Sarah L. Boyer

Deep genetic divergences in Aoraki denticulata (Arachnida, Opiliones, Cyphophthalmi): a widespread ‘mite harvestman’ defies DNA taxonomy

Aoraki denticulata (Arachnida, Opiliones, Cyphophthalmi, Pettalidae), a widespread ‘mite harvestman’ endemic to the South Island of New Zealand, is found in leaf littler habitats throughout Nelson and Marlborough, and as far south as Arthurs Pass. We investigated the phylogeography and demographic history of A. denticulata in the first genetic population‐level study within Opiliones. A total of 119 individuals from 17 localities were sequenced for 785 bp of the gene cytochrome c oxidase subunit I; 102 of these individuals were from the Aoraki subspecies A. denticulata denticulata and the remaining 17 were from the subspecies A. denticulata major. An extraordinarily high degree of genetic diversity was discovered in A. denticulata denticulata, with average uncorrected p‐distances between populations as high as 19.2%. amova, average numbers of pairwise differences, and pairwise FST values demonstrated a significant amount of genetic diversity both within and between populations of this subspecies. Phylogenetic analysis of the data set revealed many well‐supported groups within A. denticulata denticulata, generally corresponding to clusters of specimens from single populations with short internal branches, but separated by long branches from individuals from other populations. No haplotypes were shared between populations of the widespread small subspecies, A. denticulata denticulata. These results indicate a subspecies within which very little genetic exchange occurs between populations, a result consistent with the idea that Cyphophthalmi are poor dispersers. The highly structured populations and deep genetic divergences observed in A. denticulata denticulata may indicate the presence of cryptic species. However, we find a highly conserved morphology across sampling localities and large genetic divergences within populations from certain localities, equivalent to those typically found between populations from different localities. Past geological events may have contributed to the deep genetic divergences observed between sampling localities; additionally, the high divergence within populations of A. denticulata denticulata suggests that the rate of COI evolution may be accelerated in this taxon. In contrast, the larger subspecies A. denticulata major shows much less differentiation between and within sampling localities, suggesting that it may disperse more easily than its smaller counterpart. The fact that the remarkable genetic divergences within populations of A. denticulata denticulata from certain localities are equivalent to divergences between localities poses a challenge to the rapidly spreading practice of DNA taxonomy

Spirirestis rafaelensis gen. et sp. nov. (Cyanophyceae), a new cyanobacterial genus from arid soils

A new cyanobacterial genus and species, Spirirestis rafaelensis , is described from soils of a semi-arid Utah juniper community in the San Rafael Swell, Utah, U.S.A. Multiple isolates of the organism have only been recovered from well-crusted, protected, and totally undisturbed soils at this site; it has not been recovered from any of the other 40 sites we have examined in the Sonoran, Mojave, Chihuahuan, Colorado Plateau, or Great Basin deserts during the last eight years. Spirirestis shares morphological characters with members of both the Scytonemataceae and Microchaetaceae, principally heterocyte formation, false branching, and presence of sheath. However, unlike the trichomes of all previously described genera in these families, most trichomes of Spirirestis are tightly spiraled. 16S rRNA sequence data suggest that Spirirestis is more closely related to members of the Microchaetaceae than to members of the Scytonemataceae or Rivulariaceae. The data also support the maintenance of Microchaetaceae and Scytonemataceae as separate families.

A new model Gondwanan taxon: systematics and biogeography of the harvestman family Pettalidae (Arachnida, Opiliones, Cyphophthalmi), with a taxonomic revision of genera from Australia and New Zealand

The phylogeny of the temperate Gondwanan harvestman family Pettalidae is investigated by means of a new morphological matrix of 45 characters, and DNA sequence data from five markers, including two nuclear ribosomal genes (18S rRNA and 28S rRNA), one nuclear protein coding gene (histone H3), and two mitochondrial genes–one protein coding (cytochrome c oxidase subunit I) and one ribosomal (16S rRNA). Phylogenetic analyses using an array of homology schemes (dynamic and static), criteria (parsimony and maximum likelihood), and sampling strategies (optimal trees versus Bayesian phylogenetics) all agree on the monophyly of Pettalidae as well as several of its subclades, each of which is restricted to a modern landmass. While most genera as traditionally defined are monophyletic, Rakaia and Neopurcellia, distributed across Queensland (Australia) and New Zealand, are not. Instead, the species from Queensland, previously described under three genera, constitute a well‐supported clade, suggesting that in this case biogeography prevails over traditional taxonomy. A taxonomic emendation of the genera from Queensland and New Zealand is presented, and the new genus Aoraki is erected to include the species of the New Zealand denticulata group. A biogeographical hypothesis of the relationships of the former temperate Gondwana landmasses (with the exception of Madagascar) is presented, although ambiguity in the deep nodes of the pettalid tree renders such inference provisional. The data suggest that neither the South African fauna, the New Zealand fauna nor the Australian fauna is monophyletic but instead monophyly is found at smaller geographic scales (e.g., Western Australia, Queensland, NE South Africa).

