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Phylogeny of Pachylis Lepeletier & Serville, 1825 (Hemiptera, Coreidae, Coreinae) with Thasus Stal, 1865 as a new synonym, and the redescription of Pachylis laticornis (Fabricius, 1798)
Abstract
Pachylis Lepeletier & Serville, 1825 is one out of 22 genera of Nematopodini Amyot & Serville, 1843, which contains some of the largest species of Coreidae Leach, 1815. With eight species, the genus is characterized by the presence of expansion on antennomeres III and ventrally on metatibiae. Pachylis is sometimes confused with Thasus Stål, 1865, but the metatibial expansions are dorsal and ventral in the latter. Pachylis and Thasus have already been treated as closely related from a taxonomic perspective, although this relationship has never been tested in previous phylogenetic analyses. A phylogeny including seven Pachylis species and four Thasus species is performed here, based on morphological data and under implied weighting. Pachylis laticornis (Fabricius, 1798) is redescribed and P. furvus Brailovsky & Guerrero, 2014 is proposed as its new synonym. The outgroup contains 44 species, 30 out of them representative of other Nematopodini, and 14 species representing other tribes and subfamilies of Coreidae. We recovered Pachylis monophyletic and sister to T. rutilus Brailovsky & Barrera in Brailovsky et al., 1994 with the remaining three species of Thasus recovered sister to the clade of T. rutilus and Pachylis. Here we propose Thasus as a new junior synonym of Pachylis following our phylogenetic results. Our results also indicate Nematopodini, Melucha Amyot & Serville, 1843, and Piezogaster Amyot & Serville, 1843 are not monophyletic, emphasizing the need for further phylogenetic studies including these taxa.
Supplementary resource (1)
Allometry is the scaling relationship between a trait and body size. This relationship can often explain considerable morphological variation within and among species. Nevertheless, much remains unknown about the factors that underlie allometric patterns. For example, when different allometric relationships are observed amongst closely related species, these differences are regularly considered to be products of selection. However, directional selection on allometry (particularly the slope) has rarely been tested and observed in natural populations. Here, we investigate selection on the scaling relationship between weapon size and body size (i.e., weapon allometry) in a wild population of giant mesquite bugs, Pachylis neocalifornicus (previously Thasus neocalifornicus). Males in this species use their weapons (enlarged femurs) to compete with one another over access to resources and females. We found that large males with relatively large weapons successfully secured access to mates. However, we also found that small males with relatively small weapons could access mates as well. These two patterns together can increase the allometric slope of the sexually selected weapon, suggesting a straightforward process by which the allometric slope can evolve.
A commented list including full specimen data and representative photographs, of the 57 species and morphospecies of true bugs of the family Coreidae (Insecta: Hemiptera: Heteroptera) housed in the Museo Nacional de Historia Natural del Paraguay collection is provided.The list is followed by a brief discussion and a map about the collection localities. Twelve species are recorded for the first time from Paraguay.
The genus Pachylis Le Peletier and Serville (Coreidae: Nematopodini) is revised; 2 new species from Colombia, Ecuador and Peru are described; P. hector Stål is sinonimized under P. nervosus Dallas, and P. serus Berg under P. laticornis (Fabricius); 2 species, P. obscura Spinola and P. striatus (Thunberg), are considered as incertae sedis. New distribution records are provided for P. argentinus Berg, P. bipunctatus (Thunberg), P. laticornis, P. nervosus, P. pharaonis (Herbst) and P. tenuicornis Dallas. Pictures of habitus, antennae, male genital capsule and parameres are provided. A key to the known species is presented.
Immature coreid bugs, probably Thasus acutangulus, form aposematic feeding aggregations on twigs of the legume tree, Pithecellobium dulce, during the dry season in Guanacaste, Costa Rica. Nymphs are bright orange, yellow, and black, and, if disturbed, individuals of the aggregation pulsate, spray jets of anal fluid into the air, and exude a defensive secretion over the abdominal terga. An aggregation pheromone, perceived by receptors on the distal segment of each antenna, enables bugs displaced from aggregations to reaggregate. Alarm behavior was never observed when an open bottle of (E)-2-hexenal was held below an aggregation; only mechanical disturbance released the aposematic display. Adults of T. acutangulus are migratory and conspicuously large, but are not aposematically colored.
