Dictyoptera

Reconstruction of Manoblatta bertrandi, from Vršanský et al. (2002).

Belongs within: Polyneoptera.
Contains: Caloblattinoidea, Blattaria, Isoptera, Mantodea.

The Dictyoptera includes the cockroaches, mantids, termites and related fossil taxa, with the earliest representatives known from the Middle Carboniferous (Vršanský et al. 2002). Though commonly referred to as ‘cockroaches’, stem-group dictyopterans differed from modern taxa in retaining an elongate ovipositor rather than producing eggs in cases (oothecae) like modern cockroaches or mantids. Notable examples of basal dictyopterans include the Raphidiomimidae, a Late Mesozoic family with a narrow head and pronotum, elongate maxillary palps, and raptorial fore legs with short ventral spines on the femur (Grimaldi & Ross 2004). The Late Jurassic Skok svaba had long hind legs adapted for jumping.

Ponopterix axelrodi
Published 6 November 2009
Ponopterix axelrodi, from Bechly, 2007.

Ponopterix axelrodi is a member of the Jurassic to Cretaceous insect family Umenocoleidae from the Lower Cretaceous Crato Formation of Brazil. Umenocoleids were originally described in 1973 as beetles, which they resemble in having the front pair of wings hardened into a pair of elytra (wing covers). However, while elytra are only found in two orders among the Recent insect fauna (beetles and earwigs), umenocoleids represent a third independent origin of elytra and are in fact related to dictyopterans (the clade that includes cockroaches, mantids and termites). The retention of a short ovipositor in Umenocoleidae (visible in the specimen above at the very end of the abdomen) places them just outside crown Dictyoptera, though a position closer to polyphagoid cockroaches has also been suggested (which would imply more than one loss of the ovipositor among dictyopterans).

Umenocoleids differ from beetles in that wing venation is still marginally visible on the elytra (among crown-group beetles, the original venation has been completely obliterated) and in the presence of cerci (two tail-like appendages at the end of the abdomen, one on either side of the ovipositor in females; cerci are absent in paraneopteran and holometabolous insects). The anterior light patch at the base of the elytron in the specimen above is also present in another specimen of the same species illustrated in Grimaldi & Engel (2005), so this was the original colour pattern of the animal when it was alive*.

*Don’t let the poor reputation of cockroaches put you off—many roaches are very attractive insects, boldly patterned in contrasting colours**.

**Just be careful of the desert cockroaches that walk around with their backsides pointed into the air. If they feel that a potential threat is approaching too close, they can fire a stream of foul-smelling liquid towards it from a pair of abdominal glands. Not pleasant.

Umenocoleids also inspire the one detail in Grimaldi & Engel (2005) that causes me to scream with frustration. In the caption to their photo of Ponopterix axelrodi, G & E make the remark, “Umenocoleid roaches are known from the Late Jurassic to Cretaceous, though a putative living species exist”. A living umenocoleid? Tell me more! Unfortunately, Grimaldi and Engel provide no citation for this statement, and I have been unable to find any reference to a living umenocoleid anywhere else. I’m still holding out hope, though.

Two new insect orders?
Published 3 March 2017

When a new species of insect is described as being distinct enough to represent a new order, it’s kind of a big deal. So it certainly caught my attention over the past year when, not one, but two species from Cretaceous Burmese amber were considered worthy of the honour. Now, I’m going to be up front here and say that, while both are very interesting specimens, in both cases I think that the ‘new order’ label may be a trifle overblown. What’s interesting to me is that my reasons for thinking so are different for both. Let’s take a look, shall we?

Lateral and dorsal views of holotype of Alienopterus brachyelytrus, from Bai et al. (2016). Pink scale bar = 1 mm.

The first was published in March of last year by Bai et al. (2016) under the name of Alienopterus brachyelytrus. In overall appearance, Alienopterus resembled a long-legged cockroach, but with the head clearly visible instead of hidden by the pronotum in the cockroach manner. The head would have been mobile and capable of being turned in the manner of a modern cockroach or mantis. The forewings were hardened and reduced to small pads covering only the base of the hind wings, which retained their full length. The femora of the front legs bore a pair of dense rows of setae on their underside, and Bai et al. suggested that Alienopterus may have used these setae to help it grab prey.

