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Wiley Online Library : Cladistics
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July 22, 2014
Role of Caribbean Islands in the diversification and biogeography of Neotropical Heraclides swallowtails
Numerous hypotheses on the evolution of Neotropical biodiversity have stimulated research to provide a better understanding of diversity dynamics and distribution patterns of the region. However, few studies integrate molecular and morphological data with complete sampling of a Neotropical group, and so there has been little synthesis of the multiple processes governing biodiversity through space and time. Here, a total-evidence phylogenetic approach is used to reconstruct the evolutionary history of the butterfly subgenus Heraclides. We used DNA sequences for two mitochondrial genes and one nuclear gene and coded 133 morphological characters of larvae and adults. A robust and well-resolved phylogeny was obtained using several analytical approaches, while molecular dating and biogeographical analyses indicated an early Miocene origin (22 Mya) in the Caribbean Islands. We inferred six independent dispersal events from the Caribbean to the mainland, and three from the mainland to the Caribbean, and we suggest that cooling climates with decreasing sea levels may have contributed to these events. The time-calibrated tree is best explained by a museum model of diversity in which both speciation and extinction rates remained constant through time. By assessing both continental and fine-scale biodiversity patterns, this study provides new findings, for instance that islands may act as source of diversity rather than as a sink, to explain spatio-temporal macroevolutionary processes within the Neotropical region.
July 17, 2014
A recent article published in Cladistics is critical of a number of heuristic methods for phylogenetic inference based on parsimony scores. One of my papers is among those criticized, and I would appreciate the opportunity to make a public response. The specific criticism is that I have re-invented an algorithm for economizing parsimony calculations on trees that differ by a subtree pruning and regrafting (SPR) rearrangement. This criticism is justified, and I apologize for incorrectly claiming originality for my presentation of this algorithm. However, I would like to clarify the intent of my paper, if I can do so without detracting from the sincerity of my apology. My paper is not about that algorithm, nor even primarily about parsimony. Rather, it is about a novel strategy for Markov chain Monte Carlo (MCMC) sampling in a state space consisting of trees. The sampler involves drawing from conditional distributions over sets of trees: a Gibbs-like strategy that had not previously been used to sample tree-space. I would like to see this technique incorporated into MCMC samplers for phylogenetics, as it may have advantages over commonly used Metropolis-like strategies. I have recently used it to sample phylogenies of a biological invasion, and I am finding many applications for it in agent-based Bayesian ecological modelling. It is thus my contention that my 2005 paper retains substantial value.
July 15, 2014
Protodrilidae is a group of small, superficially simple-looking annelids, lacking chaetae and appendages, except for two prostomial palps. Originally considered to be one of the primitive “archiannelid” families, its affinity within Annelida is still highly debated. Protodrilids are found worldwide in the interstices of intertidal and subtidal marine sediments. Despite their simple appearance they constitute one of the most species-rich interstitial families, with 36 described species in two genera, Protodrilus and the gutless Astomus. Here we present the first phylogenetic study of Protodrilidae employing five gene fragments, 55 morphological characters and 73 terminals (including seven outgroups) analysed under direct optimization and parsimony as well as model-based methods. The large data set includes all 36 described species of Protodrilidae (17 of which are represented only by the morphological partition) as well as 30 undescribed or uncertain species (represented by both morphology and molecules). This comprehensive, inclusive and combined analysis revealed a new perspective on the phylogeny of Protodrilidae: the family is shown to contain six cosmopolitan subclades, each supported by several morphological apomorphies, and with the genus Astomus consistently nested among the other five clades rather than next to these. Consequently, the diagnosis of Protodrilus is emended, Astomus remains unchanged and the four remaining lineages are diagnosed and named Megadrilus n. gen, Meiodrilus gen. nov., Claudrilus n. gen and Lindrilus gen. nov. Character transformations showed that large size and presence of pigmentation, oviducts and eyes are plesiomorphies of the family, retained in Protodrilus, Megadrilus gen. nov. and Lindrilus gen. nov. These features are secondarily lost in the gutless Astomus with epidermal uptake of nutrients, as well as in Meiodrilus gen. nov. and some species of Claudrilus n. gen, with smaller size correlated to life in interstices of finer sediments.
