Thursday, May 23, 2013

Ithonoidea Are the Odd Lacewings Out

Line drawings of various larvae belonging to the suborder Myrmeleontiformia
Throughout the various species of the order Neuroptera (the net-winged insects), larval carnivory is nearly a cut-and-dried rule. There are parasitoids of other insects (Mantispidae) and some (Sisyridae) attacking freshwater sponges, of all things; yet they evolved from carnivorous ancestors, as the larvae of the mantispid subfamily Calomantispinae show (being still predatory). Adults (if they feed at all) universally retain this carnivory, with the owlflies (Ascalaphidae) truly formidable aerial hunters; the only exceptions would be the extinct nectarivorous kalligrammatids and aetheogrammatids (Ren & Engel, 2008).

Figure 1 Parakseneura nigromacula gen. et sp. nov., holotype CNU-NEU-NN2011009.
Fossil and drawing of Parakseneura nigromacula's forewing
But there are even dietary aberrations amongst neuropteran larvae: and all of them lie within the superfamily Ithonoidea, regarded as some of the least derived neuropterans; they are often placed as the sister group to the remainder of the suborder Hemerobiiformia (Aspöck, 2002; Aspöck & Aspöck, 2008)and if that taxon contains the myrmeleontiforms (as some neuropterists suggest; Ponomarenko, 1992; Haring & Aspöck, 2004; Makarkin & Menon, 2005), the ithonoids would be second only to the Nevrorthidae (sole member of the Nevrorthiformia) as the basalmost net-winged insects. The superfamily consists of two extant families: the Ithonidae and Polystoechotidae; recent phylogenies have sometimes sunk the latter into the former (Winterton & Makarkin, 2010), but here I will consider them separate. In addition, the extinct Parakseneuridae can be placed in the group (Yang et al., 2012); a number of other Mesozoic families regarded as "psychopsidoids" (the Prohemerobiidae, Brongniartiellidae, Osmylopsychopidae, etc.; Martynova, 1949) resemble the Ithonoidea (Riek, 1974; Yang et al., 2012), but their kinship to that taxon sensu stricto remains an open question.

Moth ? - Platystoechotes lineatus
Platystoechotes lineatus (Polystoechotidae), photographed in the Sierra Nevada by Beth Sands
This taxonomic quibble is impertinent to the matter at hand: the ithonids and polystoechotids themselves, or the moth lacewings and giant lacewings, as they are referred to respectively in the vernacular. The latter are so named because of their prodigious wingspan of 55-65 mm. (in Polystoechotes punctata), and although most of their autapomorphies are plesiomorphic (e.g., nygmata* and trichosors are present), their wing venation remains distinctive (Carpenter, 1940). Restricted nowadays to two discontinuous patches of land in the Americas (temperate North America southwards along the Mesoamerican mountains until the Cordillera de Talamanca; and central Chile) (Oswald, 1998), giant lacewings inhabited Eurasia as recently as the Paleogene Period; and the Triassic Lithosmylidia, the earliest known genus referable to the Polystoechotidae, hailed from Australia: although it, or at least those species it contains aside from L. lineata (Lambkin, 1988) (if not all of them) may actually belong to the unrelated Archeosmylidae (Makarkin et al., 2012). Overall, their preferred habitat would seem to be moist, mesothermic woodland. 

Image of Ithonoidea
Oliarces clara, photographed by Shaun Winterton
Moth lacewings encompass a greater scope of lifestyle, but each taxon seems rather strict in its preferences. Three genera are distinctly inhabitants of arid climes: Varnia is only known from scattered localities in central and southwestern Australia (mostly in the vicinity of the Simpson Desert), the monotypic Oliarces is restricted to the Sonoran and Mojave Deserts of southwestern North America, and Ithone is widespread across xeric regions of Australia; the remainder of moth lacewings flutter in moist tropical to temperate upland forests in Mesoamerica, Queensland, and New South Wales (Tillyard, 1919; Riek, 1974), with one genus (Rapisma, until recently classified in its own family; Penny, 1996) living throughout Indochina (Makarkin & Archibald, 2009). Although their scattered distribution would imply antiquity, fossils identifiable as moth lacewings are rarer than the remains of their "giant" cousins (Makarkin & Archibald, 2009), with the oldest one being approximately 105 million years younger than the aforementioned L. lineata (Gradstein et al., 2004; Jepson et al., 2009).    

