Cladistics最新文献

Informative and consistent taxonomy above the species level is essential to communication about evolution, biodiversity and conservation, and yet the practice of taxonomy is considered opaque and subjective by non-taxonomist scientists and the public alike. While various proposals have tried to make the basis for the ranking and inclusiveness of taxa more transparent and objective, widespread adoption of these ideas has lagged. Here, we present TaxonomR, an interactive online decision-support tool to evaluate alternative taxonomic classifications. This tool implements an approach that quantifies the criteria commonly used in taxonomic treatments and allows the user to interactively manipulate weightings for different criteria to compare scores for taxonomic groupings under those weights. We use the butterfly taxon Argynnis to demonstrate how different weightings applied to common taxonomic criteria result in fundamentally different genus-level classifications that are predominantly used in different continents and geographic regions. These differences are objectively compared and quantified using TaxonomR to evaluate the kinds of criteria that have been emphasized in earlier classifications, and the nature of the support for current alternative taxonomic arrangements. The main role of TaxonomR is to make taxonomic decisions transparent via an explicit prioritization scheme. TaxonomR is not a prescriptive application. Rather, it aims to be a tool for facilitating our understanding of alternative taxonomic classifications that can, in turn, potentially support global harmony in biodiversity assessments through evidence-based discussion and community-wide resolution of historically entrenched taxonomic tensions.

The owlet moths (Noctuoidea; ~43–45K described species) are one of the most ecologically diverse and speciose superfamilies of animals. Moreover, they comprise some of the world's most notorious pests of agriculture and forestry. Despite their contributions to terrestrial biodiversity and impacts on ecosystems and economies, the evolutionary history of Noctuoidea remains unclear because the superfamily lacks a statistically robust phylogenetic and temporal framework. We reconstructed the phylogeny of Noctuoidea using data from 1234 genes (946.4 kb nucleotides) obtained from the genome and transcriptome sequences of 76 species. The relationships among the six families of Noctuoidea were well resolved and consistently recovered based on both concatenation and gene coalescence approaches, supporting the following relationships: Oenosandridae + (Notodontidae + (Erebidae + (Nolidae + (Euteliidae + Noctuidae)))). A Yule tree prior with three unlinked molecular clocks was identified as the preferred BEAST analysis using marginal-likelihood estimations. The crown age of Noctuoidea was estimated at 74.5 Ma, with most families originating before the end of the Paleogene (23 Ma). Our study provides the first statistically robust phylogenetic and temporal framework for Noctuoidea, including all families of owlet moths, based on large-scale genomic data.

The fifth mass extinction event (MEE) at the Cretaceous–Palaeogene (K–Pg) boundary 66 million years ago (Ma) led to massive species loss but also triggered the diversification of higher taxa. Five models have been proposed depending on whether this diversification occurred before, during or after the K–Pg boundary and the rate of species accumulation. While the effects of the K–Pg MEE on vertebrate evolution are relatively well understood, the impact on invertebrates, particularly in freshwater ecosystems, remains controversial. One example is the hyperdiverse Hydrobiidae—the most species-rich family of freshwater gastropods. Whereas some studies place its origin in the Jurassic or even Carboniferous, most fossil records postdate the K–Pg event. We therefore used robustly time-calibrated multi-locus phylogenies of >400 species representing >100 hydrobiid genera to unravel its evolutionary history and patterns of diversification. We found that the family started diversifying shortly after the K–Pg boundary (∼60 Ma; 95% highest posterior density 52–69 Ma). Lineage richness gradually increased to the present and phylogenetic diversity until ∼25 Ma. These findings suggest that diversification was not initially driven by ecological opportunity. Combining the two criteria of timing and rate of diversification, a soft-explosive diversification model of aquatic vertebrates best fits the patterns observed. We also show that most higher hydrobiid taxa (i.e. subfamilies) diversified from the Middle Oligocene to Middle Miocene (i.e. 12–28 Ma). Two of the 15 major clades delimited are described here as new subfamilies (i.e. Bullaregiinae n. subfam. and Pontobelgrandiellinae n. subfam.), whose members are restricted to subterranean waters. Our results are an important contribution to understanding how the fifth MEE has shaped evolution and patterns of biodiversity in continental aquatic systems. Given the high extinction risks faced by many hydrobiids today, they also emphasise the need to study the biodiversity of vulnerable ecosystems.