New distributions are given for Thasus neocalifornicus Brailovsky and Barrera, T. gigas (Klug), T. acutangulus (Stål), T. luteolus Brailovsky and Barrera, and T. rutilus Brailovsky and Barrera. Measurements of several instars and a key to the last three instars of the first three species are given. These new country records are given: T. acutangulus, El Salvador; T. luteolus, Panama; T. rutilus, Bolivia. The distribution of T. neocalifornicus is discussed, as are differences among its populations and between them and T. gigas. We conclude, tentatively, that T. neocalifornicus from the United States-Mexican landmass more closely resembles the neocalifornicus-gigas common ancestor than do T. neocalifornicus populations from Baja California Sur.
The large coreid bug,Pachylis laticornis (Hemiptera: Coreidae), feeds on several mimosaceous trees in Guanacaste, Costa Rica. In addition to the presumably defensive metathoracic exocrine glands that occur in both sexes of this species, the adult males also possess a ventral abdominal gland, opening midventrally in the 7-8th abdominal intersegmental membrane, that releases volatile compounds. Two esters, (E)-2-hexenyl tiglate and (E)-2-hexenyl (E)-2-hexenoate, account for over 90% of the total volatiles in the ventral abdominal gland secretion of males. (E)-2-Octenyl tiglate and (E)-2-hexenyl benzoate are present at low concentrations, as are at least three other unidentified compounds. The biological role for this fragrant male-specific exudate is unknown.
Host plant and habitat associations are reported for 62 Arizona Heteroptera: one acanthosomated, 12 coreids, one cydnid, 42 pentatomids, three scutellerids and three thyreocorids. At least 90 new breeding hosts are documented; the first known hosts are reported for at least nine species. Seven species are reported from Arizona for the first time, and Piezogaster spurcus (Stal) (Coreidae) is recorded from the United States. Several new parasitoid associations are recorded.
Abstract— The relations among polarity, outgroups and rooting are clarified. The “outgroup algorithm” and “outgroup substitution method” are irrelevant forms of relaxed parsimony. They should be discarded in favor of unconstrained, simultaneous analysis of all terminals. A revised outgroup method is described both in text and with a computer-generated flowchart. Lundberg rooting is consistent with cladistic parsimony only under specific circumstances involving hypothetical ancestors.
"Both sides seemed convinced that the ‘real enemy’is a vicious conspiracy of some kind."
Hunter S. Thompson (1979: 145).
Among the 32 tribes of Coreinae currently recognized, Spartocerini comprises 66 extant species distributed in six genera: Euagona Dallas, Eubule Stål, Menenotus Laporte, Molchina Amyot & Serville, Sephina Amyot & Serville and Spartocera Laporte, distributed exclusively in the Western Hemisphere. We performed cladistic analyses using equal (EW) and also implied weighting (IW) based on 56 terminals (23 belonging to the ingroup) and 115 morphological characters, including male and female genitalia. Spar-tocerini was polyphyletic both under EW and IW because Molchina was nested in Mictini. We remove Molchina from Spartocerini and consider the genus as incertae sedis. Spartocera, Eubule, and Sephina were not recovered as monophyletic. Sephina pubera (Erichson) is considered as incertae sedis within Spartocer-ini, Eubule ampliata (Valdés) is transferred to Spartocera as a new combination, and Mamurius is included in Anisoscelini.
Baits targeting invertebrate ultraconserved elements (UCEs) are becoming more common for phylogenetic studies. Recent studies have shown that invertebrate UCEs typically encode proteins - and thus, are functionally different from more conserved vertebrate UCEs - can resolve deep divergences (e.g., superorder to family ranks). However, the ability of the invertebrate UCE baits to robustly resolve relationships at shallower phylogenetic scales (i.e., tribes and congeners) has been generally limited to Coleoptera and Hymenoptera. Here, we assessed the ability of a recently designed Hemiptera UCE bait set to reconstruct more recent phylogenetic relationships in the largest leaf-footed bug subfamily, the Coreinae (Hemiptera: Coreidae), using a taxon-rich sample representing 21 of the 32 coreine tribes. Many well-supported, novel relationships were congruent in maximum likelihood and summary coalescent analyses. We also found evidence for the para- and polyphyly of several tribes and genera of Coreinae, as well as the subfamilies Coreinae and Meropachyinae. Our study, along with other recent UCE studies, provides evidence that UCEs can produce robust and novel phylogenetic hypotheses at various scales in invertebrates. Additionally, we used different DNA extraction and target enrichment protocols and recovered more UCE data using a touch-down hybridization approach.