Habitus of I. fusca grub
Neither of these families are terribly commonNarodona (Ithonidae) is known from only a single specimen from Colima (Navás, 1930)—and the tendency of neuropteran larvae to be less conspicuous than conspecific adults (myrmeleontids are a notable exception) is, alas, also true of these lacewings. After the first scientific description of an adult ithonoid, a full 121 years elapsed before a larva belonging to that superfamily was (literally) unearthed. The first-instar larva of P. punctata turned out to be campodeiform, as is typical of neuropterans; thus, neuropterists naturally assumed that it, like all the rest, was carnivorous (Welch, 1914). The first hint that ithonoids were far from conventional as larvae came with the description of the final larval instar of the moth lacewing Ithone fusca: it was pale, blind, and C-shaped—in other words, scarabaeiform; a condition found elsewhere among the Neuroptera only in later instars of the Mantispinae (Imms, 1957). Still, I. fusca's status as a subterranean predator was taken for granted (Tillyard, 1922).

nj grub control service
Brown patches in a lawn—desecration! Blasphemy! Those irreligious Phyllophaga...
Observation of moth lacewing larvae revealed an unforeseen truth: they were sap-sucking (phytosuccivorous), puncturing roots with their tusk-like jaws and imbibing the contents; this diet is shared by all those Platystoechotidae and Ithonidae whose larvae are known (Faulkner, 1990)another convergence with scarabaeid grubs, specifically fruit chafers (Cetoniinae) and May beetles (Melolonthinae); the latter are notorious for their frequent damage to fescue (or pretty much any sort of grass). It may be that root-sucking constitutes a true autapomorphy of the Ithonoidea, along with the grub-like morphology of older larvae (Aspöck et al., 2001): however, the only description of a later-instar giant lacewing larva inconveniently omits any detail on whether that larva was scarabaeiform or not (MacLeod, 1963). (I mean, come on...)

Giant Lacewing - Polystoechotes punctata
A Californian P. punctata, photographed by Jim Moore
Lastly, I must reiterate that we remain largely ignorant of ithonid and polystoechotid ecology. Consider the United States' only ithonid, Oliarces clara: its grubs (Grebennikov, 2004) are never found away from creosote bushes (Larrea tridentata)—but since females seemingly deposit their greenish eggs (500 per brood) on the sand at random, how do hatchlings find their way to their (presumptive) host plant? And this lacewing is by no means rare: the short-lived adults, which eclose simultaneously cicada-style sometime between mid-April and mid-May, have been recorded as occurring in densities as great as 250,000 individuals per acre (Johnson, 1992). This lack of knowledge has done little good for the giant lacewing first described scientifically, Polystoechotes punctata (Fabricius, 1793): widespread across North America south of 56°N until World War II, by 1950 it had vanished from the continent east of the Rocky Mountains, a region where it was hitherto common. Nobody knows the cause of its disappearanceinvasive ground beetles (Carabidae)? Light pollution? Wildfire suppression?nor the reason for that event's chronological and geographical placement (P. punctata thrives to the present day in suitable habitats west of the Continental Divide, as photographic evidence on BugGuide attests) (Marshall, 2006). 

Determining the solutions to this puzzle would be useful not just to neuropterists, but to anyone researching the United States' biotic history; and until we are so enlightened, our understanding of how our species has affected Earth's biosphere will be sadly incomplete.

*Sensory patches/bumps on insect wings, especially those of Neuroptera. 
Hairy, thickened portions of neuropteran wing margins.           
‡Featuring mild temperatures with little variation.

Aspöck, U.; Plant, J. D.; and Nemeschkal, H. L. (2001). Cladistic analysis of Neuroptera and their systematic position within Neuropterida (Insecta: Holometabola: Neuropterida: Neuroptera). Systematic Entomology, 26, 73-86.

Aspöck, U. (2002). Phylogeny of the Neuropterida (Insecta: Holometaboloa). Zoologica Scripta, 31, 51-55.

Aspöck, U. and Aspöck, H. (2008). Phylogenetic relevance of the genital sclerites of Neuropterida (Insecta: Holometabola). Systematic Entomology, 33, 97-127. Retrieved 5/13/13 from

Carpenter, F. M. (1940). A Revision of the Neararctic Hemerobiidae, Berothidae, Sisyridae, Polystoechotidae, and Dilaridae (Neuroptera). Proceedings of the American Academy of Arts and Sciences, 74, 193-280.

Fabricius, J. (1793). Entomologica Systematica emendata et aucta secundum classes, ordines, genera, species, adjectis synonimis, locis observationibus, descriptionibus; tome #2. Hafniae: Christ. Gottl. Proft. 

