Does plasticity drive speciation? Host‐plant shifts and diversification in nymphaline butterflies (Lepidoptera: Nymphalidae) during the tertiary

How and why the great diversity of phytophagous insects has evolved is not clear but, if the explanation is the diversity of plants as a resource, colonizations of novel plant taxa can be expected to be associated with higher net speciation rates. In the present study, we make use of recent advances in plant and butterfly systematics to trace the evolution of host-plant utilization in the butterfly subfamily Nymphalinae (tribes Nymphalini, Melitaeini, and the probably paraphyletic 'Kallimini'). A clear historical pattern emerges, with an ancestral host-plant theme of 'urticalean rosids' and two major colonizations of novel distantly-related plant clades. The asterid order Lamiales was colonized by an ancestor of 'Kallimini' + Melitaeini and the family Asteraceae in Asterales was later colonized by Melitaeini butterflies. These colonization events appear to have been followed by increases in the rate of net butterfly diversification. Two not mutually exclusive scenarios to explain such patterns have been suggested: (1) adaptive radiation due to release from competition following host-plant shifts or (2) higher rates of net speciation during a relatively long-lasting potentially polyphagous (plastic) state. In support of the 'plasticity scenario', phylogenetic traces of a long-lasting stage with some potential to feed on more than one host-plant clade can still be seen, despite the ancient age of the colonizations. When angiosperm communities changed after the K/T boundary due to extinctions and subsequent diversification, herbivore taxa that could occupy several alternative niches may have had the greatest opportunity to diversify in turn.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 115–130.     

Phylogenetics and morphological evolution of coral‐dwelling barnacles (Balanomorpha: Pyrgomatidae)

Pyrgomatid barnacles are a family of balanomorphs uniquely adapted to symbiosis on corals. The evolution of the coral‐dwelling barnacles is explored using a multi‐gene phylogeny (COI, 16S, 12S, 18S, and H3) and phenotypic trait‐mapping. We found that the hydrocoral associate Wanella should be excluded, while some archaeobalanids in the genus Armatobalanus should be included in the Pyrgomatidae. Three well supported clades were recovered: clade I is the largest group and is exclusively Indo‐West Pacific, clade II contains two plesiomorphic Indo‐West Pacific genera, while clade III is comprised of East and West Atlantic taxa. Some genera did not form reciprocally monophyletic groups, while the genus Trevathana was found to be paraphyletic and to include members of three other apomorphic genera/tribes. The highly unusual coral‐parasitic hoekiines appear to be of recent origin and rapidly evolving from Trevathana sensu lato. Pyrgomatids include six‐, four‐, and one‐plated forms, and exhibit convergent evolutionary tendencies towards skeletal reduction and fusion, loss of cirral armature, and increased host specificity. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 162–179.     

Cryptic speciation in the southern African vlei rat Otomys irroratus complex: evidence derived from mitochondrial cyt b and niche modelling

The vlei rat Otomys irroratus has a wide distribution in southern Africa with several datasets indicating the presence of two putative species (O. irroratus and O. auratus). In the present study we use mitochrondrial cyt b data (～950 bp) from 98 specimens (including museum material) collected throughout the range of the species to determine the geographical limits of the two recognized species, and we link this to niche modelling to validate these species. Phylogenetic analysis of the DNA sequence data, using maximum parsimony, neighbour joining and Bayesian inference, retrieved two divergent statistically well‐supported clades. Clade A occurs in the Western and Eastern Cape while Clade B occurs in the Free State, KwaZulu‐Natal, Northern Cape and Mpumalanga provinces of South Africa and Zimbabwe. Mean sequence divergence between the two clades (A and B) was 7.0% and between sub‐clades comprising clade B it was 4.8%; the two clades diverged during the Pleistocene. Within Clade A the mean sequence divergence among specimens was 1.91%. Niche modelling revealed that the incipient species occupy distinct bioclimatic niches associated with seasonality of precipitation. Our data allow insightful analysis into the factors that could have led to cladogenesis within this rodent. More significantly, the new data enable us to pinpoint the Eastern Cape province as a contact zone for the divergent species. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 192–206.     

