Evolution Of Character States Research Articles

Basal Anseriformes from the Early Paleogene of North America and Europe

We describe nearly complete skeletons of basal Anseriformes from the Latest Paleocene to the early Eocene of North America and Europe. Collectively, these birds appear to be representative of anseriforms near the divergence of Anhimae and Anseres, but their exact positions relative to these clades remains uncertain. A new family, Anachronornithidae nov. fam., is erected on the basis of one of these, Anachronornis anhimops nov. gen., nov. gen. et sp., to which the others cannot be confidently assigned. The new fossils augment a growing collection of early Pan-Anseriformes, which in their diversity do not paint an unambiguous picture of phylogeny or character state evolution on the path to or within crown-Anseriformes. Anachronornis nov. gen. is similar in some aspects of both cranial and postcranial anatomy to other well-represented early Paleogene Anseriformes and members of Anseres, such as Presbyornis Wetmore, 1926. However, it exhibits a more landfowl-like bill, like that of Anhimae and unlike the spatulate bill of Anseres. Additional specimens of similar basal Anseriformes of uncertain affinities from the early Eocene of North America and Europe further complicate interpretation of character state polarity due to the mosaicism of primitive and derived characters they exhibit.

Phylogeny, taxonomy, and character evolution in Entoloma subgenus Nolanea.

Nolanea is a well-known and long-established subgenus of the genus Entoloma traditionally defined mainly by the mycenoid basidiocarps of the included species. Until now, revisions of this subgenus including molecular data exist only on a regional scale. In this study, the phylogeny of species of Nolanea is analysed based on multi-gene DNA sequences including data of specimens from all continents. New primers are designed for the mitochondrial small subunit and RPB2. The performance of the DNA loci in reconstructing the phylogeny in subg. Nolanea is evaluated. An ancestral state reconstruction is used to infer the character state evolution as well as the importance and reliability of morphological characters used to define subclades below subgeneric rank. Based on the results, seven sections are recognised in Nolanea: the sections Holoconiota, Infularia, Mammosa, Nolanea, Papillata, Staurospora, and the newly described sect. Elegantissima. A large phylogeny based on the fungal barcode rDNA ITS with numerous type sequences is used to evaluate current species concepts. Several names are revealed to be synonyms of older names. Four species new to science are described, namely E. altaicum, E. argillaceum, E. cornicolor, and E. incognitum. Lectotypes, epitypes or neotypes are designated for E. cetratum, E. clandestinum, E. conferendum, E. cuspidiferum, E. hebes, E. minutum, E. nitens, and E. rhodocylix. The re-evaluation of the limits of subg. Nolanea leads to an altered concept excluding species with distinct, lageniform cheilocystidia. The section Ameides is placed in subg. Leptonia. For several species formerly accommodated in Nolanea, but excluded now, viz., E. lepiotoides, E. rhombisporum, E. subelegans, and E. velenovskyi the taxonomic position remains unclear, because of the yet unresolved phylogeny of the whole genus Entoloma. Citation: Reschke K, Morozova OV, Dima B, et al. 2022. Phylogeny, taxonomy, and character evolution in Entoloma subgenus Nolanea. Persoonia 49: 136-170. https://doi.org/10.3767/persoonia.2022.49.04.

A new species of Sphenomorphus (Squamata: Scincidae) from Phu Quoc Island, Vietnam with a discussion of biogeography and character state evolution in the S. stellatus group.

An integrative taxonomic analysis of the Sphenomorphus stellatus group recovered a newly discovered museum specimen from Phu Quoc Island, Kien Giang Province, Vietnam as a new species most closely related to S. preylangensis from Phnom Chi in central Cambodia, approximately 175 km to the northeast. Most notably, S. phuquocensis sp. nov. lacks the derived condition of having black dorsal stripes that diagnose S. annamiticus-the sister species to S. preylangensis plus S. phuquocensis sp. nov. A BioGeoBEARS analysis recovered the ancestor of the S. stellatus group to likely have ranged across forested regions on an exposed Sunda Shelf from southwestern Indochina to Peninsular Malaysia prior to diverging into northern and southern lineages separated by the Gulf of Thailand. Episodic fluctuations in sea levels and concomitant changes in the physiography of the Mekong Delta contributed to the fragmented distribution within and between species of the northern lineage. Sphenomorphus phuquocensis sp. nov. represents the second species of reptile endemic to Phu Quoc Island.

