On the systematic position of the family Gyrinidae (Coleoptera: Adephaga)

Various characters of adult and larval members of Adephaga and Cupedidae were analyzed, and suggest that Gyrinidae are the sister-group of the remaining Adephaga, and are not closely related to the remaining aquatic Adephaga. The aquatic families Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae seem to form a well founded monophyletic unit. The following characters are considered as synapomorphies of Adephaga excluding Gyrinidae: bifurcate condition of the muscle (= M.) tentoriopraementalis inferior, reduction of hypopharynx, strongly developed prosternal process, reduction in size and specialized modification of the ventral sclerite of the mesothorax, strongly developed mesofurcal arms, a high mesopleural ridge, globular mesocoxae restricted to rotatory movements, invaginated sternum VIII (coxostemum), the strongly curved base of the median lobe of the aedeagus, which articulates with the parameres, the rotated position of the aedeagus in repose, fusion of the larval clypeolabrum with the frons and reduction of the larval lacinia. Mesal shifting of M. episterno-coxalis prothoracis, and the fusion of the apical portions of the malpighian tubules of either side are considered as synapomorphies of Adephaga excluding Rhysodidae and Gyrinidae. Lateral reduction of the meta “sternal” transverse ridge and the presence of the subcubital setal binding patch of the hind wing are considered as synapomorphic characters of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. We postulate that the metacoxal fusion occurred independently in gyrmids and the common ancestor of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. Consequently we consider this character state as another synapomorphy of Trachypachidae and Hydradephaga excluding Haliplidae and Gyrinidae. The following characters are considered as synapomorphies of Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae: Loss of tactile setae on the head capsule, metafurcal origin on the intercoxal wall, expansion of the intercoxal wall, elongation of the subcubital setal binding patch, loss of Mm. furca-coxale anterior and posterior, reduction of the larval abdominal segments IX and X, and the shifting of the uropmphi onto the ventral side of segment VIII. Presence of M. tentorio-mandibularis and M. stipitopalpalis intemus are certainly primitive features of adult gyrinids but the distribution of these character states among most members of Adephaga is yet unclear. Chemical defence gland constituents point towards a very isolated position of Gyrinidae. The old age of the group, documented by a larva found in upper Permian deposits, may support the hypothesis of a sister-group relation-ship between Gyrinidae and the remainder of Adephaga.     

The morphological evolution of the Adephaga (Coleoptera)

The evolution of the coleopteran suborder Adephaga is discussed based on a robust phylogenetic background. Analyses of morphological characters yield results nearly identical to recent molecular phylogenies, with the highly specialized Gyrinidae placed as sister to the remaining families, which form two large, reciprocally monophyletic subunits, the aquatic Haliplidae + Dytiscoidea (Meruidae, Noteridae, Aspidytidae, Amphizoidae, Hygrobiidae, Dytiscidae) on one hand, and the terrestrial Geadephaga (Trachypachidae + Carabidae) on the other. The ancestral habitat of Adephaga, either terrestrial or aquatic, remains ambiguous. The former option would imply two or three independent invasions of aquatic habitats, with very different structural adaptations in larvae of Gyrinidae, Haliplidae and Dytiscoidea.     

Molecular phylogeny of the highly disjunct cliff water beetles from South Africa and China (Coleoptera: Aspidytidae)

