The Psocomorpha are a major subgroup of the barklice characterised by the presence of non-annulated antennae and, in winged forms, a sclerotised pterostigma. The likely basalmost subgroup of the clade is the Archipsocidae, a predominantly tropical group with densely setose, usually leathery fore wings with largely obscure venation (New & Lienhard 2007).
Barklice and booklice and such
Published 25 February 2008
Psocoptera is arguably the least deservedly obscure of the obscure insect orders. They’re not uncommon—there’s a reasonable chance that you’ll have seen one in your life. You probably squashed it without giving much thought to what it was. And yet, so obscure is this order of insects that there isn’t even a good vernacular name for the group. Psocoptera are minute insects (usually only a couple of millimetres long) that generally live among bark and litter, feeding on fungi. Some wingless species can be found in houses (where you might have seen one) and feed on such delicacies as dust or the glue used in book bindings, leading to their being known as booklice. The tree-living forms are sometimes referred to as barklice in comparison to booklice. Most entomologists that I know simply refer to the group as psocids, and that’s exactly what I’m going to do.
Technically speaking, ‘Psocoptera’ is a paraphyletic group. The Phthiraptera, the true lice*, are derived from within the psocids. At the moment, things seem to be going through a transitional phase, with many authors dropping the paraphyletic ‘Psocoptera’ for the name Psocodea, which refers to the total group of psocids and lice. The ‘Psocoptera’ are divided into three suborders, the Trogiomorpha, Psocomorpha and Troctomorpha, the Phthiraptera being properly speaking a subgroup of the last. A representative of the second group can be seen at the top of this post, and it’s the Psocomorpha that I’m looking at today.
*And holders of what is probably the worst insect order name of all to pronounce.
With over 3500 species, the Psocomorpha are generally regarded as the largest of the psocid suborders, though the Troctomorpha could give them a run for their money once the Phthiraptera are taken into account. We should probably be careful about making definite statements about this—because of their neglected nature, new species and sometimes even families of psocids continue to appear in the literature at a respectable rate. At the moment, though, it is a psocomorph that holds the honour of being probably the only invertebrate to get its picture plastered over Tetrapod Zoology, due to the nomenclatural issues that have arisen from the similarity in names of the psocid Caecilius and the amphibian Caecilia. The photo above is the one featured in Tet Zoo, and shows an identified member of the Caeciliusidae.
Most Psocomorpha are dwellers on bark or rocks. One group, the Caeciliusoidea, inhabits living foliage. Adults may be winged or wingless—many species have both forms. Many psocids cluster as nymphs—the photo above* shows one such congregation—and spin protective webs, but this is taken to the extreme in the genus Archipsocus. Archipsocus species form large colonies, and may build webs large enough to obscure tree-trunks, as can be seen in the picture below. As with Embioptera, these colonies appear to be conglomerations of convenience, and there is no real social behaviour. Like aphids, Archipsocus may go through multiple generations in a summer, and the colony will contain individuals at all stages of development, both winged and wingless forms (Mockford 1957). Once winter arrives, the colony breaks down and disperses, the survivors diapausing until the spring when they will start new colonies.
*The page it comes from also records a fantastic common name for psocids—”bark cattle”, apparently because the nymphs move like a herd when disturbed.
Molecular and morphological data are mostly in agreement that the Psocomorpha can mostly be divided between four infraorders, the Psocetae, Homilopsocidea, Epipsocetae and Caeciliusetae (Johnson & Mockford 2003; Yoshizawa 2002). Both studies also agreed in placing Archipsocus outside these groups, as the basalmost member of the Psocomorpha. Unfortunately, beyond the bare morphology, information about most psocid groups seems to be few and far between, and there is a great deal about the order that we have yet to know.
Systematics of Psocomorpha
Characters (from Yoshizawa 2002): Head usually with rounded vertex; antennae 13-segmented; flagellomeres never annulated; maxilla without stipito-galeal muscle; hypopharyngeal filaments fused for most of their length; labial palpus 1-segmented. Forewing with nodus and thickened pterostigma; nodulus hook-shaped, formed by truncated spines fused at their base; CuP ending together with A1 at wing margin. Apex of first axillary sclerite usually with minute proximal process. Subgenital plate lacking median sclerite.