Phylogenetic reconstruction of the genus Tephrocactus (Cactaceae) based on molecular, morphological, and cytogenetical data

AbstractTephrocactus comprises species mainly endemic to Argentina. Molecular phylogenetic analyses of all proposed species of the genus as well as classical (chromosome number, karyotype) and molecular cytogenetical techniques (DNA content, heterochromatin amount, rDNA genes) were conducted. Sequence data of two plastid DNA markers of Tephrocactus taxa were analyzed. Evolution of character states of cytogenetical and morphological (growth form, presence of leaves, glochids and tepal spiny mucrons, flower color) traits were reconstructed. Species show x = 11 with different ploidy levels (2n = 22, 44, 66, 77, 242, 319), small chromosomes, and symmetrical karyotypes. Tephrocactus was recovered as monophyletic with three main clades including 12 species, using molecular and morphological data. Tephrocactus geometricus, T. halophilus, and T. paediophilus are recognized as distinct species. Banding patterns showed CMA+/DAPI− constitutive heterochromatin associated with nuclear organized regions. Heterochromatin amount ranged from 2.99% to 6.50%. The 18S‐5.8S‐26S ribosomal DNA (rDNA) sites coincided with the CMA+/DAPI− signals. The 5S sites varied with ploidy levels of the taxa. DNA content (2C = 1.99–24.50 pg) had a significant and positive correlation with ploidy level and the number of rDNA genes. The ancestor is reconstructed to have been a dwarf shrub with strong articulation, glochids, and deciduous leaves, white, pink or pearly tepals without spiny mucrons, 2n = 22, low DNA content, and one pair of each rDNA gene followed by three polyploidization events. Tephrocactus diversification has been associated with polyploidy and few cumulative small cryptic chromosomal changes.

Testing for a facultative locomotor mode in the acquisition of archosaur bipedality.

Bipedal locomotion is a defining characteristic of humans and birds and has a profound effect on how these groups interact with their environment. Results from extensive hominin research indicate that there exists an intermediate stage in hominin evolution—facultative bipedality—between obligate quadrupedality and obligate bipedality that uses both forms of locomotion. It is assumed that archosaur locomotor evolution followed this sequence of functional and hence character-state evolution. However, this assumption has never been tested in a broad phylogenetic context. We test whether facultative bipedality is a transitionary state of locomotor mode evolution in the most recent early archosaur phylogenies using maximum-likelihood ancestral state reconstructions for the first time. Across a total of seven independent transitions from quadrupedality to a state of obligate bipedality, we find that facultative bipedality exists as an intermediary mode only once, despite being acquired a total of 14 times. We also report more independent acquisitions of obligate bipedality in archosaurs than previously hypothesized, suggesting that locomotor mode is more evolutionarily fluid than expected and more readily experimented with in these reptiles.

The species of Ecnomocephala Gibson (Hymenoptera: Eupelmidae).

The species of the New World genus Ecnomocephala Gibson (Hymenoptera: Chalcidoidea: Eupelmidae: Eupelminae) are revised. Seven species are recognized, the type species, E. townesi Gibson, 1995 (♀♂: USA), and the following six new species: E. ashei Gibson n. sp. (♀♂: French Guiana, Guyana, Venezuela), E. boliviensis Gibson n. sp. (♀: Bolivia), E. gilli Gibson n. sp. (♀♂: Brazil, Costa Rica, Panama), E. hypha Gibson n. sp. (♀: Costa Rica), E. retia Gibson n. sp. (♀: Mexico), and E. speculum Gibson n. sp. (♀: Colombia, Ecuador, Peru). The species are illustrated through macrophotography and keyed. Morphology of the sexes is compared to each other relative to sexual dimorphism and examined for implications for inferring function, character-state evolution, and phylogenetic relationships within the subfamily.