A phylogenetic analysis of Alienopterus placed it together with the modern cockroaches and mantids, specifically as the sister group to the latter. Because Alienopterus lacked the primary distinguishing features of a mantis (such as the spined raptorial forelegs), and because of its distinctive wing morphology, Bai et al. made it the type and only species of a new order, the Alienoptera. But there are a number of reasons why I find this designation problematic. It is generally agreed these days that cockroaches and mantids (and termites) together form a clade known as the Dictyoptera. Many people have an idea that cockroaches are one of the oldest living groups of insects, having supposedly been around for hundreds of millions of years. But modern cockroaches and mantids only diverged sometime during the Jurassic and Cretaceous; earlier members of the Dictyoptera were cockroach-like, certainly, but they were just as close to mantids as to cockroaches, and also had features very distinct from either. If we are to recognise a distinct ‘order’ for Alienopterus purely on phylogenetic grounds, then we would also have accept several separate ‘orders’ for each of the various lineages of stem-dictyopterans. And as distinctive as Alienopterus is morphologically, it is not the only (or even the most) unusual member of the Dictyoptera. This is, after all, the lineage that has given the termites with their wood-chomping biology and baroque caste system, beetle-like taxa with full-on elytra, and active leapers like the Jurassic Skok svaba or the modern Saltoblattella montistabularis.

There is a definite paradox at play here. On the one hand, the question of which lineages get designated ‘orders’ is completely arbitrary because there is no formal definition for an ‘order’ except that it is a taxon that is somehow more significant than a ‘family’ (itself a completely arbitrary level). From that perspective, there is no inherent reason why the Dictyoptera should not get divided between any number of orders. But on the other hand, the concept of ‘order’ has a certain cultural cachet. ‘Orders’ are kind of the base units of entomology: the first thing that any student of entomology is likely to do is learn to distinguish between the various insect orders. Labelling a particular taxon an ‘order’ is a statement of value; it says that that taxon is somehow fundamentally important in a way that other taxa are not. And while, again, Alienopterus is a very interesting animal in terms of what it can potentially tell us about cockroach-mantis relationships, it is hard to see how it can be called ‘fundamental’. There have been extinct ‘orders’ recognised from the fossil record, such as the Palaeodictyoptera, but such taxa represent notable radiations. With only a single known species, referring to Bai et al.‘s taxon as ‘Alienoptera’ tells us little more than calling it an unplaced species within the Dictyoptera.

Various views of Aethiocarenus burmanicus from Poinar & Brown (2016).

The other new ‘order’ made its appearance in December, when Poinar & Brown (2017) published Aethiocarenus burmanicus (if you’re confused about the date, it reflects the difference between the online and print publication). This was a very odd little insect: a flattened and wingless yet long-legged animal with long antennae. The most distinctive feature of Aethiocarenus is its head, which is globular with great bulging eyes and placed on a narrow neck. Poinar & Brown suggest that it may have made its living hunting in confined spaces, such as crevices in bark or among epiphytes. Because of its highly distinctive appearance from any other known insect, Poinar & Brown placed it in its own new order, the Aethiocarenodea.

In this case, my issue with the establishment of a new ‘order’ is that it is essentially a statement of ignorance. As distinctive as Aethiocarenus is, there are many equally unusual-looking insects that are not placed in their own ‘order’—particularly among wingless forms that can get up to all sorts of freakiness. The overall ‘jizz’ of Aethiocarenus, particularly the distinct cerci, suggest that its affinities probably lie somewhere within the Polyneoptera, the group of insects including such forms as cockroaches, grasshoppers and stoneflies. Within other polyneopteran orders, a novice entomologist would be hard-pressed to recognise a sandgroper as a grasshopper, or the Javan cave-dweller Arixenia esau as an earwig. Similarly, without a formal analysis it is difficult to exclude the possibility that Aethiocarenus represents a kooky member of some already recognised order. And again, with only one known species, recognition of an ‘order’ Aethiocarenodea tells us little more than recognition of an unplaced Aethiocarenus.

Systematics of Dictyoptera

Synapomorphies (from Vršanský et al. 2002; Grimaldi & Engel 2005): Pronotum large, shield-like, with paranota circular, much enlarged and concealing head at rest; head opistognathous; forewing tegminous, R and RS weakly individualised, anal area (clavus) wide, lanceolate, with arched, groove-like claval suture, anal veins gently curved, weakly branching if at all; cercus short.