The superfamily Dytiscoidea contains six families with an aquatic lifestyle, with most of its extant diversity in two families: the burrowing water beetles (Noteridae) and the diving beetles (Dytiscidae). The other families have few species (up to six) and generally highly disjunct extant distributions. Aspidytidae currently contains one genus with two species, one in China and one in South Africa. Here we provide the first molecular data for the Chinese species, allowing us to explore the phylogenetic relationships and position of both species of this small family for the first time. Based on a matrix of 11 genes we inferred a phylogenetic hypothesis for Dytiscoidea including all extant families. Unexpectedly, Aspidytidae were consistently recovered as paraphyletic relative to Amphizoidae, despite being well characterized by apparently synapomorphic adult features. A re‐examination of larval characters in the two aspidytid species revealed that the larva of the Chinese species is strikingly similar to that of Amphizoidae. Both share a series of plesiomorphic features but also some potential synapomorphies, including a dense vestiture of short setae on the head capsule, anteriorly shifted posterior tentorial grooves and widely separated labial palps. Arguably these features may belong to the groundplan of the clade Aspidytidae + Amphizoidae, with far‐reaching secondary modifications (including reversals) in the South African Aspidytes niobe. At present we retain the family Aspidytidae, however, due to the strong adult morphological synapomorphies of the two extant species, and the fact that the molecular paraphyly of the family may result from the highly divergent nature of the two extant species. This long evolutionary separation and strong divergence, in terms of gene sequences and larval features, is undeniable, substantial levels of saturation in third codon positions of protein‐coding genes being present between the two taxa. We address this issue taxonomically by introducing the new genus S inaspidytes gen. nov. for the Chinese Aspidytes wrasei. The continued contentious relationships amongst Dytiscidae, Hygrobiidae, Aspidytidae and Amphizoidae highlight the need for more data to address dytiscoid phylogenetics, possibly involving a genomic approach. © 2016 The Linnean Society of London     

Studies of the metathorax of the trout-stream beetle,Amphizoa lecontei Matthews (Coleoptera : Amphizoidae): Contribution towards clarification of the systematic position of Amphizoidae

Skeleton and musculature of the metathorax and the abdominal nerve cord of Amphizoa lecontei (Coleoptera : Amphizoidae) Matthews were examined and compared to those of other members of Adephaga (Coleoptera). The following characters may be important for phylogenetic analysis. The narrow prescutal area and moderately developed mesophragma with distinctly separated median phragmal lobes in Amphizoa is considered as plesiomorphic, whereas the median phragmal lobes lying closely together or fused is a possible synapomorphy of Hygrobiidae and Dytiscidae. The short 1st axillary sclerite of Amphizoa may be an autapomorphy of the group. The weakly arched notum and the poorly developed metaphragma arc obviously the result of tendency towards flightlessness. The anepisternum meets the middle coxal cavity. The prosternal process does not reach the meta “sternum” (“sternum” = preepisternum + basisternum presternum + spinasternum 2). The specialized pro-meso-meta “sternal” articulation in Hygrobia and Dytiscidae is considered a synapomorphy of both groups. The amphizoid metafurca is distinctly reduced in size. Pouch-like anterolateral excavations are considered plesiomorphic. Strong dorsolateral and weak ventrolateral projections of the metafurca may be a synapomorphy of Hygrobiidae and Dytiscidae. The hind legs of Amphizoa are not adapted for swimming, except for very sparse fringes of thin setae. Swimming hind legs are considered as a synapomorphy of Hygrobiidae and Dytiscidae. The main flight muscles were degenerated in all specimens of Amphizoa examined. Absence of muscle (M) 65 may be autapomorphic for Amphizoidae. Presence of M 72 is a symplesiomorphy of Amphizoidae and Dytiscidae. M 81 and M 83 arc absent. The strong M 82 is considered as plesiomorphic. The moderate size of M 85 is connected with the lack of swimming ability. The elongate abdominal nerve cord in Amphizoa points towards a sistergroup relationship between Hygrobiidae and Dytiscidae in both of which the abdominal nerve cord shows a high degree of fusion.The phylogenetic propositions of Baehr (1979), and Kavanaugh (1986), are not consistent with the interpretation provided herein, whereas the conclusions of Burmeister (1976), Ruhnau (1986) and Beutel (1986) seem to correlate well. Therefore, it is suggested that the Amphizoidae are the sistergroup of Hygrobiidae + Dytiscidae.     

