Comparing ant morphology measurements from microscope and online AntWeb.org 2D z-stacked images.

Unprecedented technological advances in digitization and the steadily expanding open-access digital repositories are yielding new opportunities to quickly and efficiently measure morphological traits without transportation and advanced/expensive microscope machinery. A prime example is the AntWeb.org database, which allows researchers from all over the world to study taxonomic, ecological, or evolutionary questions on the same ant specimens with ease. However, the reproducibility and reliability of morphometric data deduced from AntWeb compared to traditional microscope measurements has not yet been tested. Here, we compared 12 morphological traits of 46 Temnothorax ant specimens measured either directly by stereomicroscope on physical specimens or via the widely used open-access software tpsDig utilizing AntWeb digital images. We employed a complex statistical framework to test several aspects of reproducibility and reliability between the methods. We estimated (i) the agreement between the measurement methods and (ii) the trait value dependence of the agreement, then (iii) compared the coefficients of variation produced by the different methods, and finally, (iv) tested for systematic bias between the methods in a mixed modeling-based statistical framework. The stereomicroscope measurements were extremely precise. Our comparisons showed that agreement between the two methods was exceptionally high, without trait value dependence. Furthermore, the coefficients of variation did not differ between the methods. However, we found systematic bias in eight traits: apart from one trait where software measurements overestimated the microscopic measurements, the former underestimated the latter. Our results shed light on the fact that relying solely on the level of agreement between methods can be highly misleading. In our case, even though the software measurements predicted microscope measurements very well, replacing traditional microscope measurements with software measurements, and especially mixing data collected by the different methods, might result in erroneous conclusions. We provide guidance on the best way to utilize virtual specimens (2D z-stacked images) as a source of morphometric data, emphasizing the method's limitations in certain fields and applications.

Broadly sympatric occurrence of two thief ant species Solenopsisfugax (Latreille, 1798) and S.juliae (Arakelian, 1991) in the East European Pontic-Caspian region (Hymenoptera, Formicidae) is disclosed.

This paper presents numeric morphology-based evidence on the broadly overlapping distribution of two thief ant species Solenopsisfugax (Latreille, 1798) and S.juliae (Arakelian, 1991) in the East European Pontic-Caspian region. The paper integrates two autonomous data collections and independent analyses performed by different researchers, using different equipment, considering different character combinations, and evaluating partially different samples. Five type series, the neotype series of Solenopsisfugax (Latreille 1798) and the type series of S.flavidula (Nylander, 1849), S. (Diplorhoptrum) fugax var. furtiva Santschi, 1934, S. (Diplorhoptrum) fugax var. pontica Santschi, 1934, S. (Diplorhoptrum) fugax var. scytica Santschi, 1934 were nested in one cluster and we propose the junior synonymy of the latter four taxa names with S.fugax. The other cluster contained only one type specimen of Solenopsisnitida (Dlussky & Radchenko, 1994) measured from AntWeb images. The naming of this cluster was based on both verbal statements and measurements of gynes given in the original description of Solenopsisjuliae (Arakelian, 1991), which represents the oldest available name for this cluster. Hence, S.nitida is proposed as junior synonym of S.juliae. Solenopsiscypridis Santschi, 1934 is raised to species rank based on investigation of worker and gyne type specimens.

From Parasitized to Healthy-Looking Ants (Hymenoptera: Formicidae): Morphological Reconstruction Using Algorithmic Processing.

