taxonID	type	description	language	source
CA1ECF28FF99214EFEC98786464AFE0C.taxon	description	It may be that things are not that simple. The apparently primitive zygentoman family Lepidotrichidae was originally described from the mid-Eocene Baltic amber genus Lepidotrix Menge, 1854, and is now represented by a single living species, Tricholepidion gertschi Wygodzinsky, 1961, from northern California. The family Lepidotrichidae itself may not be monophyletic, since Tricholepidion Wygodzinsky, 1961 (the only zygentoman with distinct ocelli) may be more primitive than Lepidotrix and less closely related to the Euzygentoma (= Nicoletiidae s. lat. + Lepismatidae + Maindroniidae). The Lepidotrichidae possess large abdominal sterna with posteriorly attached coxopodites, and a large number of pregenital abdominal styli and eversible sacs. Five characters have been proposed to support intrazygentoman position of Tricholepidion (see GRIMALDI & ENGEL (2005) and references therein). They include (i) unique sensillar structures on the terminal filament (shared by Tricholepidion and the Nicoletiidae), (ii) a widened apical segment of the labial palp, (iii) obliteration of the superlingua, (iv) mating behaviour (the male deposits a spermatophore on a web which he has spun during the final phase of foreplay; the female picks up the spermatophore using her ovipositor; see STURM (1997 )), and (v) sperm conjugation (putatively shared by Tricholepidion and the Lepismatidae). However, even in the nicoletiids (Atelura Heyden, 1855), sperm bundles are stored in the proximal part of the testes, intermingled with dense granules and forming the so called ‘ spermatolophids’. Sperm aggregation in the Zygentoma is, therefore, quite diverse (DALLAI et al. 2001 a, b, 2002) and its phylogenetic interpretation is uncertain.	en	Zrzavý, Jan (2008): Four chapters about the monophyly of insect ‘ orders’: A review of recent phylogenetic contributions. Acta Entomologica Musei Nationalis Pragae 48 (2): 217-232, DOI: 10.5281/zenodo.5340840
CA1ECF28FF99214EFEC98786464AFE0C.taxon	description	In molecular analyses, the position of Tricholepidion was highly unstable, ranging from conventional placement as a sister group of the Euzygentoma (MISOF et al. (2007): 18 S ribosomal DNA) to an unorthodox intra-pterygote position next to the Odonata (KJER (2004), using the same molecular marker). Mitochondrial genomes have not yet been conclusive, evidently owing to poor taxon sampling, but they seem to support zygentoman monophyly (see COOK et al. 2005, CAMERON et al. 2006, CARAPELLI et al. 2006). GIRIBET et al. (2004) analyzed relationships among basal hexapods on the basis of a cladistic analysis of five genes and 189 morphological characters in a simultaneous analysis. Morphological characters solely corroborated monophyletic Zygentoma (Tricholepidion vs. Euzygentoma) but with very low support; the same applied to the multigene molecular analysis. Using a sensitivity analysis approach and testing for stability within the combined morphological-molecular analysis, the most congruent parameters resolved Tricholepidion as a sister group to the remaining Dicondylia (with very low support again), whereas most suboptimal parameter sets grouped Tricholepidion with the Euzygentoma. Finally, in the combined analysis by KJER et al. (2006), using eight gene sequences and 170 morphological characters, Tricholepidion appeared as a sister group of the Euzygentoma. The position of the enigmatic Tricholepidion remains controversial as none of the data sets provides substantial support for either of the two competing hypotheses (i. e. monophyletic or paraphyletic Zygentoma). It seems only clear that a sister-group relationship between Tricholepidion and the Nicoletiidae has not yet been supported by morphology and molecular analyses. By all means, Tricholepidion is the most promising candidate for a new insect ‘ order’ (or, in other words, the only insect species whose ordinal classification remains uncertain), either as a sister group of the Euzygentoma, or of the Euzygentoma-Pterygota superclade.	en	Zrzavý, Jan (2008): Four chapters about the monophyly of insect ‘ orders’: A review of recent phylogenetic contributions. Acta Entomologica Musei Nationalis Pragae 48 (2): 217-232, DOI: 10.5281/zenodo.5340840
