Higher-level phylogeny of the Ithomiinae (Lepidoptera: Nymphalidae): classification, patterns of larval hostplant colonization and diversification

We present a higher‐level phylogenetic hypothesis for the diverse neotropical butterfly subfamily Ithomiinae, inferred from one of the largest non‐molecular Lepidoptera data sets to date, including 106 species (105 ingroup) and 353 characters (306 informative) from adult and immature stage morphology and ecology. Initial analyses resulted in 1716 most parsimonious trees, which were reduced to a single tree after successive approximations character weighting. The inferred phylogeny was broadly consistent with other past and current work. Although some deeper relationships are uncertain, tribal‐level clades were generally strongly supported, with two changes required to existing classification. The tribe Melinaeini is polyphyletic and Athesis + Patricia require a new tribe. Methona should be removed from Mechanitini into the restored tribe Methonini. Dircennini was paraphyletic in analyses of all data but monophyletic based on adult morphology alone, and its status remains to be confirmed. Hypothyris, Episcada, Godyris, Hypoleria and Greta are paraphyletic. A simulation analysis showed that relatively basal branches tended to have higher partitioned Bremer support for immature stage characters. Larval hostplant records were optimized on to a reduced, generic‐level phylogeny and indicate that ithomiines moved from Apocynaceae to Solanaceae twice, or that Tithoreini re‐colonized Apocynaceae after a basal shift to Solanaceae. Ithomiine clades have specialized on particular plant clades suggesting repeated colonization of novel hostplant niches consistent with adaptive radiation. The shift to Solanum, comprising 70% of neotropical Solanaceae, occurs at the base of a clade containing 89% of all ithomiines, and is interpreted as the major event in the evolution of ithomiine larval hostplant relationships. © The Willi Hennig Society 2006.     

Chondrocranial morphology of Leptodactylus larvae (Leptodactylidae: Leptodactylinae): Its utility in phylogenetic reconstruction

Chondrocranial morphology of leptodactylid frogs is scarcely known and has not been completely described for any species of Leptodactylus. We describe the diversity of chondrocranial morphology in the genus Leptodactylus based on the analysis of 22 species, representing the four species groups: the fuscus Group, ocellatus Group, melanonotus Group, and pentadactylus Group. Furthermore, 26 characters are identified and used in a phylogenetic analysis. The phylogenetic analysis using Physalaemus, Crossodactylus, and Hylodes as outgroups suggests two monophyletic clades within Leptodactylus: the melanonotus-ocellatus clade and the pentadactylus-fuscus clade. However, it does not support the monophyly of the species groups as currently recognized and it suggests a paraphyletic Leptodactylus. Enforcing the monophyly of the ingroup, i.e., Leptodactylus, results in the same major two clades of Leptodactylus. Leptodactylus riveroi, a taxon previously unassigned to any species group, appears most closely related to the melanonotus-ocellatus clade based on chondrocranial characteristics. J. Morphol. 238:287–305, 1998. © 1998 Wiley-Liss, Inc.     

First case of ranavirus-associated mass mortality in a natural population of the Huanren frog (Rana huanrenensis) tadpoles in South Korea

Globally, ranavirus is often responsible for the mass mortality of a variety of captive and wild amphibians. In Asia, several mass mortality cases of captive amphibians by ranavirus are known, but one mass mortality case in the wild has been reported in a non-endemic larval bullfrog population in Japan. In order to verify factors involved in mass mortality of Rana huanrenensis tadpoles (> 200 tadpoles) in a mountain stream in South Korea, we investigated possible infections by ranavirus, chytrid fungus, and lethal bacteria by conducting PCR assays of pathogens with specific primers. We found that all R. huanrenensis tadpoles collected (two alive and ten carcasses) showed positive PCR results for two different ranavirus primer sets targeting partial genes of a major capsid protein (MCP). The identified MCP sequence was more closely related to Rana catesbeiana virus JP MCP, isolated from invasive bullfrog tadpoles in Japan. We could not detect any lethal bacteria or chytrid fungus in the specimens. Our finding is the first report in Asia that ranavirus is involved in the mass mortality of endemic wild amphibians.     