BACKGROUND: Parasites cause predictable alternative phenotypes of host individuals. Investigating these parasitogenic phenotypes may be essential in cases where parasitism is common or taxa is described based on a parasitized individual. Ignoring them could lead to erroneous conclusions in biodiversity-focused research, taxonomy, evolution, and ecology. However, to date, integrating alternative phenotypes into a set of wild-type individuals in morphometric analysis poses extraordinary challenges to experts. This paper presents an approach for reconstructing the putative healthy morphology of parasitized ants using algorithmic processing. Our concept enables the integration of alternative parasitogenic phenotypes in morphometric analyses. METHODS: We tested the applicability of our strategy in a large pool of Cestoda-infected and healthy individuals of three Temnothorax ant species (T. nylanderi, T. sordidulus, and T. unifasciatus). We assessed the stability and convergence of morphological changes caused by parasitism across species. We used an artificial neural network-based multiclass classifier model to predict species based on morphological trait values and the presence of parasite infection. RESULTS: Infection causes predictable morphological changes in each species, although these changes proved to be species-specific. Therefore, integrating alternative parasitogenic phenotypes in morphometric analyses can be achieved at the species level, and a prior species hypothesis is required. CONCLUSION: Despite the above limitation, the concept is appropriate. Beyond parasitogenic phenotypes, our approach can also integrate morphometric data of an array of alternative phenotypes (subcastes in social insects, alternative morphs in polyphenic species, and alternative sexes in sexually dimorphic species) whose integrability had not been resolved before.

A striking color variation is detected in Poneratestacea Emery, 1895 (Hymenoptera, Formicidae) across its Western Palaearctic geographic range.

In this paper, we provide numeric morphology-based evidence that the dark-colored Poneracoarctatavar.lucida Emery, 1898, formerly considered a synonym of P.coarctata (Latreille, 1802), is conspecific with the lighter-colored Poneratestacea Emery, 1895. Species hypotheses are developed via NC-PART clustering, combined with Partitioning Algorithm based on Recursive Thresholding (PART), and via PCA combined with gap statistics. We obtained our results from an extensive dataset from the 10 continuous morphometric traits measured on 165 workers belonging to 73 nest samples. Linear discriminant analysis (LDA) confirmed the grouping of hypotheses generated by exploratory analyses with 100% classification success when all ten morphometric traits were involved. The Anatolian Turkish black and the predominantly European yellow samples, did not separate based on their morphometric characteristics. These two color variations broadly overlap in their geographic range in Anatolian Turkey. The investigated type series of Poneracoarctatavar.lucida Emery, 1898 (collected from Kazakhstan) fell within the P.testacea cluster instead of P.coarctata and is also classified with high certainty as P.testacea by confirmatory LDA. Therefore, we propose the synonymy of Poneracoarctatavar.lucida Emery, 1898 with Poneratestacea Emery, 1895. As no other morphological differences than color patterns were detected between the "black" and "pale" P.testacea samples, we hold that these populations constitute geographically occurring color variations of the same species. Finally, our quantitative morphology-based results show that relying on color patterns is not a robust approach in identifying European Ponera samples, particularly in the east, but using multivariate analyses of morphometric traits is advised instead.

Formerly considered rare, the ant species Cryptoponeochracea (Mayr, 1855) can be commonly detected using citizen-science tools.

Citizen science is a valuable tool for monitoring different species, especially in cases concerning truly rare and difficult-to-detect species where time-consuming field studies are limited and long-term research projects are uncertain. To better understand the distribution of the rarely collected Cryptoponeochracea (Mayr, 1855) (Hymenoptera, Formicidae) in Hungary, we obtained the occurrence data with photos uploaded by non-professionals to the page of the largest Hungarian Facebook group dealing with ants and a citizen-science website dealing with biological data collection. In this article, we expand the known distribution of C.ochracea to include 46 new records from Hungary and one from Serbia. With two historical records, this previously undersampled species has now been found 48 times in Hungary. Our results prove that social media platforms and other websites for citizen science projects offer new and useful opportunities for researchers to involve non-professionals in scientific work and, thus, obtain large amounts of valuable data, even for understudied arthropod species.

Ectoparasitic fungi Rickia wasmannii infection is associated with smaller body size in Myrmica ants.