Morphological characters add support for some members of the basal grade of Asteraceae

Recent molecular studies in Asteraceae have divided tribe Mutisieae (sensu Cabrera) into 13 tribes and eight subfamilies. Each of the major clades is well supported but the relationships among them are not always clear. Some of the new taxa are easily characterized by morphological data but others are not, chief among the latter being three subfamilies (Stifftioideae, Wunderlichioideae and Gochnatioideae) and the tribe Hyalideae. To understand evolution in the family it is critical to investigate potential morphological characters that can help to evaluate the basal lineages of the Asteraceae. The data for this study were taken from 52 species in 24 genera representing the basal groups in the family. Many characters were examined but most of the useful ones were from reproductive structures. Several apomorphies supported a few of the clades. For instance, members of subfamily Wunderlichioideae (Hyalideae and Wunderlichieae) share predominantly ten‐ribbed achenes and members of Wunderlichioideae + Stifftioideae share two synapomorphies: 100–150 (200) pappus elements, arranged in (three) four or five series. These apomorphies can be viewed as an indication of a sister‐group relationship between the two subfamilies as the placement of Stifftieae was not well resolved by the molecular data. Members of Wunderlichieae are characterized by having a paleaceous receptacle, style branches that are strongly papillose above and below the bifurcation, and a pappus of scales. Hyalis and Ianthopappus (Hyalideae) share venation type and an apiculate anther appendage but these are also found in Gochnatieae. Other clades have fewer supporting characters. These characters are just a beginning. Cladograms with morphology characters plotted, illustrations and a key to the basal grade of Asteraceae are provided. © 2013 The Linnean Society of London     

Genetic population structure of buckeye butterflies (Junonia) from Argentina

There are nine named species of buckeye butterflies (genus Junonia Hübner) in the Western Hemisphere. There is considerable geographic variation within Junonia species, and possible ongoing hybridization between species, suggesting that Junonia may be a ring species, but also making this a very difficult group to define taxonomically. We tried to determine whether two forms of Junonia from Argentina – conventionally referred to as Junonia genoveva hilaris C. & R. Felder, the light buckeye butterfly, and Junonia evarete flirtea (Fabricius), the dark buckeye butterfly – were genetically distinct species or simply colour forms of a single species using morphological characters, mitochondrial cytochrome oxidase I (COI) DNA barcodes, nuclear wingless (wg) locus DNA sequences, and anonymous nuclear Randomly Amplified Fingerprints (RAF). Phylogenetic analysis of COI identified two distinct mitochondrial haplotypes that differ by about 4% sequence divergence; one confined to light‐coloured Junonia specimens and one shared between some light‐coloured Junonia and all of dark‐coloured Junonia specimens. Analysis of nuclear wingless sequences revealed 32 alleles among 22 Junonia specimens and showed significant genetic differentiation between light‐coloured and dark‐coloured Junonia. Analysis of RAF genotypes suggests that there are actually three genetically distinct Junonia populations in Argentina: two with light wing coloration, and one with dark wing coloration. Genetic evidence of recent hybridization among these populations was also observed, consistent with the ring species hypothesis. Careful comparisons of morphological characters between Argentinian Junonia and Junonia species from elsewhere in South America suggests that the two light‐coloured populations correspond to J. genoveva and either a genetically disparate population of the same species or an undescribed cryptic Junonia species, The dark‐coloured population may correspond to J. wahlbergi Brévignon. Our data suggest that COI DNA barcodes by themselves are not very useful for studying Junonia taxonomy, population structure or evolution.     