Functional mechanisms of an inducible defence in tadpoles: morphology and behaviour influence mortality risk from predation

In many amphibian larvae a suite of morphological and behavioural characters varies together in an induced defence against predators, but it remains unclear which features are functionally related to defence. We independently manipulated behaviour and morphology in tadpoles of Hyla versicolor and assessed their consequences for swimming performance and predator escape. Data on burst swimming showed that tadpoles which accelerated rapidly were elongate, with shallow bodies and tails. Predator escape was measured by exposing tadpoles to predators (larval Anax dragonflies or larval Ambystoma salamanders) and recording time until death. Tadpoles were first reared for 30 days in ponds containing either caged Anax or no predators; individuals responded to predators by developing large brightly coloured tails and short bodies. We placed tadpoles of both morphological phenotypes into plastic tubs, and manipulated their behaviour using food and chemical cues from predators. Mortality risk experienced by the predator‐induced phenotype was about half that of the no‐predator phenotype, and risk increased with time spent swimming. An interaction between morphology and behaviour arose because increasing activity caused higher risk for tadpoles with deep tail fins but not shallow tail fins.     

Phylogenetic analysis of the Malvadendrina clade (Malvaceae s.l.) based on plastid DNA sequences

Phylogenetic relationships within Malvaceae s.l., a clade that includes the traditional families Bombacaceae, Malvaceae s.str., Sterculiaceae, and Tiliaceae, have become greatly clarified thanks to recent molecular systematic research. In this paper, we use DNA sequences of four plastid regions (atpB, matK, ndhF, and rbcL) to study relationships within Malvadendrina, one of the two major clades of Malvaceae s.l. The four data sets were generally in agreement, but five terminal taxa manifested highly unexpected affinities in the rbcL partition, and the non-coding sequences of the trnK intron were found to provide limited phylogenetic information for resolving relationships at the base of Malvadendrina. The remaining data strongly support the existence of six major clades within Malvadendrina: Brownlowioideae, Dombeyoideae, Helicteroideae, Malvatheca (comprising Bombacoideae and Malvoideae), Sterculioideae, and Tilioideae. These data also resolve the placement of two problematic taxa: Nesogordonia (in Dombeyoideae) and Mortoniodendron (in Tilioideae). The relationships among the six clades are not definitively resolved, but the best-supported topology has Dombeyoideae as sister to the remainder of Malvadendrina (posterior probability PP=80%) and Sterculioideae as sister to Malvatheca (PP=86%). This early branching position of Dombeyoideae is supported by similarities in floral characters between members of that clade and outgroup taxa in Byttnerioideae. Similarly, the sister-group relationship of Sterculioideae and Malvatheca receives support from androecial characteristics, like subsessile or sessile anthers and an absence of staminodes, shared by these two clades.     

Phylogenetic Relationships and Morphological Character Evolution of Photosynthetic Euglenids (Excavata) Inferred from Taxon‐rich Analyses of Five Genes

Photosynthetic euglenids acquired chloroplasts by secondary endosymbiosis, which resulted in changes to their mode of nutrition and affected the evolution of their morphological characters. Mapping morphological characters onto a reliable molecular tree could elucidate major trends of those changes. We analyzed nucleotide sequence data from regions of three nuclear‐encoded genes (nSSU, nLSU, hsp90), one chloroplast‐encoded gene (cpSSU) and one nuclear‐encoded chloroplast gene (psbO) to estimate phylogenetic relationships among 59 photosynthetic euglenid species. Our results were consistent with previous works; most genera were monophyletic, except for the polyphyletic genus Euglena, and the paraphyletic genus Phacus. We also analyzed character evolution in photosynthetic euglenids using our phylogenetic tree and eight morphological traits commonly used for generic and species diagnoses, including: characters corresponding to well‐defined clades, apomorphies like presence of lorica and mucilaginous stalks, and homoplastic characters like rigid cells and presence of large paramylon grains. This research indicated that pyrenoids were lost twice during the evolution of phototrophic euglenids, and that mucocysts, which only occur in the genus Euglena, evolved independently at least twice. In contrast, the evolution of cell shape and chloroplast morphology was difficult to elucidate, and could not be unambiguously reconstructed in our analyses.     

Pond attributes influence competitive interactions between tadpoles and mosquito larvae

Abstract Tadpoles and mosquito larvae often coexist in natural freshwater bodies. We studied competitive interactions between: (i) tadpoles of the striped marsh frog (Limnodynastes peronii) and larvae of the mosquito Culex quinquefasciatus; and (ii) tadpoles of the common eastern froglet (Crinia signifera) and larvae of the mosquito Aedes australis. These two sets of taxa occur in natural water bodies in the Sydney region. Laboratory trials revealed competition between mosquito larvae and tadpoles in both systems. For example, mosquitoes displayed reduced rates of survival, growth and development, and smaller size at metamorphosis, when they were raised with tadpoles. The intensity of competitive suppression was influenced by attributes such as pond size (and hence, larval density), the location of food (on the water surface vs the substrate), and the extent of opportunities for direct physical interactions between the two competing organisms. These effects differed between the two study systems, suggesting that the mechanisms of suppression also differed. Limnodynastes peronii tadpoles suppressed C. quinquefasciatus even when the two types of organisms were separated by a physical partition, suggesting that chemical or microbiological cues may be responsible. Pond attributes also affected the impact of C. signifera tadpoles on Aedes larvae, but (unlike the Limnodynastes–Culex system) these effects disappeared when densities were lowered or when the tadpoles and mosquito larvae were physically separated. Thus, direct physical interactions may suppress mosquitoes in the Crinia–Aedes system. Our results suggest that tadpoles suppress the viability of larval mosquitoes by multiple pathways.     

