Molecular phylogeny and biogeography of the eastern Tapaculos (Aves: Rhinocryptidae: Scytalopus, Eleoscytalopus): Cryptic diversification in Brazilian Atlantic Forest

Scytalopus and the recently erected Eleoscytalopus are among the Neotropical groups of birds whose taxonomy is most difficult to resolve given their very conservative morphology. We investigated the phylogeny and species limits of Eleoscytalopus and the eastern Scytalopus using two mitochondrial genes and two nuclear introns of multiple individuals from all species of these groups. The eastern Scytalopus are separated in three well defined clades also supported by morphological or vocal characteristics, although the relationships between these clades could not be resolved. We found several allopatric and very divergent lineages in these genera whose characteristics are consistent with species-level divergence, especially in S. speluncae. The great divergence between E. psychopompus and its sister species supports the former as a valid species. Our results corroborate the importance of the Bahia refuge as an avian center of endemism.     

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.     

Phylogeny of the shore crab family Grapsidae (Decapoda: Brachyura: Thoracotremata) based on a multilocus approach

The Grapsidae are a thoracotreme crab family with 40 species in eight genera (in their strict definition), and possess a number of morphological and molecular synapomorphies. Previous phylogenetic studies based on mitochondrial DNA markers established the monophyly of this family, but suggested possible paraphyly or polyphyly of some of the constituent genera. To test the validity of previous hypotheses, the present study reconstructed a molecular phylogeny of the grapsid crabs based on five molecular markers, including mitochondrial DNA markers and the first use of nuclear protein‐coding markers to address this issue. Monophyly of Grapsidae was confirmed, with the exception of the position of the monotypic genus Leptograpsodes. The polyphyly of the genus Pachygrapsus is consistent with previous molecular phylogenies, as members from this genus are dispersed throughout our gene tree. Grapsus and Planes were shown to be paraphyletic, with species of Pachygrapsus nested within them. Our study found incongruences between the currently adopted classification of the family, and hence taxonomic revisions will be needed. We hereby demonstrate the use of nuclear protein‐coding markers for high confidence reconstruction of decapod phylogenies, resolving most of the early splits that mitochondrial DNA markers alone are unable to tackle. © 2015 The Linnean Society of London     

Phylogeny of the flyingfish family Exocoetidae (Teleostei, Beloniformes)

The phylogeny of the flyingfish family Exocoetidae is studied cladistically, using 41 morphological characters encompassing early life history, and external and internal features. The monophyly of the family is supported by 10 synapomorphies. Within the family,Oxyporhamphus is the sister group to all other genera, the monophyly of the latter being defined by 10 synapomorphies.Fodiator is the sister group of genera characterized by the presence of chin barbels in juveniles.Parexocoetus is the sister group ofExocoetus, Cypselurus, Prognichthys andHirundichthys, the latter being defined by four synapomorphies. In the latter group,Exocoetus is the sister group of the other three genera. The phylogeny of the Exocoetidae is characterized by the stepwise upgrading of gliding capability, with sequential modifications of the caudal, pectoral and pelvic fins. The subfamily Oxyporhamphinae is resurrected.     