Parasitism-generated negative effects on ant societies are multifaceted, implying individual and colony-level responses. Though laboratory based evidence shows that the sublethal fungus Rickia wasmannii is responsible for physiological and behavioral responses that may negatively affect individual workers' resilience and life expectancy in Myrmica ant workers, colony-level stress response to this parasite is largely unknown. Here, we focus on understanding of a long-term, colony-level effect of Rickia infection on Myrmica scabrinodis ant populations by tracking trait size-based changes. We collected worker specimens from infected and uninfected colonies from the same population in order to: (1) compare body size in response to parasitism, (2) assess the extent to which possible changes in size are associated with the severity of infection, and (3) investigate shifts in body size in response to infection over time by testing correlation of workers' ages and sizes. We found that workers from infected colonies were significantly smaller than their healthy congeners, but neither infection level nor the age of the workers showed significant correlation with the size in infected colonies. Decreasing body sizes in infected colonies can be ascribed to workers' mediated effect toward developing larvae, which are unable to attain the average body size before they pupate.

Taxonomic revision of the Malagasy Aphaenogaster swammerdami group (Hymenoptera: Formicidae).

BACKGROUND: Madagascar is famous for its extremely rich biodiversity; the island harbors predominantly endemic and threatened communities meriting special attention from biodiversity scientists. Continuing ongoing efforts to inventory the Malagasy ant fauna, we revise the species currently placed in the myrmicine genus Aphaenogaster Mayr. One species described from Madagascar, Aphaenogaster friederichsi Forel, is synonymized with the Palearctic A. subterranea Latreille syn. nov. This species is considered neither native to Madagascar nor established in the region. This revision focuses on the balance of species in the A. swammerdami group which are all endemic to Madagascar. METHODS: The diversity of the Malagasy Aphaenogaster fauna was assessed via application of multiple lines of evidence involving quantitative morphometric, qualitative morphological, and DNA sequence data. (1) Morphometric investigation was based on hypothesis-free Nest Centroid clustering (NC-clustering) combined with PArtitioning based on Recursive Thresholding (PART) to estimate the number of morphological clusters and determine the most probable boundaries between them. This protocol provides a repeatable and testable approach to find patterns in continuous morphometric data. Species boundaries and the reliability of morphological clusters recognized by these exploratory analyses were tested via confirmatory Linear Discriminant Analysis (LDA). (2) Qualitative, external morphological characteristics (e.g., shape, coloration patterns, setae number) were subjectively evaluated in order to create a priori grouping hypotheses, and confirm and improve species delimitation. (3) Species delimitation analyses based on mitochondrial DNA sequences from cytochrome oxidase I (COI) gene fragments were carried out to test the putative species previously delimited by morphological and morphometric analyses. RESULTS: Five species can be inferred based on the integrated evaluation of multiple lines of evidence; of these, three are new to science: Aphaenogaster bressleri sp. n., A. gonacantha (Emery, 1899), A. makay sp. n., A. sahafina sp. n., and A. swammerdami Forel, 1886. In addition, three new synonymies were found for A. swammerdami Forel, 1886 (A. swammerdami clara Santschi, 1915 syn. n., A. swammerdami curta Forel, 1891 syn. n. and A. swammerdami spinipes Santschi, 1911 syn. n.). Descriptions and redefinitions for each taxon and an identification key for their worker castes using qualitative traits and morphometric data are given. Geographic maps depicting species distributions and biological information regarding nesting habits for the species are also provided.

Insect morphometry is reproducible under average investigation standards.