June 30, 2014
First phylogenetic analysis of the family Neriidae (Diptera), with a study on the issue of scaling continuous characters
Neriidae are a small family of acalyptratae flies, mostly distributed in the tropics. Very little is known about their biology, and the evolutionary relationships among species have never been evaluated. We perform the first comprehensive phylogenetic analysis of the family, including 48 species from all biogeographic regions inhabited, as well as five species of Micropezidae and one Cypselosomatidae as outgroups. We build a morphological data matrix of 194 characters, including 72 continuous characters. We first explore ways to deal with the issue of scaling continuous characters, including rescaling ranges to unity and using implied weighting. We find that both strategies result in very different phylogenetic hypotheses, and that implied weighting reduces the problem of scaling, but only partially. Furthermore, using implied weighting after rescaling characters improves the congruence between partitions and results in higher values of group support. With respect to the Neriidae, we confirm the monophyly of the family and of most its genera, although we do not obtain any of the currently accepted suprageneric groups. We propose to restrict the Eoneria and Nerius groups exclusively to the Neotropical fauna, and synonymize Glyphidops subgenus Oncopsia Enderlein with Glyphidops subgenus Glyphidops Enderlein, eliminating the subgeneric divisions. This revised phylogeny presents a striking biogeographic consistency, and shows that previous main divisions of the family were based on events of convergence.
Phylogeny of fossil and extant glypheid and litogastrid lobsters (Crustacea, Decapoda) as revealed by morphological characters
A phylogenetic analysis of a total of 31 species: 27 fossil species from seven families (Glypheidae, Litogastridae, Mecochiridae, Pemphicidae, Erymidae, Clytiopsidae, Chimaerastacidae), and four extant species from three families (Glypheidae, Nephropidae, Stenopodidae) is proposed. Most of the genera considered are coded exclusively based upon their type species and, as much as possible, based upon the type specimens. The cladistic analysis demonstrates that the glypheidean lobsters (infraorder Glypheidea) form a monophyletic group including two superfamilies: Glypheoidea and Pemphicoidea new status. Glypheoidea includes three families: Glypheidae, Mecochiridae and Litogastridae. Litogastridae is the sister group of the clade Glypheidae + Mecochiridae. Pemphicoidea includes a single family: Pemphicidae. A new classification of Glypheidea is proposed and currently known genera are rearranged based upon the phylogenetic analysis.
The present paper is mainly concerned with homology assessment through phylogenetic analyses. It raises a fundamental question: What are the epistemological differences between modern parsimony and model-based analyses in relation to homology assessment and phylogenetic inference? Although these methods usually achieve concordant topological results, they may generate discordant inferences of character evolution from the same datasets. This indicates that method selection has serious implications for evolutionary scenarios and classificatory arrangements. Notwithstanding that parsimony and model-based approaches use the Hennigian concepts of monophyly and synapomorphy, they employ different epistemological ways of dealing with the monophyly/synapomorphy relationship. Independently of their differences, these analyses should take into account all relevant evidence in support of the phylogenetic inferences. A focus on morphological homologues means that they must be included in data matrices, evaluated as part of the phylogenetic analysis, and cannot be ignored in calculation of the tree(s) length (parsimony), maximum-likelihood (maximum-likelihood), and posterior probabilities (Bayes).
June 25, 2014
Polyphyly of Caddoidea, reinstatement of the family Acropsopilionidae in Dyspnoi, and a revised classification system of Palpatores (Arachnida, Opiliones)
Among the least studied harvestmen are the members of the family Caddidae sensu Shear, , a group of Opiliones with massive eyes and the putative sister group of the remaining Eupnoi. Caddids were originally described as two families, Caddidae and Acropsopilionidae, but these are currently treated as subfamilies of Caddidae. These minute arachnids are rarely collected and present some interesting biogeographical patterns, including a disjunct distribution between East Asia and eastern North America, and some of the few cases of trans-Pacific genera in southern hemisphere Opiliones. We therefore obtained samples from most of the landmasses inhabited by Caddidae and undertook a phylogenetic study using nuclear and mitochondrial genes for as many samples as possible. Our results, based on a broad taxonomic sampling, surprisingly showed polyphyly of Caddidae, with the genus Caddo forming the sister group of the remaining Eupnoi, whereas the southern hemisphere genera, many of which were originally placed in Acropsopilionidae, within Dyspnoi, formed the sister clade of the remaining Dyspnoi. In addition, the more recently described genus Hesperopilio, from Western Australia and Chile, was unrelated to either Caddidae or Acropsopilionidae, despite having the supposedly diagnostic large ocularium, and instead appeared deeply nested within the Eupnoi superfamily Phalangioidea. Our results are robust to analytical treatment and to homology scheme (dynamic vs. static notions of homology), resulting in a new phylogenetic proposal for Eupnoi and Dyspnoi. Ancestral state reconstruction suggests that the ancestral Palpatores was probably a tiny harvestman with an enlarged ocularium and glandular palpal setae in its enlarged and armed palps. We take the following taxonomic actions: Acropsopilionidae is removed from synonymy under Caddidae and its family status and membership in Dyspnoi are restored. Hesperopilio Shear, is removed from Caddoidea/Caddidae and transferred to Phalangioidea, but it is not assigned to any family.