Faulkner, D. K. (1990). Current of the biology of the moth-lacewing Oliarces clara Banks (Insecta: Neuroptera: Ithonidae). Advances in Neuropterology. Proceedings of the Third National Symposium on Neuropterology, Pretoria, RSA; pp. 197-203.

Grebennikov, V. V. (2004). Grub-like larvae of Neuroptera (Insecta): a morphological review of the families Ithonidae and Polystoechotidae and a description of Oliarces clara. European Journal of Entomology, 101, 409-417. Retrieved 5/21/13 from

Gradstein, F. M.; Ogg, J. G.; and Smith, A. G. (2004). A Geologic Time Scale. Cambridge: Cambridge University Press.

Haring, E. and Aspöck, U. (2004). Phylogeny of the Neuropterida: a first molecular approach [electronic version]. Systematic Entomology, 29(3), 415-430. Retrieved 5/16/13 from

Imms, A. D. (1957). A General Textbook of Entomology. London: Methuen.

Jepson, J. E.; Makarkin, V. N.; and Jarzembowski, E. A. (2009). New lacewings (Insecta: Neuroptera) from the Lower Cretaceous Wealden Supergroup of Southern England [electronic version]. Cretaceous Research, 30, 1325-1338. Retrieved 5/23/13 from  
Johnson, R. (1992). Cheese-weed owlfly (Oliarces clara). Unpublished short abstract for United States Fish & Wildlife Service. Phoenix: Arizona Ecological Services.

Lambkin, K. J. (1988). A re-examination of Lithosmylidia Riek from the Triassic of Queensland with notes on Mesozoic "osmylid-like" fossil Neuroptera (Insecta: Neuroptera). Memoirs of the Queensland Museum, 25, 445-458.

MacLeod, E. G. (1964). A Comparative Morphological Study of the Head Capsule and Cervix of Larval Neuroptera (Insecta). Unpublished PhD thesis, Department of Biology, Harvard University, Cambridge, Massachusetts. 

Makarkin, V. N. and Menon, F. (2005). New species of the Mesochrysopidae (Insecta, Neuroptera) from the Crato Formation of Brazil (Lower Cretaceous), with taxonomic treatments of the family [electronic version]. Cretaceous Research, 26(5), 801-812. Retrieved 5/10/13 from

Makarkin, V. N.; Yang, Q.; and Ren, D. (2012). A new basal osmylid neuropteran insect from the Middle Jurassic of China linking Osmylidae to the Permian-Triassic Archeosmylidae [electronic version]. Acta Palaeontologica Polonica. Retrieved 5/23/13 from

Makarkin, V. N. and Archibald, S. B. (2003). Family Affinity of the Genus Palaeopsychops Andersen with Description of a New Species from the Early Eocene of British Columbia, Canada (Neuroptera: Polystoechotidae). Annals of the Entomological Society of America, 96(3), 171-180. Retrieved 5/22/13 from

Makarkin, V. N. and Archibald, S. B. (2009). A new genus and first Cenozoic fossil record of moth lacewings (Neuroptera: Ithonidae) from the Early Eocene of North America. Zootaxa, 2063, 55-63. Retrieved 5/12/13 from

Marshall, S. (2006). Insects: Their Natural History and Diversity. Richmond Hill: Firefly Books.

Martynova, O. M. (1948). Mesozoic lacewings (Neuroptera) and their bearing on concepts of phylogeny and systematics of the order. Trudy Paleontologicheskogo Instituta Akademii Nauk SSSR, 7(1), 1-232.

Navás, L. (1930). Insectos neotropicos. Revista Chilena de Historia Natural, 33, 17-24.

Oswald, J. D. (1998). Rediscovery of Polystoechotes gazullai Navás (Neuroptera: Polystoechotidae). Proceeding of the Entomological Society of Washington, 100, 389-394.

Penny, N. D. (1996). A remarkable new genus and species of Ithonidae from Honduras (Neuroptera). Journal of Kansas Entomology, 69, 81-86.  

Ponomarenko, A. G. (1992). Neuroptera (Insecta) from the Lower Cretaceous of Transbaikalia. Palaeontological Journal, 26(3), 56-66.

Ren, D. and Engel, M. S. (2008). Aetheogrammatidae, a new family of lacewings from the Mesozoic of China (Neuroptera: Myrmeleontiformia). Journal of the Kansas Entomological Society, 81(3), 161-167.  

Riek, E. F. (1974). The Australian moth-lacewings (Neuroptera: Ithonidae). Journal of the Australian Entomological Society, 15, 37-54.

