Taxonomic Hypotheses Research Articles

Effects of tectonics and large scale climatic changes on the evolutionary history of Hyalomma ticks

Hyalomma Koch, 1844 are ixodid ticks that infest mammals, birds and reptiles, to which 27 recognized species occur across the Afrotropical, Palearctic and Oriental regions. Despite their medical and veterinary importance, the evolutionary history of the group is enigmatic. To investigate various taxonomic hypotheses based on morphology, and also some of the mechanisms involved in the diversification of the genus, we sequenced and analysed data derived from two mtDNA fragments, three nuclear DNA genes and 47 morphological characters. Bayesian and Parsimony analyses based on the combined data (2242 characters for 84 taxa) provided maximum resolution and strongly supported the monophyly of Hyalomma and the subgenus Euhyalomma Filippova, 1984 (including H. punt Hoogstraal, Kaiser and Pedersen, 1969). A predicted close evolutionary association was found between morphologically similar H. dromedarii Koch, 1844, H. somalicum Tonelli Rondelli, 1935, H. impeltatum Schulze and Schlottke, 1929 and H. punt, and together they form a sister lineage to H. asiaticum Schulze and Schlottke, 1929, H. schulzei Olenev, 1931 and H. scupense Schulze, 1919. Congruent with morphological suggestions, H. anatolicum Koch, 1844, H. excavatum Koch, 1844 and H. lusitanicum Koch, 1844 form a clade and so also H. glabrum Delpy, 1949, H. marginatum Koch, 1844, H. turanicum Pomerantzev, 1946 and H. rufipes Koch, 1844. Wide scale continental sampling revealed cryptic divergences within African H. truncatum Koch, 1844 and H. rufipes and suggested that the taxonomy of these lineages is in need of a revision. The most basal lineages in Hyalomma represent taxa currently confined to Eurasia and molecular clock estimates suggest that members of the genus started to diverge approximately 36.25 million years ago (Mya). The early diversification event coincides well with the collision of the Indian and Eurasian Plates, an event that was also characterized by large scale faunal turnover in the region. Using S-Diva, we also propose that the closure of the Tethyan seaway allowed for the genus to first enter Africa approximately 17.73Mya. In concert, our data supports the notion that tectonic events and large scale global changes in the environment contributed significantly to produce the rich species diversity currently found in the genus Hyalomma.

Guidelines and quantitative standards to improve consistency in cetacean subspecies and species delimitation relying on molecular genetic data

AbstractTaxonomy is an imprecise science that delimits the evolutionary continuum into discrete categories. For marine mammals, this science is complicated by the relative lack of morphological data for taxa that inhabit remote and often vast ranges. We provide guidelines to promote consistency in studies relying primarily on molecular genetic data to delimit cetacean subspecies from both populations and species. These guidelines identify informational needs: basis for the taxonomic hypothesis being tested, description of current taxonomy, description of relevant life history, sample distribution, sample size, number and sequence length of genetic markers, description of measures taken to ensure data quality, summary statistics for the genetic markers, and analytical methods used to evaluate the genetic data. We propose an initial set of quantitative and qualitative standards based on the types of data and analytical methods most readily available at present. These standards are not expected to be rigidly applied. Rather, they are meant to encourage taxonomic arguments that are consistent and transparent. We hope professional societies, such as the Society for Marine Mammalogy, will adopt quantitative standards that evolve as new data types and analytical methods become widely available.

An integrative systematic framework helps to reconstruct skeletal evolution of glass sponges (Porifera, Hexactinellida)