Phylogeny of hydradephagan water beetles inferred from 18S rRNA sequences

Several families in the beetle suborder Adephaga have an aquatic life style and are commonly grouped in the "Hydradephaga," but their monophyly is contentious and relationships between and within these families are poorly understood. Here we present full-length 18S rRNA sequence for 84 species of Hydradephaga, including representatives of most major groups down to the tribal level, and a total of 68 species of the largest family, Dytiscidae. Using a direct optimization method for the alignment of length-variable regions, the preferred tree topology was obtained when the cost of gaps and the cost of nucleotide changes were equal, and three hypervariable regions of 18S rRNA were downweighted by a factor of five. Confirming recent molecular studies, the Hydradephaga were found to be monophyletic, indicating a single colonization of the aquatic medium. The most basal group within Hydradephaga is Gyrinidae, followed in a comb-like arrangement by families Haliplidae, Noteridae, Amphizoidae, and Hygrobiidae plus Dytiscidae. Under most alignment parameters, Hygrobiidae is placed amid Dytiscidae in an unstable position, suggesting a possible data artifact. Basal relationships within Dytiscidae are not well established, nor is the monophyly of subfamilies Hydroporinae and Colymbetinae. In contrast, relationships at the genus level appear generally well supported. Despite the great differences in the rates of change and the significant incongruence of the phylogenetic signal in conserved vs hypervariable regions of the 18S rRNA gene, both contribute to establish relationships at all taxonomic levels.     

Evolution of the Juan Fernández diving beetle,Rhantus selkirki (Coleoptera,Dytiscidae)

Here we provide evidence that confinement in Robinson Crusoe Island (located about 660 km west of continental Chile) over evolutionary time leads to strong morphological modifications in diving beetle (Dytiscidae) larvae. We analysed a large set of morphological larval characters for all currently recognised genera of Colymbetinae as a framework, to infer phylogenetic relationships within the large genus Rhantus Dejean, 1833 and, in particular, of the charismatic Juan Fernández diving beetle, Rhantus selkirki Jäch, Balke & Michat, 2015, comparing our results with a recent phylogeny of the Colymbetinae based on DNA sequence data. We suggest that adaptation to the island's particular habitats resulted in the reversal of certain characters of R. selkirki back to the plesiomorphic states. This may cause the species to be erroneously interpreted as more ‘primitive’ if only morphological characters are analysed. Confinement in the particular, shallow and barely vegetated aquatic habitats of Robinson Crusoe Island for a long time seems to have led to this divergent morphology, particularly in characters related to swimming ability such as several leg and urogomphal setae. In this way, R. selkirki larvae secondarily resemble those of some earlier diverging dytiscid lineages such as Agabinae and Copelatinae, which typically creep on the bottom of water bodies and do not swim well.     

Discovery of Aspidytidae,a new family of aquatic Coleoptera

The six extant aquatic families of Hydradephaga (Coleoptera) known so far represent a diverse group of beetles morphologically highly modified for life in the water. We report the discovery of a new genus with two species from South Africa and China, which differ greatly from all extant families, but resemble the Jurassic-Cretaceous dagger Liadytidae (the dagger symbol indicates that the taxa are known only as fossils). Based on a combined phylogenetic analysis of molecular and morphological data we erect a new family, Aspidytidae, which is the sister group of Dytiscidae plus Hygrobiidae. We propose a new scenario for the evolution of swimming behaviour in adephagan beetles, in which the transition into the aquatic environment is followed by complex and repeated changes in lifestyles, including the secondary complete loss of swimming ability in Aspidytidae.     

Multigene phylogeny of land plants with special reference to bryophytes and the earliest land plants

A widely held view of land plant relationships places liverworts as the first branch of the land plant tree, whereas some molecular analyses and a cladistic study of morphological characters indicate that hornworts are the earliest land plants. To help resolve this conflict, we used parsimony and likelihood methods to analyze a 6, 095-character data set composed of four genes (chloroplast rbcL and small-subunit rDNA from all three plant genomes) from all major land plant lineages. In all analyses, significant support was obtained for the monophyly of vascular plants, lycophytes, ferns (including PSILOTUM: and EQUISETUM:), seed plants, and angiosperms. Relationships among the three bryophyte lineages were unresolved in parsimony analyses in which all positions were included and weighted equally. However, in parsimony and likelihood analyses in which rbcL third-codon-position transitions were either excluded or downweighted (due to apparent saturation), hornworts were placed as sister to all other land plants, with mosses and liverworts jointly forming the second deepest lineage. Decay analyses and Kishino-Hasegawa tests of the third-position-excluded data set showed significant support for the hornwort-basal topology over several alternative topologies, including the commonly cited liverwort-basal topology. Among the four genes used, mitochondrial small-subunit rDNA showed the lowest homoplasy and alone recovered essentially the same topology as the multigene tree. This molecular phylogeny presents new opportunities to assess paleontological evidence and morphological innovations that occurred during the early evolution of terrestrial plants.     