Plastid phylogenomics improve phylogenetic resolution in the Lauraceae

Abstract The family Lauraceae is a major component of tropical and subtropical forests worldwide, and includes some commercially important timber trees and medicinal plants. However, phylogenetic relationships within Lauraceae have long been problematic due to low sequence divergence in commonly used markers, even between morphologically distinct taxa within the family. Here we present phylogenetic analyses of 43 newly generated Lauraceae plastomes together with 77 plastomes obtained from GenBank, representing 24 genera of Lauraceae and 17 related families of angiosperms, plus nine barcodes from 19 additional species in 18 genera of Lauraceae, in order to reconstruct highly supported relationships for the Lauraceae. Our phylogeny supports the relationships: sisterhood of the Lauraceae and a clade containing Hernandiaceae and Monimiaceae, with Atherospermataceae and Gomortegaceae being the next sister groups, followed by Calycanthaceae. Our results highlight a monophyletic Lauraceae, with nine well‐supported clades as follows: Hypodaphnis clade, Beilschmiedia–Cryptocarya clade, Cassytha clade, Neocinnamomum clade, Caryodaphnopsis clade, Chlorocardium–Mezilaurus clade, Machilus–Persea clade, Cinnamomum–Ocotea clade, and Laurus–Neolitsea clade. The topology recovered here is consistent with the patterns of plastome structural evolution and morphological synapomorphies reported previously. More specifically, flower sex, living type, inflorescence type, ovary position, anther locus number, leaf arrangement, leaf venation, lateral vein number, tree height, and inflorescence location all represent morphological synapomorphies of different lineages. Our findings have taxonomic implications and two new tribes, Caryodaphnopsideae and Neocinnamomeae, are described, and the composition of four other tribes is updated. The phylogeny recovered here provides a robust phylogenetic framework through which to address the evolutionary history of the Magnoliids, the third‐largest group of Mesangiospermae.     

Molecular phylogeny of the ant tribe Myrmicini (Hymenoptera: Formicidae)

The interrelationships within ant subfamilies remain elusive, despite the recent establishment of the phylogeny of the major ant lineages. The tribe Myrmicini belongs to the subfamily Myrmicinae, and groups morphologically unspecialized genera. Previous research has struggled with defining Myrmicini, leading to considerable taxonomic instability. Earlier molecular phylogenetic studies have suggested the nonmonophyly of Myrmicini, but were based on limited taxon sampling. We investigated the composition of Myrmicini with phylogenetic analyses of an enlarged set of taxa, using DNA sequences of eight gene fragments taken from 37 representatives of six of the seven genera (Eutetramorium, Huberia, Hylomyrma, Manica, Myrmica, and Pogonomyrmex), and eight outgroups. Our results demonstrate the invalidity of Myrmicini as currently defined. We recovered sister‐group relationships between the genera Myrmica and Manica, and between Pogonomyrmex and Hylomyrma. This study illustrates that to understand the phylogeny of over 6000 myrmicine species, comprehensive taxon sampling and DNA sequencing are an absolute requisite. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 482–495.     

Phylogeny of the bee subtribe Caenohalictina Michener (Hymenoptera,Apidae s.l., Halictinae s.l.)

Gonçalves, R. B. & Melo, G. A. R. (2009). Phylogeny of the bee subtribe Caenohalictina Michener (Hymenoptera, Apidae s.l., Halictinae s.l.). —Zoologica Scripta, 39, 187–197. Recently, Caenohalictina Michener, 1954 was formally proposed as a group within Halictini based on a phylogenetic analysis using DNA data. Morphological synapomorphies for the subtribe are not stabilized and the relationships among its attributed genera were not completely reconstructed. Also, there are different propositions for the scope and classification of the genera. This study investigates the monophyly of Caenohalictina based on morphological characters and presents a hypothesis for the relationships among its genera and subgenera. For this purpose, a matrix of 36 terminals and 96 characters was coded. The cladistic analysis using character equal weighting resulted in one most parsimonious tree with 189 steps. According to this hypothesis, the subtribe is monophyletic with five synapomorphies supporting it. The relationships among Caenohalictina taxa are: Habralictus(Caenohalictus (((Agapostemon s.s. + Notagapostemon) (Agapostemonoides (Rhinetula (Paragapostemon + Dinagapostemon)))) + ((Ruizanthedella (Ruizantheda + Oragapostemon)) + (Brasilagapostemon (Pseudagapostemon s.s. + Neagapostemon))))). The subgenus Habralictus s.s. is paraphyletic with respect to Habralictus (Zikaniella) crassipes, hence both subgenera are not recognized. Comments on alternative generic classifications and biogeographic patterns are presented.     

