Psocodea

Mating pair of Rhyopsocus eclipticus (male on left), copyright Diane Young.

Belongs within: Paraneoptera.
Contains: Psocathropetae, Trogioidea, Lepidopsocidae, Psocomorpha, Nanopsocetae, Amphientometae.

The Psocodea include the barklice, small insects that mostly feed on fungi and other micro-organisms, as well as the true parasitic lice. It is now generally accepted that the latter are a derived subgroup of the former. Free-living Psocodea have heads with a large, bulbous postclypeus and long, filiform antennae.

The most basal division in the Psocodea is between the clades Trogiomorpha and Psocina. Trogiomorpha have antennae with more than twenty segments and a strong posterior spine on the paraproct (the lateral sclerites alongside the anus) whereas Psocina have fewer antennal segments and lack the paraproct spine. Psocina also have the hypopharyngeal filaments fused for at least part of their length whereas they remain separate in Trogiomorpha. Trogiomorpha are divided between the Psocathropetae and Atropetae, with the Atropetae having a short, broad head, a conical sensillum on the inner side of the second segment of the maxillary palp, and no nodulus on the fore wing (if present) (New & Lienhard 2007). Within the Psocina, members of the Troctomorpha lineage have antennae with at least some segments secondarily annulated, wings lacking a pterostigma and often a triangular or T-shaped sclerite on the large subgenital plate (Mockford 1993).

The Psocoptera of Barrow Island
Published 5 December 2012
Courtenay Smithers, courtesy of the Sydney Morning Herald.

Our lab has just recently added to its publication list with Gunawardene et al. (2012), which is part of a special issue of the Australian Entomologist printed in memory of the late Courtenay Smithers, who passed away last year. For many years, Courtenay was one of Australia’s leading entomologists, particularly for those unfairly overlooked animals the bark-lice (non-parasitic Psocodea). An obituary for him can be found here.

We wanted to include this paper as a tribute to Courtenay, as it basically presents some identification work that he had done for us in the last few years. As some of you already know, we’ve been working for the last few years on surveying the terrestrial invertebrates of Barrow Island, off the north-west coast of Australia. Courtenay had first surveyed the bark-lice of Barrow back in 1982, when he collected only five species of Psocodea all up, including the cosmopolitan synanthrope Liposcelis entomophila (Smithers 1984). Because Barrow Island is a very arid habitat, with little to no standing fresh water, Courtenay felt that “The small size of the fauna is probably a reality not an illusion”.

A cute litte critter from our collection that still only goes by the name of ‘Pteroxanium sp. A’.

As it turns out, he was wrong. At least 26 species of Psocodea have been found on Barrow so far (the paper says 25, but we’ve had at least one more turn up since it was accepted for publication). Most of these have currently only been identified as morphospecies: identification of bark-lice is often a difficult task, and many Australian species probably remain undescribed (as an example, Courtenay’s 1996 tally of the total described Australian Psocodea for the Zoological Catalogue of Australia includes less species of Liposcelididae than have been collected on Barrow Island alone). Three of the recorded species are synanthropes collected in buildings on the island; as far as we know, these species are not found in unmodified habitat. One of these, Dorypteryx domestica, was particularly interesting to me as it had not been recorded previously from Australia (and was my first real success at identifying a psocodean right down to species level, hurrah!), though Tim New (Australia’s remaining bark-louse expert) informed us that its presence has always been expected. I have to say, while bark-lice in general are among the cutest of all insects, but the little jumping Dorypteryx really amps the cuteness right up there.

And here it is! (Photo from Gunawardene er al. 2012.) Dorypteryx domestica is probably found worldwide, but records are scattered because of its unassuming nature.

Unfortunately, Courtenay’s passing highlights that a large proportion of taxonomic expertise currently resides in the minds of retired individuals (of the experts who have made identifications of material from the Barrow Island project, nearly a third were either retired or amateur taxonomists working in their spare time). There is no shortage of material out there, but we still need the people to tell us what it is.