The ovipositor morphology of Trichophora (Hemiptera: Heteroptera) is revisited. Skeletomuscular structure of the ovipositor of selected species and outgroups is documented. Homologies of the structures are established, different homology hypotheses of previous authors are discussed and rejected. The groundplan of the trichophoran ovipositor is reconstructed, apomorphic conditions of each part of the ovipositor are documented. A standard nomenclature is proposed for muscles associated with the ovipositor and extrinsic muscles of the female inner ectodermal genital tracts. Character transformations of the ovipositor are reconstructed via cladistic analysis. The concepts of "lanceolate ovipositor" and "plate-like ovipositor", frequently used in the literature, are discussed; it is concluded that no unambiguous definition of them is possible on a morphological basis, these terms refer merely to evolutionary grades rather than strictly distinct character states. "Plate-like ovipositors" evolved at least four times within Trichophora; they exhibit considerable differences among and within these clades. It is demonstrated that the "M- or W-shaped sclerites" of Pyrrhocoridae and Urostylididae are not homologous: in Pyrrhocoridae they are expansions of the mesal face of the posterior portion of valvifers IX, whilst the superficially similar structures in Urostylididae are infoldings of the ventral rim of the mesal portion of laterotergites IX.
Next‐generation sequencing technologies (NGS) allow systematists to amass a wealth of genomic data from non‐model species for phylogenetic resolution at various temporal scales. However, phylogenetic inference for many lineages dominated by non‐model species has not yet benefited from NGS, which can complement Sanger sequencing studies. One such lineage, whose phylogenetic relationships remain uncertain, is the diverse, agriculturally important and charismatic Coreoidea (Hemiptera: Heteroptera). Given the lack of consensus on higher‐level relationships and the importance of a robust phylogeny for evolutionary hypothesis testing, we use a large data set comprised of hundreds of ultraconserved element (UCE) loci to infer the phylogeny of Coreoidea (excluding Stenocephalidae and Hyocephalidae), with emphasis on the families Coreidae and Alydidae. We generated three data sets by including alignments that contained loci sampled for at least 50%, 60%, or 70% of the total taxa, and inferred phylogeny using maximum likelihood and summary coalescent methods. Twenty‐six external morphological features used in relatively comprehensive phylogenetic analyses of coreoids were also re‐evaluated within our molecular phylogenetic framework. We recovered 439–970 loci per species (16%–36% of loci targeted) and combined this with previously generated UCE data for 12 taxa. All data sets, regardless of analytical approach, yielded topologically similar and strongly supported trees, with the exception of outgroup relationships and the position of Hydarinae. We recovered a monophyletic Coreoidea, with Rhopalidae highly supported as the sister group to Alydidae + Coreidae. Neither Alydidae nor Coreidae were monophyletic; the coreid subfamilies Hydarinae and Pseudophloeinae were recovered as more closely related to Alydidae than to other coreid subfamilies. Coreinae were paraphyletic with respect to Meropachyinae. Most morphological traits were homoplastic with several clades defined by few, if any, synapomorphies. Our results demonstrate the utility of phylogenomic approaches in generating robust hypotheses for taxa with long‐standing phylogenetic problems and highlight that novel insights may come from such approaches.
