Sphaeropsocidae

Introduction

The family Sphaeropsocidae includes 3 genera and 15 species with worldwide distribution, but absent from Asia.  Within North America, two species of Sphaeropsocus have been found in ground litter in California and another species, Sphaeropsocopsis argentina, has been found in agricultural products introduced from Argentina.

Sphaeropsocids are tiny bark lice that resemble beetles.  Body color is brown.  They have been found in ground litter and dead leaves.

Characteristics

• General appearance:
• Body is very small, not flattened, with short, hardened wings and a beetle-like appearance.
• Head:
  
• Antennae usually have 15 segments.
• Antennal segments have ringed sculpturing (annulations) on bottom segments.
• Eyes are reduced, composed of just 3-10 ommatidia (eye segments).
• Ocelli are absent.
• Legs:
  
• Tarsi have 3 segments.
• Coxae are close together (not widely separated as in Liposcelidae).
• Abdomen:
  
• Some of the posterior abdominal segments are fused on the back.
• Wings:
  
• Adults are wingless or have short, thickened forewings with granular texture and convex shape.
• Forewings veins are reduced and very thick.
• Hindwings are absent.
• Male: 
  
• Phallosome is closed at the base with a complex posterior region (aedeagus).
• Female: 
  
• Subgenital plate has T-shape sclerite.
• Gonapophyses are complete, hairless, and arise from a common stem.
• External valve is broad and may be rounded or bilobed.

Discussion of Phylogenetic Relationships

Molecular analysis including one species of Badonnelia placed family Sphaeropsocidae in infraorder Amphientometae (18S nDNA; Johnson et al. 2004), but relationships within the family have not been investigated with molecular data.  Morphological study of the male genitalia of Troctomorpha supports the placement of Sphaeropsocidae as sister to the other members of infraorder Nonopsocetae (Yoshizawa & Johnson 2006).

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.

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.

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.

Smithers, C.N. 1972. The classification and phylogeny of the Psocoptera. Memoirs of the Australian Museum 14: 1–349.