BackgroundGlass sponges (Class Hexactinellida) are important components of deep-sea ecosystems and are of interest from geological and materials science perspectives. The reconstruction of their phylogeny with molecular data has only recently begun and shows a better agreement with morphology-based systematics than is typical for other sponge groups, likely because of a greater number of informative morphological characters. However, inconsistencies remain that have far-reaching implications for hypotheses about the evolution of their major skeletal construction types (body plans). Furthermore, less than half of all described extant genera have been sampled for molecular systematics, and several taxa important for understanding skeletal evolution are still missing. Increased taxon sampling for molecular phylogenetics of this group is therefore urgently needed. However, due to their remote habitat and often poorly preserved museum material, sequencing all 126 currently recognized extant genera will be difficult to achieve. Utilizing morphological data to incorporate unsequenced taxa into an integrative systematics framework therefore holds great promise, but it is unclear which methodological approach best suits this task.ResultsHere, we increase the taxon sampling of four previously established molecular markers (18S, 28S, and 16S ribosomal DNA, as well as cytochrome oxidase subunit I) by 12 genera, for the first time including representatives of the order Aulocalycoida and the type genus of Dactylocalycidae, taxa that are key to understanding hexactinellid body plan evolution. Phylogenetic analyses suggest that Aulocalycoida is diphyletic and provide further support for the paraphyly of order Hexactinosida; hence these orders are abolished from the Linnean classification. We further assembled morphological character matrices to integrate so far unsequenced genera into phylogenetic analyses in maximum parsimony (MP), maximum likelihood (ML), Bayesian, and morphology-based binning frameworks. We find that of these four approaches, total-evidence analysis using MP gave the most plausible results concerning congruence with existing phylogenetic and taxonomic hypotheses, whereas the other methods, especially ML and binning, performed more poorly. We use our total-evidence phylogeny of all extant glass sponge genera for ancestral state reconstruction of morphological characters in MP and ML frameworks, gaining new insights into the evolution of major hexactinellid body plans and other characters such as different spicule types.ConclusionsOur study demonstrates how a comprehensive, albeit in some parts provisional, phylogeny of a larger taxon can be achieved with an integrative approach utilizing molecular and morphological data, and how this can be used as a basis for understanding phenotypic evolution. The datasets and associated trees presented here are intended as a resource and starting point for future work on glass sponge evolution.

New endemic mammal species for Europe: Sciurus meridionalis (Rodentia, Sciuridae)

Combining genetic, morphological and geographical data, we re-evaluate Sciurus meridionalis , Lucifero 1907 as a tree squirrel species. The species, previously considered a subspecies of the Eurasian red squirrel, Sciurus vulgaris , is endemic to South Italy with a disjunct distribution with respect to S. vulgaris . The new species has a typical, monomorphic coat colour characterized by a white ventral fur and a very dark-brown to blackish fur on the back, sides and tail. Specimens of S. meridionalis have a larger hind foot length and weigh about 35% more than live-caught S. vulgaris from northern Italy. S. meridionalis is larger than S. vulgaris specimens from three other regions in Italy for mandible length, skull width and skull (condylobasal) length, and principal component scores indicate significant shape differences of specimens from the Calabria population ( S. meridionalis ) compared to all other specimens ( S. vulgaris ). These morphological differences are further supported by genetic evidence at three mitochondrial markers (D-loop, cytochrome b and the DNA barcoding region COI) using the widest molecular dataset ever assembled for Sciurus vulgaris and S. meridionalis . All the investigated markers revealed exclusive haplotypes for S. meridionalis well separated from those of S. vulgaris and previously published results based on nuclear markers further support our taxonomic hypothesis. We suggest Calabrian black squirrel as common name for this new taxon.

New species and records in the fern genus Didymoglossum for the flora of Seychelles, with notes on the Southeast Asian D. motleyi complex (Hymenophyllaceae)

The fern flora of the Seychelles archipelago remains relatively poorly known. Recent projects involving the development of the Seychelles National Herbarium and study of key biodiversity areas have resulted in extensive explorations of the ferns on the granitic islands. Historical literature, newly collected specimens and older collections have been revised for the fern family Hymenophyllaceae as a prelude for a fern checklist, resulting in several discoveries. In Didymoglossum, specimens were found with a very unusual character: exsert sori. Revision of the specimens, including phylogenetic analyses, revealed that these belong to two distinct species: Didymoglossum beccarianum comb. nov. (until now only known from Southeast Asia) and a new species endemic to Seychelles, which is described as D. beaverianum below. The exact identity of the Southeast Asian species required to review a complex of species previously considered synonymous to D. motleyi. As a result, we propose a taxonomic hypothesis where Didymoglossum motleyi is in fact known from the type only (from Borneo); D. beccarianum includes the synonyms Trichomanes cognatum, T. sayeri and T. minutissimum and is widely distributed from Seychelles to the western Pacific Ocean and finally Didymoglossum (Trichomanes) cultratum comb. nov., which is maintained as a separate species (endemic to Fiji and known from the type only). We conclude by emphasizing the main diagnostic characters in this complex of species, including characters that have been neglected in the past.

Integrative taxonomy reveals the first record and a new species for the previously monotypic genus Tethytimea (Tethyida: Tethyidae) in the Gulf of Mexico.