Target enrichment of conserved genomic regions facilitates collecting sequences of many orthologous loci from non-model organisms to address phylogenetic, phylogeographic, population genetic, and molecular evolution questions. Bait sets for sequence capture can simultaneously target thousands of loci, which opens new avenues of research on speciose groups. Current phylogenetic hypotheses on the >103,000 species of Hemiptera have failed to unambiguously resolve major nodes, suggesting that alternative datasets and more thorough taxon sampling may be required to resolve relationships. We here use a recently designed ultraconserved element (UCE) bait set for Hemiptera, with a focus on the suborder Heteroptera, or the true bugs, to test previously proposed relationships. We present newly generated UCE data for 36 samples representing three suborders, all seven heteropteran infraorders, 23 families, and 34 genera of Hemiptera and one thysanopteran outgroup. To improve taxon sampling, we also mined additional UCE loci in silico from published hemipteran genomic and transcriptomic data. We obtained 2,271 UCE loci for newly sequenced hemipteran taxa, ranging from 265 to 1,696 (average 904) per sample. These were similar in number to the data mined from transcriptomes and genomes, but with fewer loci overall. The amount of missing data correlates with greater phylogenetic divergence from taxa used to design the baits. This bait set hybridizes to a wide range of hemipteran taxa and specimens of varying quality, including dried specimens as old as 1973. Our estimated phylogeny yielded topologies consistent with other studies for most nodes and was strongly-supported. We also demonstrate that UCE loci are almost exclusively from the transcribed portion of the genome, thus data can be successfully integrated with existing genomic and transcriptomic resources for more comprehensive phylogenetic sampling, an important feature in the era of phylogenomics. UCE approaches can be used by other researchers for additional studies on hemipteran evolution and other research that requires well resolved phylogenies.
Version 1.5 of the computer program TNT completely integrates landmark data into phylogenetic analysis. Landmark data consist of coordinates (in two or three dimensions) for the terminal taxa; TNT reconstructs shapes for the internal nodes such that the difference between ancestor and descendant shapes for all tree branches sums up to a minimum; this sum is used as tree score. Landmark data can be analysed alone or in combination with standard characters; all the applicable commands and options in TNT can be used transparently after reading a landmark data set. The program continues implementing all the types of analyses in former versions, including discrete and continuous characters (which can now be read at any scale, and automatically rescaled by TNT). Using algorithms described in this paper, searches for landmark data can be made tens to hundreds of times faster than it was possible before (from T to 3T times faster, where T is the number of taxa), thus making phylogenetic analysis of landmarks feasible even on standard personal computers.
The family Coreidae is distributed worldwide, but these phytophagous bugs are most abundant in the tropics and subtropics. In the Neotropical region, all of the subfamilies and 16 tribes are represented. In tropical ecosystems, these bugs feed on herbs and shrubs in open areas of forests as well as at the forest edge. Some species are spectacularly colored, and unusual expansions of antennae, humeral angles, femora, or tibiae occur in many groups. Some of them move lazily even when disturbed and hardly fly to escape; others are extremely nimble, fast flying away when disturbed. They are frequently encountered in crops, representing important pests in several commodities. No one common name is universally accepted for the family, and none of the frequently used names (e.g., squash bug, leatherbug, leaf-footed bug, Randwanzen) are collectively appropriate for all members of the family. © Springer Science+Business Media Dordrecht 2015. All rights reserved.
Three new genera and six new species from New Guinea are described in the tribe Colpurini (Coreidae). Habitus illustrations and drawings of the male and female genitalia, as well as head and pronotum are provided.
Additional distributional records are given and discussed for Thasus gigas (Klug), T. acutangulus (Stål), and T. neocalifornicus Brailovsky and Barrera. In particular, we emphasize the almost certain absence of T. neocalifornicus from New Mexico, and we discuss its population centers near Tucson, Arizona, and at the southern tip of Baja California Sur. Sinaloa and Chihuahua (Mexico) are new state records for T. gigas, and Chihuahua is a new state record for T. neocalifornicus.
Studies on the New World Coreidae have languished for more than a century. Neglect of these often large, abundant, and occasionally economically important bugs has been due, I believe, to the lack of means to identify them. Most literature treating the New World Coreidae has been restricted to the North American fauna, except for the recent efforts of Brailovsky (1975 to 2007).