A CLADISTIC ANALYSIS OF THE CYPHOPHTHALMID GENERA (OPILIONES, CYPHOPHTHALMI)

Abstract A phylogenetic analysis of the genera of Cyphophthalmi is undertaken by studying 32 morphological characters in 43 species representing all families and most genera. The analysis is complemented with a molecular analysis using 18S rRNA and 28S rRNA sequence data of twelve cyphophthalmid species representing ten genera. The Cyphophthalmi are monophyletic, as are the families Stylocellidae and Pettalidae. However, the families Sironidae, Ogoveidae, and Neogoveidae are not monophyletic. Relationships among families need more data, but molecular characters strongly support the monophyly of Troglosironidae + Neogoveidae. Rooting the cyphophthalmid tree by using sequence data of one Eupnoi, one Dyspnoi, and one Laniatores results in two alternatives, one proposing a sister group relationship of Stylocellidae to the remaining taxa, or alternatively Pettalidae (with Suzukielus?) as sister group of the remaining cyphophthalmids. The position of Troglosiro, Suzukielus, Metasiro, Huitaca, and the epigean “Neogovea” mexasca are re-evaluated and discussed.

'Moa's Ark' or 'Goodbye Gondwana': is the origin of New Zealand's terrestrial invertebrate fauna ancient, recent, or both?

Evaluating the hypothesis of New Zealand’s total submersion during the Oligocene requires the strictest tests, including sound phylogenetic data and dating of phylogenies. Although New Zealand has been traditionally considered to host ancient biota that originated by vicariance after it separated from Australia ~80u2009Mya, the ancient origins of its biota have been recently questioned, with some authors even suggesting that all current land organisms had to arrive to the islands after it re-emerged from the ocean 22u2009million years ago. Here we examine examples of short-range endemic soil-dwelling invertebrates and find compelling evidence that at least some of them are the result of old lineages that diversified in New Zealand before the hypothesised submersion event 22u2009million year ago. We conclude that New Zealand indeed has old lineages as well as recently diversified lineages and compare this situation with that of other more stable areas of the Neotropics.

A DNA-barcoding approach to identifying juvenile freshwater mussels (Bivalvia:Unionidae) recovered from naturally infested fishes

Abstract We developed a multilocus deoxyribonucleic acid (DNA)-barcoding approach to identify newly transformed juvenile mussels collected from naturally infested fishes in a federally protected waterway that is home to a diverse mussel community, the St Croix River (Minnesota/Wisconsin, USA). We used new and publicly available data downloaded from GenBank to build reference databases for identified adult mussels. We assessed the efficacy of the mitochondrial loci cytochrome oxidase c subunit I (COI) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) for DNA barcoding. We concluded that the barcoding gap between average intra- and interspecific genetic distances is wider for ND1 than for COI, but both loci perform well for species identification in character-based phylogenetic analyses. Almost every species formed a monospecific clade with high bootstrap and posterior-probability support. We obtained newly transformed juvenile mussels by collecting individuals of 3 different fish species that were infested with unionid larvae. We held the fish in aquaria until the mussels emerged naturally. We then extracted DNA and sequenced our loci of interest. When sequences from the juveniles were included in phylogenetic analyses, they grouped with single species (or, in one case, a pair of closely related species) with high bootstrap and posterior-probability support. Identifying juveniles using morphology alone is difficult and, in some cases, impossible. Therefore, our approach will be useful to researchers interested in the relationship between unionid mussels and their fish hosts.