The first record of the previous monotypic genus Tethytimea and the description of a new species from cryptic habitats of Gulf of Mexico are presented. Tethytimea carmelita sp. nov., is a red orange cushion shaped sponge (about 5 mm thick) with a tuberculate to granular surface. The spicular complement is formed by tylostyles (200-1120 µm length), smooth spheres (12.5-55 µm in diameter); megasters-spheroxyasters (12.5-90 µm in diameter); and micrasters in two categories: oxy-strongylasters (12.5-27.5 µm in diameter) and spherotylasters (2.5-25 µm in diameter). The new species differs from the only species known T. tylota (Hentschel, 1912) mainly by differences in the size and shape of spicules. T. tylota possesses tylostyles in two size categories; megasters include giant oxyspherasters up 250 µm and micrasters in a single category. Additionally, to the morphological characteristics, we integrated partial sequences of a large sub-unit ribosomal 28S rDNA gene region (D1-D2 domains), in order to establish the molecular taxonomic position of our new species (and genus). Tree topologies (Maximum Likelihood and Bayesian Inference) were congruent in phylogenetic hypothesis, retrieving the Order Tethyida as monophyletic. In this clade, the family Timeidae was separated from the other families Tethyidae + Hemiastrellidae. Inside this latter group and according to the taxonomic hypothesis based on morphology, Tethytimea carmelita sp. nov. was included in Tethyidae clade, together with a sequence of Tethya sp. (AY626300), forming a sister group with representatives of genera Xenospongia and Thectitethya. Our new species constitutes the second valid known species for the genus Tethytimea and the first record of genus for the Atlantic Ocean.

The status of amur beak gudgeon Microphysogobio amurensis (Taranetz 1937) inferred from complete mitochondrial genome analysis

The complete mitogenome sequence of Microphysogobio amurensis has been amplified and sequenced in this study. The overall base composition of M. amurensis mitogenome is: A (30%), C (26.8%), G (17.2%), T (26%), with an obvious A + T bias (56%). The assembled mitogenome, consisting of 16605 bp, has 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. To estimate the status of M. amurensis, all available mitogenomes of Microphysogobio were downloaded from GenBank for phylogenetic analysis. The result strongly supported the traditional taxonomic hypothesis that M. amurensis was sister to M. brevirostris and M. koreensis. However, taxonomic confusion on its generic assignment remains to be further studied, as this study and other relevant molecular studies not only suggested that Microphysogobio could be divided in two major clusters (viz. the Palearctic species group and the Oriental species group), but also that two allied genera (Biwia, Rostrogobio) were embedded within the Palearctic species group of Microphysogobio.

Integrative taxonomy of Leptonetela spiders (Araneae, Leptonetidae), with descriptions of 46 new species.

Extreme environments, such as subterranean habitats, are suspected to be responsible for morphologically inseparable cryptic or sibling species and can bias biodiversity assessment. A DNA barcode is a short, standardized DNA sequence used for taxonomic purposes and has the potential to lessen the challenges presented by a biotic inventory. Here, we investigate the diversity of the genus Leptonetela Kratochvíl, 1978 that is endemic to karst systems in Eurasia using DNA barcoding. We analyzed 624 specimens using one mitochondrial gene fragment (COI). The results show that DNA barcoding is an efficient and rapid species identification method in this genus. DNA barcoding gap and automatic barcode gap discovery (ABGD) analyses indicated the existence of 90 species, a result consistent with previous taxonomic hypotheses, and supported the existence of extreme male pedipalpal tibial spine and median apophysis polymorphism in Leptonetela species, with direct implications for the taxonomy of the group and its diversity. Based on the molecular and morphological evidence, we delimit and diagnose 90 Leptonetela species, including the type species Leptonetela kanellisi(Deeleman-Reinhold, 1971). Forty-six of them are previously undescribed. The female of Leptonetela zhai Wang & Li, 2011 is reported for the first time. Leptonetela tianxinensis (Tong & Li, 2008) comb. nov. is transferred from the genus Leptoneta Simon, 1872;the genus Guineta Lin & Li, 2010 syn. nov. is a junior synonym of Leptonetela; Leptonetela gigachela(Lin & Li, 2010) comb. nov. is transferred from Guineta. The genus Sinoneta Lin & Li, 2010 syn. nov. is a junior synonym of Leptonetela; Leptonetela notabilis(Lin & Li, 2010) comb. nov. and Leptonetela sexdigiti(Lin & Li, 2010) comb. nov. are transferred from Sinoneta; Leptonetela sanchahe Wang & Li nom. nov. is proposed as a replacement name for Sinoneta palmata(Chen et al, 2010) because Leptonetela palmata is preoccupied.

