Ingi Agnarsson

University of Iceland | HI

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 classifi...

Islands—whether classic oceanic islands or habitat islands such as isolated thermal vents, mountain tops, or caves—often promote the diversification of lineages that colonize them. We examined CO1 mtDNA sequence divergences within the tailless whip spider genus Phrynus Lamarck, 1809 (Amblypygi: Phrynidae) among oceanic islands and among cave ’islan...

Spiders are notoriously solitary and cannibalistic, with instances of colonial or social lifestyles in only about 50-60, or ~0.1% of 50,000 described species. Population analyses indicate that most colonies consist of multiple cohorts formed by close relatives. Territorial social spiders facultatively form colonies by interlinking individual webs,...

The spatial distribution of parasitoids is closely linked to the distribution and ecological requirements of their hosts. Several studies have documented changes in the fauna composition of parasitoids in response to elevation, but data on parasitoids associated with spiders are missing. The koinobiont ichneumonid wasp Zatypota anomala is strictly...

Net-casting spiders (Deinopidae) comprise a charismatic family with an enigmatic evolutionary history. There are 67 described species of deinopids, placed among three genera, Deinopis, Menneus, and Asianopis, that are distributed globally throughout the tropics and subtropics. Deinopis and Asianopis, the ogre-faced spiders, are best known for their...

The spider genus Episinus Walckenaer, 1809 currently contains 66 species worldwide, mostly in warm temperate to tropical areas. This paper describes two new Chinese Episinus species: E. ornithorrhynchus sp. nov. (♂♀) and E. papilionaceous sp. nov. (♀). We add these two new and one known Episinus species to the phylogenetic data matrix of Liu et al....

Detritus‐based, bell‐shaped cobwebs are an ideal model to research the plasticity of web architecture due to clearly separate defense and foraging components. We performed a thorough field investigation on the web architectures of Campanicola campanulata to research its cobweb architecture variation during the growth process and analyzed the energy...

Natural silks crafted by spiders comprise some of the most versatile materials known. Artificial silks–based on the sequences of their natural brethren–replicate some desirable biophysical properties and are increasingly utilized in commercial and medical applications today. To characterize the repertoire of protein sequences giving silks their bio...

The Caribbean Archipelago is a biodiversity hotspot that plays a key role in developing our understanding of how dispersal ability affects species formation. In island systems, species with intermediate dispersal abilities tend to exhibit greater diversity, as may be the case for many of the salticid lineages of the insular Caribbean. Here, we use...

Island biogeographers have long sought to elucidate the mechanisms behind biodiversity genesis. The Caribbean presents a unique stage on which to analyze the diversification process, due to the geologic diversity among the islands and the rich biotic diversity with high levels of island endemism. The colonization of such islands may reflect geologi...

In an ongoing effort to expand knowledge of the Chinese cobweb spider fauna (Theridiidae), the genus Meotipa Simon, 1894 is reviewed. Two new species are described, Meotipa pseudopicturata sp. nov. , Meotipa striata sp. nov. , and five known species are redescribed: Meotipa argyrodiformis (Yaginuma, 1952), Meotipa pulcherrima (Mello-Leitão, 1917),...

Planetary extinction of biodiversity underscores the need for taxonomy. Here, we scrutinize spider taxonomy over the last decade (2008–2018), compiling 2083 published accounts of newly described species. We evaluated what type of data were used to delineate species, whether data were made freely available, whether an explicit species hypothesis was...

Dispersal ability can affect levels of gene flow thereby shaping species distributions and richness patterns. The intermediate dispersal model of biogeography (IDM) predicts that in island systems, species diversity of those lineages with an intermediate dispersal potential is the highest. Here, we tested this prediction on long-jawed spiders (Tetr...

Sinopoda spiders are a diverse group with limited dispersal ability. They are remarkably sympatric among related species, which often results in misidentification and incorrect matching of sexes. In order to understand the evolutionary relationships and revise the taxonomy problems in this genus, we offer the first molecular phylogeny of Sinopoda ....

Eight cobweb spider species building a detritus-based, bell-shaped retreat from China are reported in the current paper, including five new Campanicola species and three known species: Campanicola anguilliformis Li & Liu, sp. nov. , Campanicola falciformis Li & Liu, sp. nov. , Campanicola heteroidea Li & Liu, sp. nov. , Campanicola tauricornis Li &...

An extensive ongoing survey of Caribbean arachnids continues to uncover, across multiple genera and families, greater species richness than hitherto appreciated. Here, we focus on a clade of jumping spiders endemic to the Caribbean, currently all placed in the genus Antillattus. Phylogenetic analyses were conducted on Antillattus s. l., and the gro...

The spider major ampullate (MA) silk exhibits high tensile strength and extensibility and is typically a blend of MaSp1 and MaSp2 proteins with the latter comprising glycine–proline–glycine–glycine-X repeating motifs that promote extensibility and supercontraction. The MA silk from Darwin's bark spider ( Caerostris darwini ) is estimated to be two...

