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Emilie Bess and Kevin P. Johnson
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taxon links [up-->]Phyllocaecilius [up-->]Cladioneura [up-->]Heterocaecilius [up-->]Novopsocus [up-->]Kerocaecilius [up-->]Chorocaecilius [up-->]Pseudocaecilius [up-->]Mepleres [up-->]Scytopsocus [up-->]Zelandopsocus [up-->]Scottiella [up-->]Trichocaecilius [up-->]Phallocaecilius [up-->]Levucaecilius [up-->]Trimerocaecilius [up-->]Lobocaecilius [up-->]Allocaecilius [up-->]Austropsocus [up-->]Ophiodopelma [up-->]Scytopsocopsis [up-->]Allopsocus [up-->]Neocaecilius [up-->]Diplocaecilius [up-->]Mesocaecilius [up-->]Platyocaecilius [up-->]Thelocaecilius [up-->]Orbocaecilius Monophyly Uncertain[down<--]Homilopsocidea Interpreting the tree
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The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.

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Containing group: Homilopsocidea


The family Pseudocaeciliidae contains about 300 species in 23 genera distributed worldwide, with highest diversity in Asia.  Two species are known from North America in the genus: Pseudocaecilius citricola from Florida and Texas, and P. tahitiensis from Florida and several regions of Mexico.

These are medium-sized bark lice (2-3 mm, nymphs up to 3 mm) with robust bodies.  Body colors are brown or yellow. Pseudocaeciliids inhabit leaves and can often be found in clusters of dead leaves on tree branches.  Some species live under sparse webbing, alone or in small groups.




General Characters

How to Know the Family

Family Monophyly

Pseudocaeciliidae is likely not monophyletic, according to both morphological and molecular data.  There are no morphological characters supporting monophyly in the family (Yoshizawa 2002).  Molecular analysis of including 11 species of the family indicates that the family is not monophyletic and shows ambiguous relationships with families Calopsocidae and Philotarsidae (18S nDNA; Johnson et al. 2004).


Johnson, K. P. & E. L. Mockford. 2003. Molecular Systematics of Psocomorpha (Psocoptera). Systematic Entomology 28: 409-40

Johnson, K. P., K. Yoshizawa, and V. S. Smith. 2004. Multiple origins of parasitism in lice. Proceedings of the Royal Society of London B 271:1771-1776.

Lienhard, C. and C. N Smithers. 2002. Psocoptera (Insecta) World Catalogue and Bibliography. Muséum d'Histoire Naturelle, Geneva, Switzerland.

Mockford, E. L. 1993. North American Psocoptera (Insecta). Gainesville, Florida: Sandhill Crane Press,

New, T.R. 2005. Psocids, Psocoptera (Booklice and barklice), 2nd edition: Handbooks for the Identification of British Insects. Vol. 1, Part 7. Royal Entomological Society, London, UK.

Smithers, C. N. 1996. Psocoptera. Pp. 1-80, 363-372 (Index) in Wells A. (ed.) Zoological Catalogue of Australia. Vol. 26. Psocoptera, Phthiraptera, Thysanoptera. Melbourne: CSIRO Publishing, Australia.

Yoshizawa, K. 2002. Phylogeny and higher classification of suborder Psocomorpha (Insecta: Psocodea:'Psocoptera'). Zoological Journal of the Linnean Society 136: 371-400.

Title Illustrations
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Scientific Name Heterocaecilius solocipennis
Location Japan
Specimen Condition Live Specimen
Identified By K. Yoshizawa
Life Cycle Stage adult
View lateral
Size 3mm
Copyright © 2006 Kazunori Yoshizawa
About This Page

Emilie Bess
Illinois Natural History Survey, Champaign, Illinois, USA

Kevin P. Johnson
Illinois Natural History Survey, Champaign, Illinois, USA

Correspondence regarding this page should be directed to Emilie Bess at and Kevin P. Johnson at

All Rights Reserved.

Citing this page:

Bess, Emilie and Kevin P. Johnson. 2009. Pseudocaeciliidae. Version 25 March 2009 (under construction). http://tolweb.org/Pseudocaeciliidae/14475/2009.03.25 in The Tree of Life Web Project, http://tolweb.org/

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This page is a Tree of Life Branch Page.

Each ToL branch page provides a synopsis of the characteristics of a group of organisms representing a branch of the Tree of Life. The major distinction between a branch and a leaf of the Tree of Life is that each branch can be further subdivided into descendent branches, that is, subgroups representing distinct genetic lineages.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

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