Laying the foundations of evolutionary and systematic studies in crickets (Insecta,Orthoptera): a multilocus phylogenetic analysis

Orthoptera have been used for decades for numerous evolutionary questions but several of its constituent groups, notably crickets, still suffer from a lack of a robust phylogenetic hypothesis. We propose the first phylogenetic hypothesis for the evolution of crickets sensu lato, based on analysis of 205 species, representing 88% of the subfamilies and 71% tribes currently listed in the database Orthoptera Species File (OSF). We reconstructed parsimony, maximum likelihood and Bayesian phylogenies using fragments of 18S, 28SA, 28SD, H3, 12S, 16S, and cytb (~3600 bp). Our results support the monophyly of the cricket clade, and its subdivision into two clades: mole crickets and ant‐loving crickets on the one hand, and all the other crickets on the other (i.e. crickets sensu stricto). Crickets sensu stricto form seven monophyletic clades, which support part of the OSF families, “subfamily groups”, or subfamilies: the mole crickets (OSF Gryllotalpidae), the scaly crickets (OSF Mogoplistidae), and the true crickets (OSF Gryllidae) are recovered as monophyletic. Among the 22 sampled subfamilies, only six are monophyletic: Gryllotalpinae, Trigonidiinae, Pteroplistinae, Euscyrtinae, Oecanthinae, and Phaloriinae. Most of the 37 tribes sampled are para‐ or polyphyletic. We propose the best‐supported clades as backbones for future definitions of familial groups, validating some taxonomic hypotheses proposed in the past. These clades fit variously with the morphological characters used today to identify crickets. Our study emphasizes the utility of a classificatory system that accommodates diagnostic characters and monophyletic units of evolution. Moreover, the phylogenetic hypotheses proposed by the present study open new perspectives for further evolutionary research, especially on acoustic communication and biogeography.     

Phylogenetic analyses of band‐winged grasshoppers (Orthoptera,Acrididae, Oedipodinae) reveal convergence of wing morphology

Husemann, M., Namkung, S., Habel, J.C., Danley, P.D. & Hochkirch, A. (2012). Phylogenetic analyses of band‐winged grasshoppers (Orthoptera, Acrididae, Oedipodinae) reveal convergence of wing morphology. —Zoologica Scripta, 41, 515–526. Historically, morphological traits have been used to examine the relationships of distantly related taxa with global distributions. The use of such traits, however, may be misleading and may not provide the resolution needed to distinguish various hypotheses that may explain the distribution patterns of widely distributed taxa. One such taxon, the Oedipodine grasshoppers, contains two tribes principally defined by wing morphologies: the Bryodemini have broad wings whereas Sphingonotini are narrow‐winged. Through the use of morphological features alone, hypotheses concerning the evolution of these tribes cannot be distinguished. To differentiate hypotheses that may explain the distribution of Oedipodines, such as vicariance, natural dispersal and anthropogenic translocation, we used two mitochondrial and three nuclear gene fragments to reconstruct the phylogenetic relationships within and between the two tribes, and employed a molecular clock to evaluate the hypotheses of vicariance and dispersal. Our results clearly reject monophyly of the tribes and revealed monophyletic Old and New World clades, which is in agreement with previous molecular studies. The split between both clades was dated at 35 Ma (±12 Ma). This clearly rejects the vicariance hypothesis and supports a single invasion via the Beringian land bridge. In addition, our data clearly show that the similarities in wing morphology used for distinguishing both tribes are the result of at least one convergent event. Our study shows that interpretations of relationships based on the currently accepted taxonomy in the study groups will be error prone. We suggest that future revisions that consider our findings are required.     