Butterfly eyespots are wing patterns reminiscent of vertebrate eyes, formed by concentric rings of contrastingly coloured scales. Eyespots are usually located close to the wing margin and often regarded as the single most conspicuous pattern element of butterfly wing colour displays. Recent efforts to understand the processes involved in the formation of eyespots have been driven mainly by evo-devo approaches focused on model species. However, patterns of change implied by phylogenetic relationships can also inform hypotheses about the underlying developmental mechanisms associated with the formation or disappearance of eyespots, and the limits of phenotypic diversity occurring in nature. Here we present a combined evidence phylogenetic hypothesis for the genus Eunica, a prominent member of diverse Neotropical butterfly communities, that features notable variation among species in eyespot patterns on the ventral hind wing surface. The data matrix consists of one mitochondrial gene region (COI), four nuclear gene regions (GAPDH, RPS5, EF1a and Wingless) and 68 morphological characters. A combined cladistic analysis with all the characters concatenated produced a single most parsimonious tree that, although fully resolved, includes many nodes with modest branch support. The phylogenetic hypothesis presented corroborates a previously proposed morphological trend leading to the loss of eyespots, together with an increase in the size of the conserved eyespots, relative to outgroup taxa. Furthermore, wing colour pattern dimorphism and the presence of androconia suggest that the most remarkable instances of sexual dimorphism are present in the species of Eunica with the most derived eyespot patterns, and are in most cases accompanied by autapomorphic combinations of scent scales and “hair pencils”. We discuss natural and sexual selection as potential adaptive explanations for dorsal and ventral wing patterns.

The treatment of inapplicable characters has proved especially vexing to systematists. Investigators have wrestled with alternative coding scenarios to capture both the presence and absence of a feature, and its variation when present, in a reasonable manner. Three basic issues have presented themselves: (i) impossible states at internal nodes; (ii) action at a distance among disparate parts of the tree; and (iii) “secondary” (i.e. aspect variation) characters overwhelming “primary” (i.e. character presence/absence) patterns in grouping taxa. Multiple methods have been proposed to deal with these issues in the context of standard character coding with varying levels of complexity. Here, I show that these issues can be dealt with in a direct fashion by treating presence/absence not as a character, but as insertion/deletion of a character with all its potential variation. This approach removes these three problems in simple, straightforward manner.

An algorithm is described for the optimization of character data (e.g. qualitative, nucleic acid sequence) on softwired phylogenetic networks. The algorithm presented here is an extension of those developed for trees under the parsimony criterion and can form the basis for phylogenetic network search procedures. Although the problem is (in general) an NP-Hard optimization, the resolution-based algorithm we describe here capitalizes on the significant amount of shared structure in sub-graphs containing network edges, reducing the execution time and allowing for the analysis of empirical datasets.

Morphological matrices, including the conceptualization of characters and character states and scoring thereof, still are a valuable and necessary tool for phylogenetic analyses. Although they are often seen only as numerically simplified summaries of observations for the purpose of cladistic analyses, they also hold value as collections of ideas, concepts and the current state of knowledge, conveying various hypotheses on character state identity, homology and evolutionary transformations. A common and persistent issue in scoring and analysing morphological matrices is the phenomenon of inapplicable characters (“inapplicables”). Inapplicables result from the ontological dependency (based on hierarchical relationships) between characters. Traditionally handled the same as “missing data”, inapplicables were shown to be problematic in holding the potential to result in unreasonable algorithmic preference for certain cladograms over others. Recently, though, this problem has been solved by approaching parsimony as a maximization of homology rather than a minimization of transformational steps. We herein aim to further improve our theoretical understanding of the underlying hierarchical nature of morphological characters, which causes the phenomenon of ontological dependencies and, thereby, inapplicables. As a result, we present a discussion of various character-dependency scenarios and a new concept of hierarchical character relationships as being composed of four complementary sub-aspects. Building on this, a new syntax for the designation of character dependencies as part of the character statement is proposed, to help identify and apply scoring constraints for manual and automated scoring of morphological character matrices and their cladistic analysis.