The systematic position of Meruidae (Coleoptera, Adephaga) and the phylogeny of the smaller aquatic adephagan beetle families

A phylogenetic analysis of Adephaga is presented. It is based on 148 morphological characters of adults and larvae and focussed on a placement of the recently described Meruidae, and the genus‐level phylogeny of the smaller aquatic families Gyrinidae, Haliplidae and Noteridae. We found a sister group relationship between Gyrinidae and the remaining adephagan families, as was found in previous studies using morphology. Haliplidae are either the sister group of Dytiscoidea or the sister group of a clade comprising Geadephaga and the dytiscoid families. Trachypachidae was placed as the sister group of the rhysodid‐carabid clade or of Dytiscoidea. The monophyly of Dytiscoidea including Meru is well supported. Autapomorphies are the extensive metathoracic intercoxal septum, the origin of the metafurca from this structure, the loss of Mm. furcacoxalis anterior and posterior, and possibly the presence of an elongated subcubital setal binding patch. Meruidae was placed as sister group of the Noteridae. Synapomorphies are the absence of the transverse ridge of the metaventrite, the fusion of abdominal segments III and IV, the shape of the strongly asymmetric parameres, and the enlargement of antennomeres 5, 7 and 9. The Meru‐noterid clade is the sister group of the remaining Dytiscoidea. The exact position of Aspidytes within this clade remains ambiguous: it is either the sister group of Amphizoidae or the sister group of a clade comprising this family and Hygrobiidae + Dytiscidae. The sister group relationship between Spanglerogyrinae and Gyrininae was strongly supported. The two included genera of Gyrinini form a clade, and Enhydrini are the sister group of a monophylum comprising the remaining Enhydrini and Orectochilini. A branching pattern (Peltodytes + (Brychius + Haliplus)) within Haliplidae was confirmed. Algophilus, Apteraliplus and the Haliplus‐subgenus Liaphlus form a clade. The generic status of the two former taxa is unjustified. The Phreatodytinae are the sister group of Noterinae, and Notomicrus (+ Speonoterus), Hydrocoptus, and Pronoterus branch off successively within this subfamily. The search for the larvae of Meru and a combined analysis of morphological and molecular data should have high priority. © The Willi Hennig Society 2006.     

A genus-level supertree of Adephaga (Coleoptera)

A supertree for Adephaga was reconstructed based on 43 independent source trees – including cladograms based on Hennigian and numerical cladistic analyses of morphological and molecular data – and on a backbone taxonomy. To overcome problems associated with both the size of the group and the comparative paucity of available information, our analysis was made at the genus level (requiring synonymizing taxa at different levels across the trees) and used Safe Taxonomic Reduction to remove especially poorly known species. The final supertree contained 401 genera, making it the most comprehensive phylogenetic estimate yet published for the group. Interrelationships among the families are well resolved. Gyrinidae constitute the basal sister group, Haliplidae appear as the sister taxon of Geadephaga+Dytiscoidea, Noteridae are the sister group of the remaining Dytiscoidea, Amphizoidae and Aspidytidae are sister groups, and Hygrobiidae forms a clade with Dytiscidae. Resolution within the species-rich Dytiscidae is generally high, but some relations remain unclear. Trachypachidae are the sister group of Carabidae (including Rhysodidae), in contrast to a proposed sister-group relationship between Trachypachidae and Dytiscoidea. Carabidae are only monophyletic with the inclusion of a non-monophyletic Rhysodidae, but resolution within this megadiverse group is generally low. Non-monophyly of Rhysodidae is extremely unlikely from a morphological point of view, and this group remains the greatest enigma in adephagan systematics. Despite the insights gained, our findings highlight that a combined and coordinated effort of morphologists and molecular systematists is still required to expand the phylogenetic database to enable a solid and comprehensive reconstruction of adephagan phylogeny. See also Supplementary material in the online edition at doi:10.1016/j.ode.2006.05.003     