A tale of North and South America: time and mode of dispersal of the amphitropical genus Munroa (Poaceae,Chloridoideae)

Plant disjunctions have provided some of the most intriguing distribution patterns historically addressed by biogeographers. We evaluated the three hypotheses that have been postulated to explain these patterns [vicariance, stepping‐stone dispersal and long‐distance dispersal (LDD)] using Munroa, an American genus of grasses with six species and a disjunct distribution between the desert regions of North and South America. The ages of clades, cytology, ancestral characters and areas of distribution were investigated in order to establish relationships among species, to determine the time of divergence of the genus and its main lineages, and to understand further the biogeographical and evolutionary history of this genus. Bayesian inference recovered the North American M. pulchella as sister species to the rest. Molecular dating and ancestral area analyses suggest that Munroa originated in North America in the late Miocene–Pliocene (7.2 Mya; 8.2–6.5 Mya). Based on these results, we postulate that two dispersal events modelled the current distribution patterns of Munroa: the first from North to South America (7.2 Mya; 8.2–6.5 Mya) and the second (1.8 Mya; 2–0.8 Mya) from South to North America. Arid conditions of the late Miocene–Pliocene in the Neogene and Quaternary climatic oscillations in North America and South America were probably advantageous for the establishment of populations of Munroa. We did not find any relationship between ploidy and dispersal events, and our ancestral character analyses suggest that shifts associated with dispersal and seedling establishment, such as habit, reproductive system, disarticulation of rachilla, and shape and texture of the glume, have been important in these species reaching new areas. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 110–125.     

Molecular phylogeny of the Forcipulatacea (Asteroidea: Echinodermata): systematics and biogeography

We present a comprehensively sampled three‐gene phylogeny of the monophyletic Forcipulatacea, one of three major lineages within the crown‐group Asteroidea. We present substantially more Southern Hemisphere and deep‐sea taxa than were sampled in previous molecular studies of this group. Morphologically distinct groups, such as the Brisingida and the Zoroasteridae, are upheld as monophyletic. Brisingida is supported as the derived sister group to the Asteriidae (restricted), rather than as a basal taxon. The Asteriidae is paraphyletic, and is broken up into the Stichasteridae and four primary asteriid clades: (1) a highly diverse boreal clade, containing members from the Arctic and sub‐Arctic in the Northern Hemisphere; (2) the genus Sclerasterias; (3) and (4) two sister clades that contain asteriids from the Antarctic and pantropical regions. The Stichasteridae, which was regarded as a synonym of the Asteriidae, is resurrected by our results, and represents the most diverse Southern Hemisphere forcipulatacean clade (although two deep‐sea stichasterid genera occur in the Northern Hemisphere). The Labidiasteridae is artificial, and should be synonymized into the Heliasteridae. The Pedicellasteridae is paraphyletic, with three separate clades containing pedicellasterid taxa emerging among the basal Forcipulatacea. Fossils and timing estimates from species‐level phylogeographic studies are consistent with prior phylogenetic hypotheses for the Forcipulatacea, suggesting diversification of basal taxa in the early Mesozoic, with some evidence for more widely distributed ranges from Cretacous taxa. Our analysis suggests a hypothesis of an older fauna present in the Antarctic during the Eocene, which was succeeded by a modern Antarctic fauna that is represented by the recently derived Antarctic Asteriidae and other forcipulatacean lineages. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 646–660.     

An updated classification of Orchidaceae

Since the last classification of Orchidaceae in 2003, there has been major progress in the determination of relationships, and we present here a revised classification including a list of all 736 currently recognized genera. A number of generic changes have occurred in Orchideae (Orchidoideae), but the majority of changes have occurred in Epidendroideae. In the latter, almost all of the problematic placements recognized in the previous classification 11 years ago have now been resolved. In Epidendroideae, we have recognized three new tribes (relative to the last classification): Thaieae (monogeneric) for Thaia, which was previously considered to be the only taxon incertae sedis; Xerorchideae (monogeneric) for Xerorchis; and Wullschlaegelieae for achlorophyllous Wullschlaegelia, which had tentatively been placed in Calypsoeae. Another genus, Devogelia, takes the place of Thaia as incertae sedis in Epidendroideae. Gastrodieae are clearly placed among the tribes in the neottioid grade, with Neottieae sister to the remainder of Epidendroideae. Arethuseae are sister to the rest of the higher Epidendroideae, which is unsurprising given their mostly soft pollinia. Tribal relationships within Epidendroideae have been much clarified by analyses of multiple plastid DNA regions and the low‐copy nuclear gene Xdh. Four major clades within the remainder of Epidendroideae are recognized: Vandeae/Podochileae/Collabieae, Cymbidieae, Malaxideae and Epidendreae, the last now including Calypsoinae (previously recognized as a tribe on its own) and Agrostophyllinae s.s. Agrostophyllinae and Collabiinae were unplaced subtribes in the 2003 classification. The former are now split between two subtribes, Agrostophyllinae s.s. and Adrorhizinae, the first now included in Epidendreae and the second in Vandeae. Collabiinae, also probably related to Vandeae, are now elevated to a tribe along with Podochileae. Malaxis and relatives are placed in Malaxidinae and included with Dendrobiinae in Malaxideae. The increased resolution and content of larger clades, recognized here as tribes, do not support the ‘phylads’ in Epidendroideae proposed 22 years ago by Dressler. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177 , 151–174.     

