Evidence for Eurogondwana: the roles of dispersal, extinction and vicariance in the evolution and biogeography of Indo-Pacific Hormuridae (Scorpiones: Scorpionoidea)

Congruence between ultraconserved element-based matrices and phylotranscriptomic datasets in the scorpion Tree of Life

Scorpions are ancient and historically renowned for their potent venom. Traditionally, the systematics of this group of arthropods was supported by morphological characters, until recent phylogenomic analyses (using RNAseq data) revealed most of the higher-level taxa to be non-monophyletic. While these phylogenomic hypotheses are stable for almost all lineages, some nodes have been hard to resolve due to minimal taxonomic sampling (e.g. family Chactidae). In the same line, it has been shown that some nodes in the Arachnid Tree of Life show disagreement between hypotheses generated using transcritptomes and other genomic sources such as the ultraconserved elements (UCEs). Here, we compared the phylogenetic signal of transcriptomes vs. UCEs by retrieving UCEs from new and previously published scorpion transcriptomes and genomes, and reconstructed phylogenies using both datasets independently. We reexamined the monophyly and phylogenetic placement of Chactidae, sampling an additional chactid species using both datasets. Our results showed that both sets of genome-scale datasets recovered highly similar topologies, with Chactidae rendered paraphyletic owing to the placement of Nullibrotheas allenii. As a first step toward redressing the systematics of Chactidae, we establish the family Anuroctonidae (new family) to accommodate the genus Anuroctonus.

Morphological and genetic variability in cosmopolitan tardigrade species-Paramacrobiotus fairbanksi Schill, Förster, Dandekar & Wolf, 2010

Paramacrobiotus fairbanksi was described from Alaska (USA) based on integrative taxonomy and later reported from various geographical localities making it a true cosmopolitan species. The 'Everything is Everywhere' (EiE) hypothesis assumes that the geographic distribution of microscopic organisms is not limited by dispersal but by local environmental conditions, making them potentially cosmopolitan. In the present work we report four new populations of P. fairbanksi from the Northern Hemisphere which suggests that the 'EiE' hypothesis is true, at least for some tardigrade species. We also compared all known populations of P. fairbanksi at the genetic and morphological levels. The p-distances between COI haplotypes of all sequenced P. fairbanksi populations from Albania, Antarctica, Canada, Italy, Madeira, Mongolia, Spain, USA and Poland ranged from 0.002 to 0.005%. In total, twelve haplotypes (H1-H12) of COI gene fragments were identified. We also report statistically significant morphometrical differences of species even though they were cultured and bred in the same laboratory conditions. Furthermore, we also discuss differences in the potential distribution of two Paramacrobiotus species.

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

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

Two new long-rostrum cranefly species from the Cretaceous Iberian amber (Diptera, Limoniidae, Helius)

First record of the genus Helius-long-rostrum cranefly from Maestrazgo Basin (eastern Spain, Iberian Penisula) is documented. Two new fossil species of the genus Helius are described from Cretaceous Spanish amber and compared with other species of the genus known from fossil record with particular references to these known from Cretaceous period. Helius turolensis sp. nov. is described from San Just amber (Lower Cretaceous, upper Albian) Maestrazgo Basin, eastern Spain, and Helius hispanicus sp. nov. is described from Álava amber (Lower Cretaceous, upper Albian), Basque-Cantabrian Basin, northern Spain. The specific body morphology of representatives of the genus Helius preserved in Spanish amber was discussed in relation to the environmental conditions of the Maestrazgo Basin and Basque-Cantabrian Basin in Cretaceous.

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.

Monophyletic classification and information content

The connection between monophyly and efficient taxonomic diagnoses is elaborated. The inefficiency of nonmonophyletic groups is shown by reconstructing data matrices from hierarchical sets of diagnoses that are derived from apomorphies and read in order from highest to lowest rank. The practice of diagnosing nonmonophyletic groups either results in omitting data, resulting in errors in reconstructed datasets, or repeating character information to make up for the implied losses. Step-by-step demonstrations with hypothetical and real data are used as guidance. Provisions are made for missing, inapplicable and polymorphic data. Slow optimization (delayed transformation) is useful for choosing a state reconstruction in order to report apomorphies completely. The diagnoses of paraphyletic groups can be expressed in different ways, including regrafting derived clades, reanalyzing data with constraints, and reading the original diagnoses in a different order--the last is the least efficient. A cladistic version of the data compression ratio is proposed to quantify the diagnostic efficiency of a cladogram.