Molecular systematics and character evolution in the lichen family Ramalinaceae (Ascomycota: Lecanorales)

AbstractThe Ramalinaceae is the fourth‐largest family of lichenized ascomycetes with 42 genera and 913 species exhibiting considerable morphological variation. Historically, generic boundaries in the Ramalinaceae were primarily based on morphological characters. However, molecular systematic investigations of subgroups revealed that current taxonomy is at odds with evolutionary relationships. Tropical members of the family remain particularly understudied, including the large genusPhyllopsora. We have generated and collected multilocus sequence data (mtSSU, nrITS, nrLSU,RPB1, RPB2) for 149 species associated with the Ramalinaceae and present the first comprehensive molecular phylogeny of the family. We used ancestral state reconstructions on our molecular family phylogeny to trace the evolution of character states. Our results indicate that the Ramalinaceae have arisen from an ancestor with long, multiseptate ascospores living in humid temperate forests, and that the phyllopsoroid growth form has evolved multiple times within the family. Based on our results using integrative taxonomy, we discuss sister‐relations and taxon‐delimitation within five well‐supported clades: TheBacidia, Biatora‐, Ramalina‐, Rolfidium‐, andToninia‐groups. We reduce six genera into synonymy and make 49 new nomenclatural combinations. The generaBacidia, Phyllopsora, PhyscidiaandToniniaare polyphyletic and herein split into segregates. We describe the two generaBellicidiaandParallopsoraand resurrect the generaBibbya, Kiliassia, Sporacestra, andThalloidima. According to our new circumscription, which also includes some additional changes, the family Ramalinaceae now comprises 39 genera.

Integrative systematic revision of a Mediterranean earthworm family: Hormogastridae (Annelida, Oligochaeta)

The problem of reconciling earthworm taxonomy and phylogeny has shown advances with the application of molecular techniques, yet they have proven insufficient. Integrative systematics could solve this by combining multiple sources of evolutionary information. Relatively low diversity, restricted range and low nomenclatural conflict make Hormogastridae Michaelsen, 1900 a desirable target for an integrative systematics approach. The main systematic conflicts within this family are the polyphyly of the species Hormogaster pretiosa Michaelsen, 1899, the widespread presence of cryptic lineages, the lack of resolution of supraspecific relationships and the paraphyly of the genus Hormogaster Rosa, 1877 (found to be composed of four well-supported genus-level clades by molecular phylogenetic inference). This work integrates all the existing information by performing phylogenetic inference based on morphological, molecular and total evidence datasets, comparing their performance with the topology obtained by phylogenomic analyses. It also includes a comparative study of representatives of the main clades based on microcomputed tomography (µCT) reconstructions. The addition of morphological characters improved the resolution of the Hormogastridae tree; ancestral state reconstruction displayed the evolution of character states and provided morphological diagnoses for the genera within a new system, which incorporates information about ecological niches and biogeography.

Style polymorphism in Linum (Linaceae): a case of Mediterranean parallel evolution?

Heterostyly is a sex polymorphism that has challenged evolutionary biologists ever since Darwin. One of the lineages where heterostyly and related stylar conditions appear more frequently is Linum (Linaceae). This group is particularly suitable for testing competing hypotheses about ancestral and transitional stages on the evolutionary building up of heterostyly. We generated a phylogeny of Linum based on extensive sampling and plastid and nuclear DNA sequences, and used it to trace the evolution of character states of style polymorphism. We also revised available data on pollination, breeding systems, and polyploidy to analyse their associations. Our results supported former phylogenetic hypotheses: the paraphyly of Linum and the non-monophyly of current taxonomic sections. Heterostyly was common in the genus, but appeared concentrated in the Mediterranean Basin and the South African Cape. Ancestral character state reconstruction failed to determine a unique state as the most probable condition for style polymorphism in the genus. In contrast, approach herkogamy was resolved as ancestral state in some clades, giving support to recent hypotheses. Some traits putatively related to heterostyly, such as life history and polyploidy, did show marginal or non-significant phylogenetic correlation, respectively. Although pollinator data are limited, we suggest that beeflies are associated with specific cases of heterostyly. The consistent association between style polymorphism and heteromorphic incompatibility points to ecological factors as drivers of the multiple evolution of style polymorphism in Linum. Albeit based on limited evidence, we hypothesised that specialised pollinators and lack of mating opportunities drive evolution of style polymorphism and loss of the polymorphism, respectively.

An integrative approach to understanding the evolution and diversity of Copiapoa (Cactaceae), a threatened endemic Chilean genus from the Atacama Desert.