Forest monkeys and Pleistocene refugia: a phylogeographic window onto the disjunct distribution of the Chlorocebus lhoesti species group

The reconstruction of evolutionary relationships among a group of closely‐related taxa provides a valuable window onto their biogeographic history. This is the first such molecular phylogenetic study to survey all three taxa of the Chlorocebus lhoesti species group, a group of Old World monkeys that includes C. lhoesti, Chlorocebus preussi, and Chlorocebus solatus. Representatives of each species were surveyed for two Y‐chromosomal genes, TSPY (～2240 bp) and SRY (～780 bp), and one X‐chromosomal intergenic region (～9300 bp) homologous to a portion of human Xq13.3. Maximum likelihood topologies inferred from these sequences confirm that the lhoesti group is monophyletic within the tribe Cercopithecini, as suggested by earlier karyotype studies. Within this group, C. lhoesti (Albertine region) and C. preussi (Cameroon, Nigeria, Bioko) cluster to the exclusion of C. solatus (Gabon). This phylogeographic pattern, evaluated in the context of Pleistocene glacial cycles and lhoesti group ecology, suggests: (1) the common ancestor of the group probably arose in west central Africa, (2) dispersal to the Albertine region is likely to have occurred during a glacial maximum, rather than an interglacial pluvial, and (3) this dispersal probably occurred via a path north of the Congo Basin. Divergence date calculations suggest C. solatus separated from the ancestral stock at ～2.1 Ma, whereas C. preussi and C. lhoesti bifurcated later, at ～0.5 Ma. Taken together, these evolutionary analyses draw attention to one period in the Pleistocene (～0.5 MYA) when a dispersal corridor suitable to montane taxa is likely to have connected the highlands of east central and west central Africa. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 408–418.     

Molecular phylogeny and systematics of the Pieridae (Lepidoptera: Papilionoidea): higher classification and biogeography