Phylogeography of the harvestman genus Metasiro (Arthropoda, Arachnida, Opiliones) reveals a potential solution to the Pangean paradox

At both global and local scales, mite harvestmen (Opiliones, Cyphophthalmi) have been shown to have achieved their current global distribution strictly through vicariance. However, the implicit low dispersal capability of this group does not explain how they expand their ranges and come to occupy enormous landmasses prior to rifting. To investigate at the population level the limited vagility that characterizes the suborder generally, and how its dispersal capacity determines diversification dynamics, range expansion, and historical biogeography, we examined as a test case the phylogeography of the genus Metasiro. This genus consists of three widely separated, morphologically cryptic species that inhabit the Southeastern United States. Distances between sampling sites spanned a range of geographic scales, from 4xa0m to over 500xa0km. Population structure was inferred from fragments of six loci (three mitochondrial, three nuclear) amplified from 221 specimens. We tested for population structure and gene flow, constructed a dated phylogeny of the genus, and developed a program for estimating the effective population size with confidence intervals. Individuals of Metasiro americanus demonstrate remarkable population structure at scales of less than 25xa0m, but populations vary in their haplotypic diversity, and some exhibit evidence of historical gene flow. The estimated timing of cladogenesis within the genus accords closely with the geological history of the North American coastline, and the three species are at the endpoints of large watersheds. This suggests that mite harvestman lineages expand their ranges by hydrochory, providing for the first time a plausible mechanism whereby these animals dispersed across Pangea despite their low vagility in stable environments.

New species of mite harvestmen from the Wet Tropics of Queensland, Australia, with commentary on biogeography of the genus Austropurcellia (Opiliones: Cyphophthalmi: Pettalidae)

Abstract Cyphophthalmi, commonly known as mite harvestmen, are a suborder of cryptic Opiliones with a global distribution. The genus Austropurcellia Juberthie 1988 is a lineage of mite harvestmen currently known from a small number of localities in the forests of Queensland, Australia. We describe four new species of Austropurcellia (A. alata, A. culminis, A. despectata, and A. vicina) from museum lots; each new species is known from only a single collection and few specimens. We present the first key to the species of Austropurcellia, a catalogue of known collecting localities, and a distribution map. Although our current knowledge of the diversity and distribution of this genus is certainly incomplete, it is clear that these narrow-range endemics have great potential as a system for understanding the role of historical forest fragmentation in the evolution of rainforest animals.

A multilocus phylogeny of Podoctidae (Arachnida, Opiliones, Laniatores) and parametric shape analysis reveal the disutility of subfamilial nomenclature in armored harvestman systematics

The taxonomy and systematics of the armored harvestmen (suborder Laniatores) are based on various sets of morphological characters pertaining to shape, armature, pedipalpal setation, and the number of articles of the walking leg tarsi. Few studies have tested the validity of these historical character systems in a comprehensive way, with reference to an independent data class, i.e., molecular sequence data. We examined as a test case the systematics of Podoctidae, a family distributed throughout the Indo-Pacific. We tested the validity of the three subfamilies of Podoctidae using a five-locus phylogeny, and examined the evolution of dorsal shape as a proxy for taxonomic utility, using parametric shape analysis. Here we show that two of the three subfamilies, Ibaloniinae and Podoctinae, are non-monophyletic, with the third subfamily, Erecananinae, recovered as non-monophyletic in a subset of analyses. Various genera were also recovered as non-monophyletic. As first steps toward revision of Podoctidae, the subfamilies Erecananinae Roewer, 1912 and Ibaloniinae Roewer, 1912 are synonymized with Podoctinae Roewer, 1912 new synonymies, thereby abolishing unsubstantiated subfamilial divisions within Podoctidae. We once again synonymize the genus Paralomanius Goodnight & Goodnight, 1948 with Lomanius Roewer, 1923 revalidated. We additionally show that eggs carried on the legs of male Podoctidae are not conspecific to the males, falsifying the hypothesis of paternal care in this group.

Phylogeny and biogeography of the mite harvestmen (Arachnida : Opiliones : Cyphophthalmi) of Queensland, Australia, with a description of six new species from the rainforests of the Wet Tropics

Abstract. The Wet Tropics of Queensland, Australia, represent the largest remaining fragment of vast rainforests that once covered the entire continent. Over the past few decades the Wet Tropics bioregion has received much attention from biologists interested in the effect of climate change on diversity and distribution of rainforest animals. However, most such studies have focused on vertebrates, and despite considerable interest in the biota of the area, the diversity of many of Wet Tropics invertebrate taxa remains poorly known. Here we describe six new species of mite harvestman from the area, identified using a combination of morphological and molecular data. Our study represents the first detailed phylogenetic study of the genus Austropurcellia, and provides insight into the historical biogeography of these dispersal-limited arachnids.