The phylogeny of lower Hymenoptera (Insecta), with a summary of the early evolutionary history of the order

A cladistic analysis of the lower Hymenoptera, including all the ‘symphytan’ families and the apocritan families Stephanidae, Megalyridae, Trigonalyidae, Ibaliidae, Vespidae and Gasteruptiidae, has been undertaken. A total of 98 characters were scored for 21 taxa. Twenty equally parsimonious minimum-length trees were obtained. The phylogenetic status of the Xyelidae is uncertain: they might be monophyletic. or the Xyelinae might be the sistergroup of the rest of the Hymenoptera. The non-xyelid Hymenoptera are probably monophyletic; the phylogeny Tenthredinoidea + (Megalodontoidea + (Cephidae + (Anaxyelidea + (Siricidae + (Xiphydriidae + (Orussidae + Apocrita)))))) is proposed for this clade. The Blasticotomidae are probably the sistergroup of all othe Tenthredinoidea, but tenthredinoid phylogeny is otherwise uncertain. Substantial homoplasy occurs within the ‘siricoid’ families, making the relative positions of the Anaxyelidae and Siricidae uncertain. The Stephanidae might be the sistergroup of the rest of the Apocrita; the phylogeny of the remaining apocritan taxa included is insufficiently elucidated. The phylogeny proposed here supports the hypothesis that the appearance of parasitism in the Hymenoptera took place in the common ancestor of Orussidae + Apocrita, the host of which was probably wood boring insect larvae. The exact larval mode of feeding of the ancestral hymenopteran cannot be determined due ot the diversity of lifestyles in the basal lineages of the order.     

Before the wasp-waist: comparative anatomy and phylogenetic implications of the skeleto-musculature of the thoraco-abdominal boundary region in basal Hymenoptera (Insecta)

The skeleto-musculature of the metathorax and first abdominal segment was studied in representatives from all ’symphytan’ families. Forty-three informative characters were coded and scored. The distribution of character states are discussed with reference to recent cladistic treatments of the Hymenoptera. Previously unreported autapomorphies for the Hymenoptera are the separation of the metathoracic trochantins from the metepisterna and metacoxae, the position of the metafurca anteriorly on the discrimenal lamella of the metathorax and the presence of second abdominal sternum (S2)-metacoxal muscles. The absence of metapleuro-S2 muscles is an autapomorphy for the non-xyelid Hymenoptera. Putative autapomorphies of the Tenthredinoidea are: (1) the presence of transverse metanotal muscles, (2) the subdivision of the second phragmo-third phragmal muscles, part of which arises from the metalaterophragmal lobes, (3) the posterior thoracic spiracle occlusor muscles arising from the mesepisterna, (4) the absence of trochantins and metanoto-trochantinal muscles and (5) the presence of elongate lateral metafurcal arms. Having the paracoxal sulci extending along the anterior margins of the metepisterna and the anterior metafurcal arms reduced are synapomorphies for all tenthredinoid families excluding Blasticotomidae. The presence of transversely extended cenchri with hooks on their entire surface is a putative synapomorphy for Diprionidae + Cimbicidae + Argidae + Pergidae. The clade Cimbicidae + Argidae + Pergidae is supported by the absence of metanoto- metabasalar muscles, the fusion of the first abdominal tergite (T1) with the metepimera and the absence of posterior metapleuro-metafurcal muscles. Autapomorphies of the Cimbicidae are the absence of the metalaterophragmal lobes and the metalaterophragmal-metafurcal muscles. Having the mesoscutello-metanotal muscle inserting on a projection from the anterior margin of the metanotum, surrounding the tendon with sclerotised cuticle, is a synapomorphy for the Argidae and Pergidae. Autapomorphies of the Cephoidea are the absence of cenchri, the presence of distinct articulations between T1 and the metepimera, and having the paracoxal sulci extending subparallel with the metafurcal discrimen. The monophyly of the Siricidae is supported by the absence of the anapleural clefts and the presence of an elongate mesospina projecting posteriorly between the anterior metafurcal arms. The presence of a membranous pouch ventrally of T1 and of large T1-metafurcal muscles is unique to Xiphydria camelus among the taxa examined. The absence of hind wing tegulae, posterior metapleuro-metafurcal, metanoto-trochantinal and anterior metanoto-metacoxal muscles, and the presence of elongate lateral metafurcal arms are synapomorphies for Xiphydriidae + Orussidae + Apocrita. The Orussidae greatly resembles the Apocrita in the region studied, a synapomorphy for the two taxa being the presence of metepisternal depressions. An autapomorphy for the Apocrita is the fusion of T1 with the metapleural arms; these structures closely abut in Orussidae. The fusion of T1 with the metepimera was preceded by the reduction of the posterior parts of the metepimera, as observed in Anaxyelidae, Xiphydriidae, and Orussidae. This makes the lines of fusion between T1 and the metepimera confluent with the metapleural sulci in the Apocrita. There is no compelling evidence for considering the configuration of T1 and the metepimera in Cephoidea to be incipient in the formation of the propodeum in Apocrita. The close association between the meso- and metathorax and the integration of T1 in the metathorax evolved gradually twice within the basal hymenopteran lineages, culminating in the Apocrita and the Cimbicidae + Argidae + Pergidae clade. Accepted: 2 September 1999     