Tillyard, R. J. (1922). The life-history of the Australian moth-lacewing, Ithone fusca (Order Neuroptera, Planipennia). Bulletin of Entomological Research, 13, 205-223. 

Welch, P. S. (1914). The early stages of the life history of Polystoechotes punctatus Fabr. Bulletin of the Brooklyn Entomological Society, 9, 1-6.

Winterton, S. L. and Makarkin, V. N. (2010). Phylogeny of Moth Lacewings and Giant Lacewings (Neuroptera: Ithonidae, Polystoechotidae) Using DNA Sequence Data, Morphology, and Fossils [electronic version]. Annals of the Entomological Society of America, 103(4), 511-522. Retrieved 5/11/13 from

Yang, Q.; Makarkin, V. N.; Winterton, S. L.; Khramov, A. V.; and Ren, D. (2012). A Remarkable New Family of Jurassic Insects (Neuroptera) with Primitive Wing Venation and Its Phylogenetic Position in Neuropterida. PLOS One. Retrieved 5/9/13 from

Tuesday, May 7, 2013

Strashilidae Make Paleontologists Look Stupid (Not That That's Anything New)

Lectotype of Ornithopsis hulkei (Brachiosauridae?)
Science is a matter of trial and error—and in the case of paleontology, more error than its counterpart. Correctly interpreting fossil remains is a tricky business, especially since they are often incomplete: consider this drawing of a chunk of bone dating from the Barremian Epoch (130-125 m.y.a.) of England. It takes an expert's eye to determine that what we're looking is not only petrified bone (as opposed to an inorganic rock), but, to be more exact, a largish vertebra, belonging to an organism called Ornithopsis; so named because it was thought to belong to a pterosaur (Seeley, 1870), or some sort of more bird-like flying tetrapod. Nowadays, we know beyond a doubt that Ornithopsis was a sauropod (Lyddeker, 1889), and therefore a distinctly land-bound creature.

Файл:GRIMALDI 2005 Strashila incredibili.jpg
Reconstruction of S. incredibilis (bottom) with holotype (male) above (Grimaldi & Engel, 2005)
Excusable, you say? Indubitably. This specimen could be a fossilized Barremian "meadow muffin", for all I can see (which is why I didn't go into paleontology); but even the best-preserved fossils can be misinterpreted. A case in point would be the excellent remains dating from the Jurassic of Asia that are referred to the family Strashilidae: yet their fidelity to life hardly aided paleontologists in making sense of what these insects actually were. The first known strashilid (Strashila incredibilis) was described from a single Siberian specimen. Its hind legs were burly and hooked; its body was, louse-like, laterally flattened; its abdomen looked as though it was easily distended; and it appeared to have suctorial mouthparts (although subsequent damage to the holotype has prevented later paleoentomologists from corroborating this supposition): all these anatomical traits were taken to suggest that Strashila had an ectoparasitic lifestyle, probably on pterosaurs (Rasnitsyn, 1992). The other known strashilids (S. daohugouensis and Vosila sinensis, both of them Inner Mongolian and somewhat earlier than S. incredibilis) both conform to this habitus. But the pleural rows of fleshy protuberances running the length of the abdomen remained an enigma.

Mrs. and Mr. Pseudopulex wangi (Pseudopulicidae)
Examination of strashilid genitalia showed them to belong to the superorder Antliophora (consisting of the orders Mecoptera, Siphonaptera, and Diptera), often being specifically likened to fleas (Siphonaptera: Grimaldi & Engel, 2005). Fossil fleas are rare (since they are obligate ectoparasites): the majority originate in Cenozoic amber, all of these belonging to the extant families Ctenophthalmidae, Rhopalopsyllidae, and Pulicidae (Lewis & Grimaldi, 1997; Beaucornu & Wunderlich, 2001). Only two species from prior to the K-T mass extinction (the one that did in the dinosaurs, y'know) have been consistently referred to the Siphonaptera: Saurophthirus longipes (Ponomarenko, 1976), dating to 145-140 m.y.a. (Rasnitsyn, 1975); and the younger Australian Tarwinia australis (Jell & Duncan, 1986) from 125-112 m.y.a. The three genera of the notorious 4-in.-long (in females), probably dinosaur-biting Pseudopulicidae were doubtlessly akin to fleas (if not fleas themselves; Huang et al., 2013a), but may not belong strictly within the Siphonaptera (Gao et al., 2012); they lived from 165-125 m.y.a.

