Troctomorpha

Definition

A suborder of Psocodea (psocids and parasitic lice) characterized by reduced wing venation, simplified tarsi, and a distinctive arrangement of mouthparts. Troctomorpha contains more than 30 families and approximately 5,800 described species, including the parasitic lice (formerly Phthiraptera) and their closest free-living relatives, the family Liposcelididae (booklice). The suborder is divided into two infraorders: Amphientometae (free-living barklice) and Nanopsocetae (minute barklice and parasitic lice).

Etymology

From Troctes (type genus of Liposcelididae, from Greek troktēs 'gnawer') + -morpha ('form'), referring to the morphological similarity to this genus.

Example

The human head louse Pediculus humanus and the body louse Pediculus humanus humanus belong to Troctomorpha, having evolved from within the barklice lineage rather than representing a separate origin of parasitism.

Related Terms

• Psocodea
• Psocomorpha
• Trogiomorpha
• Liposcelididae
• Phthiraptera
• Nanopsocetae
• Amphientometae
• barklice
• booklice
• parasitic lice

Usage Notes

Troctomorpha is one of three suborders of Psocodea, distinguished from Psocomorpha (the most diverse barklice suborder) and Trogiomorpha (basal barklice with distinct wing-coupling apparatus). The inclusion of parasitic lice within Troctomorpha reflects the 2010s taxonomic consensus that lice evolved from within Psocoptera, rendering 'Phthiraptera' paraphyletic if maintained as a separate order. When discussing barklice diversity, specialists may contrast Troctomorpha's reduced morphology with the more plesiomorphic features of Trogiomorpha.