The final-stage larvae of Brunettia (Diptera: Psychodidae: Psychodinae) and their evolutionary significance

Abstract

The semi-terrestrial final instar larva of the Australian species Brunettia (Atrichobrunettia) scitula Duckhouse is described using revised chaetotaxic terminology, as a basis for broader systematic studies. That of Brunettia (Mirousiella) angustipennis (Tonnoir), the only other Brunettia larva known, is redescribed, compared with that of B. scitula and found to be different enough to support its present classification in a separate subgenus. The pupae of both species remain largely enclosed in the last larval skin, the protected parts being unsclerotised and the whole body having reduced sensory setae.

Examination of outgroups shows that the stem-form of the Psychodinae was most probably terrestrial. From here the general trend has been towards marginal and finally aquatic habits. Earlier genealogical hypotheses are elaborated along these lines by adding subsidiary hypotheses, including Clytocerus Eaton as a basal offshoot of this subfamily.

Brunettia resembles Mormia Enderlein in both larva and adult. It is also very like Clytocerus and Nemoneura Tonnoir in its larva, but not its adult. These incongruences are discussed. The assertions that Brunettia and Mormia share very few characters and do not belong in the same tribe, and that Mormia belongs instead with Telmatoscopus Eaton and Panimerus Eaton in the Paramormiini, are tested, and it is shown that there is no evidence for a paramormiine relationship. It is instead confirmed that Mormia belongs with Brunettia in the same tribe, Mormiini.