Paratype of Coonilla longictena (Ischnopsyllidae)
Tarwinia is most probably a true flea, as it has many distinctive siphonapteran traits: laterally flattened body, helmet-like head, shortened thorax, and saltatorial hind legs (Krasnov, 2008). Saurophthirus bears elongated and ctenidium*-bearing extremities and shortened antennae, suggesting an ecology analogous to the modern bat bugs (Polyctenidae) or bat flies (Streblidae sensu lato*) and no leaping capability; a lifestyle of clambering on a downy integument, such as pterosaurs are known to have borne (Ponomarenko, 1976), thus drawing comparison to the Strashilidae: but comparison and phylogenetic relation are two different things. The idea that strashilids were "pre-fleas" (Rasnitsyn, 2002) never really took hold by consequence; and the resultant hypothesis that basal fleas were initially pterosaur parasites (later transferring to Mammalia) also failed under scrutiny, since living bat-specialist fleas (Ischnopsyllidae and Hectopsylla) aren't at all similar to Saurophthirus (Whiting et al., 2008). And if S. longipes isn't a genuine flea, than it must be admitted that strashilids bear no resemblance to fleas whatsoever. Instead, a new order was proposed to contain the "nasty-looking creature" (Rasnitsyn, 1992) and its kin: Nakridletia, the "paragliders"; an antliophoran lineage that developed ectoparasitism independently from the Siphonaptera, and was restricted to pterosaurian hosts (Vršanský et al., 2010).

A parasitic taxon uniquely occurring on pterosaurs has interesting ramifications for vertebrate paleontology, since it implies that these volant reptiles were endothermic and social (Vršanský et al., 2010). Which would be pretty darn coolif it were true.
Reconstruction of S. daohugouensis ' natural history
Up until a few months ago, there was a gap in our knowledge of the Strashilidae: all known specimens were male. Females turned out to be critical to our understanding of the family, for they bore a single pair of broad, seta-fringed wings, utterly lacking in venation. Not only that, but some male specimens were likewise equipped; and a few females were apterous. Additionally piquing paleoentomologists' interest are several traits exhibited in these newly described remains that reveal sexual dimorphism: females' hind legs were not muscular and bristly, as were those belonging to the opposite gender; and the male abdominal processes, hitherto so inexplicable, turned out to be feathery gills evidently retained from the larval stage—an atavism unknown among holometabolous insects aside from the Strashilidae (Huang et al., 2013b). 

Palaeodipteron walkeri, wing
Line drawing of N. walkeri's wing (Kevan & Cutten, 1981)
These discoveries drew attention to a previously ignored fact: strashilid genitals were quite similar to those of certain living insects; namely, nematocerous flies, such as gnats (Chironomidae) and mosquitoes (Culicidae). Thus, it can be safely declared that strashilids were true flies (Diptera), apparently shedding their wings after eclosion (probably during copulation); most likely in order to submerge themselves for oviposition. (This hypothesis is summarized in the artist's reconstruction shown in the previous paragraph.) How can we guess all this regarding their behavior? Because the Strashilidae closely parallel an extant fly taxon in their phenology (Huang et al., 2013b): the Nymphomyiidae, tiny (1.5-2.5) insects restricted to cold montane streams in eastern Asia and North America (Marshall, 2006) and classified in the single genus Nymphomyia (Oliver, 1981). Their maggots inhabit aquatic mosses, grasping the substrate with 8 pairs of prolegs; the non-feeding adults' wings are reduced to rachides flanked with long setae (see above) shed by both sexes before they descend into the waters and oviposit there, subsequently dying in flagrante delicto (Courtney, 1994). Because of their extreme specialization, the Nymphomyiidae have been frequently regarded as the earliest-diverging living lineage of Diptera (Rohdendorf, 1964; Griffiths, 1990), although this phylogeny is presently out of favor (Wiegmann et al., 2011).

In summation, the Strashilidae were not at all ectoparasitic, despite the universal consensus for the past 21 years that they were. The lesson we can derive from of all this is that (as the Raptorex fiasco amply displayed) in paleontology, "the experts" can (and will) screw up. Repeatedly. It's not dissimilar to other professional fields—say, medicine—but paleontologists will own up to their mistakes without the prodding of litigation.            

*"In the broad sense"—including the Nycteribiidae (see "Mormotomyiids' Terrible Hairiness").
Not belonging to the suborder Brachycera: that is, their antennae have more than 3 segments and lack an arista.
Muscular extensions of the abdomens of some insect larvae, which act as legs. The flies whose maggots possess prolegs (Nymphomyiidae, Blephariceridae, and Deuterophlebiidae) were at one time classified together in the infraorder Blephariceromorpha on the basis of that characteristic (Wood & Borkent, 1989).   

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