Recognition of two major clades and early diverged groups within the subfamily Cyperoideae (Cyperaceae) including Korean sedges

We aim to present phylogenetic major groups within the subfamily Cyperoideae (Cyperaceae) on the basis of three molecular data sets; nuclear ribosomal internal transcribed spacer and 5.8S ribosomal RNA region, the ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit gene, and trnL intron and trnL-F intergenic spacer. Three molecular data and two combined data sets were used to obtain robust and detailed phylogenetic trees by using maximum parsimony and Bayesian inference, respectively. We analyzed 81 genera and 426 species of Cyperaceae, including Korean species. We suggest one early diverged group (EDGs), and two major clades (FAEC and SDC) within the subfamily Cyperoideae. And the clade EDGs comprises six tribes (Schoeneae, Bisboeckelereae, Sclerieae, Cryptangieae, Trilepideae, and Rhynchosporeae) at the basal nodes of Cyperoideae. The FAEC clade (posterior probability [PP]/bootstrap value [BS] = 1.00/85) comprises four tribes (Fuireneae, Abildgaardieae, Eleocharideae, Cypereae), and the SDC clade (PP/BS = 1.00/86) comprises three tribes (Scirpeae, Dulichieae, Cariceae). These three clades used for phylogenetic groups in our study will be useful for establishing the major lineage of the sedge family. The phylogeny of Korean sedges was also investigated within the whole phylogeny of Cyperaceae. The 20 genera of Korean sedges were placed in 10 tribes forming 14 clades.     

Phylogenetic signal in the evolution of body colour and spicule skeleton in calcareous sponges

Some of the morphological characters used in Porifera taxonomy have often been shown to be inconsistent. In the present study, we tested the phylogenetic coherence of currently used taxonomic characters of the calcarean genus Clathrina. For this, 20 species of Clathrina and three other calcinean genera (Ascandra, Guancha, and Leucetta) were sequenced for the ITS and D2 region of the 28S ribosomal DNA. Maximum‐likelihood and maximum‐parsimony algorithms were used to reconstruct phylogenetic trees. Deep divergences were observed in our tree and Clathrina was shown to be paraphyletic. The major split in our topology showed a clear‐cut distinction between sponges with and without tetractine spicules. Moreover, a group of yellow‐coloured Clathrina was clearly separated from the remaining white‐coloured species. Our results show that the presence of diactines, water‐collecting tubes, the degree of cormus anastomosis, and actine shapes do not correlate with the major clades of the calcinean phylogeny. On the other hand, the presence of tripods, the absence of tetractines, and the presence of spines in the apical actine of tetractines seem to be good synapomorphies for clades in our tree. Our results demonstrate that skeleton characters can be reliably used in higher level taxonomy in Clathrinida. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 1026–1034.     

Phylogenetic study of the Characinae (Teleostei: Characiformes: Characidae)

The Characinae is a subunit of the Characidae of special significance in including Charax, the type genus of the family and the order Characiformes. Twelve genera and 79 species have been traditionally assigned to the Characinae, but the subfamily still lacks a phylogenetic diagnosis. Herein, a data matrix including 150 morphological characters and 64 taxa (35 species representing all genera of the Characinae and 29 included in other lineages within the Characiformes) was submitted to two cladistic analyses that differ in the inclusion/exclusion of Priocharax due to the difficulty of coding most of the character states in the miniature species of this genus. Both analyses resulted in a non‐monophyletic Characinae and this subfamily is herein restricted to only seven of the original 12 genera forming the clade (Phenacogaster((Charax Roeboides)(Acanthocharax(Cynopotamus(Acestrocephalus Galeocharax))))), which is supported by ten non‐ambiguous synapomorphies and is more closely related to other genera of the Characidae than those traditionally placed in the subfamily. A second clade includes the members of the tribe Heterocharacini (Lonchogenys(Heterocharax Hoplocharax)) as the sister‐group of Gnathocharax, supported by seven non‐ambiguous synapomorphies. This clade is more closely related to a taxon formed by Roestes and Gilbertolus based on seven non‐ambiguous synapomorphies. Results do not corroborate a close relationship between Roestes–Gilbertolus and the Cynodontinae. Inclusion of the genus Priocharax suggests that it is related more closely to the Heterocharacini, but the profound modifications in its anatomy possibly related to ontogenetic truncations obscure a better understanding of its relationships. A new classification of the Characinae and the Heterocharacinae is proposed. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 809–915.     