Species of the endemic Chilean cactus genus Copiapoa have cylindrical or (sub)globose stems that are solitary or form (large) clusters and typically yellow flowers. Many species are threatened with extinction. Despite being icons of the Atacama Desert and well loved by cactus enthusiasts, the evolution and diversity of Copiapoa has not yet been studied using a molecular approach. Sequence data of three plastid DNA markers (rpl32-trnL, trnH-psbA, ycf1) of 39 Copiapoa taxa were analyzed using maximum likelihood and Bayesian inference approaches. Species distributions were modeled based on geo-referenced localities and climatic data. Evolution of character states of four characters (root morphology, stem branching, stem shape, and stem diameter) as well as ancestral areas were reconstructed using a Bayesian and maximum likelihood framework, respectively. Clades of species are revealed. Though 32 morphologically defined species can be recognized, genetic diversity between some species and infraspecific taxa is too low to delimit their boundaries using plastid DNA markers. Recovered relationships are often supported by morphological and biogeographical patterns. The origin of Copiapoa likely lies between southern Peru and the extreme north of Chile. The Copiapó Valley limited colonization between two biogeographical areas. Copiapoa is here defined to include 32 species and five heterotypic subspecies. Thirty species are classified into four sections and two subsections, while two species remain unplaced. A better understanding of evolution and diversity of Copiapoa will allow allocating conservation resources to the most threatened lineages and focusing conservation action on real biodiversity.

Which came first: The lizard or the egg? Robustness in phylogenetic reconstruction of ancestral states.

Changes in parity mode between egg-laying (oviparity) and live-bearing (viviparity) have occurred repeatedly throughout vertebrate evolution. Oviparity is the ancestral amniote state, and viviparity has evolved many times independently within amniotes (especially in lizards and snakes), with possibly a few reversions to oviparity. In amniotes, the shelled egg is considered a complex structure that is unlikely to re-evolve if lost (i.e., it is an example of Dollo's Principle). However, a recent ancestral state reconstruction analysis concluded that viviparity was the ancestral state of squamate reptiles (lizards and snakes), and that oviparity re-evolved from viviparity many times throughout the evolutionary history of squamates. Here, we re-evaluate support for this provocative conclusion by testing the sensitivity of the analysis to model assumptions and estimates of squamate phylogeny. We found that the models and methods used for parity mode reconstruction are highly sensitive to the specific estimate of phylogeny used, and that the point estimate of phylogeny used to suggest that viviparity is the root state of the squamate tree is far from an optimal phylogenetic solution. The ancestral state reconstructions are also highly sensitive to model choice and specific values of model parameters. A method that is designed to account for biases in taxon sampling actually accentuates, rather than lessens, those biases with respect to ancestral state reconstructions. In contrast to recent conclusions from the same data set, we find that ancestral state reconstruction analyses provide highly equivocal support for the number and direction of transitions between oviparity and viviparity in squamates. Moreover, the reconstructions of ancestral parity state are highly dependent on the assumptions of each model. We conclude that the common ancestor of squamates was oviparous, and subsequent evolutionary transitions to viviparity were common, but reversals to oviparity were rare. The three putative reversals to oviparity with the strongest phylogenetic support occurred in the snakes Eryx jayakari and Lachesis, and the lizard, Liolaemus calchaqui. Our results emphasize that because the conclusions of ancestral state reconstruction studies are often highly sensitive to the methods and assumptions of analysis, researchers should carefully consider this sensitivity when evaluating alternative hypotheses of character-state evolution.

Leaf epidermal character variation and evolution in Gaultherieae (Ericaceae)

The taxonomic value and evolutionary significance of 30 leaf epidermal characters from 238 samples representing 127 species of all seven genera in the tribe Gaultherieae (Ericaceae) and two outgroup genera were investigated by scanning electron microscopy. The character states were coded and optimized onto a maximum-likelihood tree based on previous molecular data with Fitch parsimony and hierarchical Bayesian analysis to trace the evolution of character states throughout all internodes in the phylogenetic tree for Gaultherieae. Leaf epidermal characters were found to be largely consistent within species, but highly variable at interspecific and higher taxonomic levels. The most recent common ancestral states of 15 characters diagnosed various lineages recovered from prior studies, some with no prior morphological support. Relatively high frequencies of state change occur in the eastern Asian clade Gaultheria series Gymnobotrys + Diplycosia, the American clade G. subsection Dasyphyta p.p., the core East Asian clade and the Australia/New Zealand clade. The characters with the highest frequencies of state change are the outer stomatal ledge ornamentation type, the stomatal apparatus level, stomatal density and area, and the type of abaxial trichomes. These character state change patterns may provide insight into the ecological adaptions of Gaultherieae during their evolutionary history.