STENOCEPHALINI Stenocephalus agilis Scop. 1-2. Staff, Fichtelgebirge, Bavaria. — 3. Toulon, 1894, Dr. Nodier. — 4-5. Cauterets. — 6. Rivièra, France, 1896, Brants. — 7. Capo di Ponte, Italia, August 1895, Fokker. — 8. Ivize, Spain, Schmiedeknecht. — 9. Finstermünz, Tyrol, Sept. 1895, Fokker. — 10-13. Gospić, Croatia, Sequens. — 14. Corsica, May 1893, D. v. d. Hoop. — 15-16. Amasia. — 17. Oran, 1895, Dr. Schmiedeknecht. — 18-23. Tunis, 1898, Dr. Schmiedeknecht. (The specimens 1-23 in Fokker's collection). — 24-26. Germany. — 27-28. Dalmatia, Cantraine. — 29. Italia, Cantraine. — 30. Zermatt, Switzerland, June 1906, Dr. H. J. Veth. — 31-34. Algeria, Richter. — 35. Göttingen, Everts. — 36. Laubach, v. Hasselt. — 37-38. Brig, 13-19 July 1924, R. v. d. Veen. — 39-41. ?. — 42. Algeria, April 1899, A. Legras. — 43. Cape of Good Hope ( ?), Horstock. Var. femoralis Noualh. 44. Ain Fezza, Algeria, Staudinger 1934. — 45. Sidi-Bel-Abbes, Staudinger 1934. Stenocephalus albipes F. 1. Thüringen, Dr. O. M. Schmiedeknecht. — 2-6. Charente, H. Giraudeau. — 7-8. S. France, L. Duda. — 9. Grasse, S. France, D. v. d. Hoop. — 10. Chiclana, Andalusia. — 11-18. Palma, Baleares, Dr. O. M. Schmiedeknecht. — 19-20. Colle dei Giori, Genoa, Mantero. — 21-26. Monte Brione, Lago di Garda, Dr. O. Schmiedeknecht. — 27-28. Riva, Tyrol, August, Fokker. — 29. Gospić, Croatia, Sequens. — 30-31. Corfu, 1889, Schmiedeknecht. — 32-40. Corfu, 1901, Schmiedeknecht. — 41-48. Olympia, 1901, Schmiedeknecht. — 49. Hungaria, Sajó. — 50. Sarepta, A. Becker. (The specimens 1-50 in
Abstract A cladistic analysis of the Asiatic genera of Mictini (s. str.) is made in the present paper. The results indicate that this group is monophyletic and their genitalia structrues are very similar, in spite of their variegated external forms. Derepterini Hsiao is proved to be a paraphyletic group and its synonymy with Mictini (s. str.) is supported by the cladograms. The cladograms show that there are some major differences between the mainly African Anoplocnemis and the other Asiatic genera.
Abstract Systematists have questioned the distinction between characters and character states and their alignment with the traditional concept of homology. Previous definitions for character and character state show surprising variation. Here it is concluded that characters are simply features expressed as independent variables and character states the mutually exclusive conditions of a character. Together, characters and character states compose what are here termed character statements. Character statements are composed of only four fundamental functional components here identified as locator, variable, variable qualifier, and character state, and these components exist in only two patterns, neomorphic and transformational. Several controversies in character coding and the use of “absent” as a character state are understood here as a consequence of incomplete character statements and the inappropriate mixing of neomorphic and transformational character statements. Only a few logically complete patterns for morphological character data exist; their adoption promises to greatly reduce current variability in character data between analyses. © The Willi Hennig Society 2007.