Phylogenetic analysis of Magnoliales and Myristicaceae based on multiple data sets: implications for character evolution

Magnoliales, consisting of six families of tropical to warm-temperate woody angiosperms, were long considered the most archaic order of flowering plants, but molecular analyses nest them among other eumagnoliids. Based on separate and combined analyses of a morphological matrix (115 characters) and multiple molecular data sets (seven variable chloroplast loci and five more conserved genes; 14 536 aligned nucleotides), phylogenetic relationships were investigated simultaneously within Magnoliales and Myristicaceae, using Laurales, Winterales, and Piperales as outgroups. Despite apparent conflicts among data sets, parsimony and maximum likelihood analyses of combined data converged towards a fully resolved and well-supported topology, consistent with higher-level molecular analyses except for the position of Magnoliaceae: Myristicaceae + (Magnoliaceae + (( Degeneria + Galbulimima ) + ( Eupomatia + Annonaceae))). Based on these results, we discuss morphological evolution in Magnoliales and show that several supposedly plesiomorphic traits are synapomorphies of Magnoliineae, the sister group of Myristicaceae (e.g. laminar stamens). Relationships within Annonaceae are also resolved with strong support ( Anaxagorea basal, then ambavioids). In contrast, resolution of relationships within Myristicaceae is difficult and still incomplete, due to a very low level of molecular divergence within the family and a long stem lineage. However, our data provide good evidence that Mauloutchia is nested among other Afro-Malagasy genera, contradicting the view that its androecium and pollen are plesiomorphic  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 125–186.     

Phylogenetic relationships of Pieridae (Lepidoptera: Papilionoidea) in China based on seven gene fragments

The butterfly family Pieridae includes approximately 1000 described extant species distributed worldwide. Among these, 154 species belonging to 24 genera are recorded in China. There has been no previous comprehensive phylogenetic study of the molecular phylogeny of Chinese pierids based on molecular data. In this study, 52 species representing 21 genera distributed in China were sampled. We reconstructed their evolutionary history based on four mitochondrial (COII, ND1, Cytb and 16S rDNA) and three nuclear (28S rRNA (D2–D3), 28S rRNA (D8) and EF‐1α) gene fragments using maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI). Our results are congruent with recent studies and support the monophyly of three subfamilies, with Dismorphiinae sister to Coliadinae + Pierinae. Relationships among five genera of Coliadinae are: Eurema + (Dercas + (Goneperyx + (Catopsilia + Colias))). Relationships among the largest subfamily Pierinae are consistently recovered as follows: Leptosiaini + ((Nepheroniini + Teracolini) + (Anthocharidini + Pierini)). The division of three subgenera of Aporia (Aporia, Metaporia and Mesapia) is not supported because both the Aporia (Aporia) and Aporia (Metaporia) are found to be strongly paraphyletic, with Mesapia nested within Aporia sensu lato.     

Morphology,morphogenesis, and molecular phylogeny of a new marine urostylid ciliate (Ciliophora,Stichotrichia) from the South China Sea,and a brief overview of the convergent evolution of the midventral pattern within the Spirotrichea