CHARACTER EVOLUTION OF THE BENTHIC THECATE DINOFLAGELLATE, GAMBIERDISCUS (DINOPHYCEAE), WITH AN INTRODUCTION OF THE INTERACTIVE KEY TO SPECIES

The genus Gambierdiscus is one of the benthic marine dinoflagellates that are known to produce biotoxins, causing ciguatera food poisoning (CFP) in humans after consuming the contaminated marine fishes. These benthic marine dinoflagellates are commonly found in the warm tropical and subtropical waters. The phenomena associated with high cell abundance or “blooms” is referred to Benthic Harmful Algal Blooms (BHABs). Precise species identification is crucial as not all of the species in the genus are toxic. In this study, morphological characteristics of Gambierdiscus species widely used in species identification were analyzed, and the character states coded. Taxon sampling on the large subunit (LSU) rDNA of all Gambierdiscus species were carried out, and used for the phylogenetic reconstruction. The character states were mapped onto the Maximum Parsimony (MP) tree to investigate the character state evolution of Gambierdiscus species. Morphological information and the distribution of the 13 species were used to develop a comprehensive taxonomic database of Gambierdiscus, a web-based interactive identification key for species identification is presented. ABSTRACT Genus Gambierdiscus adalah salah satu dinoflagelat bentik marin yang menghasilkan biotoksin penyebab keracunan ikan ciguatera (CFP) pada manusia akibat termakan ikan marin yang tercemar. Dinoflagelat ini biasanya ditemui di perairan tropika dan subtropika yang panas. Fenomena ini yang berkaitan dengan kepadatan sel yang tinggi atau ledakan adalah dirujuk sebagai “Benthic Harmful Algal Bloom (BHAB)”. Pengecaman spesis yang tepat adalah penting kerana tidak semua spesies dalam genus ini adalah beracun. Dalam kajian ini, ciri-ciri morfologi digunakan secara meluas dalam pengecaman spesies Gambierdiscus telah dianalisa, dan pengkodan keadaan ciri-ciri ditentukan. Persampelan takson jujukan ribosamal subunit besar (LSU) rDNA semua spesies Gambierdiscus telah dijalankan, dan digunakan untuk pembinaan semula filogenetik. Keadaan ciri-ciri telah dipetakan ke atas pokok kekikiran maksimum (MP) untuk mengkaji evolusi keadaan ciri morfologi spesies Gambierdiscus. Maklumat morfologi 13 spesies dan taburan mereka telah digunakan untuk menghasilkan pangkalan data taksonomi Gambierdiscus yang komprehensif. Kekunci pengecaman spesies interaktif sesawang untuk tujuan pengecaman dibentangkan. Keywords: Benthic dinoflagellates; ciguatera; harmful; interactive key; morphological characters

Color pattern evolution in Vanessa butterflies (Nymphalidae: Nymphalini): non-eyespot characters.

A phylogenetic approach was used to study color pattern evolution in Vanessa butterflies. Twenty-four color pattern elements from the Nymphalid ground plan were identified on the dorsal and ventral surfaces of the fore- and hind wings. Eyespot characters were excluded and will be examined elsewhere. The evolution of each character was traced over a Bayesian phylogeny of Vanessa reconstructed from 7750 DNA base pairs from 10 genes. Generally, the correspondence between character states on the same surface of the two wings is stronger on the ventral side compared to the dorsal side. The evolution of character states on both sides of a wing correspond with each other in most extant species, but the correspondence between dorsal and ventral character states is much stronger in the forewing than in the hindwing. The dorsal hindwing of many species of Vanessa is covered with an extended Basal Symmetry System and the Discalis I pattern element is highly variable between species, making this wing surface dissimilar to the other wing surfaces. The Basal Symmetry System and Discalis I may contribute to behavioral thermoregulation in Vanessa. Overall, interspecific directional character state evolution of non-eyespot color patterns is relatively rare in Vanessa, with a majority of color pattern elements showing non-variable, non-directional, or ambiguous character state evolution. The ease with which the development of color patterns can be modified, including character state reversals, has likely made important contributions to the production of color pattern diversity in Vanessa and other butterfly groups.

Behavioral and ecological factors account for variation in the mass-independent energy expenditures of endotherms.