CA1ECF28FF9B214BFEF786774603FEAD.taxon	description	The morphology-based phylogeny of blattarian families was explored, e. g., by GRANDCOLAS (1996), GRANDCOLAS & D’HAESE (2001), KLASS (2001), and KLASS & MAIER (2006). The major contributions agree that the basalmost divergence is between the Blattidae (possibly paraphyletic; see KLASS (2001), KLASS & MAIER (2006) and references therein) and the rest of roaches, and that the Blattellidae and the Blaberidae form a clade. The Polyphagidae are placed somewhere between basal blattids and the blattelid-blaberid clade; the genus Cryptocercus Scudder, 1862, is the subject of the greatest disparity between the published phylogenies. By all means, it is related to the Polyphagidae, either as its deeply nested member (and consequently not related to the termites; see GRANDCOLAS (1993), GRANDCOLAS & DELEPORTE (1996 )), or forming together with the termites a sister group of the polyphagids (see KLASS & MAIER 2006). The relict wingless, long-lived, and social ‘ woodroach’ Cryptocercus is then one of the most intriguing insect genera. There are several species living in forests of North America and East Asia. Usually a pair of parents and about 20 offspring inhabit galleries in a soft, rotten log, remaining together for at least three years (the brood care probably lasts until the death of the adults), with larvae maturing in approximately six years (see NALEPA & BANDI (2000), KAMBHAMPATI et al. (2002) and references therein). The juveniles are pale, termite-like, with highly reduced eyes, and they feed on liquids exuded by an adult from the anus (proctodeal trophallaxis) for approximately their first year (1 st and 2 nd instars). This behaviour allows them to acquire symbiotic oxymonadid and hypermastigid protists, required for the digestion of wood. Young larvae actively groom older juveniles and adults. An overwhelming molecular evidence from recent years (LO et al. 2000, 2003, 2007; TERRY & WHITING 2005; KJER et al. 2006; PELLENS et al. 2007; INWARD et al. 2007 a; LEGENDRE et al. 2008; WARE et al. 2008) shows that the Isoptera are a sister group of Cryptocercus. The most comprehensive molecular analysis by INWARD et al. (2007 a) included 107 species of the Dictyoptera (five of the 15 mantid families, all six cockroach families as well as 22 of the 29 cockroach subfamilies, and all termite families and subfamilies), along with 11 outgroups, and five gene loci (two mitochondrial: 12 S rDNA and cytochrome oxidase II, three nuclear: 28 S rDNA, 18 S rDNA, and histone 3). The Isoptera- Cryptocercus clade was found as sister to the Blattidae, and that combined clade as sister to the Blattellidae + Blaberidae. The Polyphagoidea (Polyphagidae + Nocticolidae) are then sister to all the other cockroaches (including the termites). Similar phylogenetic patterns have been received from an analysis of the bacterial intracellular symbionts (Blattabacterium Mercier, 1906) that reside in specialized cells of cockroaches and the basalmost termite Mastotermes Froggatt, 1897; the analysis found a close relationship between endosymbionts from termites and woodroaches (LO et al. 2003). WARE et al. (2008) showed, using four gene loci (cytochrome oxidase II, 16 S rDNA, 18 S rDNA, and 28 S rDNA) and morphological data for 62 species (including eight outgroups), that the choice of both outgroup and ingroup taxa as well as data partition greatly affects tree topology. Depending on the outgroup selection, the most basal splitting event within the Dictyoptera is either between the Mantodea and the Blattodea (cockroaches and termites), or between the Polyphagoidea and the rest of the Dictyoptera (including mantids). Within the non-polyphagoid Blattodea, the next problematic issue is the relationship among the Blattellidae + Blaberidae, Blattidae, and Cryptocercus + Isoptera (probably a sister group of the blattids). This is in strong contrast to earlier hypotheses that assumed a position of the Isoptera outside a monophyletic Blattaria (THORNE & CARPENTER 1992) and a subordinate position of Cryptocercus inside the cockroach family Polyphagidae (GRANDCOLAS 1996). In all molecular analyses all included species of the Polyphagidae (LO et al. 2003, 2007; KJER et al. 2006; INWARD et al. 2007 a, b; KLASS et al. 2008; LEGENDRE et al. 2008; WARE et al. 2008) clustered together unambiguously, while the whole polyphagid clade is remote from the Cryptocercus - Isoptera clade. Consequently, the hypothesis of Cryptocercus being deeply nested in the Polyphagidae (close to Therea Billberg, 1820) should eventually be dismissed. The only evidence that may still contradict a Cryptocercus- Isoptera clade is the analysis of hypertrehalosaemic neuropeptides from corpora cardiaca (GÄDE et al. 1997), but this is based on very few informative characters. Morphologically, the sister-group relationship between Cryptocercus and Isoptera is based on the morphology of the proventriculus, dentition of the mandibles, possibly also detailed structure of the antennal segments, relatively small genome size (KOSHIKAWA et al. 2008), and predominantly on numerous behavioural and ecological characters (see KLASS et al. (2008) for a review). They include shared (and unique) ability to nest in and ingest fairly recalcitrant dead wood sources that may take decades to degrade. All studied cockroach and termite species have endogenous cellulase genes, which suggests a widespread ability to use cellulose-based