The phylogeny of diving beetles (Coleoptera: Dytiscidae) and the evolution of sexual conflict

A model of evolution based on conflicts of interest between the sexes over mating decisions is examined in relation to diving beetles (Dytiscidae). The model predicts the following evolutionary sequence: (1) cost to females of mating increases, (2) females evolve behavioural resistance to male mating attempts, (3) males evolve devices to overcome female resistance, and (4) females evolve morphological counter-adaptations to the male devices. This model is tested using species of Dytiscidae, in which (1) some species have a very long mating duration while others mate quickly, (2) females of some species resist male mating attempts by swift and erratic swimming when seized by a male, (3) males of some species possess a grasping device in the form of sucker-shaped setae on the legs used to adhere to the pronota or elytra of females prior to mating, and (4) females of some species have a modified dorsal cuticle with irregular sculpturing which appears to interfere with the male adhesive setae. The predicted order of evolution of some of these features was tested in a cladistic analysis of 52 taxa in Dytiscidae and Hygrobiidae using characters from adult and larval morphology and a portion of the gene wingless . The combined analysis resulted in nine most parsimonious cladograms. The consensus cladogram of these indicates that male sucker setae arose a single time in a clade of Dytiscinae. Nested within this clade are five groups with an independently derived, modified dorsal cuticle in females. This pattern of characters in Dytiscinae is consistent with the prediction implied by the model of sexual selection. The utility of wingless as a marker for phylogenetic analysis of diving beetles is discussed, and the resulting phylogeny is compared with previous analyses and current classification.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 359–388.     

豉甲科及水生肉食亚目的分子系统发育学分析(昆虫纲：鞘翅目)

利用PAUP和MrBayes软件,对线粒体COⅠ基因序列3个密码子位置的数据模块分别进行了豉甲科(Gyrinidae)和水生肉食亚目(Hydradephaga)在亚科或科水平上的系统发育学分析,结果表明第二密码子数据模块获得了理想的分析结果。由PAUP生成的豉甲科最优树来自第二密码子数据模块的分析,而由MrBayes生成的最优树来自全部密码子数据模块的分析。此外,用对应的氨基酸序列生成的ME和MP树与第二密码子数据模块分析的结果也一致。亚科Orectochilinae和Gyrininae以高的支持率形成了单系。然而,来自亚科Enhydrinae的种Porrorhynchus landaisi landaisi呈现了异常的位置。SH-test检验也支持该异常位置,表明这个种可能代表了一个科。在来自第二密码子数据模块的水生肉食亚目最优ML树中,整个Hydradephaga树呈现单系,豉甲科位于树的基部,表明了该科在水生肉食亚目中是一个早期的分支。在树中还产生了一个单系的Dytiscoidea总科,由Dytiscidae、Hygrobiidae、Noteridae和Amphizoidae 4个科组成,单系的Haliplidae与之成为姐妹群。此外线粒体分子钟的结果表明豉甲科的5对相近种间的分化是一个短时期内发生的(0.01～1.81百万年前),这点可能与它们的特殊地理分布有关。     