Phylogeny of the water strider genus Rheumatobates (Heteroptera: Gerridae)

The genus Rheumatobates comprises thirty‐seven species and subspecies of New World water striders belonging to subfamily Rhagadotarsinae. Among species, males vary dramatically in the degree and nature of modifications of the antennae, three pairs of legs and abdominal and genital segments. Characters describing this modification have traditionally been used to differentiate and group species. The general assumption has been that modified species belong to one group and unmodified species to another. These two ‘species groups’ are subdivided into ‘subgroups’, but little effort has been made to resolve relationships among them. We conduct the first numerical cladistic analysis of Rheumatobates using a data set comprised of 102 characters, primarily describing modification of male external morphology. To address concerns about the inclusion of characters to be optimized on the phylogeny, characters describing modification of antennae and hind legs were included and then excluded in separate analyses. A preferred phylogeny was chosen from the four equally parsimonious cladograms found after successive reweighting of characters. There was good resolution at all levels of the phylogeny. Most of the major clades and terminal relationships were moderately to strongly supported, whereas the basal relationships were less well supported. The general assumption that unmodified and modified species form two monophyletic groups was not supported. However, traditionally recognized ‘subgroups’ within the modified species group were largely upheld. The analysis also suggested several major clades and relationships among these clades that were not previously recognized. The exclusion of characters describing modification of antennae and hind legs did not change the resolved major clades of the reconstructed phylogeny.     

Searching for new morphological characters in the systematics of scleractinian reef corals: comparison of septal teeth and granules between Atlantic and Pacific Mussidae

Recent molecular analyses have challenged the traditional classification of scleractinian corals at all taxonomic levels suggesting that new morphological characters are needed. Here we tackle this problem for the family Mussidae, which is polyphyletic. Most of its members belong to two molecular clades composed of: (1) Atlantic Mussidae and Faviidae (except Montastraea) and (2) Pacific Mussidae (Cynarina, Lobophyllia, Scolymia, Symphyllia) and Pectiniidae. Other Pacific mussids (e.g. Acanthastrea) belong to additional clades. To discover new characters that would better serve as phylogenetic markers, we compare the skeletal morphology of mussid genera in different molecular‐based clades. Three sets of characters are considered: (1) macromorphology (budding; colony form; size and shape of corallites; numbers of septal cycles), (2) micromorphology (shapes and distributions of septal teeth and granules), and (3) microstructure (arrangement of calcification centres and thickening deposits within costosepta). Although most traditional macromorphological characters exhibit homoplasy, several new micromorphological characters are effective at distinguishing clades, including the shapes and distribution of septal teeth and granules, the area between teeth, and the development of thickening deposits. Arrangements of calcification centres and fibres differ among clades, but the fine‐scale structure of thickening deposits does not.     

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     

Deceptive single‐locus taxonomy and phylogeography: Wolbachia‐associated divergence in mitochondrial DNA is not reflected in morphology and nuclear markers in a butterfly species

The satyrine butterfly Coenonympha tullia (Nymphalidae: Satyrinae) displays a deep split between two mitochondrial clades, one restricted to northern Alberta, Canada, and the other found throughout Alberta and across North America. We confirm this deep divide and test hypotheses explaining its phylogeographic structure. Neither genitalia morphology nor nuclear gene sequence supports cryptic species as an explanation, instead indicating differences between nuclear and mitochondrial genome histories. Sex‐biased dispersal is unlikely to cause such mito‐nuclear differences; however, selective sweeps by reproductive parasites could have led to this conflict. About half of the tested samples were infected by Wolbachia bacteria. Using multilocus strain typing for three Wolbachia genes, we show that the divergent mitochondrial clades are associated with two different Wolbachia strains, supporting the hypothesis that the mito‐nuclear differences resulted from selection on the mitochondrial genome due to selective sweeps by Wolbachia strains.     

