Ctenostylidae

Definition

A small, enigmatic family of rare acalyptrate flies (Diptera) characterized by the absence of ocelli, a trait once interpreted as evidence of close relationship with Pyrgotidae. Subsequent morphological analysis undermined this hypothesis, and the family is currently unassignable to any superfamily—the only family within Acalyptratae with this uncertain placement. The group comprises very few described species and remains poorly collected and studied.

Etymology

Example

Specimens of Ctenostylidae are seldom encountered in Malaise trap samples or museum collections, and their systematic position continues to be debated alongside other problematic acalyptrate lineages such as certain Tephritoidea.

Related Terms

• Acalyptratae
• Pyrgotidae
• Tephritoidea
• ocelli
• autapomorphy

Usage Notes

Formerly treated as a subordinate group within Pyrgotidae; now recognized as a distinct family of uncertain affinities. The absence of ocelli, while conspicuous, is considered convergent rather than synapomorphic with Pyrgotidae. Specialists note this as a key example of how reduction of sensory structures can mislead phylogenetic inference when not evaluated alongside broader character suites.