DNA sequence variation in the fruit tree Inga inicuil (Leguminosae: Mimosoideae) from contrasting altitude distinguishes two different species

Background: Inga inicuil is a leguminous tree in Veracruz, Mexico whose fruits are locally commercialized. One taxonomic hypothesis suggests that I. inicuil is a species with a wide altitudinal range, while another segregates I. paterno from I. inicuil by altitude and morphology. The aim of this study was to explore variation in non-coding regions from the chloroplast and nuclear genomes within individuals of I. inicuil from contrasting altitude.
 Hypothesis: Phylogenetic analyses with sequence data would separate exemplars of I. inicuil in two different species and as the case with other metabolites, the sugar content in the sarcotesta would vary with altitude.
 Studied species: Inga inicuil 
 Study site: The mountainous region of Coatepec and the coastal region of Tolome and San Pancho in Veracruz, Mexico.
 Methods: Representative individuals of I. inicuil were selected from localities with contrasting altitude. Maximum Likelihood and Bayesian Phylogenetic Inference approaches were used for phylogenetic analyses with sequence data from the ITS1-5.8S-ITS2 and trn L-F. Sugar content in ripe fruit was measured using a refractometer.
 Results: Sugar content was not related to altitude or with sequence variation. However, sequences from the trn L-F revealed an insertion/deletion of approximately 309 nucleotides present only in trees growing at the coastal plain. Phylogenetic analyses with sequence data support the hypothesis that I. inicuil and I. paterno are two different species.
 Conclusions: The remarkable differences of sequence data from the trn L-F within the species make necessary further research increasing taxon sampling along with its distribution range for clarifying its taxonomy.

Taxonomy as a hypothesis: testing the status of the Bermuda buckeye butterfly Junonia coenia bergi (Lepidoptera: Nymphalidae)

AbstractSpecies determination and definition in eukaryotes have traditionally been based on morphology, with little focus on genetic differentiation. Molecular methods allow for the independent assessment of morphology‐based taxonomic hypotheses. Three criteria used to define a full species for taxonomic purposes are morphological distinction, formation of a monophyletic lineage, and reproductive isolation. Junonia butterflies (Nymphalidae) are becoming an important experimental model system, but the taxonomy of many New World Junonia species is unclear. One of these species is J. coenia, which contains the subspecies J. coenia coenia, J. coenia grisea and J. coenia bergi. Previous studies suggest that J. coenia grisea may meet the criteria for full species status. Therefore, we evaluated the geographically isolated and rarely studied Bermuda buckeye butterfly J. coenia bergi to determine if it was similarly distinct. Physical examination of specimens and phylogenetic and population genetic analyses of mitochondrial cytochrome c oxidase subunit I, nuclear wingless, and complete mitochondrial genome sequences suggest that while J. coenia bergi is smaller in body size than many Junonia and has distinctive ventral hindwing colouration, it does not form a monophyletic lineage and shows indications of continued gene flow with North American mainland J. coenia coenia populations. Thus, J. coenia bergi does not meet the criteria for full species designation, but geographic isolation, morphological distinctiveness, and cultural importance suggest that it remain recognized as a subspecies of J. coenia. Similar analyses will be useful for addressing further taxonomic questions in Junonia and other taxa, especially where morphology‐based taxonomic determinations are ambiguous.

Host specificity versus plasticity: testing the morphology-based taxonomy of the endoparasitic copepod family Splanchnotrophidae with COI barcoding