Simultaneous analysis of basal Hymenoptera (Insecta): introducing robust-choice sensitivity analysis

Molecular characters are analysed on their own and in combination with morphological data to examine the phylogenetic relationships of the basal lineages of Hymenoptera ('Symphyta'). This study covers 47 sawfly genera and nine apocritan families and includes molecular sequences from five genes − 12S, 16S, 18S and 28S ribosomal genes and cytochrome oxidase 1 − as well as 343 morphological characters. A robust-choice sensitivity analysis is performed with the data. First, the simultaneous analysis is repeated three times, each time employing a different step matrix for weighting the transformations of the molecular characters. Then, the results of all three simultaneous analyses are summarized in a strict consensus in order to avoid basing the conclusions on a narrow set of assumptions. This methodology is discussed in the paper. The relationships among superfamilies largely confirm previous hypotheses, being (Xyeloidea (Tenthredinoidea s.l. (Pamphilioidea (Cephoidea (Siricoidea (Xiphydrioidea (Orussoidea Apocrita))))))), where Siricoidea is understood as Siricidae+Anaxyelidae. However, the relationships within Tenthredinoidea s.s. proposed here are novel: ({Argidae Pergidae}[ Athalia {(Diprionidae Cimbicidae) Tenthredinidae minus Athalia }]).  © 2003 The Linnean Society of London . Biological Journal of the Linnean Society , 2003, 79, 245–275.     

Simultaneous analysis of the basal lineages of Hymenoptera (Insecta) using sensitivity analysis

The first simultaneous analysis of molecular and morphological data of basal hymenopterans that includes exemplars from all families is presented. DNA sequences (of approximately 2000–2700 bp for each taxon) from the nuclear genes 18S and 28S and the mitochondrial genes 16S and CO1 have been sequenced for 39 taxa (four outgroup taxa, 29 symphytans, and six apocritans). These DNA sequences and 236 morphological characters from Vihelmsen [Zool. J. Linnean Soc. 131 (2001) 393] were analyzed separately as well as simultaneously. All analyses were performed on unaligned sequences, using the optimization alignment (= direct optimization) method. Sensitivity analysis sensu Wheeler [Syst. Biol. 44 (1995) 321] was applied by analyzing the data under nine different combinations of analysis parameter values. The superfamily level relationships of basal hymenopterans as proposed by Vilhelmsen [Zool. J. Linnean Soc. 131 (2001) 393] and Ronquist et al. [Zool. Scr. 28 (1999) 13] are mostly confirmed, except that Pamphilioidea is the sister group to Tenthredinoidea s.l. and that Anaxyelidae (i.e., Syntexis libocedrii) and Siricidae are supported as a monophyletic group, partly reestablishing the traditional concept of Siricoidea. The resulting hypothesis that best represents the combined evidence from morphology and DNA sequences is (Xyeloidea (Tenthredinoidea s.l. Pamphilioidea) (Cephoidea (Siricoidea (Xiphydrioidea (Orussidae Apocrita))))), with Siricoidea = Anaxyelidae +Siricidae. The phylogenetic system within Tenthredinoidea s.l., derived from the combined evidence, is (Blasticotomidae (Tenthredinidae including Diprionidae (Cimbicidae (Argidae Pergidae)))).     

Phylogenetic relationships among superfamilies of Hymenoptera

The first comprehensive analysis of higher‐level phylogeny of the order Hymenoptera is presented. The analysis includes representatives of all extant superfamilies, scored for 392 morphological characters, and sequence data for four loci (18S, 28S, COI and EF‐1α). Including three outgroup taxa, 111 terminals were analyzed. Relationships within symphytans (sawflies) and Apocrita are mostly resolved. Well supported relationships include: Xyeloidea is monophyletic, Cephoidea is the sister group of Siricoidea + [Xiphydrioidea + (Orussoidea + Apocrita)]; Anaxyelidae is included in the Siricoidea, and together they are the sister group of Xiphydrioidea + (Orussoidea + Apocrita); Orussoidea is the sister group of Apocrita, Apocrita is monophyletic; Evanioidea is monophyletic; Aculeata is the sister group of Evanioidea; Proctotrupomorpha is monophyletic; Ichneumonoidea is the sister group of Proctotrupomorpha; Platygastroidea is sister group to Cynipoidea, and together they are sister group to the remaining Proctotrupomorpha; Proctotrupoidea s. str. is monophyletic; Mymarommatoidea is the sister group of Chalcidoidea; Mymarommatoidea + Chalcidoidea + Diaprioidea is monophyletic. Weakly supported relationships include: Stephanoidea is the sister group of the remaining Apocrita; Diaprioidea is monophyletic; Ceraphronoidea is the sister group of Megalyroidea, which together form the sister group of [Trigonaloidea (Aculeata + Evanioidea)]. Aside from paraphyly of Vespoidea within Aculeata, all currently recognized superfamilies are supported as monophyletic. The diapriid subfamily Ismarinae is raised to family status, Ismaridae stat. nov. © The Will Henning Society 2011.     