The Greater Antilles is one of the planet’s recognized biodiversity hotspots (6,8). The area is complex both geologically (e.g. landbridge or Wallacean fragment islands, volcanic or Darwinian islands, uplifted coral shelves) and geographically (complex topography and diverse climates). These factors make it an important model system for studying di...

The Caribbean biodiversity hotspot harbors vast reserves of undiscovered species. A large-scale inventory of Caribbean arachnids (CarBio) is uncovering new species across the arachnid tree of life, and allowing inference of the evolutionary history that has generated this diversity. Herein we describe ten new species of Heteroonops (Oonopidae, or g...

Background Modern molecular analyses are often inconsistent with pre-cladistic taxonomic hypotheses, frequently indicating higher richness than morphological taxonomy estimates. Among Caribbean spiders, widespread species are relatively few compared to the prevalence of single island endemics. The taxonomic hypothesis Gasteracantha cancriformis cir...

Vicariance and dispersal events, combined with intricate global climatic history, have left an imprint on the spatiotemporal distribution and diversity of many organisms. Anelosimus cobweb spiders (Theridiidae), are organisms ranging in behavior from solitary to highly social,l with a cosmopolitan distribution in temperate- to-tropical areas. Their...

Spintharus is a genus of spiders that contained only two species until 2018 when it was demonstrated that a ‘widespread’ species was instead composed of multiple short-range endemics. This note redescribes Spintharus gracilis Keyserling and describes a new species of Spintharus (Araneae, Theridiidae), S. levergersp. nov. , both based on specimens f...

The Caribbean archipelago offers one of the best natural arenas for testing biogeographic hypotheses. The intermediate dispersal model of biogeography (IDM) predicts variation in species richness among lineages on islands to relate to their dispersal potential. To test this model, one would need background knowledge of dispersal potential of lineag...

Vicariance biogeography seeks geo-physical explanations for disjunct distributions of organisms. Optimally, vicariance hypotheses are tested on the basis of the comparison of unrelated lineages of organisms that share geographic arenas. The fundamental approach is to marry geology and biology in the study of current and historical patterns of biodi...

Darwin's bark spider (Caerostris darwini) produces giant orb webs from dragline silk that can be twice as tough as other silks, making it the toughest biological material. This extreme toughness comes from increased extensibility relative to other draglines. We show C. darwini dragline-producing major ampullate (MA) glands highly express a novel si...

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...

Group-living behaviour is rare in spiders but has evolved repeatedly, yielding several species, some showing cooperation among close kin, and others living in colonies where each female builds its own web and is territorial. The most frequent origins of group living are seen in the cobweb spiders (Theridiidae) that commonly build three-dimensional...

Group-living behaviour is rare in spiders but has evolved repeatedly, yielding several species, some showing cooperation among close kin, and others living in colonies where each female builds its own web and is territorial. The most frequent origins of group living are seen in the cobweb spiders (Theridiidae) that commonly build three-dimensional...

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 evolve...

Island systems provide excellent arenas to test evolutionary hypotheses pertaining to gene flow and diversification of dispersal-limited organisms. Here we focus on an orbweaver spider genus Cyrtognatha (Tetragnathidae) from the Caribbean, with the aims to reconstruct its evolutionary history, examine its biogeographic history in the archipelago, a...

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 evolve...

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 evolve...

The Caribbean archipelago offers one of the best natural arenas for testing biogeographic hypotheses. The intermediate dispersal model of biogeography (IDM) predicts variation in species richness among lineages on islands to relate to their dispersal potential. To test this model, one would need background knowledge of dispersal potential of lineag...

Organismal variation in dispersal ability can directly affect levels of gene flow amongst populations, therefore importantly shaping species distributions and species richness patterns. The intermediate dispersal model of biogeography (IDM) predicts that in island systems, species diversity of those lineages with an intermediate dispersal potential...

Six new Colombian species of Otiothops (O. besotes sp. n., O. doctorstrange sp. n., O. chicaque sp. n., O. vaupes sp. n.) and Fernandezina (F. andersoni sp. n., F. eduardoi sp. n.) are described. Diagnostic illustrations and distribution maps are provided for all of the new species, along with new records for O. macleayi Banks, 1929 and O. amazonic...

Island systems provide excellent arenas to test evolutionary hypotheses pertaining to gene flow and diversification of dispersal-limited organisms. Here we focus on an orbweaver spider genus Cyrtognatha (Tetragnathidae) from the Caribbean, with the aims to reconstruct its evolutionary history, describe its biogeographic history in the archipelago,...

Instances of sexual size dimorphism (SSD) provide the context for rigorous tests of biological rules of size evolution, such as Copes Rule (phyletic size increase), Renschs 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 fe...

Six new species of Otiothops (Otiothops besotes sp. n., O. doctorstrange sp. n., O. chicaque sp. n., O. waikana sp. n.) and Fernandezina (Fernandezina andersoni sp. n. and F. eduardoi sp. n.) from Colombia are described. Diagnostic illustrations and distributions maps are provided for all the new species and the new records of O. macleayi and O. am...