The Splanchnotrophidae is a family of highly modified endoparasitic copepods known to infest nudibranch or sacoglossan sea slug hosts. Most splanchnotrophid species appear to be specific to a single host, but some were reported from up to nine different host species. However, splanchnotrophid taxonomy thus far is based on external morphology, and taxonomic descriptions are, mostly, old and lack detail. They are usually based on few specimens, with intraspecific variability rarely reported. The present study used molecular data for the first time to test (1) the current taxonomic hypotheses, (2) the apparently strict host specificity of the genusIsmailaand (3) the low host specificity of the genusSplanchnotrophuswith regard to the potential presence of cryptic species. Phylogenetic analyses herein used sequences of the barcoding region of the cytochrome oxidase I (COI) gene from 40 specimens representing 13 species of five genera. Species delimitation approaches include distance and barcoding gap analyses, haplotype networks and diagnostic nucleotides. Molecular results are largely compatible with the commonly accepted, morphology-based taxonomy of the Splanchnotrophidae. Strict host specificity could be confirmed for twoIsmailaspecies. COI analyses also supported the idea thatSplanchnotrophus angulatusis host-promiscuous. InIsmaila, morphology seems more suitable than barcoding to display speciation events via host switches in a recent Chilean radiation. InSplanchnotrophus, some genetic structure suggests ongoing diversification, which should be investigated further given the inadequate morphology-based taxonomy. The present study thus supports the presence of two different life history strategies in splanchnotrophids, which should be explored integratively.

Morphological, chemical and species delimitation analyses provide new taxonomic insights into two groups of Rinodina.

The genus Rinodina (Physciaceae), with approximately 300 species, has been subject to few phylogenetic studies. Consequently taxonomic hypotheses in Rinodina are largely reliant on phenotypic data, while hypotheses incorporating DNA dependent methods remain to be tested. Here we investigate Rinodina degeliana/R. subparieta and the Rinodina mniaraea group, which previously have not been subjected to comprehensive molecular and phenotypic studies. We conducted detailed morphological, anatomical, chemical, molecular phylogenetic and species delimitation studies including 24 newly sequenced specimens. We propose that Rinodina degeliana and R. subparieta are conspecific and that chemical morphs within the R. mniaraea group should be recognized as distinct species. We also propose the placement of the recently described genus Oxnerella in Physciaceae.

A test of color-based taxonomy in nudibranchs: Molecular phylogeny and species delimitation of the Felimida clenchi (Mollusca: Chromodorididae) species complex

Traditionally, species identification in nudibranch gastropods relies heavily on body color pattern. The Felimida clenchi species complex, a group of brightly colored Atlantic and Mediterranean species in the family Chromodorididae, has a history of exceptional controversy and discussion among taxonomists. The most widely accepted hypothesis is that the complex includes four species (Felimida clenchi, F. neona, F. binza and F. britoi), each with a characteristic body color pattern. In this study, we investigated the taxonomic value of coloration in the Felimida clenchi complex, using molecular phylogenetics, species-delimitation analyses (ABGD, GMYC, PTP), haplotype-network methods, and the anatomy of the reproductive system. None of our analyses recovered the traditional separation into four species. Our results indicated the existence of three species, a result inconsistent with previous taxonomic hypotheses. We distinguished an undescribed species of Felimida and redefined the concepts of F. clenchi and F. binza, both highly polychromatic species. For the first time, molecular data support the existence of extreme color polymorphism in chromatic nudibranch species, with direct implications for the taxonomy of the group and its diversity. The polychromatism observed in the F. clenchi complex apparently correlates with the regional occurrence of similar color patterns in congeneric species, suggesting different mimicry circles. This may represent a parallel in the marine environment to the mechanisms that play a major role in the diversification of color in terrestrial and fresh-water chromatic groups, such as heliconian butterflies.

DNA barcodes as a tool in biodiversity research: testing pre-existing taxonomic hypotheses in Delphic Apollo butterflies (Lepidoptera, Papilionidae)

Numerous studies have demonstrated that DNA barcoding is an effective tool for detecting DNA clusters, which can be viewed as operational taxonomic units (OTUs), useful for biodiversity research. Frequently, the OTUs in these studies remained unnamed, not connected with pre-existing taxonomic hypotheses, and thus did not really contribute to feasible estimation of species number and adjustment of species boundaries. For the majority of organisms, taxonomy is very complicated with numerous, often contradictory interpretations of the same characters, which may result in several competing checklists using different specific and subspecific names to describe the same sets of populations. The highly species-rich genus Parnassius (Lepidoptera: Papilionidae) is but one example, such as several mutually exclusive taxonomic systems have been suggested to describe the phenotypic diversity found among its populations. Here we provide an explicit flow chart describing how the DNA barcodes can be combined with the existing knowledge of morphology-based taxonomy and geography (sympatry versus allopatry) of the studied populations in order to support, reject or modify the pre-existing taxonomic hypotheses. We then apply this flow chart to reorganize the taxa within the Parnassius delphius species group, solving long-standing taxonomic problems.

Phylogenetic relationships of the New World titi monkeys (Callicebus): first appraisal of taxonomy based on molecular evidence.