Phylogeny of the symphytan grade of Hymenoptera: new pieces into the old jigsaw(fly) puzzle

The Hymenoptera constitutes one of the largest, and ecologically and economically most important, insect orders. During the past decade, a number of hypotheses on the phylogenetic relationships among hymenopteran families and superfamilies have been presented, based on analyses of molecular and/or morphological data. Nevertheless, many questions still remain, particularly concerning relationships within the hyperdiverse suborder Apocrita, but also when it comes to the evolutionary history of the ancestrally herbivorous “sawfly” lineages that form the basal, paraphyletic grade Symphyta. Because a large part of the uncertainty appears to stem from limited molecular and taxonomic sampling, we set out to investigate the phylogeny of Hymenoptera using nine protein‐coding genes, of which five are new to analyses of the order. In addition, we more than tripled the taxon coverage across the symphytan grade, introducing representatives for many previously unsampled lineages. We recover a well supported phylogenetic structure for these early herbivorous hymenopteran clades, with new information regarding the monophyly of Xyelidae, the placement of the superfamily Pamphilioidea as sister to Tenthredinoidea + Unicalcarida, as well as the interrelationships among the tenthredinoid families Tenthredinidae, Cimbicidae, and Diprionidae. Based on the obtained phylogenies, and to prevent paraphyly of Tenthredinidae, we propose erection of the tribe Heptamelini to family status (Heptamelidae). In particular, our results give new insights into subfamilial relationships within the Tenthredinidae and other species‐rich sawfly families. The expanded gene set provides a useful toolbox for future detailed analyses of symphytan subgroups, especially within the diverse superfamily Tenthredinoidea.     

Evidence for AT-Transversion Bias in Wasp (Hymenoptera: Symphyta) Mitochondrial Genes and Its Implications for the Origin of Parasitism

We inferred the incidence of nucleotide conversions in the COI and 16S rRNA mitochondrial genes of members of the Symphyta and basal Apocrita (Hymenoptera). Character-state reconstructions in both genes suggested that conversions between A and T (AT transversions) occurred much more frequently than any other type of change, although we cannot wholly discount an underlying transition bias. Parsimony analysis of COI nucleotide characters did not recover phylogeny; e.g., neither the Tenthredinoidea nor Apocrita were recovered as monophyletic. However, analysis of COI amino acid characters did recover these relationships, as well as others based on fossil and morphological evidence. Analysis of 16S rRNA characters also recovered these relationships providing conversions between A and T were down-weighted. Analysis of the combined data sets gave relatively strong support for various relationships, suggesting that both data sets supported similar topographies. These data sets, both separately and combined, suggested that the phytophagous Siricidae were more closely related to the predominantly parasitic Apocrita than were the ectoparasitic Orussoidea. This suggests that the wasp parasitic lifestyle did not have a single origin, unless the Siricidae have more recently reverted to phytophagy. Alternatively, parasitism evolved twice independently, once in the Orussoidea and again in the Apocrita. The latter scenario is supported by the observation that the evolution of parasitism was accompanied by a tendency for the larvae to develop inside plant tissues. Adaptations that accompanied the movement of wasps into a confined, wood-boring habitat may have preadapted them to becoming ectoparasitic. Received: 27 March 1996 / Accepted: 2 August 1996     

On the edge of parasitoidism: a new Lower Cretaceous woodwasp forming the putative sister group of Xiphydriidae + Euhymenoptera