Morphometric research is being applied to a growing number and variety of organisms. Discoveries achieved via morphometric approaches are often considered highly transferable, in contrast to the tacit and idiosyncratic interpretation of discrete character states. The reliability of morphometric workflows in insect systematics has never been a subject of focused research, but such studies are sorely needed. In this paper, we assess the reproducibility of morphometric studies of ants where the mode of data collection is a shared routine.We compared datasets generated by eleven independent gaugers, that is, collaborators, who measured 21 continuous morphometric traits on the same pool of individuals according to the same protocol. The gaugers possessed a wide range of morphometric skills, had varying expertise among insect groups, and differed in their facility with measuring equipment. We used intraclass correlation coefficients (ICC) to calculate repeatability and reproducibility values (i.e., intra- and intergauger agreements), and we performed a multivariate permutational multivariate analysis of variance (PERMANOVA) using the Morosita index of dissimilarity with 9,999 iterations.The calculated average measure of intraclass correlation coefficients of different gaugers ranged from R = 0.784 to R = 0.9897 and a significant correlation was found between the repeatability and the morphometric skills of gaugers (p = 0.016). There was no significant association with the magnification of the equipment in the case of these rather small ants. The intergauger agreement, that is the reproducibility, varied between R = 0.872 and R = 0.471 (mean R = 0.690), but all gaugers arrived at the same two-species conclusion. A PERMANOVA test revealed no significant gauger effect on species identity (R 2 = 0.69, p = 0.58).Our findings show that morphometric studies are reproducible when observers follow the standard protocol; hence, morphometric findings are widely transferable and will remain a valuable data source for alpha taxonomy.

The Myrmecofauna (Hymenoptera: Formicidae) of Hungary: Survey of Ant Species with an Annotated Synonymic Inventory.

Ants (Hymenoptera: Forimicidae) are exceedingly common in nature. They constitute a conspicuous part of the terrestrial animal biomass and are also considered common ecosystem engineers. Due to their key role in natural habitats, they are at the basis of any nature conservation policy. Thus, the first step in developing adequate conservation and management policies is to build a precise faunistic inventory. More than 16,000 valid ant species are registered worldwide, of which 126 are known to occur in Hungary. Thanks to the last decade's efforts in the Hungarian myrmecological research, and because of the constantly changing taxonomy of several problematic ant genera, a new checklist of the Hungarian ants is presented here. The state of the Hungarian myrmecofauna is also discussed in the context of other European countries' ant fauna. Six species (Formica lemani, Lasius nitidigaster, Tetramorium immigrans, T. staerckei, T. indocile and Temnothorax turcicus) have been reported for the first time in the Hungarian literature, nine taxon names were changed after systematic replacements, nomenclatorial act, or as a result of splitting formerly considered continuous populations into more taxa. Two species formerly believed to occur in Hungary are now excluded from the updated list. All names are nomenclaturally assessed, and complete synonymies applied in the Hungarian literature for a certain taxon are provided. Wherever it is not self-evident, comments are added, especially to explain replacements of taxon names. Finally, we present a brief descriptive comparison of the Hungarian myrmecofauna with the ant fauna of the surrounding countries. The current dataset is a result of ongoing work on inventorying the Hungarian ant fauna, therefore it is expected to change over time and will be updated once the ongoing taxonomic projects are completed.

Patterns of host use by brood parasitic Maculinea butterflies across Europe.

The range of hosts exploited by a parasite is determined by several factors, including host availability, infectivity and exploitability. Each of these can be the target of natural selection on both host and parasite, which will determine the local outcome of interactions, and potentially lead to coevolution. However, geographical variation in host use and specificity has rarely been investigated. Maculinea (= Phengaris) butterflies are brood parasites of Myrmica ants that are patchily distributed across the Palæarctic and have been studied extensively in Europe. Here, we review the published records of ant host use by the European Maculinea species, as well as providing new host ant records for more than 100 sites across Europe. This comprehensive survey demonstrates that while all but one of the Myrmica species found on Maculinea sites have been recorded as hosts, the most common is often disproportionately highly exploited. Host sharing and host switching are both relatively common, but there is evidence of specialization at many sites, which varies among Maculinea species. We show that most Maculinea display the features expected for coevolution to occur in a geographic mosaic, which has probably allowed these rare butterflies to persist in Europe. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.

Turning one into five: Integrative taxonomy uncovers complex evolution of cryptic species in the harvester ant Messor "structor".