The larval hyobranchial apparatus of discoglossoid frogs: its structure and bearing on the systematics of the Anura (Amphibia: Anura)

The morphology of the larval hyobranchial apparatus of discoglossoid frog species representing the genera Ascaphus, Alytes, Bombina, and Discoglossus is described and the resulting characters were analysed cladistically. Seven species representing seven major lineages of frogs were included in the cladistic analysis of characters. Several changes in the terminology of the musculature are introduced, and a new interpretation of the subarcualis-muscle system is presented. The phylogenetic analysis suggest that the hyobranchial apparatus was substantially altered in the lineages leading to and within the Pipanura. This notably involved fusion, reduction and loss of skeletal structures and muscles, and splitting of certain muscles into muscle groups. The result confirm previous hypotheses based on the study of adults: discoglossoid species retain the most numlerous plesiomorphic characters among extant ianurans. The larval hyobranchial apparatus is in many features structrually similar to that of urodeles. Many of their character states were most likely present in the most recent common ancestor of all living forgs. The cladistic analysis of 31 characters of ithe larval hyobranchial apparatus supports major clades: Anura, Bombinanura, Pipanura, and Pelobatoidea + Neobatrachia. The cladiostic analysis and interpretation of larval characters is in part compatible with phylogenetic hypotheses based on characters of adults and rRNA sequences, but is in conflict with the Mesobatrachia and Archaeobatrachia concepts of other authors.     

Factors influencing tadpole deposition site choice in a frog with male parental care: An experimental field study

Parents have evolved a variety of strategies to minimize risks to their offspring, including complex choices regarding suitable rearing sites, based on abiotic and biotic factors, which differentially affect offspring survival. Because availability and quality of these sites are variable, parents may have to choose between immediately available lower‐quality rearing sites or extended search time. In some frog species with larval transport, parents are known to select bodies of water that are free of predators, cannibalistic tadpoles, or intraspecific competitors for larval deposition and rearing sites. We tested whether abiotic factors and the presence of predators and conspecific tadpoles affect tadpole deposition behavior in a population of smooth guardian frog, Limnonectes palavanensis, on the island of Borneo. Females lay eggs on land and males guard them until they hatch; after hatching, tadpoles climb onto the male's back and are subsequently transported to small pools of water on the forest floor, which are scarce and patchily distributed. We estimated the abundance of natural tadpole rearing sites in our study area and conducted experiments using artificial pools to test whether abiotic characteristics of these pools affect the probability of larval deposition. We also performed choice experiments to test whether males of L. palavanensis avoid pools with conspecific tadpoles or predators. Lastly, we tested whether the tadpoles of this species exhibit cannibalism. The abundance of natural deposition sites was low, and males readily used artificial pools for tadpole deposition. Males were less likely to deposit tadpoles in artificial pools located in steep areas, and males did not avoid depositing tadpoles in pools with conspecifics or with experimentally introduced predators. Males exhibited clutch‐partitioning behavior, dividing tadpoles between adjacent artificial pools. Pool availability, rather than the presence of potential competitors or predators in a pool, affects tadpole deposition decisions in this species.     

Anatomy of the trunk mesoderm in tunicates: homology considerations and phylogenetic interpretation

The tadpole stage of tunicates has played a pivotal role in understanding chordate evolution. While the organization of the mesoderm has been given high importance in comparative anatomical studies of Bilateria, this morphological character remains largely unexplored in tunicate tadpoles. For larvae of the phlebobranch ascidian Ciona intestinalis, the presence of two mesodermal pockets had been claimed, raising the possibility that paired coelomes are present in the larval ascidian. Using computer assisted 3D-reconstructions based on complete series of 1 μm-sections analyzed by light microscopy complemented by TEM-investigation of selected regions a comparative anatomical study of tadpole stages from four major tunicate clades, Aplousobranchiata, Phlebobranchiata, Stolidobranchiata, and Appendicularia is presented. In the aplousobranch Clavelina lepadiformis numerous mesodermal cells are found throughout the entire trunk plus the unpaired ventral rudiment of the pericardium. In the phlebobranch Ascidia interrupta, massive mesodermal components occur in the posterior trunk, whereas more anteriorly situated mesoderm consists of loose streaks of cells or isolated cells. This is also the case in the stolidobranch ascidians Herdmania momus and Styela plicata. In the stolidobranch Molgula occidentalis and the appendicularian Oikopleura dioica the anterior trunk is entirely devoid of mesodermal cells. TEM-investigation revealed that all mesodermal structures in the trunk of tunicate tadpoles were mesenchymal with the exception of a ventral portion of the mesoderm in C. lepadiformis, which probably corresponds to the developing pericardium, and the differentiated pericardium of the juvenile O. dioica. Thus no evidence for paired coelomic cavities in Tunicata was found. Outgroup comparison suggests that the reduction of paired coelomic cavities is an apomorphic trait of Tunicata. Within Tunicata a stepwise evolutionary reduction of the anterior larval mesenchyme is documented.     