BackgroundTiti monkeys, Callicebus, comprise the most species-rich primate genus—34 species are currently recognised, five of them described since 2005. The lack of molecular data for titi monkeys has meant that little is known of their phylogenetic relationships and divergence times. To clarify their evolutionary history, we assembled a large molecular dataset by sequencing 20 nuclear and two mitochondrial loci for 15 species, including representatives from all recognised species groups. Phylogenetic relationships were inferred using concatenated maximum likelihood and Bayesian analyses, allowing us to evaluate the current taxonomic hypothesis for the genus.ResultsOur results show four distinct Callicebus clades, for the most part concordant with the currently recognised morphological species-groups—the torquatus group, the personatus group, the donacophilus group, and the moloch group. The cupreus and moloch groups are not monophyletic, and all species of the formerly recognized cupreus group are reassigned to the moloch group. Two of the major divergence events are dated to the Miocene. The torquatus group, the oldest radiation, diverged c. 11 Ma; and the Atlantic forest personatus group split from the ancestor of all donacophilus and moloch species at 9–8 Ma. There is little molecular evidence for the separation of Callicebus caligatus and C. dubius, and we suggest that C. dubius should be considered a junior synonym of a polymorphic C. caligatus.ConclusionsConsidering molecular, morphological and biogeographic evidence, we propose a new genus level taxonomy for titi monkeys: Cheracebus n. gen. in the Orinoco, Negro and upper Amazon basins (torquatus group), Callicebus Thomas, 1903, in the Atlantic Forest (personatus group), and Plecturocebus n. gen. in the Amazon basin and Chaco region (donacophilus and moloch groups).Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-016-0142-4) contains supplementary material, which is available to authorized users.

Taxonomic hypotheses regarding the genus Gerbillus (Rodentia, Muridae, Gerbillinae) based on molecular analyses of museum specimens.

Methodological improvements now allow routine analyses of highly degraded DNA samples as found in museum specimens. Using these methods could be useful in studying such groups as rodents of the genus Gerbillus for which i) the taxonomy is still highly debated, ii) collection of fresh specimens may prove difficult. Here we address precise taxonomic questions using a small portion of the cytochrome b gene obtained from 45 dry skin/skull museum samples (from 1913 to 1974) originating from two African and three Asian countries. The specimens were labelled Gerbillus gerbillus, Gerbillus andersoni, Gerbillus nanus, Gerbillus amoenus, Gerbillus perpallidus and Gerbillus pyramidum, and molecular results mostly confirmed these assignations. The close relationship between Gerbillus nanus (Asian origin) and Gerbillus amoenus (African origin) confirmed that they represent vicariant sibling species which differentiated in allopatry on either side of the Red Sea. In the closely related Gerbillus perpallidus and Gerbillus pyramidum, specimens considered as belonging to one Gerbillus pyramidum subspecies (Gerbillus pyramidum floweri) appeared closer to Gerbillus perpallidus suggesting that they (Gerbillus pyramidum floweri and Gerbillus perpallidus) may represent a unique species, distributed on both sides of the Nile River, for which the correct name should be Gerbillus floweri. Furthermore, the three other Gerbillus pyramidum subspecies grouped together with no apparent genetic structure suggesting that they may not yet represent genetically differentiated lineages. This study confirms the importance of using these methods on museum samples, which can open new perspectives in this particular group as well as in other groups of interest.

Geographic variation, null hypotheses, and subspecies limits in the California Gnatcatcher: A response to McCormack and Maley

ABSTRACT We interpreted the results of nuclear DNA sequencing to be inconsistent with the recognition of California Gnatcatcher (Polioptila californica) subspecies. McCormack and Maley (2015) suggested that our data did support 2 taxa, one of which was P. c. californica, listed as Threatened under the Endangered Species Act (ESA). We summarize here how 2 sets of researchers with access to the same data reached different conclusions by including different analyses. We included the southern subspecies' boundary from the taxonomy of Atwood (1991), the taxonomic basis for the ESA listing, which resulted in an Analysis of Molecular Variance that provided no support for subspecies. In contrast, using a novel taxonomic hypothesis without precedent in the literature, McCormack and Maley (2015) found statistically significant FST values for 2 loci, which they suggested supports P. c. californica. We propose that our mitochondrial and nuclear data had sufficient power to capture geographical structure at either the...

Hominin taxic diversity: Fact or fantasy?