June 24, 2014
June 13, 2014
We present POY version 5, an open source program for the phylogenetic analysis of diverse data types including qualitative, aligned sequences, unaligned sequences, genomic data, and user-defined sequences. In addition to the maximum-parsimony optimality criterion supported by POY4, POY5 supports several types of maximum likelihood as well as posterior probability. To make these analyses feasible, new heuristic search algorithms and parallelization options have been implemented for all criteria.
June 5, 2014
Computer science and parsimony: a reappraisal, with discussion of methods for poorly structured datasets
In recent years, several publications in computer science journals have proposed new heuristic methods for parsimony analysis. This contribution discusses those papers, including methods highly praised by their authors, such as Hydra, Sampars and GA + PR + LS. Trees of comparable or better scores can be obtained using the program TNT, but from one to three orders of magnitude faster. In some cases, the search methods are very similar to others long in use in phylogenetics, but the enormous speed differences seem to correspond more to poor implementations than to actual differences in the methods themselves.
June 2, 2014
Derivation of the freshwater fish fauna of Central America revisited: Myers's hypothesis in the twenty-first century
Although attempts to understand Central American freshwater fish provincialism date to the 1960s, early efforts lacked the wealth of distributional data now available. Biogeographic work on Central American freshwater fishes has been largely descriptive and regional, and lacked a broader synthesis. Here we use parsimony analysis of endemicity (PAE) to elucidate faunistic relationships between major drainages and to delineate areas of endemism. We then perform a Brooks parsimony analysis (BPA) on the resulting areas. The PAE recovered a primary division between four Pacific and six Atlantic slope areas of endemism. In contrast, the BPA recovered two Central American geographic clades, one sharing a history with North America and the other with South America. Fish diversity is uneven across Central America, with greater diversity in areas adjacent to the more species-rich regions of North and South America. In northern and nuclear Central America, the paucity of ostariophysan freshwater fishes such as catfishes and characins (groups that dominate adjacent regions) contrasts with high species richness of poeciliids and cichlids. Results of this study are consistent with Myer's hypothesis that poeciliids and cichlids dispersed to Northern or Nuclear Middle America early in the Cenozoic, long before the Plio-Pleistocene rise of the Isthmus of Panama.
May 20, 2014
Cladistic analysis of self-grooming indicates a single origin of eusociality in corbiculate bees (Hymenoptera: Apidae)
Behavioural traits have been used extensively in recent years as an important character source for making phylogenetic inferences. The phylogenetic positions of the members of the Apini subtribe are increasingly being debated, and new characters must be examined. We analysed the presence and absence of certain behavioural patterns, as well as the sequences of some of these patterns, to generate 79 characters. Eleven species comprised the ingroup, and Xylocopini comprised the outgroup. Parsimony analysis showed that the most parsimonious tree was (Euglossina(Bombina(Apina+Meliponina))). This topology is consistent with most studies that use morphological data and the few that use behavioural data, which suggests that advanced eusociality arose only once in a common ancestor of the clade Apina plus Meliponina; however, this hypothesis is inconsistent with our molecular data. Thus we considered behavioural, molecular, and morphological data and recovered the same topology, in which eusociality has a single origin in corbiculate bees.
May 14, 2014
Chemosystematics in the Opiliones (Arachnida): a comment on the evolutionary history of alkylphenols and benzoquinones in the scent gland secretions of Laniatores
Large prosomal scent glands constitute a major synapomorphic character of the arachnid order Opiliones. These glands produce a variety of chemicals very specific to opilionid taxa of different taxonomic levels, and thus represent a model system to investigate the evolutionary traits in exocrine secretion chemistry across a phylogenetically old group of animals. The chemically best-studied opilionid group is certainly Laniatores, and currently available chemical data allow first hypotheses linking the phylogeny of this group to the evolution of major chemical classes of secretion chemistry. Such hypotheses are essential to decide upon a best-fitting explanation of the distribution of scent-gland secretion compounds across extant laniatorean taxa, and hence represent a key toward a well-founded opilionid chemosystematics.
May 12, 2014
Historical linguistics as a sequence optimization problem: the evolution and biogeography of Uto-Aztecan languages
Language origins and diversification are vital for mapping human history. Traditionally, the reconstruction of language trees has been based on cognate forms among related languages, with ancestral protolanguages inferred by individual investigators. Disagreement among competing authorities is typically extensive, without empirical grounds for resolving alternative hypotheses. Here, we apply analytical methods derived from DNA sequence optimization algorithms to Uto-Aztecan languages, treating words as sequences of sounds. Our analysis yields novel relationships and suggests a resolution to current conflicts about the Proto-Uto-Aztecan homeland. The techniques used for Uto-Aztecan are applicable to written and unwritten languages, and should enable more empirically robust hypotheses of language relationships, language histories, and linguistic evolution.
The Genealogical World of Phylogenetic Networks
BMC Evolutionary Biology