Seed harvesting ants are ecosystem engineers that shape vegetation, nutrient cycles, and microclimate. Progress in ecological research is, however, slowed down by poor species delimitation. For example, it has not been resolved to date, how many species the European harvester ant Messor "structor" (Latreille, 1798) represents. Since its first description, splitting into additional taxa was often proposed but not accepted later on due to inconsistent support from morphology and ecology. Here, we took an iterative integrative-taxonomy approach - comparing multiple, independent data sets of the same sample - and used traditional morphometrics, Wolbachia symbionts, mitochondrial DNA, amplified fragment length polymorphism, and ecological niche modelling. Using the complementarity of the data sets applied, we resolved multiple, strong disagreements over the number of species, ranging from four to ten, and the allocation of individuals to species. We consider most plausible a five-species hypothesis and conclude the taxonomic odyssey by redescribing Messor structor, M. ibericus Santschi, 1925, and M. muticus (Nylander, 1849) stat.rev., and by describing two new species, M. ponticus sp.n. and M. mcarthuri sp.n. The evolutionary explanations invoked in resolving the various data conflicts include pronounced morphological crypsis, incomplete lineage-sorting or ongoing cospeciation of endosymbionts, and peripatric speciation - these ants' significance to evolutionary biology parallels that to ecology. The successful solution of this particular problem illustrates the usefulness of the integrative approach to other systematic problems of comparable complexity and the importance of understanding evolution to drawing correct conclusions on species' attributes, including their ecology and biogeography.

Taxonomic revision of imitating carpenter ants, Camponotus subgenus Myrmopytia (Hymenoptera, Formicidae) of Madagascar, using morphometry and qualitative traits.

The ant genus Camponotus (Mayr, 1861) is one of the most abundant and species rich ant genera in the Malagasy zoogeographical region. Although this group is commonly encountered, its taxonomy is far from complete. Here, we clarify the taxonomy of the Malagasy-endemic Camponotus subgenus Myrmopytia (Emery, 1920). Species delimitation was based on traditional morphological characters and multivariate morphometric analyses, including exploratory Nest Centroid clustering and confirmatory cross-validated Linear Discriminant Analysis. Four species are recognized: Camponotus imitator (Forel, 1891), Camponotus jodinasp. n., Camponotus karahasp. n., and Camponotus longicollissp. n. All four species appear to mimic co-occurring Aphaenogaster species. A diagnosis of the subgenus Myrmopytia, species descriptions, an identification key based on minor and major subcastes of workers, and the known geographical distribution of each species are provided.

Taxonomic revision of the Malagasy Camponotus grandidieri and niveosetosus species groups (Hymenoptera, Formicidae) using qualitative and quantitative morphology.

The Camponotus grandidieri species group and Camponotus niveosetosus species group of the Malagasy region are revised. Species delimitation was inferred from the evidence of both qualitative morphological analysis and multivariate morphometry. The multivariate method combined the Nest Centroid (NC)-clustering method and Partitioning Algorithm based on Recursive Thresholding (PART) function to generate hypotheses about species boundaries (clusters) based on 19 continuous morphological traits of minor workers. The proposed species hypotheses were tested by cumulative cross-validated Linear Discriminant Analysis (LOOCV-LDA) and Principal Component Analysis in a shape space (shape PCA). Morphometric ratios for the subsets of minor and major workers were used in species descriptions and redefinitions. Here, eight species are recognized, of which three are newly described and five are redescribed. Four species belong to the Camponotus grandidieri species group: auropubens Forel, efitra n. sp., grandidieri Forel, and maintikibo n. sp.; and four species belong to the Camponotus niveosetosus species group: descarpentriesi Santschi, madagascarensis Forel stat. rev., mita n. sp., and voeltzkowii Forel. Camponotus auropubens aldabrensis Forel and C. olivieri freyeri Santschi are synonymized under C. auropubens. Camponotus grandidieri atrabilis Santschi and C. grandidieri comorensis Santschi are synonymized under C. grandidieri. Illustrated species identification keys for both minor and major castes, taxonomic discussions, images, and distribution maps for each species superimposed on the ecoregions of Madagascar are also provided.

