Pachytroctidae
Emilie Bess and Kevin P. Johnson- Tapinellinae
- Pachytroctinae
Introduction
The family Pachytroctidae includes 10 genera and about 90 species distributed worldwide. Four species in the genera Nanopsocus, Tapinella, and Pachytroctes are found in North America.
Characteristics
- Head:
- Antennae usually have 15 segments.
- The first 4-5 segments of the antennae do not have sculpturing; other segments have ringed sculpturing (annulations).
- Eyes are relatively large, compared to related families.
- Legs:
- Tarsi have 3 segments.
- Hind legs are long and the femur is not flattened (as in Liposcelidae).
- Wings:
- Adults can be have full-length wings or short wings, or can be wingless.
- Full-length wings are held flat over back when at rest.
- Forewings are rounded.
- Forewing veins are distinct:
- Areola postica is narrow, long and flat.
- Pterostigma is not thickened (as in Psocomorpha).
- Vein M has 2 branches.
- Veins Cu2 and Cu1A reach the wing margin separately.
- Abdomen:
- Abdominal segments often partially membranous on back surface.
- Male:
- Clunium is absent.
- Phallosome is closed at the base with complex structures on the posterior end.
- Female:
- Subgenital plate sometimes has T-shaped sclerite, as in related families.
- Gonapophyses are complete and hairless:
- External valve is large without lobes.
How to Know the Family
- Body is not flattened, as in family Liposcelidae.
- Eyes are relatively large, compared to related families.
- Antennae usually have 15 segments.
- Forewing areola postica is narrow, long and flat.
- Forewing vein M has 2 branches.
- Forewing veins Cu2 and Cu1A reach the wing margin separately.
- In the male, the clunium is absent.
Discussion of Phylogenetic Relationships
Morphological study of the male genitalia of Troctomorpha supports monophyly of family Pachytroctidae based on the character of absence of the basal apodeme (Yoshizawa & Johnson 2006). Molecular data from six species of Pachytroctidae divides the family into two groups, Pachytroctes + Peritroctes and Tapinella + Nanopsocus, but the support for family monophlyly is ambiguous (18S nDNA; Johnson et al. 2004). Further study will be necessary to resolve the relationships within the family.
References
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.
Yoshizawa, K. and K.P. Johnson. 2006. Morphology of male genitalia in lice and their relatives and phylogentic implications. Systematic Entomology 31: 350-361.
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
Page copyright © 2009 Emilie Bess and Kevin P. Johnson
All Rights Reserved.
- First online 25 March 2009
- Content changed 25 March 2009
Citing this page:
Bess, Emilie and Kevin P. Johnson. 2009. Pachytroctidae. Version 25 March 2009 (under construction). http://tolweb.org/Pachytroctidae/14456/2009.03.25 in The Tree of Life Web Project, http://tolweb.org/