Small Molecules in the Venom of the Scorpion Hormurus waigiensis

Despite scorpion stings posing a significant public health issue in particular regions of the world, certain aspects of scorpion venom chemistry remain poorly described. Although there has been extensive research into the identity and activity of scorpion venom peptides, non-peptide small molecules present in the venom have received comparatively little attention. Small molecules can have important functions within venoms; for example, in some spider species the main toxic components of the venom are acylpolyamines. Other molecules can have auxiliary effects that facilitate envenomation, such as purines with hypotensive properties utilised by snakes. In this study, we investigated some non-peptide small molecule constituents of Hormurus waigiensis venom using LC/MS, reversed-phase HPLC, and NMR spectroscopy. We identified adenosine, adenosine monophosphate (AMP), and citric acid within the venom, with low quantities of the amino acids glutamic acid and aspartic acid also being present. Purine nucleosides such as adenosine play important auxiliary functions in snake venoms when injected alongside other venom toxins, and they may have a similar role within H. waigiensis venom. Further research on these and other small molecules in scorpion venoms may elucidate their roles in prey capture and predator defence, and gaining a greater understanding of how scorpion venom components act in combination could allow for the development of improved first aid.

Australian Scorpion Hormurus waigiensis Venom Fractions Show Broad Bioactivity Through Modulation of Bio-Impedance and Cytosolic Calcium

Scorpion venoms are a rich source of bioactive molecules, but characterisation of toxin peptides affecting cytosolic Ca2+, central to cell signalling and cell death, is limited. We undertook a functional screening of the venom of the Australian scorpion Hormurus waigiensis to determine the breadth of Ca2+ mobilisation. A human embryonic kidney (HEK293) cell line stably expressing the genetically encoded Ca2+ reporter GCaMP5G and the rabbit type 1 ryanodine receptor (RyR1) was developed as a biosensor. Size-exclusion Fast Protein Liquid Chromatography separated the venom into 53 fractions, constituting 12 chromatographic peaks. Liquid chromatography mass spectroscopy identified 182 distinct molecules with 3 to 63 components per peak. The molecular weights varied from 258 Da-13.6 kDa, with 53% under 1 kDa. The majority of the venom chromatographic peaks (tested as six venom pools) were found to reversibly modulate cell monolayer bioimpedance, detected using the xCELLigence platform (ACEA Biosciences). Confocal Ca2+ imaging showed 9/14 peak samples, with molecules spanning the molecular size range, increased cytosolic Ca2+ mobilization. H. waigiensis venom Ca2+ activity was correlated with changes in bio-impedance, reflecting multi-modal toxin actions on cell physiology across the venom proteome.

An annotated catalogue of the scorpion types (Arachnida, Scorpiones) held in the Zoological Museum Hamburg. Part I: Parvorder Iurida Soleglad & Fet, 2003

Scorpions have always inspired fear and fascination because of the potency of their venoms. Although this ancient arachnid group is relatively small (ca. 2400 species) and has been continuously studied for the past century, the taxonomy is still in a state of flux and the correct identification of species often remains difficult. With more than 725 species and 9000 specimens, the Zoological Museum in Hamburg (ZMH) holds one of the largest and most significant scorpion collections in the world. This collection also contains many historical types described by Karl Kraepelin in the early 20th century. In order to contribute to a more stable scorpion taxonomy and to assist future scorpion researchers, we present an illustrated and annotated catalogue of the ZMH scorpion collections. The type specimens of 89 species belonging to 10 families are documented, imaged and assessed alongside their primary data. For practical reasons, only the taxa belonging to the parvorder Iurida Soleglad et Fet, 2003 are presented here whilst the Parvorder Buthida Soleglad et Fet, 2003 will be catalogued in a second publication.

Phylogenetic relationships and biogeographic history of the Australian trapdoor spider genus Conothele (Araneae: Mygalomorphae: Halonoproctidae): diversification into arid habitats in an otherwise tropical radiation

In Australia, climate change and continental drift have given rise to a complex biota comprising mesic specialists, arid-adapted lineages, and taxa that have arrived on the continent from Asia. We explore the phylogenetic diversity and biogeographic history of the Australian trapdoor spider genus Conothele Thorell, 1878 that is widespread in Australia’s monsoonal tropics and arid zone. We sequenced three mtDNA and five nuDNA markers from 224 specimens. We reconstructed the phylogenetic relationships among specimens and estimated the number of operational taxonomic units (OTUs) using species delimitation methods. The timing of divergences was estimated and ancestral area reconstructions were conducted. We recovered 61 OTUs, grouped into four major clades; a single clade represented by an arboreal ecomorph, and three fossorial clades. The Australian Conothele had a crown age of ~19 million years, and ancestral area reconstructions showed a complex history with multiple transitions among the monsoonal tropics, central arid zone, south-west and Pilbara bioregion. Conothele arrived on the continent during periods of biotic exchange with Asia. Since then, Conothele has colonised much of the Australian arid and monsoonal zones, during a period of climatic instability. The Pilbara bioregion harbours high lineage diversity, emphasising the role of climate refugia.