A persistent controversy has concerned the identification of the factors that influence the quantitative variation in the physiological characters of species, an example of which is the basal rate of metabolism of endotherms. The most important factor accounting for its variation is body mass as long as the range in mass is appreciable. But mass never accounts for all of the variation and none if species have the same mass. Most of the residual variation around the mass curve is associated with behavioral characters, ecological factors, and phylogeny, i.e., history. These agents influence energy expenditure by different means and at different stages in the life history of species. Phylogeny describes the historic origin, evolution, and distribution of character states in contemporary species. However, the level of energy expenditure is quantitatively determined by the collective of realized states in combination with conditions in the environment. Therefore, two stages determine energy expenditure: (1) the evolution of character states and (2) their impact in conjunction with conditions on the environment. Behavioral characters and ecological factors, when coupled with log10 mass, usually account for >94 % of the variation in the log10 basal rates of birds and mammals, a capacity not found in phylogenetic analyses. The difficulty of determining a direct impact of phylogeny on physiological characters results from its correlation with behavioral characters. When appropriate, the passerine/non-passerine dichotomy in birds and the sub/infraclass dichotomy in mammals combine with behavioral characters, ecological factors, and log10 mass to increase r (2) to account for 96-99 % of the variation in log10 basal rate. This occurs because dichotomies incorporate factors other than those already in the analyses. The clearest demonstration of the direct impact of character states is the equality of energy expenditure in species convergent with species from other clades without any evidence of the clade to which the species belong. A multifactorial approach depends on the inclusion of life history characteristics of species, but this analysis applies only to continuous, quantitative relationships, which are often modified by discontinuous agents. Distinctive character states distinguish species and therefore must be included in any attempt to account for differences in their level of energy expenditure. No analysis that ignores life history characteristics can account for the quantitative variation in energy expenditure beyond that associated with body mass.

Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily.

BackgroundMales in some species of the genus Xiphophorus, small freshwater fishes from Meso-America, have an extended caudal fin, or sword – hence their common name “swordtails”. Longer swords are preferred by females from both sworded and – surprisingly also, non-sworded (platyfish) species that belong to the same genus. Swordtails have been studied widely as models in research on sexual selection. Specifically, the pre-existing bias hypothesis was interpreted to best explain the observed bias of females in presumed ancestral lineages of swordless species that show a preference for assumed derived males with swords over their conspecific swordless males. However, many of the phylogenetic relationships within this genus still remained unresolved. Here we construct a comprehensive molecular phylogeny of all 26 known Xiphophorus species, including the four recently described species (X. kallmani, X. mayae, X. mixei and X. monticolus). We use two mitochondrial and six new nuclear markers in an effort to increase the understanding of the evolutionary relationships among the species in this genus. Based on the phylogeny, the evolutionary history and character state evolution of the sword was reconstructed and found to have originated in the common ancestral lineage of the genus Xiphophorus and that it was lost again secondarily.ResultsWe estimated the evolutionary relationships among all known species of the genus Xiphophorus based on the largest set of DNA markers so far. The phylogeny indicates that one of the newly described swordtail species, Xiphophorus monticolus, is likely to have arisen through hybridization since it is placed with the southern platyfish in the mitochondrial phylogeny, but with the southern swordtails in the nuclear phylogeny. Such discordance between these two types of markers is a strong indication for a hybrid origin. Additionally, by using a maximum likelihood approach the possession of the sexually selected sword trait is shown to be the most likely ancestral state for the genus Xiphophorus. Further, we provide a well supported estimation of the phylogenetic relationships between the previously unresolved northern swordtail groups.ConclusionsThis comprehensive molecular phylogeny of the entire genus Xiphophorus provides evidence that a second swordtail species, X. monticolus, arose through hybridization. Previously, we demonstrated that X. clemenciae, another southern swordtail species, arose via hybridization. These findings highlight the potential key role of hybridization in the evolution of this genus and suggest the need for further investigations into how hybridization contributes to speciation more generally.

One or many genera in Mesembryanthemoideae (Aizoaceae)? Discussion of a conflict in genus perception

Summary: In the present paper, the latest, very broad generic concept of the genus Mesembryanthemum L., incorporating all hitherto recognized genera of the subfamily Mesembryanthemoideae Ihlenf., Schwantes & Straka on the basis of molecular and morphological data, is critically discussed. New insights into the possible evolution of character states within the Mesembryanthemoideae based on the published data are outlined. On the basis of a new assessment of the known character states, it is proposed to return to narrower generic boundaries. A new genus, Volkeranthus Gerbaulet, with two species, is described. All accepted genera and species are listed, some of them as new combinations.