In this review of the evidence for and against taxic diversity within the hominin clade, we begin by looking at the logic and the history of simple "ladder-like" interpretations of the hominin fossil record. We then look at the hominin fossil record in a series of time intervals and use current published evidence about the first and last appearance dates of each taxon to decide whether a species or specimens should be included in one, or more, of the intervals. Within each time interval, we consider the strength of the evidence that more than one hominin species is sampled. Decisions about whether taxonomic diversity exists depend on what alpha taxonomic hypotheses are used and although we use a relatively speciose interpretation of the hominin fossil record, we also explore what impact more inclusive interpretations of alpha taxonomy would have on assessments of hominin taxic diversity. With the exception of the oldest (7-5 Ma) all of the other time intervals have in our judgment at least one well-supported example of taxic diversity and several have multiple examples. In summary, not all new hominin taxa are created equally, but while taxic diversity may not be as prevalent as some have claimed, it is a feature of the hominin clade from 4 Ma until c.40 ka years ago.

New contributions to the molecular systematics and the evolution of host-plant associations in the genus Chrysolina (Coleoptera, Chrysomelidae, Chrysomelinae).

The taxonomic circumscription of the large and diverse leaf beetle genus Chrysolina Motschulsky is not clear, and its discrimination from the closely related genus Oreina Chevrolat has classically been controversial. In addition, the subgeneric arrangement of the species is unstable, and proposals segregating Chrysolina species into new genera have been recently suggested. In this context, the availability of a phylogenetic framework would provide the basis for a stable taxonomic system, but the existing phylogenies are based on few taxa and have low resolution. In the present study we perform a phylogenetic analysis based on mitochondrial (cox1 and rrnL) and nuclear (H3) DNA sequences from a sample of fifty-two Chrysolina species representing almost half of the subgeneric diversity of the group (thirty out of sixty-five subgenera) and most of the morphological, ecological and karyological variation in the genus. In addition, five Oreina species from two subgenera have also been analysed. The resulting phylogeny is used to evaluate some of the most relevant taxonomic hypotheses for Chrysolina, and also to reconstruct its ancestral host plant associations in a Bayesian framework. Our findings support the paraphyly of Chrysolina as currently defined due to the inclusion of Oreina, the monophyly of the Chrysolina (plus Oreina) species including the divergent Chrysolina (Polysticta) vigintimaculata (Clark, 1864), and enable inferences of deep-level evolutionary relationships among the studied subgenera. The plant family Lamiaceae is inferred as the ancestral host of the study group, whose evolution is characterized by continuous host-shifting among pre-existing host plant families. Some Chrysolina clades include mixtures of species with different levels of diet breadth, indicating that niche width has varied through time.

Spintharus flavidusin the Caribbean—a 30 million year biogeographical history and radiation of a ‘widespread species’

The Caribbean island biota is characterized by high levels of endemism, the result of an interplay between colonization opportunities on islands and effective oceanic barriers among them. A relatively small percentage of the biota is represented by ‘widespread species,’ presumably taxa for which oceanic barriers are ineffective. Few studies have explored in detail the genetic structure of widespread Caribbean taxa. The cobweb spider Spintharus flavidus Hentz, 1850 (Theridiidae) is one of two described Spintharus species and is unique in being widely distributed from northern N. America to Brazil and throughout the Caribbean. As a taxonomic hypothesis, Spintharus “flavidus” predicts maintenance of gene flow among Caribbean islands, a prediction that seems contradicted by known S. flavidus biology, which suggests limited dispersal ability. As part of an extensive survey of Caribbean arachnids (project CarBio), we conducted the first molecular phylogenetic analysis of S. flavidus with the primary goal of testing the ‘widespread species’ hypothesis. Our results, while limited to three molecular loci, reject the hypothesis of a single widespread species. Instead this lineage seems to represent a radiation with at least 16 species in the Caribbean region. Nearly all are short range endemics with several distinct mainland groups and others are single island endemics. While limited taxon sampling, with a single specimen from S. America, constrains what we can infer about the biogeographical history of the lineage, clear patterns still emerge. Consistent with limited overwater dispersal, we find evidence for a single colonization of the Caribbean about 30 million years ago, coinciding with the timing of the GAARLandia landbridge hypothesis. In sum, S. “flavidus” is not a single species capable of frequent overwater dispersal, but rather a 30 my old radiation of single island endemics that provides preliminary support for a complex and contested geological hypothesis.