The morphology, infraciliature, morphogenetic events, and small subunit ribosomal RNA (SSU rRNA) gene‐based phylogeny of a stichotrich ciliate, Bergeriella ovata gen. et sp. nov. , found in coastal waters off Daya Bay, Guangdong, South China, were investigated. The new taxon has an atypical midventral pattern, and is characterized by several rather unusual morphological features: frontal cirri forming an irregular tricorona; one nonmigratory row located right of the midventral rows, which is morphogenetically derived from the posteriormost fronto‐ventral‐transverse (FVT) streak; conspicuously enlarged postoral ventral cirri, whereas the left ventral cirri are delicate and arranged in oblique rows. Based on both the morphological and morphogenetical data, a new family, Bergeriellidae fam. nov. , is proposed. In the SSU rRNA phylogenetic trees, B. ovata gen. et sp. nov. groups with the classic urostylids (urostylids s.s.) with high nodal support. Our phylogenetic analyses have revealed at least seven separate clades for midventral pattern‐bearing taxa (e.g. Pattersoniella, Neokeronopsis, Rigidothrix, urostylids s.s., Uroleptidae, Holostichidae + Psammomitridae, and Pseudoamphisiellidae), suggesting that the order Urostylida Jankowski, 1979 sensu Lynn, 2008 is a polyphyletic assemblage, and that the convergent evolution of the urostylid midventral pattern might have occurred more times among the spirotrichs than has previously been recognized. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 697–710.     

New morphological characters for classifying Phoridae (Diptera) from the structure of the thorax

Forty‐six characters, mostly of the thoracic pleuron, are proposed for the reconstruction of the phylogenetic relationships among the major groups of the family Phoridae. Analysis of these characters, in conjunction with the pre‐existing suite of morphological characters from other body parts, provides a basis for a strongly supported new classification of the Phoridae, in which Sciadocerinae is the sister group of ((Chonocephalus Wandolleck & Cyphocephalus Borgmeier) + (Termitoxeniinae + (Metopininae + Phorinae s.l.))). A new subfamily, Chonocephalinae subfamily nov. , is proposed for Chonocephalus and Cyphocephalus, and a new genus, Hirotophora gen. nov. , is proposed for Chaetopleurophora multiseriata (Aldrich) ( comb. nov. ). © 2015 The Linnean Society of London     

Molecular phylogeny of hinge‐beak shrimps (Decapoda: Caridea: Rhynchocinetes and Cinetorhynchus) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny

The Rhynchocinetidae (‘hinge‐beak’ shrimps) is a family of marine caridean decapods with considerable variation in sexual dimorphism, male weaponry, mating tactics, and sexual systems. Thus, this group is an excellent model with which to analyse the evolution of these important characteristics, which are of interest not only in shrimps specifically but also in animal taxa in general. Yet, there exists no phylogenetic hypothesis, either molecular or morphological, for this taxon against which to test either the evolution of behavioural traits within the Rhynchocinetidae or its genealogical relationships with other caridean taxa. In this study, we tested (1) hypotheses on the phylogenetic relationships of rhynchocinetid shrimps, and (2) the efficacy of different (one‐, two‐, and three‐phase) methods to generate a reliable phylogeny. Total genomic DNA was extracted from tissue samples taken from 17 species of Rhynchocinetidae and five other species currently or previously assigned to the same superfamily (Nematocarcinoidea); six species from other superfamilies were used as outgroups. Sequences from two nuclear genes (H3 and Enolase) and one mitochondrial gene (12S) were used to construct phylogenies. One‐phase phylogenetic analyses (SATé‐II) and classical two‐ and three‐phase phylogenetic analyses were employed, using both maximum likelihood and Bayesian inference methods. Both a two‐gene data set (H3 and Enolase) and a three‐gene data set (H3, Enolase, 12S) were utilized to explore the relationships amongst the targeted species. These analyses showed that the superfamily Nematocarcinoidea, as currently accepted, is polyphyletic. Furthermore, the two major clades recognized by the SATé‐II analysis are clearly concordant with the genera Rhynchocinetes and Cinetorhynchus, which are currently recognized in the morphological‐based classification (implicit phylogeny) as composing the family Rhynchocinetidae. The SATé‐II method is considered superior to the other phylogenetic analyses employed, which failed to recognize these two major clades. Studies using more genes and a more complete species data set are needed to test yet unresolved inter‐ and intrafamilial systematic and evolutionary questions about this remarkable clade of caridean shrimps. © 2014 The Linnean Society of London     

Phylogenetic analysis of the leafhopper genus Apogonalia (Insecta: Hemiptera: Cicadellidae) and comments on the biogeography of the Caribbean islands