materials as food. Only Cryptocercus and lower termites, however, have an additional specific type of cellulose digestion that involves hindgut symbiotic flagellates, requiring vertical intergenerational transmission. Cryptocercus and lower Isoptera share many flagellates of the Oxymonadida and Hypermastigida (both Excavata) in their hindgut that are unique to them, such as the Spirotrichosomidae, Hoplonymphidae, Staurojoeninidae, and Eucomonymphidae. GRANDCOLAS (1999 a, b) and GRANDCOLAS & DELEPORTE (1996) assumed that xylophagy and intestinal symbiosis in the Isoptera and Cryptocercus was a matter of convergence and / or horizontal transfer (gut flagellates could have been passed from termites to Cryptocercus). Interestingly, several groups of the hindgut flagellates are shared exclusively between Cryptocercus and different isopteran subgroups (Leptospironympha Cleveland, 1934 and the Spirotrichosomidae shared with the Stolotermitinae; Oxymonas Janicki, 1915, Hoplonymphidae and Staurojoeninidae shared with the Kalotermitidae, and the Eucomonymphidae shared with the Rhinotermitidae). The differences in hindgut flagellate faunas of the various termite subgroups have probably been caused by mosaic-like losses from the ancestrally complete set of oxymonadids and hypermastigids (even recent, intraspecific losses have been reported; see KLASS & MEIER (2006 )). According to the lateral-transfer hypothesis, Cryptocercus should have obtained its gut fauna either through several additive tranfers from a variety of termite groups, or through a single transfer from the termite ancestor. If Cryptocercus were of Cenozoic origin (GRANDCOLAS 1999 a, b), its physical contact with the isopteran stem lineage would be impossible; several parallel contacts between cryptocercids and termites leading to sequential collection of the Cryptocercus hindgut fauna are unparsimonious at best. Recently, OHKUMA et al. (2008), based on 18 S ribosomal DNA and glyceraldehyde- 3 - phosphate dehydrogenase sequences of the woodroach and termite trichonymphid symbionts (Hypermastigida), found that the symbionts of Cryptocercus were always robustly sister to those of termites. It strongly suggests that this set of symbiotic flagellates was already present in the common ancestor of Cryptocercus and the Isoptera. As concerns their social behaviour, Cryptocercus and the Isoptera share monogamy, extended biparental care, allogrooming, and proctodeal trophallaxis. The Cryptocercus - like biparental sociality is also present in dealated pairs of termites during the early stages of colony foundation; the family switches to eusociality with the appearance of workers or pseudergates. The crucial difference in the sociality of Cryptocercus and termites is that only in the latter is the care and feeding of young brood taken over by older brood in the family. However, as a result of asynchronous hatching and the quick growth of neonates, both trophically dependent (1 st and 2 nd instars) and trophically independent nymphs (3 rd and subsequent instars) can be contemporaneous even in young families of Cryptocercus (KLASS & MEIER 2006). The finding that the termites are nested within the cockroaches causes a classificatory problem. INWARD et al. (2007 a) proposed that the ‘ Isoptera’ should no longer be used and that the species should be classified within the family Termitidae as part of the order Blattodea. This would mean that the existing termite taxa need to be downgraded by one taxonomic rank (i. e. families become subfamilies, subfamilies become tribes etc.), a taxonomical action that provoked strong counteraction (‘ Save Isoptera! ’; LO et al. 2007). In fact, there is no reason why not to preserve the well-known and widely used name ‘ Isoptera’ regardless of its phylogenetic position; naturally, this problem is a direct consequence of using the basically non-phylogenetic Linnean rank hierarchy in the phylogeny-dominated modern systematics.	en	Zrzavý, Jan (2008): Four chapters about the monophyly of insect ‘ orders’: A review of recent phylogenetic contributions. Acta Entomologica Musei Nationalis Pragae 48 (2): 217-232, DOI: 10.5281/zenodo.5340840