Aim The biogeography of terrestrial organisms across the Florida Keys archipelago is poorly understood. We used population genetics and spatioecological modeling of the Amblypygi Phrynus marginemaculatus to understand the genetic structure and metapopulation dynamics of Keys populations that are otherwise isolated by human development and ocean. L...

Although the Caribbean region is recognized as a major biodiversity hotspot, many megadiverse groups remain taxonomically understudied. The ornate spiders of the genus Spintharus Hentz, 1850 (Theridiidae, Araneae) are a good example where taxonomic boundaries have remained unclear. The genus shows profuse habitus and genitalic variation in the Cari...

Biological control using predators of key pest species is an attractive option in integrated pest management (IPM). Molecular gut analysis can provide an estimation of predator efficiency on a given prey. Here we use a combination of various experimental approaches, both in field and lab, to identify a potential biological control species of the co...

Spiders are famously aggressive and cannibalistic, and nearly all are solitary. Only about 20–25 out of over 46,000 known species display highly social behavior. Nevertheless, sociality has arisen in multiple families independently in spiders, probably via the ‘maternal care route’, with an apparent concentration of social species in the Neotropics...

Abstract The Asian citrus psyllid Diaphorina citri Kuwayama is a key pest of citrus as the vector of the bacterium causing the “huanglongbing” disease (HLB). To assess the global mtDNA population genetic structure, and possible dispersal history of the pest, we investigated genetic variation at the COI gene collating newly collected samples with al...

Correct identification of forensically important insects, such as flies in the family Calliphoridae, is a crucial step for them to be used as evidence in legal investigations. Traditional identification based on morphology has been effective, but has some limitations when it comes to identifying immature stages of certain species. DNA-barcoding, us...

Phylogenetic relationship within Calliphoridae based on a Bayesian analysis of nucleotide data from COI Numbers indicate posterior probability support values. Specimen voucher codes referred to in Table 1 are shown following species names. For specimens from Lesser Antilles (LA), the three capital letters before the voucher code refers to the name...

Phylogenetic relationship within Calliphoridae based on based on partitioned Bayesian analysis of the combined gene (COI and ITS2) data set Numbers indicate posterior probability support values. Specimen voucher codes referred to in Table 1 are shown following species names. For specimens from Lesser Antilles (LA), the three capital letters before...

Data Matrix COI

Data Matrix ITS2

Phylogenetic relationship within Calliphoridae based on a Bayesian analysis of nucleotide data from ITS Numbers indicate posterior probability support values. Specimen voucher codes referred to in Table 1 are shown following species names. For specimens from Lesser Antilles (LA), the three capital letters before the voucher code refers to the name...

Correct identification of forensically important insects, such as flies in the family Calliphoridae, is a crucial step for them to be used as evidence in legal investigations. Traditional identification based on morphology has been effective, but has some limitations when it comes to identify immature stages of certain species. DNA-barcoding, using...

Correct identification of forensically important insects, such as flies in the family Calliphoridae, is a crucial step for them to be used as evidence in legal investigations. Traditional identification based on morphology has been effective, but has some limitations when it comes to identify immature stages of certain species. DNA-barcoding, using...

The taxonomic history of the New Caledonian myrmecomorph spider, Anatea formicaria Berland (Hadrotarsinae: Theridiidae) is summarized, new records are presented and the female is figured for the first time. Two new species provisionally assigned to the genus are described from north-eastern Australia, A. monteithi Smith sp. nov. and A. elongata Smi...

Spider silks are the toughest known biological materials, yet are lightweight and virtually invisible to the human immune system, and they thus have revolutionary potential for medicine and industry. Spider silks are largely composed of spidroins, a unique family of structural proteins. To investigate spidroin genes systematically, we constructed t...

We describe a new species of the genus Sicarius Walckenaer, 1847 (Sicariidae), S. vallenato sp. nov., from the tropical dry forest in Valledupar and La Guajira, Colombia, representing the frst species of the genus from Colombia. The new species is diagnosed from other species of the genus, and compared in detail.

The phylogenetic relationships among genera of the subfamily Vespinae (yellowjackets and hornets) remain unclear. Yellowjackets and hornets constitute one of the only two lineages of highly eusocial wasps, and the distribution of key behavioral traits correlates closely with the current classification of the group. The potential of the Vespinae to...

The taxonomic impediment is characterized by dwindling classical taxonomic expertise, and slow pace of revisionary work, thus more rapid taxonomic assessments are needed. Here we pair rapid DNA barcoding methods with swift assessment of morphology in an effort to gauge diversity, establish species limits, and rapidly disseminate taxonomic informati...

The Caribbean Islands are a biodiversity hotspot harboring high levels of endemic biodiversity. In an effort to contribute to the characterization of invertebrate diversity in the region, we present an assessment of pseudoscorpion (Arachnida: Pseudoscorpiones) diversity and distribution with a focus on the superfamily Chthonioidea and the family Ol...

The Caribbean islands harbor rich biodiversity with high levels of single island endemism. Stretches of ocean between islands represent significant barriers to gene-flow. Yet some native species are widespread, indicating dispersal across oceans, even in wingless organisms like spiders. Argiopeargentata (Fabricius, 1775) is a large, charismatic, an...

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