Taxonomy of Malagasy Nesomyrmex brevicornis species-group using conventional morphology-based approach.

Here we describe the diversity of the Malagasy Nesomyrmex brevicornis-group as the final installment of series describing the complete Malagasy Nesomyrmex fauna. In the current paper introduce the Nesomyrmex brevicornis-group, a newly outlined species group. We split this group from one of the four former groups, Nesomyrmex madecassus-group (sensu Csosz and Fisher 2015). The relatively small number of individuals available within the Nesomyrmex brevicornis-group relative to the large number of OTUs hampers the use of sophisticated statistical techniques to evaluate the morphological data. Instead, we assess the diversity of the Nesomyrmex brevicornis-group via a conventional morphology-based approach relying upon non-numeric characters (shape, sculpture, color etc.) recorded by simple eye inspection. Morphometric data are used as secondary data to confirm the most probable boundaries between species, but without employing statistical analyses. We rejected prior species hypotheses imposed by the primary approach if a non-overlapping range of a single index calculated from continuous numeric traits was found between two hypothesized species. Our methods render every species in this revisionary work separable via both salient features and morphometric traits. Our approach reveals the existence of nine morphologically distinct species, Nesomyrmex brevicornis sp. n., Nesomyrmex brunneus sp. n., Nesomyrmex cingulatus sp. n., Nesomyrmex edentates sp. n., Nesomyrmex flavigaster sp. n., Nesomyrmex longiceps sp. n., Nesomyrmex minutus sp. n., Nesomyrmex punctaticeps sp. n., and Nesomyrmex sellaris sp. n.. Geographic maps showing the distribution of each species are provided, along with an updated key to workers of Malagasy Nesomyrmex species groups that includes the newly outlined Nesomyrmex brevicornis-group.

Taxonomic revision of the Malagasy Nesomyrmex madecassus species-group using a quantitative morphometric approach.

Here we reveal the diversity of the next fragment of the Malagasy elements of the ant genus Nesomyrmex using a combination of advanced exploratory analyses on quantitative morphological data. The diversity of the Nesomyrmex madecassus species-group was assessed via hypothesis-free nest centroid clustering combined with recursive partitioning to estimate the number of clusters and determine the most probable boundaries between them. This combination of methods provides a highly automated species delineation protocol based on continuous morphometric data, and thereby it obviates the need of subjective interpretation of morphological patterns. Delimitations of clusters recognized by these exploratory analyses were tested via confirmatory Linear Discriminant Analysis (LDA). Our results suggest the existence of four morphologically distinct species, Nesomyrmex flavus sp. n., Nesomyrmex gibber, Nesomyrmex madecassus and Nesomyrmex nitidus sp. n.; all are described here and an identification key for their worker castes using morphometric data is given. Two members of the newly outlined madecasus species-group, Nesomyrmex flavus sp. n. and Nesomyrmex nitidus sp. n., represent true cryptic species. Geographic maps depicting species distributions and elevational information for the sites where populations of particular species were collected are also provided.

Toward Objective, Morphology-Based Taxonomy: A Case Study on the Malagasy Nesomyrmex sikorai Species Group (Hymenoptera: Formicidae).