The fossil woodwasp Cratoenigma articulata gen. et sp.n. (Insecta: Hymenoptera) is described from the Lower Cretaceous Crato formation of Brazil. This fossil cannot be placed in any existing superfamily, but its putative phylogenetic position within Hymenoptera is discussed in detail on the basis of relevant thoracic, abdominal and wing venation characters. These characters are critically evaluated and compared with those of extant and fossil Hymenoptera. The phylogenetic position of C. articulata sp.n. is investigated relative to extant Xyelidae, Tenthredinoidea s.l., Pamphilioidea, Cephidae, Siricoidea, Xiphydriidae, Orussidae and Apocrita, and also to Mesozoic Gigasiricidae, Myrmiciidae, Daohugoidae, Sepulcidae, Anaxyelidae, Paroryssidae and Ephialtitidae. Based on the presence of a synapomorphic transscutal articulation, a plesiomorphic unconcealed mesopostnotum and autapomorphic hindwing venation (cu‐a distinctly basal to fork between M and Cu), C. articulata sp.n. most likely forms the sister group of Xiphydriidae + Euhymenoptera. This would place it well within Unicalcarida, i.e. the clade in which the transition from endophytic to parasitoid lifestyle evolved.     

Mouthpart evolution in adults of the basal, 'symphytan', hymenopteran lineages

We review feeding biology and mouthpart structure generally among adults of the basal hymenopteran, or ‘symphytan’, lineages (sawflies, woodwasps, horntails and their relatives). These insects feed on a wide range of materials: floral and extrafloral nectar, pollen, plant (floral and leaf) tissues, plant (angiosperm) sap, the juice of ripe fruit, die spermatial fluid of rust fungi, sternorrhynchan bug honeydew, and insect tissues. Adults show feeding‐related mouthpart specialization either for consuming pollen (the Xyelidae only) or for consuming ‘concealed’ floral nectar (several families). Seven functional types of elongated proboscis or ‘concealed‐nectar extraction apparatus (GNEA)’ have previously been recognized among Hymenoptera. We identify an additional type, which appears to be unique among Hy‐menoptera and has probably evolved direcdy from unspecialized mouthparts (labiomaxillary complex). In total, three types of CNEA are known to occur in ‘Symphyta’. Type 1 occurs in Pamphiliidae, Megalodontesidae, Argidae, Pergidae, Tenthredinidae, Cimbicidae and Cephidae. Type 5 occurs in Pergidae (in two unidentified species of Euryinae). Type 8 occurs in Tenthredinidae (in the genus Nipponorhynchus Takeuchi). CNEA of some type or other has arisen at least twice within the family Tenthredinidae and at least twice widiin die pergid subfamily Euryinae. Evolutionary parallelism in CNEA structure has occurred between the basal, ‘symphytan’, hymenopteran lineages and die Apocrita, a phenomenon hitherto not mentioned in the literature. Within the ‘Symphyta’, possession of Type 1 CNEA appears to be a ground plan feature of each of the following taxa: the pergid genus Eurys Newman, the megalodontesid genus Megalodontes Latreille (the only extant representative of the Megalodontesidae) and the tenthredinid genus Cuneala Zirngiebl, while possession of Type 8 appears to be a ground plan feature of die tenthredinid genus Mpponorhynchus Takeuchi. However, in general among ‘Symphyta’, possession of CNEA is characteristic of only small and taxonomically subordinate groups, suggesting that CNEA has evolved independendy many times within the basal hymenopteran lineages rather than being inherited from a common ancestor early in the evolutionary history of the Hymenoptera. In other words, ecological expediency radier than phylogenetic history mainly accounts for its distribution pattern within the basal lineages. The results of a morphological survey of ‘Symphyta’ indicate that the habit of exploiting ‘concealed nectar’, by means of CNEA, is fairly     

A synopsis of the sawflies (Hymenoptera: Symphyta) of America south of the United States: introduction, Xyelidae, Pamphiliidae, Cimbicidae, Diprionidae, Xiphydriidae, Siricidae, Orussidae, Cephidae

Abstract Eight families of Symphyta for the Western Hemisphere south of the United States are reviewed: Xyelidae (one genus, two species), Pamphiliidae (one genus, four species), Cimbicidae (five genera, nine species), Diprionidae (three genera, thirteen species), Xiphydriidae (four genera, seventeen species), Siricidae (six genera, nine species), Orussidae (five genera, twelve species), and Cephidae (one genus, one species). New taxa are Acantholyda nigrostigmata (Pamphiliidae); Zadiprionfalsus, Neodiprion bicolor, N.equalis, N.omosus (Diprionidae); Derecyrta circularis, Steirocephala lateralba (Xiphydriidae); Sirotremex, S.flammeus (Siricidae); and Ophrynopus depressatus, O.plaumanni (Orussidae). Lopesiana is a new name for Lopesia Conde (Cimbicidae). Three new combinations and six new synonyms are proposed. The Xyelidae, Pamphiliidae, Diprionidae, Siricidae and Cephidae are primarily northern groups with southern extensions into Mexico, Central America and/or Cuba. The Cimbicidae, Xiphydriidae and Orussidae are more generally distributed throughout the neotropics. Keys to families, genera and species are provided.