基于线粒体基因组序列的鞘翅目肉食亚目水生类群系统发育分析

【目的】明确肉食亚目(Adephaga)水生类群线粒体基因组的基本特征,并基于线粒体基因组序列分析肉食亚目水生类群的系统发育关系。【方法】基于Illumina HiSeq X Ten测序技术测定了圆鞘隐盾豉甲Dineutus mellyi和齿缘龙虱Eretes sticticus的线粒体全基因组序列,对其进行了基因注释,并对其tRNA基因二级结构进行了预测分析。加上已公布的鞘翅目(Coleoptera)肉食亚目水生类群17个种的线粒体基因组序列,对该类群共19个种线粒体的蛋白质编码基因(protein-coding genes, PCGs)开展了比较基因组学分析,包括AT含量、密码子偏好性、选择压力等。基于13个PCGs的氨基酸序列和核苷酸序列,利用最大似然法(ML)和贝叶斯法(BI)分别构建鞘翅目肉食亚目水生类群的系统发育关系,并通过FcLM分析进一步评估伪龙虱科(Noteridae)和瀑甲科(Meruidae)的系统发育位置。【结果】圆鞘隐盾豉甲和齿缘龙虱的线粒体基因组全长分别为16 123 bp(GenBank登录号: MN781126)和16 196 bp(GenBank登录号: MN781132),都包含13个PCGs、22个tRNA基因、2个rRNA基因和1个D-loop区(控制区)。19个肉食亚目水生类群线粒体基因组PCGs的碱基组成都呈现A+T偏好性,在密码子使用上也都偏向于使用富含A+T的密码子;在进化过程中13个PCGs的进化模式相同,都受到纯化选择。基于线粒体基因组13个PCGs的氨基酸序列的肉食亚目水生类群的系统发育关系为(豉甲科Gyrinidae+(沼梭甲科Haliplidae+((壁甲科Aspidytidae+(两栖甲科Amphizoidae+龙虱科Dytiscidae))+(水甲科Hygrobiidae+(瀑甲科Meruidae+伪龙虱科Noteridae)))))。【结论】研究结果表明,豉甲科是肉食亚目水生类群的基部类群,接下来是沼梭甲科和龙虱总科;伪龙虱科和瀑甲科互为姐妹群,并一起作为龙虱总科内部的一个分支;两栖甲科与龙虱科具有更近的亲缘关系。     

Molecular and morphological phylogenetics of weevils (coleoptera,curculionoidea): do niche shifts accompany diversification?

The main goals of this study were to provide a robust phylogeny for the families of the superfamily Curculionoidea, to discover relationships and major natural groups within the family Curculionidae, and to clarify the evolution of larval habits and host-plant associations in weevils to analyze their role in weevil diversification. Phylogenetic relationships among the weevils (Curculionoidea) were inferred from analysis of nucleotide sequences of 18S ribosomal DNA (rDNA; approximately 2,000 bases) and 115 morphological characters of larval and adult stages. A worldwide sample of 100 species was compiled to maximize representation of weevil morphological and ecological diversity. All families and the main subfamilies of Curculionoidea were represented. The family Curculionidae sensu lato was represented by about 80 species in 30 "subfamilies" of traditional classifications. Phylogenetic reconstruction was accomplished by parsimony analysis of separate and combined molecular and morphological data matrices and Bayesian analysis of the molecular data; tree topology support was evaluated. Results of the combined analysis of 18S rDNA and morphological data indicate that monophyly of and relationships among each of the weevil families are well supported with the topology ((Nemonychidae, Anthribidae) (Belidae (Attelabidae (Caridae (Brentidae, Curculionidae))))). Within the clade Curculionidae sensu lato, the basal positions are occupied by mostly monocot-associated taxa with the primitive type of male genitalia followed by the Curculionidae sensu stricto, which is made up of groups with the derived type of male genitalia. High support values were found for the monophyly of some distinct curculionid groups such as Dryophthorinae (several tribes represented) and Platypodinae (Tesserocerini plus Platypodini), among others. However, the subfamilial relationships in Curculionidae are unresolved or weakly supported. The phylogeny estimate based on combined 18S rDNA and morphological data suggests that diversification in weevils was accompanied by niche shifts in host-plant associations and larval habits. Pronounced conservatism is evident in larval feeding habits, particularly in the host tissue consumed. Multiple shifts to use of angiosperms in Curculionoidea were identified, each time associated with increases in weevil diversity and subsequent shifts back to gymnosperms, particularly in the Curculionidae.     