Madagascar is one of the world's greatest biodiversity hotspots, meriting special attention from biodiversity scientists. It is an excellent testing ground for novel techniques in taxonomy that aim to increase classification objectivity and yield greater taxonomic resolving power. Here we reveal the diversity of a unique and largely unexplored fragment of the Malagasy ant fauna using an advanced combination of exploratory analyses on quantitative morphological data allowing for increased objectivity in taxonomic workflow. The diversity of the Nesomyrmex sikorai species-group was assessed via hypothesis-free nest-centroid-clustering combined with recursive partitioning to estimate the number of morphological clusters and determine the most probable boundaries between them. This combination of methods provides a highly automated and objective species delineation protocol based on continuous morphometric data. Delimitations of clusters recognized by these exploratory analyses were tested via confirmatory Linear Discriminant Analysis (LDA) and Multivariate Ratio Analysis (MRA). The final species hypotheses are corroborated by many qualitative characters, and the recognized species exhibit different spatial distributions and occupy different ecological regions. We describe and redescribe eight morphologically distinct species including six new species: Nesomyrmex excelsior sp. n., N. modestus sp. n., N. reticulatus sp. n., N. retusispinosus (Forel, 1892), N. rugosus sp. n., N. sikorai (Emery, 1896), N. striatus sp. n., and N. tamatavensis sp. n. An identification key for their worker castes using morphometric data is provided.

Taxonomic revision of the Malagasy members of the Nesomyrmex angulatus species group using the automated morphological species delineation protocol NC-PART-clustering.

Background. Applying quantitative morphological approaches in systematics research is a promising way to discover cryptic biological diversity. Information obtained through twenty-first century science poses new challenges to taxonomy by offering the possibility of increased objectivity in independent and automated hypothesis formation. In recent years a number of promising new algorithmic approaches have been developed to recognize morphological diversity among insects based on multivariate morphometric analyses. These algorithms objectively delimit components in the data by automatically assigning objects into clusters. Method. In this paper, hypotheses on the diversity of the Malagasy Nesomyrmex angulatus group are formulated via a highly automated protocol involving a fusion of two algorithms, (1) Nest Centroid clustering (NC clustering) and (2) Partitioning Algorithm based on Recursive Thresholding (PART). Both algorithms assign samples into clusters, making the class assignment results of different algorithms readily inferable. The results were tested by confirmatory cross-validated Linear Discriminant Analysis (LOOCV-LDA). Results. Here we reveal the diversity of a unique and largely unexplored fragment of the Malagasy ant fauna using NC-PART-clustering on continuous morphological data, an approach that brings increased objectivity to taxonomy. We describe eight morphologically distinct species, including seven new species: Nesomyrmex angulatus (Mayr, 1862), N. bidentatus sp. n., N. clypeatus sp. n., N. devius sp. n., N. exiguus sp. n., N. fragilis sp. n., N. gracilis sp. n., and N. hirtellus sp. n.. An identification key for their worker castes using morphometric data is provided. Conclusions. Combining the dimensionality reduction feature of NC clustering with the assignment of samples into clusters by PART advances the automatization of morphometry-based alpha taxonomy.

Revision of the Malagasy Camponotus edmondi species group (Hymenoptera, Formicidae, Formicinae): integrating qualitative morphology and multivariate morphometric analysis.

The Malagasy Camponotus edmondi species group is revised based on both qualitative morphological traits and multivariate analysis of continuous morphometric data. To minimize the effect of the scaling properties of diverse traits due to worker caste polymorphism, and to achieve the desired near-linearity of data, morphometric analyses were done only on minor workers. The majority of traits exhibit broken scaling on head size, dividing Camponotus workers into two discrete subcastes, minors and majors. This broken scaling prevents the application of algorithms that uses linear combination of data to the entire dataset, hence only minor workers were analyzed statistically. The elimination of major workers resulted in linearity and the data meet required assumptions. However, morphometric ratios for the subsets of minor and major workers were used in species descriptions and redefinitions. Prior species hypotheses and the goodness of clusters were tested on raw data by confirmatory linear discriminant analysis. Due to the small sample size available for some species, a factor known to reduce statistical reliability, hypotheses generated by exploratory analyses were tested with extreme care and species delimitations were inferred via the combined evidence of both qualitative (morphology and biology) and quantitative data. Altogether, fifteen species are recognized, of which 11 are new to science: Camponotus alamainasp. n., Camponotus androysp. n., Camponotus bevohitrasp. n., Camponotus galokosp. n., Camponotus matsilosp. n., Camponotus mifakasp. n., Camponotus orombesp. n., Camponotus tafosp. n., Camponotus tratrasp. n., Camponotus varatrasp. n., and Camponotus zavosp. n. Four species are redescribed: Camponotus echinoploides Forel, Camponotus edmondi André, Camponotus ethicus Forel, and Camponotus robustus Roger. Camponotus edmondi ernesti Forel, syn. n. is synonymized under Camponotus edmondi. This revision also includes an identification key to species for both minor and major castes, information on geographic distribution and biology, taxonomic discussions, and descriptions of intraspecific variation. Traditional taxonomy and multivariate morphometric analysis are independent sources of information which, in combination, allow more precise species delimitation. Moreover, quantitative characters included in identification keys improve accuracy of determination in difficult cases.