The male sexual apparatus in the order Scorpiones (Arachnida): a comparative study of functional morphology as a tool to define hypotheses of homology

BACKGROUND

Insemination in scorpions is carried out by means of a partly sclerotized structure, the spermatophore, which is composed of two separate halves, the hemispermatophores. In most genera these reproductive structures can be used to differentiate species. However, many taxa such as the genus Euscorpius and the family Diplocentridae lack the morphological diversity observed in the copulatory organs of many other arthropods, rendering them useless for species level taxonomy. Such structural stasis, however, suggests that hemispermatophores have evolved relatively slowly and may thus provide a stronger phylogenetic signal for recognizing supra-generic ranks than previously thought. Based on the postulate that the phenotypic stability observed in some groups is the consequence of functional constraint, the most comprehensive comparative study of the male sexual apparatus to date was conducted for a complete reassessment of the morphology, phylogenetic value and hypotheses of homology of these structures.

RESULTS

Hemispermatophores, pre- and post-insemination spermatophores, as well as the inherent mechanisms of insemination, were studied across the whole order, allowing the recognition and description of a series of five basic bauplans for the capsular region. For the most part, these patterns appear to be consistent within each major taxonomic group, but several cases of incongruence between spermatophore morphology and taxonomy raises questions about the monophyly of some clades. The Bothriuridae are traditionally regarded as a basal scorpionoid family. However, except for the genus Lisposoma, bothriurid hemispermatophores and spermatophores are morphologically more similar to those of the Chactoidea than to those of scorpionoids. On the other hand, the male copulatory structures of the hormurid clade (Hormiops (Hormurus + Liocheles)) are more akin to those of Diplocentridae and Heteroscorpionidae than to those of other hormurids.

CONCLUSIONS

Spermatophore capsular patterns appears to be congruent with a recent phylogeny of the order Scorpiones based on phylogenomic data that placed Bothriuridae outside of Scorpionoidea and Liocheles outside of Hormuridae, in contradicton with earlier phylogenetic reconstructions based on morphology. This raises questions about the potential use of functionally constrained traits to assess the reliability of contradicting phylogenetic hypotheses and emphasizes the need for a thorough reassessment of the scorpion phylogenetic relationships.

Genetic and morphological analyses indicate that the Australian endemic scorpion Urodacus yaschenkoi (Scorpiones: Urodacidae) is a species complex

BACKGROUND

Australian scorpions have received far less attention from researchers than their overseas counterparts. Here we provide the first insight into the molecular variation and evolutionary history of the endemic Australian scorpion Urodacus yaschenkoi. Also known as the inland robust scorpion, it is widely distributed throughout arid zones of the continent and is emerging as a model organism in biomedical research due to the chemical nature of its venom.

METHODS

We employed Bayesian Inference (BI) methods for the phylogenetic reconstructions and divergence dating among lineages, using unique haplotype sequences from two mitochondrial loci (COXI, 16S) and one nuclear locus (28S). We also implemented two DNA taxonomy approaches (GMYC and PTP/dPTP) to evaluate the presence of cryptic species. Linear Discriminant Analysis was used to test whether the linear combination of 21 variables (ratios of morphological measurements) can predict individual's membership to a putative species.

RESULTS

Genetic and morphological data suggest that U. yaschenkoi is a species complex. High statistical support for the monophyly of several divergent lineages was found both at the mitochondrial loci and at a nuclear locus. The extent of mitochondrial divergence between these lineages exceeds estimates of interspecific divergence reported for other scorpion groups. The GMYC model and the PTP/bPTP approach identified major lineages and several sub-lineages as putative species. Ratios of several traits that approximate body shape had a strong predictive power (83-100%) in discriminating two major molecular lineages. A time-calibrated phylogeny dates the early divergence at the onset of continental-wide aridification in late Miocene and Pliocene, with finer-scale phylogeographic patterns emerging during the Pleistocene. This structuring dynamics is congruent with the diversification history of other fauna of the Australian arid zones.