Suspiciously posed-looking photo, used in Gunawardene et al. (2012), of yours truly supposedly demonstrating an insect collection method.
Systematics of Psocodea

Characters (from Rasnitsyn 2002, for Psocidea): Size small, rarely medium. General appearance highly variable depending on free living or parasitic habit and mode of parasitism. Head with clypeus strongly convex to house cibarial muscles (secondarily less developed in some parasitic forms). Mandible chewing (reverted and thus tearing instead of biting in elephant louse, reduced in sucking lice). Lacinia free of remaining maxilla, rod-like. Hypopharynx with two ovoid sclerites. Pronotum small. Wings often lost, when present roof-like at rest, rather poor in venation, coupled in flight except in some Palaeozoic species with homonomous wings. Legs cursorial or, in parasites, clinging, with tarsus 1–3-segmented (4-segmented in some extinct forms). First abdominal sternum lost. Ovipositor present or lost. Aedeagus lost in living species. Cercus lost. Extant forms with abdominal ganglia fused in single ganglionic mass and with 4 or less Malpighian tubes. Ovaries polytrophic. Chromosomes holokinetic.

<==Psocodea [Copeognatha, Corrodentia, Psocida, Psocidea, Psocoptera]
    |--Trogiomorpha [Trogiina]Y02
    |    |--PsocathropetaeNL07
    |    `--Atropetae [Trogiformia]NL07
    |         |--TrogioideaNL07
    |         |--LepidopsocidaeNL07
    |         `--Psoquillidae [Psoquilloidea]L02
    |              |--Balliella Badonnel 1949M93
    |              |    `--*B. ealensis Badonnel 1949M93
    |              |--Psoquilla Hagen 1865 [incl. Heteropsocus Verrill 1902]L02
    |              |    |--*P. marginepunctata Hagen 1865NL07 [incl. *Heteropsocus dispar Verrill 1902NL07, L02, P. disparB49]
    |              |    `--P. infuscata Badonnel 1949B49
    |              |--EosillaNL07
    |              |    |--*E. (Eosilla) jacobsoni Ribaga 1908NL07
    |              |    `--E. (Empheriella) denervosaNL07
    |              `--Rhyopsocus Hagen 1876 [incl. Deipnopsocus Enderlein 1903, Rhyopsocopsis Pearman 1929]L98
    |                   |--*R. eclipticus Hagen 1876L98 [incl. R. phillipsae Sommerman 1956M93]
    |                   |--R. afer (Badonnel 1948) [=Deipnopsocus afer]B49
    |                   |--R. bentonae Sommerman 1956M93
    |                   |--R. bicornis Badonnel 1986B86
    |                   |--R. disparilis (Pearman 1931)L98 (see below for synonymy)
    |                   |--R. maculosusM93
    |                   |--R. micropterus Mockford 1971M93
    |                   |--R. orthatusB86
    |                   |--R. pandanicola Thornton, Lee & Chui 1972NL07
    |                   |--R. peregrinus (Pearman 1929)L98 [=*Rhyopsocopsis peregrinaNL07]
    |                   |--R. phillipsae Sommerman 1956S56
    |                   |--R. spheciophilus (Enderlein 1903)L98 [=*Deipnopsocus speciophilusNL07]
    |                   `--R. texanus (Banks 1930) (see below for synonymy)M93
    `--PsocinaR02
         |--PsocomorphaY02
         `--Troctomorpha [Amphientomiformia, Amphientomomorpha, Troctopsocoidea]Y02
              |--NanopsocetaeYL10
              `--AmphientometaeYL10
Psocodea incertae sedis:
  Tshekarcephalus [Tshekarcephalidae]R02
    `--T. bigladipotensR02
  Surijokopsocus [Surijokopsocidae]R02
  Sinopsocus oligovenus Lin 1976L02
  Diploperipsocus phagococcus Li & Mockford 1993L02
  Mascaropsocus spinosus Badonnel & Pearman 1971SN08
  Miotroctes Pierce 1960YL10
    `--*M. rousei Pierce 1960NPA04
  Westphalopsocus Azar, Nel et al. in Nel, Roques et al. 2013 [Westphalopsocidae]NR13
    `--*W. pumilio Azar, Nel et al. in Nel, Roques et al. 2013NR13
  Zygopsocus [Zygopsocidae]NR13