Taxonomic Synopsis of the Ponto-Mediterranean Ants of Temnothorax nylanderi Species-Group.

In the current revisionary work, the Temnothorax nylanderi species-group of myrmicine ants is characterized. Eighteen species belonging to this group in the Ponto-Mediterranean region are described or redefined based on an integrative approach that combines exploratory analyses of morphometric data and of a 658bp fragment of the mitochondrial gene for the cytochrome c oxidase subunit I (CO I). The species group is subdivided into five species complexes: T. angustifrons complex, T. lichtensteini complex, T. nylanderi complex, T. parvulus complex, T. sordidulus complex, and two species, T. angulinodis sp. n. and T. flavicornis (Emery, 1870) form their own lineages. We describe seven new species (T. angulinodis sp. n., T. angustifrons sp. n., T. ariadnae sp. n., T. helenae sp. n., T. lucidus sp. n., T. similis sp. n., T. subtilis sp. n.), raise T. tergestinus (FINZI, 1928) stat.n. to species level, and propose a new junior synonymy for T. saxonicus (SEIFERT, 1995) syn.n. (junior synonym of T. tergestinus). We describe the worker caste and provide high quality images and distributional maps for all eighteen species. Furthermore, we provide a decision tree as an alternative identification key that visually gives an overview of this species-group. We make the first application to Formicidae of the Semantic Phenotype approach that has been used in previous taxonomic revisions.

Diagnostic survey of Malagasy Nesomyrmex species-groups and revision of hafahafa group species via morphology based cluster delimitation protocol.

Madagascar and its surrounding islands are among the world's greatest biodiversity hotspots, harboring predominantly endemic and threatened communities meriting special attention from biodiversity scientists. Building on the considerable efforts in recent years to inventory the Malagasy ant fauna, the myrmicine genus Nesomyrmex is reviewed and (1) subdivided into four major groups based on salient morphological features corroborated by numeric morphology: angulatus-, hafahafa-, madecassus- and sikorai-groups, and (2) the hafahafa species-group endemic to Madagascar is revised. Diversity within hafahafa species-group was assessed via hypothesis-free nest-centroid-clustering combined with gap statistic to assess the number of clusters and to determine the most probable boundaries between them. This combination of methods provides a highly automatized, objective species delineation protocol based on continuous morphometric data. Delimitations of clusters recognized by these exploratory analyses were tested via confirmatory Linear Discriminant Analysis. These results suggest the existence of four morphologically distinct species, Nesomyrmex capricornis sp. n., Nesomyrmex hafahafa sp. n., Nesomyrmex medusus sp. n. and Nesomyrmex spinosus sp. n.; all are described and an identification key for their worker castes using morphometric data is provided. Two members of the newly outlined hafahafa species-group, Nesomyrmex hafahafa sp. n., Nesomyrmex medusus sp. n., are distributed along the southeastern coast Madagascar and occupy rather large ranges, but two other species, Nesomyrmex capricornis sp. n. and Nesomyrmex spinosus sp. n., are only known to occur in small and isolated forest, highlighting the importance of small forest patches for conserving arthropod diversity.