CA1ECF28FF902146FF0D80D54176FE8A.taxon	description	The process of resilin secretion in fleas (pleural arch) and Boreus Latreille, 1816 (wing base) is similar, and different from that of the locust and the dragonfly. Both groups share the ability to jump when disturbed (probably via a similar mechanism) and both often feign death after their leaps. The proventricular spines in fleas and boreids have similar morphology. Other features are the absence of extrinsic labral muscles, absence of arolium, elongation of the labrum and maxillolabium, reduced or lost ocelli, reduced or lost larval legs, and sexual dimorphism in the ventral nerve cord (males having more ganglia than females). Among mecopteroids, only fleas and boreids form silken pupal cocoons. Phylogenetic analysis of longwavelength opsins from the three lineages (flea, snow flea, panorpid) revealed a high degree of similarity between flea and boreid opsins (TAYLOR et al. 2005). Both groups have multiple sex chromosomes and sperm axoneme coiling around the mitochondrion. On the contrary, some spermatological similarities of Panorpa Linnaeus, 1758, and Boreus (two longitudinal extra-axonemal rods and a glycocalyx consisting of longitudinal parallel ridges or filaments; see DALLAI et al. 2003) suggest either monophyly of the conventional Mecoptera (quite improbable if confronted with the huge amount of conflicting evidence), or homoplasy. The most convincing morphological evidence comes from research on ovarioles, which demonstrates that boreid ovaries are fundamentally different from those in other Mecoptera (ŠTYS & BILIŃSKI 1990, BILIŃSKI & BÜNING 1998, BILIŃSKI et al. 1998). Fleas and boreids share the secondary loss of nurse cells (‘ neopanoism’), completion of initial stages of oogenesis during postembryonic development, occurrence of rDNA amplification and resulting appearance of multiple nucleoli, differentiation of the late previtellogenic ooplasm into two clearly recognizable regions, and presence of accumulations of membrane-free, clathrin-like cages. These data suggest that the Mecoptera, as currently constituted, are a paraphyletic assemblage. While it seems certain that the Boreidae and the Siphonaptera are sister groups, their placement relative to the other Mecoptera is not that well supported by the data. Moreover, while it seems clear that the Nannochoristidae should occupy a basal position, it is not clear whether it is a sister group to the flea-boreid clade or the whole Mecoptera (including the Siphonaptera). The most comprehensive, morphology and four-gene molecular analysis (WHITING et al. 2003) supports a major division of the Mecoptera into two clades: the Nannochoristidae- (Boreidae-Siphonaptera) and the Eumecoptera (= remaining Mecoptera). This pattern is strongly supported also by the histology of nannochoristid ovaries (SIMICZYJEW 2002). They are (neo) panoistic, with multiple nucleoli in the oocyte nucleus, which suggests an extrachromosomal amplification of the ribosomal DNA. The structure of the ovarioles and the course of oogenesis in nannochoristids thus share derived features with boreids and fleas, but differ significantly from all eumecopterans. BEUTEL & BAUM (2008) have recently proposed a possible clade comprising the Nannomecoptera, Siphonaptera, and Diptera, supported by the presence of a labral food channel, the absence of the galea, a sheath for the paired mouthparts formed by the labium, very strongly developed labial palp muscles and cibarial dilators, and the presence of a well-defined postcerebral pharyngeal pumping chamber. Moreover, close affinities of the Nannomecoptera with the Diptera are suggested by the presence of a unique sensorial groove on the third maxillary palpomere, the elongate and blade-like lacinia, and possibly by the presence of a frontal apodeme and a primarily lamelliform mandible without teeth. The presence of a salivary channel on the laciniae and a subdivided labrum are shared derived features of Nannochorista and Siphonaptera. On the contrary, the secretion with a strongly developed intrinsic muscle of the salivary duct might be a possible synapomorphy of the Mecoptera including the Boreidae but excluding the Nannomecoptera. By all means, it seems that the Nannomecoptera, Neomecoptera, and Siphonaptera are closely related, and that the precise position of the Diptera within the mecopteroid complex requires more investigation. The new phylogeny of the mecopteroid complex (= Eumecoptera, Nannomecoptera, Neomecoptera, Siphonaptera) provides a plausible ecological scenario of the origin of fleas, a situation highly reminiscent of the proposed relationships between liposcelidid psocopterans and the lice. The transition from mosses into mammal nests and dens (during the Mesozoic period, as evidenced by the Late Jurassic-Early Cretaceous boreid Palaeoboreus Sukatcheva & Rasnitsyn, 1992, and by the early Cretaceous stem-lineage flea Tarwinia Jell & Duncan, 1986 (see GRIMALDI & ENGEL (2005) and references therein) was followed by the Mesozoic / Cenozoic radiation of the mammals (and their parasites) and by multiple, relatively recent colonizations of birds by the fleas. The fleas (2,380 described species) are by far the most speciose group of the otherwise relictual Mecoptera, a good example of the relatively recent radiation correlated with their parasitism (WHITING et al. 2008).	en	Zrzavý, Jan (2008): Four chapters about the monophyly of insect ‘ orders’: A review of recent phylogenetic contributions. Acta Entomologica Musei Nationalis Pragae 48 (2): 217-232, DOI: 10.5281/zenodo.5340840