DISCUSSION

Our results indicate that the taxonomic status of U. yaschenkoi requires revision, and we provide recommendations for such future efforts. A complex evolutionary history and extensive diversity highlights the importance of conserving U. yaschenkoi populations from different Australian arid zones in order to preserve patterns of endemism and evolutionary potential.

eadem figura manet: Measuring morphological convergence in diplocentrid scorpions (Arachnida : Scorpiones : Diplocentridae) under a multilocus phylogenetic framework

Morphology still plays a key role in the systematics and phylogenetics of most of the scorpion families and genera, including the Diplocentridae Karsch, 1880. The monophyly of this family, and the monophyly of its two subfamilies is supported by morphological characters; however, neither hypothesis has been tested using molecular data. The lack of a molecular phylogeny has prevented the study of the evolution of morphology within the family. Here, we examine the morphological evolution of several key character systems in diplocentrid systematics. We tested the monophyly of the Diplocentridae, and subsequently the validity of its two subfamilies using a five-locus phylogeny. We examined the variation and evolution of the shape of the carapace, the external surface of the pedipalp patella and the retrolateral surface of the pedipalp chelae of males and females. We also examined the phylogenetic signal of discrete and continuous characters previously reported. We show that Diplocentridae is monophyletic, but Nebinae is nested within Diplocentrinae. Therefore, Nebinae is synonymised with Diplocentrinae (new synonymy). Finally, we show that a new character system proposed here, tarsal spiniform and macrosetal counts, retains high phylogenetic signal and circumscribes independently evolving substructures within this character system.

The Centipede Genus Scolopendra in Mainland Southeast Asia: Molecular Phylogenetics, Geometric Morphometrics and External Morphology as Tools for Species Delimitation

Seven Scolopendra species from the Southeast Asian mainland delimited based on standard external morphological characters represent monophyletic groups in phylogenetic trees inferred from concatenated sequences of three gene fragments (cytochrome c oxidase subunit 1, 16S rRNA and 28S rRNA) using Maximum likelihood and Bayesian inference. Geometric morphometric description of shape variation in the cephalic plate, forcipular coxosternite, and tergite of the ultimate leg-bearing segment provides additional criteria for distinguishing species. Colouration patterns in some Scolopendra species show a high degree of fit to phylogenetic trees at the population level. The most densely sampled species, Scolopendra dehaani Brandt, 1840, has three subclades with allopatric distributions in mainland SE Asia. The molecular phylogeny of S. pinguis Pocock, 1891, indicated ontogenetic colour variation among its populations. The taxonomic validation of S. dawydoffi Kronmüller, 2012, S. japonica Koch, 1878, and S. dehaani Brandt, 1840, each a former subspecies of S. subspinipes Leach, 1814 sensu Lewis, 2010, as full species was supported by molecular information and additional morphological data. Species delimitation in these taxonomically challenging animals is facilitated by an integrative approach that draws on both morphology and molecular phylogeny.

Phylogenomic resolution of scorpions reveals multilevel discordance with morphological phylogenetic signal

Scorpions represent an iconic lineage of arthropods, historically renowned for their unique bauplan, ancient fossil record and venom potency. Yet, higher level relationships of scorpions, based exclusively on morphology, remain virtually untested, and no multilocus molecular phylogeny has been deployed heretofore towards assessing the basal tree topology. We applied a phylogenomic assessment to resolve scorpion phylogeny, for the first time, to our knowledge, sampling extensive molecular sequence data from all superfamilies and examining basal relationships with up to 5025 genes. Analyses of supermatrices as well as species tree approaches converged upon a robust basal topology of scorpions that is entirely at odds with traditional systematics and controverts previous understanding of scorpion evolutionary history. All analyses unanimously support a single origin of katoikogenic development, a form of parental investment wherein embryos are nurtured by direct connections to the parent's digestive system. Based on the phylogeny obtained herein, we propose the following systematic emendations: Caraboctonidae is transferred to Chactoidea new superfamilial assignment: ; superfamily Bothriuroidea revalidated: is resurrected and Bothriuridae transferred therein; and Chaerilida and Pseudochactida are synonymized with Buthida new parvordinal synonymies: .

The genus Hormiops Fage, 1933 (Hormuridae, Scorpiones), a palaeoendemic of the South China Sea: systematics and biogeography

The monotypic genus Hormiops Fage, 1933 is so far only known from two groups of granitic islands off the coasts of Peninsular Malaysia and Vietnam. Examination of newly collected material from both archipelagos and of the type series of Hormiops davidovi Fage, 1933 reveals previously disregarded morphological differences sufficient to assign the Malaysian specimens to a distinct species, described here as Hormiops infulcra sp. nov. An updated diagnosis of the genus, as well as a dichotomic key enabling the determination of Hormiops from its close relatives, Hormurus Thorell, 1876 and Liocheles Sundevall, 1833 are also provided. The phylogenetic position, distribution pattern, and ecology of these insular scorpions suggest that they are palaeoendemics, remnants of a previously more widely distributed lineage. A biogeographical model is proposed for the genus based on these observations and on a synthesis of palaeogeographical and palaeoenvironmental data currently available for Sundaland.