The systematic relationships of the butterfly family Pieridae are poorly understood. Much of our current understanding is based primarily on detailed morphological observations made 50–70 years ago. However, the family and its putative four subfamilies and two tribes, have rarely been subjected to rigorous phylogenetic analysis. Here we present results based on an analysis of molecular characters used to reconstruct the phylogeny of the Pieridae in order to infer higher‐level classification above the generic level and patterns of historical biogeography. Our sample contained 90 taxa representing 74 genera and six subgenera, or 89% of all genera recognized in the family. Three complementary approaches were employed: (1) a combined analysis of a 30 taxon subset for sequences from four gene regions, including elongation factor‐1 alpha (EF‐1α), wingless, cytochrome oxidase subunit I (COI), and 28S (3675 bp, 1031 parsimony‐informative characters), mainly to establish higher‐level relationships, (2) a single‐gene analysis of the 90 taxon data set for sequences from EF‐1α (1066 bp, 364 parsimony‐informative characters), mainly to establish lower‐level relationships, and (3) an all available data analysis of the entire data set for sequences from the four genes, to recover both deep and shallow nodes. Analyses using maximum parsimony, maximum likelihood and Bayesian inference provided similar results. All supported monophyly for the four subfamilies but not for the two tribes, with the Anthocharidini polyphyletic and the Pierini paraphyletic. The combined and all available data analyses support the following relationships among the subfamilies: ((Pseudopontiinae + Dismorphiinae) + (Coliadinae + Pierinae)), corroborating Ehrlich’s 1958 phenetic hypothesis. On the basis of these analyses, and additional morphological and life history evidence, we propose a reclassification of the subfamily Pierinae into two tribes (Anthocharidini s.s., Pierini s.s.) and two informal groups (Colotis group, Leptosia), with the tribe Pierini s.s. subdivided into three subtribes (Appiadina, Pierina, Aporiina) and three genera (Elodina, Dixeia, Belenois) of uncertain status (incertae sedis). The combined and all available data analyses support the following relationships among the Pierinae: (Colotis group + Anthocharidini s.s. + Leptosia + (Elodina + ((Dixeia + Belenois) + Appiadina + Pierina + Aporiina))). Application of a molecular clock calibrated using fossil evidence and semiparametric rate smoothing suggests that divergence between the Pierina and Aporiina occurred no later than the Palaeocene (> 60 Myr). The minimum estimate for the age of the crown‐group of the Pieridae was 112–82 Myr, with a mean of 95 Myr. A historical biogeographical hypothesis is proposed to explain the present‐day distribution of the clade Pseudopontiinae + Dismorphiinae, which argues for an origin of the two subfamilies in western Gondwana (Africa + South America) during the Late Cretaceous. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 147 , 239–275.     

Angiosperm phylogeny inferred from 18S rDNA, vbcL, and atpB sequences

A phylogenetic analysis of a combined data set for 560 angiosperms and seven outgroups based on three genes, 18S rDNA (1855 bp), rbcL (1428 bp), and atpB (1450 bp) representing a total of 4733 bp is presented. Parsimony analysis was expedited by use of a new computer program, the RATCHET. Parsimony jackknifing was performed to assess the support of clades. The combination of three data sets for numerous species has resulted in the most highly resolved and strongly supported topology yet obtained for angiosperms. In contrast to previous analyses based on single genes, much of the spine of the tree and most of the larger clades receive jackknife support 250%. Some of the noneudicots form a grade followed by a strongly supported eudicot clade. The early‐branching angiosperms are Amborellaceae, Nymphaeaceae, and a clade of Austrobaileyaceae, Illiciaceae, and Schi‐sandraceae. The remaining noneudicots, except Ceratophyllaceae, form a weakly supported core eumagnoliid clade comprising six well‐supported subclades: Chloranthaceae, monocots, WinteraceaeICanellaceae, Piperales, Laurales, and Magnoliales. Ceratophyllaceae are sister to the eudicots. Within the well‐supported eudicot clade, the early‐diverging eudicots (e.g. Proteales, Ranunculales, Trochodendraceae, Sabiaceae) form a grade, followed by the core eudicots, the monophyly of which is also strongly supported. The core eudicots comprise six well‐supported subclades: (1) Berberidopsidaceae/Aextoxicaceae; (2) Myrothamnaceae/ Gunneraceae; (3) Saxifragales, which are the sister to Vitaceae (including Leea) plus a strongly supported eurosid clade; (4) Santalales; (5) Caryophyllales, to which Dilleniaceae are sister; and (6) an asterid clade. The relationships among these six subclades of core eudicots do not receive strong support. This large data set has also helped place a number of enigmatic angiosperm families, including Podostemaceae, Aphloiaceae, and Ixerbaceae. This analysis further illustrates the tractability of large data sets and supports a recent, phylogenetically based, ordinal‐level reclassification of the angiosperms based largely, but not exclusively, on molecular (DNA sequence) data.     