The group of the Aradidae was largely made accessible by the excellent work of R. L. Usinger & R. Matsuda (Classification of the Aradidae, London 1959). It gave me the possibility of revising the collection of the Rijksmuseum van Natuurlijke Historie, from which already some species had been described by C. J. Drake and R. L. Usinger before. As a consequence of their ecology, the collecting of Aradidae is not very easy. The work done by the numerous collectors for our museum resulted in a medium-sized collection from a restricted number of localities, as in some cases the number of individuals in one capture is very high, and for the rest the captures are incidental only. A single remark may be made regarding the drawings in this paper. Many specimens offer a notable asymmetry; in those cases I have not symmetrized the figure by turning the half of it, as this often would have changed the total aspect. In one case, where the right side is hidden by incrustations and rubbish, the drawing shows the left side only. The data are given as found on the labels. Only in exceptional instances is the information translated into English, or the name of the locality transcribed. Again I am much indebted to the staff of the British Museum (Natural History), for assistance during my stay in the Hemiptera section. l SODERMINAE Isodermus gayi Spin. 1-3. Punta Arenas, Straits of Magellan, Walker, British Museum leg. Isodermus planus Er. 1-2. Van Diemensland, Klug. ARADINAE
We show the pantrppical tribe Mictini to be polyphyletic, and we separate it into 3: Mictini (s.s.) Amyot and Serville (Old World), Nematopodini Amyot and Serville (New World), and Acanthocerini Bergroth (New World). These tribes do not appear to be closely related to one another. We list the genera now placed in each tribe.
Food plant records are tabulated for five coreoid families, and feeding preferences are analyzed within the Coreinae (Coreidae). With the exception of the Coreinae, food plant associations are characteristic at the subfamily or tribal level. Within the Coreinae, no clear pattern of food plant preference can be discerned. Angiosperms are preferred over gymnosperms, dicots over monocots; but members of all six dicot subclasses are used as food plants. Comparison among the dicot subclasses, weighted to equalize plant group size, shows Caryophyllidae to be the most preferred group, with Magnoliidae and Asteridae least preferred. A dichotomy in use of plant parts is apparent; reproductive organs are preferred by some groups, whereas vascular feeding on vegetative parts is characteristic of others. Breadth of diet, however, is highly variable, ranging from extreme polyphagy to restricted feeding on a single plant species.
Members of the 3 unrelated coreine tribes Mictini, Acanthocerini, and Nematopodini prefer members of the Leguminosae to those of other plant families. The insects feed on the parts of the plant richest in concentrated nutrients.
A method that allows estimating consensus trees without exhaustive searches is described. The method consists of comparing the results of different independent superficial searches. The results of the searches are then summarized through a majority rule, consensed with the strict consensus tree of the best trees found overall. This assumes that to the extent that a group is recovered by most searches, it is more likely to be actually supported by the data. The effect of different parameters on the accuracy and reliability of the results is discussed. Increasing the cutoff frequency decreases the number of spurious groups, although it also decreases the number of correct nodes recovered. Collapsing trees during swapping reduces the number of spurious groups without significantly decreasing the number of correct nodes recovered. A way to collapse branches considering suboptimal trees is described, which can be extended as a measure of relative support for groups; the relative support is based on the Bremer support, but takes into account relative amounts of favorable and contradictory evidence. More exhaustive searches increase the number of correct nodes recovered, but leave unaffected (or increase) the number of spurious groups. Within some limits, the number of replications does not strongly affect the accuracy of the results, so that using relatively small numbers of replications normally suffices to produce a reliable estimation.
The family Characidae, including more than 1000 species, lacks a phylogenetic diagnosis, with many of its genera currently considered as incertae sedis. The aims of the present study are to propose a phylogenetic diagnosis and to assess higher-level relationships of and within Characidae. In this regard, 360 morphological characters are studied for 160 species of Characidae and related families. Phylogenetic analyses under implied weighting and self-weighted optimization are presented, exploring a broad range of parameters. The analysis under self-weighted optimization is innovative for this size of matrices. Familial status of Serrasalmidae is supported, and Acestrorhynchidae and Cynodontidae are included in a monophyletic Characidae. Engraulisoma taeniatum is transferred from Characidae to Gasteropelecidae. Thus constituted, the monophyly of Characidae is supported by seven synapomorphies. A new subfamily, Heterocharacinae, is proposed, and the subfamilies Aphyocharacinae, Aphyoditeinae, Characinae, Gymnocharacinae, and Stevardiinae are redefined. The Glandulocaudinae are included in Stevardiinae together with remaining members of “clade A” (sensuMalabarba and Weitzman, 2003. Comun. Mus. Ciênc. Tecnol. PUCRS, Sér. Zool. 16, 67–151.) and the genera Aulixidens and Nantis. Most incertae sedis genera are assigned, at least tentatively, to a phylogenetically diagnosed clade.