A Likelihood Method for Detecting Trait-Dependent Shifts in the Rate of Molecular Evolution

Rate heterogeneity within groups of organisms is known to exist even when closely related taxa are examined. A wide variety of phylogenetic and dating methods have been developed that aim either to test for the existence of rate variation or to correct for its bias. However, none of the existing methods track the evolution of features that account for observed rate heterogeneity. Here, we present a likelihood model that assumes that rate variation is caused, in part, by species' intrinsic characteristics, such as a particular life-history trait, morphological feature, or habitat association. The model combines models of sequence and character state evolution such that rates of sequence change depend on the character state of a lineage at each point in time. We test, using simulations, the power and accuracy of the model to determine whether rates of molecular evolution depend on a particular character state and demonstrate its utility using an empirical example with halophilic and freshwater daphniids.

Divergence of courtship and mating behaviors among endemic Hawaiian swordtail crickets

Crickets in the family Gryllidae are well known for their elaborate mating behaviors; however, behavior of the subfamily Trigonidiinae is poorly understood. A large portion of this clade is endemic to Hawaii, including three genera: Trigonidium , Laupala and Prolaupala . The only Hawaiian genus that has been studied is Laupala , which exhibits unusual nuptial feeding in the form of spermless 'micro' spermatophores. Microspermatophore donation has been suggested to increase sperm transfer, constituting a novel mechanism of mating effort in crickets. We observed mating from representatives of each genus to investigate behavioral diversity and reconstruct character state evolution. We found that Prolaupala species produce microspermatophores during a behavioral sequence very similar to Laupala . Trigonidium do not produce microspermatophores, but exhibit other behavioral strategies that likely function to improve insemination, such as prolonged copulation and post-copulatory guarding. We also observed spermatophore and copulation characteristics that were previously considered unique to other gryllids. Behavioral diversity among the Hawaiian fauna reflects the evolutionarily labile nature of gryllid mating behavior and convergence of behavioral strategies in response to sexual selection. Furthermore, our results suggest that microspermatophore donation may be a common mating effort strategy within Trigonidiinae.

Phylogeny and DNA barcoding of inquiline oak gallwasps (Hymenoptera: Cynipidae) of the Western Palaearctic

We examine phylogenetic relationships within the Synergus complex of herbivorous inquiline gallwasps (Hymenoptera; Cynipidae; Synergini) associated with cynipid host galls on oak, a biologically diverse group whose genus-level morphological taxonomy has long been considered stable but whose species level taxonomy is problematic. We incorporate data for over 70% of recognised Western Palaearctic species in five morphology-based genera (Ceroptres, Saphonecrus, Synergus, Synophrus, Ufo), comprising sequence for two mitochondrial loci (coxI, cytb) and one nuclear locus (28S D2). In particular, we assess the evidence for monophyly of two long-established, morphology-defined sections within the genus Synergus that differ in a range of biological traits. To aid analyses of ecological interactions within oak cynipid communities, we also consider the utility of cytochrome oxidase I (coxI) DNA barcodes in the oak inquilines. In this assessment, we do not assume that species are delineated at a single threshold value of sequence divergence for a single gene, but examine concordance in the composition of molecular operational Taxonomic units (MOTUs) across a range of sequence divergences in each gene and across genes. We also assess the impact of sampling effort on MOTU stability.Phylogenetic reconstructions for all three loci support monophyly for Synergus and Synophrus, but reject monophyly for Saphonecrus and for the two sections within Synergus. The suites of traits associated with the two sections of the genus Synergus are thus homoplasious. All three loci also reject monophyly for three Synergus species (S. hayneanus, S. pallipes, S. umbraculus). Sequences for each locus identify robust MOTUs that are largely concordant across loci for a range of cut-off values. Though many MOTU’s correspond to recognised Linnean species, there is significant, multigene disagreement between groupings supported by morphology and sequence data, with both allocation of different morphospecies to the same MOTU and allocation of the same morphospecies to multiple MOTUs, regardless of cut-off value. Our results imply that while DNA barcoding has considerable utility within this group, morphology-based identification needs major revision at both genus and species levels. Further, lifehistory traits currently attributed to single morphospecies probably confound attributes of multiple lineages. Revealing patterns of character state evolution in Synergus requires collection of new host association and life history data explicitly linked to DNA barcode data for the specimens concerned.