Phylogeographic diversification of antelope squirrels (Ammospermophilus) across North American deserts

We investigated the biogeographic history of antelope squirrels, genus Ammospermophilus, which are widely distributed across the deserts and other arid lands of western North America. We combined range‐wide sampling of all currently recognized species of Ammospermophilus with a multilocus data set to infer phylogenetic relationships. We then estimated divergence times within identified clades of Ammospermophilus using fossil‐calibrated and rate‐calibrated molecular clocks. Lastly, we explored generalized distributional changes of Ammospermophilus since the last glacial maximum using species distribution models, and assessed responses to Quaternary climate change by generating demographic parameter estimates for the three wide‐ranging clades of A. leucurus. From our phylogenetic estimates we inferred strong phylogeographic structure within Ammospermophilus and the presence of three well‐supported major clades. Initial patterns of historical divergence were coincident with dynamic alterations in the landscape of western North America, and the formation of regional deserts during the Late Miocene and Pliocene. Species distribution models and demographic parameter estimates revealed patterns of recent population expansion in response to glacial retreat. When combined with evidence from co‐distributed taxa, the historical biogeography of Ammospermophilus provides additional insight into the mechanisms that impacted diversification of arid‐adapted taxa across the arid lands of western North America. We propose species recognition of populations of the southern Baja California peninsula to best represent our current understanding of evolutionary relationships among genetic units of Ammospermophilus. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 949–967.     

Molecular phylogenetic analysis of Podostemaceae: implications for taxonomy of major groups

The river‐weed family Podostemaceae (c. 300 species in c. 54 genera) shows a number of morphological innovations to be adapted to its unusual aquatic habitat, and its unique or rare bauplan features have been reflected in the traditional (i.e. non‐molecular) classification recognizing numerous monotypic or oligospecific genera. The infrasubfamilial relationships of many genera remained unclear. The present study used molecular phylogenetic analysis of matK sequences for 657 samples (c. 132 species/c. 43 genera). The family was traditionally divided into three subfamilies (Podostemoideae, Tristichoideae and Weddellinoideae). American Podostemoideae were shown to be polyphyletic and divided into four clades, i.e. Ceratolacis, Diamantina, Podostemum and all other genera. Among the podostemoid clades, Diamantina was the first branching clade and a clade comprising Mourera and the Apinagia subclade was then sister to the remainder of the New World and Old World Podostemoideae with low statistic supports. The Old World Podostemoideae comprised four monophyletic clades, i.e. two African clades, one Madagascan clade and one Asian clade, although the relationships among these clades and American Ceratolacis and Podostemum were poorly resolved. African Podostemoideae were polyphyletic, with Saxicolella pro parte being weakly supported as sister to the remaining Old World Podostemoideae plus Ceratolacis and Podostemum. In contrast to the American and African clades, monophyly of four Asian subclades was well supported. Plants of Tristicha (Tristichoideae) and of Weddellina (Weddellinoideae), which are currently treated as monospecific, had great matK differentiation equivalent to at least interspecific variation. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 461–492.     

Congruent patterns of lineage diversity in two species complexes of planktonic crustaceans,Daphnia longispina (Cladocera) and Eucyclops serrulatus (Copepoda), in East European mountain lakes

Cladocerans and copepods are globally important freshwater zooplankton groups, differing in reproductive modes and dispersal abilities. We compared genetic variation of two common taxa of these crustaceans, the Daphnia longispina species complex (known to harbour multiple cryptic lineages) and Eucyclops serrulatus (morphologically and ecologically variable morphospecies), in lakes of ten Eastern European mountain ranges. We expected to discover cryptic lineages in both groups, and to observe different geographical patterns of diversity because of differences in life cycles. Within E. serrulatus, limited sampling through lowland habitats indeed showed the presence of eight highly divergent clades, probably cryptic species, but most of these were not found in the studied mountain lakes. Such a pattern was congruent with the diversity of the D. longispina complex. Regional coexistence of multiple clades within respective species complexes (two in Eucyclops and three in Daphnia) was observed only in the Tatra Mountains (on the Polish?Slovak border). In all other studied mountain ranges (in the Balkans), only single lineages of Daphnia and Eucyclops, respectively, were present, showing similar intraspecific patterns and no evidence for stronger dispersal limitation in Eucyclops than in Daphnia. Our results indicate that substantial cryptic variation may be expected in seemingly widespread copepod taxa. However, detection of cryptic lineages is not a general pattern in mountain lakes, although these habitats harbour substantial genetic diversity in crustacean zooplankton. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 754–767.     