A molecular and morphological phylogeny of the extant Augochlorini (Hymenoptera,Apoidea) with comments on implications for biogeography

The Augochlorini Beebe is a New World tribe of bees comprising 663 described species. Relationships among the genera of this monophyletic tribe remain uncertain. Here I provide a comprehensive phylogeny using morphological and molecular information. In all, 54 Augochlorini species plus 16 outgroups and 3017 molecular and 105 morphological characters were analysed. Sequences for four genes were analysed using Bayesian inference, maximum likelihood and parsimony. Morphological characters were taken from a literature review and analysed alone and in combination with molecular data using parsimony. The monophyly of Augochlorini and most genera is confirmed, with divergence of the main lineages of the tribe around 55–20 Ma. Seven clades were supported by most analyses and are here treated as genus‐level groups, as follows (combined analysis topology): (Corynura group, (Chlerogella group, (Rhinocorynura group, (Augochloropsis, (Megaloptidia group, (Neocorynura group, (Augochlora group, Megalopta group))))))). According to this topology, dim‐light foraging and cleptoparasitism arose three times in the tribe. According to my hypothesis, the diversification of Augochlorini may have begun as a response to vicariant events, including the split of the Neotropical/Andean regions and marine transgressions in the Amazon region.     

Multiple data sets,congruence, and hypothesis testing for the phylogeny of basal groups of the lizard genus Sceloporus (Squamata,Phrynosomatidae)

Several data partitions, including nuclear and mitochondrial gene sequences, chromosomes, isoenzymes, and morphological characters, were used to propose a new phylogeny and to test previously published hypotheses about the phylogenetic positions of basal clades of the lizard genus Sceloporus and the relationship of Sceloporus to the former genus "Sator". In accord with earlier studies, our results grouped "Sator" as internal to Sceloporus, and both support a hypothesis of transgulfian vicariance for the origin of the former genus "Sator" on islands in the Sea of Cortez. Robustness of support for internal nodes in our best tree was established though widely used indices (bootstrap proportions, decay values) but also through congruence among independent data partitions. Several deep nodes in the tree recovered by several methods, including equally weighted and differentially weighted parsimony and maximum likelihood models, are only weakly supported by the traditional indices. This methodological concordance is taken as evidence for insensitivity of the deep structure of the topology to alternative assumptions.     

Phylogenetic significance of morphological characters in the taxonomy of Pestalotiopsis species

There has been considerable disagreement regarding the relationships among Pestalotiopsis species and their delimitations. A molecular phylogenetic analysis was conducted on 32 species of Pestalotiopsis in order to evaluate the utility of morphological characters currently used in their taxonomy. Phylogenetic relationships were inferred from nucleotide sequences in the ITS regions and 5.8S gene of the rDNA under four optimality criteria: maximum parsimony, weighted parsimony, maximum likelihood, and neighbor joining. Phylogenies estimated from all analyses yielded trees of essentially similar topology and revealed 3 major groups that correspond with morphology-based classification systems. Molecular data indicated that the genus contains two distinct lineages based on pigmentation of median cells and four distinct groupings based on morphology of apical appendages. The analyses did not support reliability of other phenotypic characters of this genus, such as spore dimensions. Characters with particular phylogenetic significance are discussed in relation to the taxonomy of Pestalotiopsis.     

Systematic placement of the recently discovered beetle family Meruidae (Coleoptera: Dytiscoidea) based on molecular data

The family Meruidae has been established recently for the newly discovered species Meru phyllisae Spangler & Steiner, 2005 from Southern Venezuela. These beetles are morphologically highly distinct and at a body length of 0.8 mm represent the perhaps smallest individuals of Adephaga. Here, we use DNA sequence data to place this enigmatic taxon relative to other aquatic groups in this suborder. Meruidae was most closely associated with Noteridae, supporting a previous analysis of morphological structures which had suggested this sister relationship, albeit with weak support. While different alignment strategies did not affect the topology, the precise placement of Meruidae was affected by the choice of tree reconstruction method. Bayesian inference suggests a sister relationship of Meruidae + Noteridae, while parsimony analyses retrieve Meruidae + Notomicrus (a basal noterid genus), which combined are the sister group of all remaining Noteridae. Considering morphological evidence, the former placement appears more plausible.