The butterfly subtribe Coenonymphina (Nymphalidae: Satyrinae) comprises four main clades found, respectively, in (1) the Solomon Islands, (2) Australasia, (3) NW South America and (4) Laurasia, with a phylogeny: 1 (2 (3 + 4)). In assessing biogeographic evolution in the group we rejected the conversion of fossil-calibrated clade ages to likely maximum clade ages by the imposition of arbitrary priors. Instead, we used biogeographic–tectonic calibration, with fossil-calibrated ages accepted as minima. Previous studies have used this approach to date single nodes (phylogenetic–biogeographic breaks) in a group, but we extended the methodology to date multiple nodes. Within the Coenonymphina as a whole, 14 nodes coincide spatially with ten major tectonic events. In addition, the phylogenetic sequence of these nodes conforms to the chronological sequence of the tectonic events, consistent with a vicariance origin of the clades. Dating of the spatially coincident tectonic features provides a timescale for the vicariance events. The tectonic events are: pre-drift intracontinental rifting between India and Australia (150 Ma); seafloor spreading at the margins of the growing Pacific plate, and between North and South America (140 Ma); magmatism flare-up along the SW Pacific Whitsunday Volcanic Province–Median Batholith (130 Ma); a change from extension in the Clarence basin, eastern Australia, to uplift of the Great Dividing Range (114 Ma); Pamir Mountains uplift, foreland basin dynamics and high eustatic sea-levels leading to marine transgression of the proto-Paratethys Ocean eastward to Central Asia and Xinjiang (100 Ma); predrift rifting and seafloor spreading west of New Caledonia (100–50 Ma); sinistral strike-slip displacement along the proto-Alpine fault, New Zealand (100–80 Ma); thrust faulting in the Longmen Shan and foreland basin dynamics around the Sichuan Basin (85 Ma); pre-drift rifting in the Coral Sea basin (85 Ma); and dextral displacement on the Alpine fault (20 Ma).

The leaf-roller moth tribe Grapholitini comprises about 1200 described species and contains numerous notorious pests of fruits and seeds. The phylogeny of the tribe has been little studied using contemporary methods, and the monophyly of several genera remains questionable. In order to provide a more robust phylogenetic framework for the group, we conducted a multiple-gene phylogenetic analysis of 104 species representing 27 genera of Grapholitini and 29 outgroup species. Divergence time, ancestral area, and host plant usage were also inferred to explore evolutionary trends in the tribe. Our analyses indicate that Larisa and Corticivora, traditionally assigned to Grapholitini, are best excluded from the tribe. After removal of these two genera, the tribe is found to be monophyletic, represented by two major lineages—a Dichrorampha clade and a Cydia clade, the latter of which can be divided into seven generic groups. The genus Grapholita was found to be polyphyletic, comprising three different clades, and we propose three genera to accommodate these groups: Grapholita (sensu stricto), Aspila (formerly a subgenus of Grapholita) and Ephippiphora (formerly considered a synonym of Grapholita). We summarize each generic group, including related genera not included in our analysis, providing morphological, pheromone and food plant characters that support particular branches within the molecular hypotheses. Biogeographical analyses indicate that Grapholitini probably originated in the Nearctic, Afrotropical and Neotropical regions in the Lutetian of the middle Eocene (ca. 44.3 Ma). Our results also indicate that most groups in Grapholitini originated from Fabaceae-feeding monophagous or oligophagous ancestors, and that host plant shifts probably promoted species diversification within the tribe.

The Himalayan foothills and associated environment are well-known for driving the rapid diversification of many species and the formation of biodiversity hotspots. The effects of environmental change since the Miocene have accelerated species diversification, and hence are useful for studying population genetic structure, and evolutionary relationships via genetic approaches. To date, the effects of climatic fluctuations on the biogeography of large-bodied lizards have not been assessed comprehensively. Herein, we examine the diversification of Varanus bengalensis, focusing on its genetic structure to provide insights into how landscape structure and climatic fluctuations have shaped species differentiation. We confirm the existence of two distinct lineages within V. bengalensis distributed across the Himalayan foothills and the remainder of mainland India. Divergence analyses revealed the split between the Himalayan foothills and the remainder of the mainland lineages of V. bengalensis in the mid-Pliocene ~3.06 Ma, potentially as a consequence of the Siwalik broadening and climatic fluctuations across the Himalayan foothills. The results suggest recognition of a new lineage of V. bengalensis from the Himalayan foothills as a distinctive evolutionarily significant unit.