Rhyopsocus disparilis (Pearman 1931)L98 [=Deipnopsocus spheciophilus var. disparilisL98, R. spheciophilus disparilisMG56]

Rhyopsocus texanus (Banks 1930) [=Deipnopsocus texanus; incl. R. pescadori García Aldrete 1984, R. squamosus Mockford & Gurney 1956]M93

*Type species of generic name indicated

References

[B49] Badonnel, A. 1949. Psocoptères de la Cote d’Ivoire. Mission Paulian-Delamare (1945). Revue Française d’Entomologie 16: 20–46.

[B86] Badonnel, A. 1986. Psocoptères de Colombie (Insecta, Psocoptera). Spixiana 9 (2): 179–223.

Gunawardene, N. R., C. K. Taylor &amp; J. D. Majer. 2012. Revisiting the Psocoptera (Insecta) of Barrow Island, Western Australia. Australian Entomologist 39 (4): 253–260.

[L02] Li F. 2002. Psocoptera of China vol. 1. Science Press: Beijing.

[L98] Lienhard, C. 1998. Faune de France. France et Régions Limitrophes. 83. Psocoptères Euro-Méditerranéens. Fédération Française des Sociétés de Sciences Naturelles: Paris.

[M93] Mockford, E. L. 1993. North American Psocoptera (Insecta). Sandhill Crane Press, Inc.

[NPA04] Nel, A., G. De Ploëg & D. Azar. 2004. The oldest Liposcelididae in the lowermost Eocene amber of the Paris Basin (Insecta: Psocoptera). Geologica Acta 2 (1): 31–36.

[NR13] Nel, A., P. Roques, P. Nel, A. A. Prokin, T. Bourgoin, J. Prokop, J. Szwedo, D. Azar, L. Desutter-Grandcolas, T. Wappler, R. Garrouste, D. Coty, D. Huang, M. S. Engel & A. G. Kirejtshuk. 2013. The earliest known holometabolous insects. Nature 503: 257–261.

[NL07] New, T. R., & C. Lienhard. 2007. The Psocoptera of Tropical South-east Asia. Brill: Leiden.

[R02] Rasnitsyn, A. P. 2002. Superorder Psocidea Leach, 1815. In: Rasnitsyn, A. P., & D. L. J. Quicke (eds) History of Insects pp. 125–133. Kluwer Academic Publishers: Dordrecht.

[SN08] Schmidt, E. R., & T. R. New. 2008. The Psocoptera (Insecta) of Tasmania, Australia. Memoirs of Museum Victoria 65: 71–152.

Smithers, C. N. 1984. The Psocoptera of Barrow and Boodie Islands, Western Australia. Entomologica Scandinavica 15: 215–226.

Smithers, C. N. 1996. Psocoptera. In: Wells, A. (ed.) Zoological Catalogue of Australia. Psocoptera, Phthiraptera, Thysanoptera pp. 1–79. CSIRO Publishing: Melbourne.

[S56] Sommerman, K. M. 1956. Two new species of Rhyopsocus (Psocoptera) from the U.S.A., with notes on the bionomics of one household species. Journal of the Washington Academy of Sciences 46 (5): 145–149.

[Y02] Yoshizawa, K. 2002. Phylogeny and higher classification of suborder Psocomorpha (Insecta: Psocodea: ‘Psocoptera’). Zoological Journal of the Linnean Society 136: 371–400.

[YL10] Yoshizawa, K., & C. Lienhard. 2010. In search of the sister group of the true lice: a systematic review of booklice and their relatives, with an updated checklist of Liposcelididae (Insecta: Psocodea). Arthropod Systematics and Phylogeny 68 (2): 181–195.

 

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