Dictyoptera [Archimylacroidea, Blattida, Blattidea, Blattodea, Mylacridoidea, Phyloblattoidea, Polyphagoidea]
    |--+--SubioblattaRJ93 [SubioblattidaeVVR02]
    |  |    `--S. karatavicaRJ93
    |  `--ArchimylacrididaeVVR02
    |       |--Archaeotiphites captiosusZ02
    |       |--Manoblatta bertrandiGE05
    |       |--Uraloblatta insignisVVR02
    |       |--Archimylacris lericheiR70
    |       `--Miroblatta costalis Laurentiaux-Vieira & Laurentiaux 1987RJ93
    `--+--Dictyomylacris Brogniart 1893V02 [Archoblattinidae, MylacrididaeVVR02]
       |    `--D. insignisVVR02
       |--+--NecymylacrisRJ93 [NecymylacrididaeVVR02]
       |  |    `--N. handlirschiRJ93
       |  `--+--PoroblattaRJ93 [Diechnoblattinidae, PoroblattinidaeVVR02]
       |     |    `--P. duffienxiRJ93
       |     `--Spiloblattinidae [Compsoblattinidae]VVR02
       |          |--Sysciophlebia ilfeldensisRDS03
       |          `--Kinklidoblatta moriniRJ93
       `--+--Phyloblatta Handlirsch 1906GE05, V02 [Phylloblattidae]
          |    |--P. alienaZ02
          |    `--P. gallicaGE05
          `--+--CaloblattinoideaV10
             `--+--BlattariaGE05
                `--+--IsopteraV10
                   |--Skok [Skokidae]V10
                   |    `--S. svaba Vršanský 2007BP10
                   |--BlattulidaeV02
                   |    |--Tarakanula shcherbakoviVLR09
                   |    |--Mesoblattula sincera Lin 1986RJ93
                   |    `--Elisama Giebel 1856V02
                   |         |--E. americana Vršanský 2002V02
                   |         |--E. tsaganica Vršanský 1999V02
                   |         `--E. vidlickai Vršanský 2004V10
                   |--LiberiblattinidaeV10
                   |    |  i. s.: Brachyblatta Vršanský 2002V02
                   |    |--Kazachiblattina Vršanský 2002V02
                   |    |    `--K. asiatica (Vishniakova 1968)V02
                   |    `--+--Liberiblattina Vršanský 2002V02
                   |       |    `--*L. ihringovae Vršanský 2002V02
                   |       `--Gurvanoblatta Vishniakova 1986V02
                   |            `--G. mongolica Vishniakova 1986V02
                   `--+--EadiidaeV10
                      |--MantodeaV10
                      `--RaphidiomimidaeV02
                           |--Cretacechorista qilianshanensis Hong et al. 1989RJ93
                           |--Rhipidoblattina katavicaGE05
                           |--Cameloblatta variegataGR04
                           |--Raphidiomimula Grimaldi & Ross 2004GR04
                           |    `--*R. burmitica Grimaldi & Ross 2004GR04
                           `--Raphidiomima Vishniakova 1973GR04
                                |--R. chimaera Vishniakova 1973V02
                                `--R. cognata Vishniakova 1973V02
Dictyoptera incertae sedis:
  Sinogramma reticularisR02
  Parellipsidion pachycercumWPT01
  Ignaroblatta sibiricaZ02
  Celerioblattina minorWFS04
  LeucophaeaK-P83
    |--L. maderaeB96
    `--L. surinamensisK-P83
  Karataublatta longicaudataGE05
  Byrsotria fumigataLY07
  Stenomylacris Handlirsch 1906V02
  Pararchimylacris Laurentiaux 1967V02
  Sogdoblatta Martynov 1937V02
  Nannoblattina Scudder 1886V02
  Rithma Giebel 1856V02
  Praeblattella Vršanský 2002V02
  Alienopterus Bai, Beutel et al. 2016 [Alienoptera, Alienopteridae]BB16
    `--*A. brachyelytrus Bai, Beutel et al. 2016BB16
  Ponopterix axelrodiBB16, GE05
  Jantaropterix newjerseyBB16
  Manipulator modificaputisBB16
  Compsoblatta [Compsoblattidae]RJ93
    `--C. frankeiRJ93
  Hebeitermes weichangensis [=Hopeitermes weichangensis]RJ93
  PermoblattinaT61
    |--P. curtaT61
    `--P. permiana Sellards 1908T61

*Type species of generic name indicated

References

[BB16] Bai, M., R. G. Beutel, K.-D. Klass, W. Zhang, X. Yang & B. Wipfler. 2016. Alienoptera—a new insect order in the roach-mantodean twilight zone. Gondwana Research 39: 317–326.

Bechly, G. 2007. ‘Blattaria’: cockroaches and roachoids. In: Martill, D. M., G. Bechly & R. F. Loveridge (eds) The Crato Fossil Beds of Brazil: window into an ancient world. Cambridge University Press.