<==Psocomorpha [Eupsocida, Psociformia] | i. s.: Paramesopsocus Azar, Hajar et al. 2008 [Paramesopsocidae]AH08 | |--*P. lu Azar, Hajar et al. 2008AH08 | `--P. adibi Azar, Hajar et al. 2008AH08 |--Archipsocidae [Archipsocetae, Archipsocoidea]Y02 | |--PararchipsocinaeNL07 | | |--*Notarchipsocus macrurus [=Archipsocus macrurus]NL07 | | |--Pseudarchipsocus Mockford 1974NL07, M74 | | | `--*P. guajiro Mockford 1974M74 | | `--PararchipsocusY02 | | |--*P. poblanusNL07 | | `--P. pacificusY02 | `--ArchipsocinaeNL07 | |--Archipsocopsis Badonnel 1948NL07, M93 | | |--*A. mendax (Badonnel 1948)NL07, B55 [=Archipsocus mendaxNL07] | | |--A. antiguus (Mockford 1969) [=Archipsocus (Archipsocopsis) antiguus]P92 | | |--A. fernandi (Pearman 1934)NL07 | | |--A. frater (Mockford 1957) [=Archipsocus frater]M93 | | |--A. inornataM93 | | `--A. parvula (Mockford 1953) [=Archipsocus (Archipsocopsis) parvulus]M93 | `--Archipsocus Hagen 1882L02 | |--*A. puber Hagen 1882L02 | |--A. albofasciatus Badonnel 1949B55 | |--A. alternatus Vaughan, Thornton & New 1989NL07 | |--A. aneura Badonnel 1948B55 | |--A. badonneliB86 | |--A. bicolorB55 | |--A. castriiB86 | |--A. floridanus Mockford 1953M93 | |--A. fuscopalpus Badonnel 1955B55 | |--A. ghesquierei Badonnel 1946 (see below for synonymy)B55 | | |--A. g. ghesquiereiB55 | | `--A. g. longicornis Badonnel 1955B55 | |--A. gurneyi Mockford 1953M93 | |--A. machadoi Badonnel 1955B55 | |--A. minutus Badonnel 1955B55 | |--A. modestusB86 | |--A. nomas Gurney 1939M93 | |--A. panama Gurney 1939M74 | |--A. polytrichus Li 2002L02 | |--A. recens Enderlein 1903NL07 | `--A. sanurensis Thornton 1984NL07 `--+--+--PsocetaeY02 | `--+--HomilopsocideaY02 | `--+--CaeciliusetaeY02 | `--EpipsocetaeY02 `--Hemipsocidae [Hemipsocetae, Hemipsocoidea]Y02 |--AnopistoscenaY02 |--Cyclohemipsocus Li 2002L02 | `--*C. chinensis Li 2002L02 |--Hemipsocus Selys-Longchamps 1872L02 | |--*H. chloroticus (Hagen 1858)NL07 [=Psocus chloroticusNL07; incl. H. hyalinus Enderlein 1906M93] | |--H. africanus Enderlein 1907NL07 | |--H. funebris Badonnel 1969L02 | |--H. luridus Enderlein 1903NL07 (see below for synonymy) | |--H. maculatus New 1973NL07 | |--H. maritiensis Turner 1976L02 | |--H. massulatus Li 2002L02 | |--H. parallelicus Li 1996L02 | |--H. pretiosus Banks 1930M93 | `--H. roseus (Hagen 1859)NL07 `--Metahemipsocus Li 1995L02 [=Metabemipsocus (l. c.)L03] |--*M. longicornis Li 1995L02 |--M. bellatulus Li 2002L02 |--M. bicuspidatus Li 2002L02 |--M. bimaculatus Li 2002L02 |--M. cunestus Li 1996L03, L02 [=M. cuneatus (l. c.)L03] |--M. flabellatus Li 2002L02 |--M. guangxiensis Li 2002L02 |--M. interaus Li 1995L02 |--M. longifurcus Li 2001L03 |--M. octofarius Li 1999L02 |--M. recurvicornis (Li 1992) [=Hemipsocus recurvicornis]L02 |--M. scitulus Li 2002L02 |--M. spilopterus Li 1996L02 |--M. tenuatus Li 1997L02 |--M. triangularis Li 2002L02 |--M. trimerus Li 2002L02 |--M. vitellinus Li 2002L02 `--M. yunnanicus Li 2002L02
Archipsocus ghesquierei Badonnel 1946 [incl. A. ghesquierei var. albomaculatus Badonnel 1955, A. neens f. macropterus Badonnel 1946]B55
Hemipsocus luridus Enderlein 1903NL07 [=H. chloroticus var. luridusS95, H. selysianus luridusS95; incl. H. selysianus Enderlein 1919S95, H. luridus selysianusS95]
*Type species of generic name indicated
[AH08] Azar, D., L. Hajar, C. Indary & A. Nel. 2008. Paramesopsocidae, a new Mesozoic psocid family (Insecta: Psocodea “Psocoptera”: Psocomorpha). Annales de la Société Entomologique de France (N. S.) 44 (4): 459–470.
[B55] Badonnel, A. 1955. Psocoptères de l’Angola. Diamang Publicações Culturais 26: 11–267.
[B86] Badonnel, A. 1986. Psocoptères de Colombie (Insecta, Psocoptera). Spixiana 9 (2): 179–223.
Johnson, K. P., & E. L. Mockford. 2003. Molecular systematics of Psocomorpha (Psocoptera). Systematic Entomology 28: 409–416.
[L02] Li F. 2002. Psocoptera of China vol. 1. Science Press: Beijing.
[L03] Lienhard, C. 2003. Nomenclatural amendments concerning Chinese Psocoptera (Insecta), with remarks on species richness. Revue Suisse de Zoologie 110 (4): 695–721.
Mockford, E. L. 1957. Life history studies on some Florida insects of the genus Archipsocus (Psocoptera). Bulletin of the Florida State Museum—Biological Sciences 1 (5): 254–274.
[M74] Mockford, E. L. 1974. Records and descriptions of Cuban Psocoptera. Entomologica Americana 48 (2): 103–215.
[M93] Mockford, E. L. 1993. North American Psocoptera (Insecta). Sandhill Crane Press, Inc.
[NL07] New, T. R., & C. Lienhard. 2007. The Psocoptera of Tropical South-east Asia. Brill: Leiden.
[P92] Poinar, G. O., Jr. 1992. Life in Amber. Stanford University Press: Stanford.
[S95] Smithers, C. N. 1995. Psocoptera (Insecta) of Christmas Island. Invertebrate Taxonomy 9: 529–561.
[Y02] Yoshizawa, K. 2002. Phylogeny and higher classification of suborder Psocomorpha (Insecta: Psocodea: ‘Psocoptera’). Zoological Journal of the Linnean Society 136: 371–400.