Triassic, the group has received comparatively little attention with respect to its phylogeny and higher classification. The few phylogenies published all share the common thread that a stable classification scheme for the group remains unresolved. METHODS AND FINDINGS: We report here a reevaluation of mygalomorph phylogeny using the rRNA genes 18S and 28S, the nuclear protein-coding gene EF-1γ, and a morphological character matrix. Taxon sampling includes members of all 15 families representing 58 genera. The following results are supported in our phylogenetic analyses of the data: (1) the Atypoidea (i.e., antrodiaetids, atypids, and mecicobothriids) is a monophyletic group sister to all other mygalomorphs; and (2) the families Mecicobothriidae, Hexathelidae, Cyrtaucheniidae, Nemesiidae, Ctenizidae, and Dipluridae are not monophyletic. The Microstigmatidae is likely to be subsumed into Nemesiidae. Nearly half of all mygalomorph families require reevaluation of generic composition and placement. The polyphyletic family Cyrtaucheniidae is most problematic, representing no fewer than four unrelated lineages. CONCLUSIONS: Based on these analyses we propose the following nomenclatural changes: (1) the establishment of the family Euctenizidae (NEW RANK); (2) establishment of the subfamily Apomastinae within the Euctenizidae; and (3) the transfer of the cyrtaucheniid genus Kiama to Nemesiidae. Additional changes include relimitation of Domiothelina and Theraphosoidea, and the establishment of the Euctenizoidina clade (Idiopidae + Euctenizidae). In addition to these changes, we propose a "road map" for future sampling across the infraorder with the aim of solving many remaining questions that hinder mygalomorph systematics.

Phylogenetic reconsideration of Myrmekiaphila systematics with a description of the new trapdoor spider species Myrmekiaphila tigris (Araneae, Mygalomorphae, Cyrtaucheniidae, Euctenizinae) from Auburn, Alabama.

The trapdoor spider genus Myrmekiaphila currently comprises 11 nominal species. A recent molecular phylogenetic evaluation of the group identified a number of problems with respect to how species and species groups were delineated by Bond and Platnick in their 2007 taxonomic revision of the genus. We report herein the discovery of a new species, Myrmekiaphila tigrissp. n. The phylogenetic position of the species is evaluated using a molecular phylogenetic approach based on a set of mtDNA markers. Our preferred phylogenetic hypothesis supports the recognition of a new species and further highlights the need to more carefully investigate species boundaries within the genus. These results further indicate that palpal bulb morphology is rapidly evolving and has likely been a contributing factor in rendering a number of species paraphyletic with respect to the molecular data.