[BP10] Bohn, H., M. Picker, K.-D. Klass & J. Colville. 2010. A jumping cockroach from South Africa, Saltoblattella montistabularis, gen. nov., spec. nov. (Blattodea: Blattellidae). Arthropod Systematics and Phylogeny 68 (1): 53–69.

[B96] Buczek, A. 1996. Regeneration of legs in Argas (Argas) reflexus (Fabricius) (Argasidae). In: Mitchell, R., D. J. Horn, G. R. Needham & W. C. Welbourn (eds) Acarology IX vol. 1. Proceedings pp. 709–711. Ohio Biological Survey: Columbus (Ohio).

[GE05] Grimaldi, D., & M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press: New York.

[GR04] Grimaldi, D. A., & A. J. Ross. 2004. Raphidiomimula, an enigmatic new cockroach in Cretaceous amber from Myanmar (Burma) (Insecta: Blattodea: Raphidiomimidae). Journal of Systematic Palaeontology 2: 101–104.

[K-P83] Kukalová-Peck, J. 1983. Origin of the insect wing and wing articulation from the arthropodan leg. Canadian Journal of Zoology 61: 1618–1669.

[LY07] Liu, J., X. Yang, Y. Zhang & Z. Liu. 2007. Effects of exogenous juvenile hormone III on the ixodid tick, Haemaphysalis longicornis Neumann (Acari: Ixodidae). In: Morales-Malacara, J. B., V. M. Behan-Pelletier, E. Ueckermann, T. M. Pérez, E. G. Estrada-Venegas & M. Badii (eds) Acarology XI: Proceedings of the International Congress pp. 209–213. Instituto de Biología and Faculdad de Ciencias, Universidad Nacional Autónoma de México, Sociedad Latinoamericana de Acarología: México.

Poinar, G., Jr & A. E. Brown. 2017. An exotic insect Aethiocarenus burmanicus gen. et sp. nov. (Aethiocarenodea ord. nov., Aethiocarenidae fam. nov.) from mid-Cretaceous Myanmar amber. Cretaceous Research 72: 100–104.

[R02] Rasnitsyn, A. P. 2002. Cohors Cimiciformes Laicharting, 1781. In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 104–115. Kluwer Academic Publishers: Dordrecht.

[R70] Riek, E. F. 1970. Fossil history. In: CSIRO. The Insects of Australia: A textbook for students and research workers pp. 168–186. Melbourne University Press.

[RJ93] Ross, A. J., & E. A. Jarzembowski. 1993. Arthropoda (Hexapoda; Insecta). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 363–426. Chapman & Hall: London.

[RDS03] Rössler, R., J. A. Dunlop & J. W. Schneider. 2003. A redescription of some poorly known Rotliegend arachnids from the Lower Permian (Asselian) of the Ilfeld and Thuringian Forest Basins, Germany. Paläontologische Zeitschrift 77 (2): 417–427.

[T61] Tasch, P. 1961. Paleolimnology: Part 2—Harvey and Sedgwick counties, Kansas: stratigraphy and biota. Journal of Paleontology 35: 836–865.

[V02] Vršanský, P. 2002. Origin and the early evolution of mantises. AMBA Projekty 6 (1): 1–16.

[V10] Vršanský, P. 2010. Cockroach as the earliest eusocial animal. Acta Geologica Sinica (English Edition) 84 (4): 793–808.

[VLR09] Vršanský, P., J.-H. Liang & D. Ren. 2009. Advanced morphology and behaviour of extinct earwig-like cockroaches (Blattida: Fuziidae fam. nov.). Geologica Carpathica 60 (6): 449–462.

[VVR02] Vršanský, P., V. N. Vishniakova & A. P. Rasnitsyn. 2002. Order Blattida Latreille, 1810. The cockroaches (=Blattodea Brunner von Wattenvill, 1882). In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 263–270. Kluwer Academic Publishers: Dordrecht.

[WPT01] Wharton, D. A., R. Poulin & C. L. Tyrell. 2001. Parasites of anostostomatid insects. In: Field, L. H. (ed.) The Biology of Wetas, King Crickets and Their Allies pp. 259–267. CABI Publishing: Wallingford (UK).

[WFS04] Winks, C. J., S. V. Fowler & L. A. Smith. 2004. Invertebrate fauna of boneseed, Chrysanthemoides monilifera ssp. monilifera (L.) T. Norl. (Asteraceae: Calenduleae), an invasive weed in New Zealand. New Zealand Entomologist 27: 61–72.

[Z02] Zherikhin, V. V. 2002. Pattern of insect burial and conservation. In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 17–63. Kluwer Academic Publishers: Dordrecht.

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