A phylogenetic analysis of the leafhopper genus Apogonalia was conducted based on a matrix of 40 terminal taxa and 147 morphological characters. The analysis yielded 1391 equally most‐parsimonious trees, which do not support the monophyly of Apogonalia in the strict consensus. A successive weighting procedure yielded 62 trees in which the genus appeared as a monophyletic group. The strict consensus of these 62 trees is almost entirely dichotomous, showing only two polytomies. The test of phylogenetic integrity was applied for distinct variations of three species: A. germana, A. sanguinipes, and A. histrio. Only for the first species was the conjecture that its variations belong to the same entity corroborated. The best‐supported clade within Apogonalia, which has several synapomorphies and high branch support indices, comprises nine Antillean endemic species. This distributional pattern probably was originated by vicariance in the Late Cretaceous, when the Proto‐Antillean archipelago was pushed north‐eastward by the Caribbean Plate to become the modern Greater Antilles. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 548–570.     

IS SPECIALIZATION A DEAD END? THE PHYLOGENY OF HOST USE IN DENDROCTONUS BARK BEETLES (SCOLYTIDAE)

Ecological explanations for the prevalence of resource specialists are abundant, whereas phylogenetic evidence on their origins is scarce. In this paper, we provide a molecular phylogenetic study of the 19 specialist or generalist species in the bark beetle genus Dendroctonus, which collectively attack species in four different genera in the conifer family Pinaceae. Given substantial variation in diet breadth, we asked two general questions concerning the evolution of resource use in this group. How conservative is the evolution of host use in these insects? Does specialization tend to be derived (i.e., a “dead end”)? To answer these questions, we estimated the phylogeny of Dendroctonus using mitochondrial DNA sequences and mapped transitions in resource use on the resulting phylogeny estimate. The evolution of affiliations with Pinus and Picea hosts in Dendroctonus was conservative among beetle species (PTP test; P < 0.012), but there was no significant correspondence between the phylogeny of these beetles and the phylogeny among their Pinaceae hosts (among genera, P = 0.28; among Pinus species, P = 0.82). Degree of specialization, as measured in the proportion of hosts used, was bimodally distributed with “generalist” species utilizing < 60% of the congeneric hosts within their range and six specialist species utilizing < 40% of the available hosts. Among the generalists, we found a strong correlation between the number of hosts encountered and the number of hosts utilized (R = 0.97, P < 0.0001), whereas there was no significant correlation among the specialists (R = 0.27, P = 0.59). The evolution of specialization in Dendroctonus proved highly labile—specialists arose from generalists at least six separate times (without reversal) all in derived positions, and closer examination of some specialists revealed instances where they appear to have lost particular host species from their diet. However, evidence from the ecological literature also suggests that several Dendroctonus generalists may have increased their range of host genera within the Pinaceae.     

Patterns of morphological evolution of the cephalic region in damselfishes (Perciformes: Pomacentridae) of the Eastern Pacific

Pomacentridae are one of the most abundant fish families inhabiting reefs of tropical and temperate regions. This family, comprising 29 genera, shows a remarkable diversity of habitat preferences, feeding, and behaviours. Twenty‐four species belonging to seven genera have been reported in the Eastern Pacific region. The present study focuses on the relationship between the diet and the cephalic profile in the 24 endemic damselfishes of this region. Feeding habits were determined by means of underwater observations and the gathering of bibliographic data. Variations in cephalic profile were analyzed by means of geometric morphometrics and phylogenetic methods. The present study shows that the 24 species can be grouped into three main trophic guilds: zooplanktivores, algivores, and an intermediate group feeding on small pelagic and benthic preys. Shape variations were low within each genus except for Abudefduf. Phylogenetically adjusted regression reveals that head shape can be explained by differences in feeding habits. The morphometric phylogeny recovered the subfamily Stegastinae and the relationship between Abudefduf troschelii and Chromis species. The cephalic profile of damselfishes contains a clear and strong phylogenetic signal. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 593–613.