Phylogenetic relationships within a patagonian clade of reptiles (Liolaemidae: Phymaturus) based on DNA sequences and morphology

Phymaturus is a clade of lizards that occurs at moderate to high elevations in western Argentina and the adjacent central region of Chile, as well as in various volcanic plateaus of the Patagonian region of Argentina. This genus had previously been divided into two groups: the patagonicus and the palluma groups. In this study, we analyzed relationships within the patagonicus group. The data set was built for 23 species plus nine other terminal taxa of undetermined taxonomic status. In total, 10,631 bp (ND4, Cytb, 12S, COI, five protein coding nuclear genes and seven anonymous nuclear loci) and 254 morphological characters were analyzed in a combined data set for 35 ingroup taxa and nine outgroups. We also ran separate DNA sequence and morphological data sets. We identified four main clades, and revealed congruencies and incongruences with previous studies. The indistinctus clade is recovered as the most basal within the patagonicus group in the strict parsimony analysis, while the somuncurensis clade is the most basal under Bayesian inference. The previously recovered calcogaster clade resulted paraphyletic in both analyses and part of their species are included in a redefined somuncurensis clade. We found low support at basal nodes provoked in part by contradictory evidence shown by rogue taxa. We show the phylogenetic information given by each partition/marker and how they contribute to relationships found in the total evidence analysis. We discuss the phylogenetic position of Phymaturus manuelae, Phymaturus tenebrosus, and Phymaturus patagonicus.     

The peculiar nemertean larva pilidium recurvatum belongs to Riserius sp., a basal heteronemertean that eats Carcinonemertes errans,a hoplonemertean parasite of Dungeness crab

A typical nemertean pilidium larva resembles a hat with ear flaps. But one type, called pilidium recurvatum, looks more like a sock, swimming heel first. This distinctive larva was discovered in 1883 off the coast of Rhode Island and subsequently found in plankton samples from other parts of the world. Despite the long time since discovery, and its significance in discussions of larval evolution, this larva remained unidentified even to the family level. We collected pilidium recurvatum larvae from plankton samples in Coos Bay, OR, and identified them as belonging to the heteronemertean genus Riserius based on juvenile morphology and DNA sequence data. Phylogenetic analysis suggests that two distinct types of pilidium recurvatum from Oregon represent two new species within this currently monotypic genus. We describe the morphology of pilidium recurvatum using confocal microscopy and compare it to that of the typical pilidium, discussing possible implications for larval feeding. We also report our surprising discovery that juveniles of Riserius sp. from Oregon prey on another nemertean, Carcinonemertes errans, an egg predator of Cancer magister (Dungeness crab), a commercially important species. We speculate that the species‐level diversity and geographic distribution of Riserius may be much greater than currently appreciated.     

Does your lip stick? Evolutionary aspects of the mouth morphology of the Indo‐Pacific clinging goby of the Sicyopterus genus (Teleostei: Gobioidei: Sicydiinae) based on mitogenome phylogeny

Sicydiinae gobies have an amphidromous life cycle. Adults grow, feed, and reproduce in rivers, while larvae have a marine dispersal phase. Larvae recruit back to rivers and settle in upstream habitats. Within the Sicydiinae subfamily, the Sicyopterus genus, one of the most diverse (24 species), is distributed in the tropical islands of the Indo‐Pacific. One of the characters used to determine Sicyopterus species is the upper lip morphology, which can be either smooth, crenulated, or with papillae, and with (2 or 3) or without clefts. The mouth is used as a secondary locomotor organ along with the pelvic sucker. It is thus strongly related to the climbing ability of species and is of major importance for the upstream migration and the colonization of insular freshwater systems. The mouth also has an important role in the feeding mechanism of these herbivorous species. In this paper, we have established a molecular phylogeny of the genus based on the 13 mitochondrial protein‐coding genes to discuss the relationship between 18 Sicyopterus species. There is a well‐supported dichotomy in the molecular phylogeny of the Sicyopterus genus and this separation into two clades is also morphologically visible, with the distinction of species with three clefts and species with 0 or 2 clefts on the upper lip. The mouth morphology can thus be separated with regard to the molecular phylogeny obtained. The evolution of the mouth morphology is discussed in terms of the adaptation of the Sicyopterus genus to settlement and life in tropical insular river systems.