Crystal types and their distribution in the bark of African genistoid legumes (Fabaceae tribes Sophoreae,Podalyrieae, Crotalarieae and Genisteae)

The occurrence and distribution of seven crystal types in 114 bark samples from 25 genera and 91 species, representing all four tribes of African genistoid legumes, are reported. The seven types are prismatic, druse (including irregular crystal clusters), navicular (including truncated navicular, here reported for the first time), spherical crystal cluster, styloid, crystal sand and acicular crystals in sheaf‐like aggregates. Unlike most studies, the elemental composition of the crystals was examined using X‐ray microanalyses. With the exception of acicular crystals, all crystals showed the typical peaks of calcium (sometimes accompanied by small amounts of magnesium). Acicular crystals in sheaf‐like aggregates were composed only of carbon and oxygen, indicating that they are organic and precipitate during drying or after fixation in alcohol. These crystals are found only in the two early‐diverging lineages of Podalyrieae (Cyclopia and Virgilia+Calpurnia clades), consistent with the phylogenetic pattern in the tribe (indicating a secondary loss). Navicular crystals are restricted to Podalyrieae and Crotalarieae. Prismatic crystals in bark are proposed to be the ancestral condition, with multiple losses (or reversals) in Podalyrieae, Crotalarieae and Genisteae. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 620–632.     

Phylogenetic systematics of Erythronium (Liliaceae): morphological and molecular analyses

For a nearly complete set of species of Erythronium (Liliaceae), we examined two plastid loci (the rps16 intron and the 5′ trnK intron, excluding the matK exon), one nuclear locus (nrITS) and morphology to evaluate species relationships and that of Erythronium to Amana, the putatively most closely allied genus. A matrix of morphological characters was developed through observation of around 900 living and herbarium specimens; evolution of these was examined using character optimization on the combined (total‐evidence) tree. Parsimony methods were used to examine the morphological and molecular data sets produced, both separately and in combination, with Bayesian methods also used on the molecular data sets. These established that the genus is probably sister to Amana (although most analyses placed Amana inside Erythronium) and that Tulipa is sister to the pair of Erythronium and Amana. Within Erythronium, there are three strongly supported geographically distinct clades: (1) Eurasian and (2) eastern and (3) western North American. Separation of species in these three clades is less clear, particularly among the western North American taxa. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ●●, ●●–●●.     

The flightless marine midge Pontomyia (Diptera: Chironomidae): ecology,distribution, and molecular phylogeny

Pontomyia Edwards, 1926 (Diptera: Chironomidae) is a genus of exclusively marine flightless midges. There are four described species from the Indo‐Pacific, and one undescribed species known only from females, pupal skins, and larvae from the Atlantic/Caribbean. They are poorly known owing to their small size (～1.0 mm), extremely short adult life (< 3 h), and unusual habitat for an insect (coastal lagoons, bays, or rock pools). We reviewed scattered literature on their biology and systematics, presented photomicrographs of the male hypogium, and updated the geographic distribution of each species. We carried out the first molecular study to elucidate relationships among and within three of the species. Results from our four‐gene phylogenetic reconstruction using combined gene tree and species tree approaches showed that Pontomyia natans, Pontomyia oceana, and Pontomyia pacifica are each well‐supported clades, with P. natans as sister to P. oceana + P. pacifica. Genetic distances based on mitochondrial cytochrome oxidase I are extraordinarily large within P. natans and P. pacifica, which suggests that they may be cryptic species complexes. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 443–456.