Overview
The Tipulidae are the largest family of Diptera, with some 15,000 described species worldwide. Although many Australian species were described by Alexander, Dobrotworsky and Theischinger, there are many more still to be named. Commonly known as 'crane flies', the Tipulidae span an appreciable size range from 2-3 mm to over 60 mm in body length. Some species are wingless.
Continental European students of the Tipulidae tend to elevate the three constituent subfamilies, Tipulinae, Cylindrotominae and Limoniinae to family rank. Although each grouping appears to be monophyletic, there is no obvious phylogenetic basis for such elevation of ranks. Thus, the broader family concept used by most Anglophone workers is retained in this key. Contemporary views on the phylogenetic position of the Tipulidae are changing from a basal position close to the Tanyderidae (based on retention in the adult of many characters in the plesiomorphic condition), to a more highly derived position, with immature stage features showing derived similarities with 'higher' Diptera.
The biology of the Tipulidae varies greatly among larvae, and very little among adults, which are predominantly found in moist and shaded environments, presumably close to the larval habitat. The latter range from aquatic and semi-aquatic habitats, such as marshes, flowing waters, the hygropetric zone, interstitial sand and pebbles, immersed wood and depositional areas. Some aquatic species tolerate elevated salinities, being found in marine rock pools and brackish and estuarine conditions. Many species live in more terrestrial habitats such as rotting wood, leaf litter and decomposing vegetation and a few are even associated with living materials such as mosses and grass roots.
The Tipulidae are well represented in the fossil record, with Tipulinae reported as early as the Upper Cretaceous, Limoniinae from the upper Triassic and the Cylindrotominae from the Eocene.
Description
Recognition of the adult is based upon wing venation in which two anal veins reach the margin, and in which the second anal vein is not short and strongly curved as in most Trichoceridae.
In the immature stages, the Tipulidae form a quite heterogenous grouping. Larval head capsules range from complete (that is, with the dorsal margin a continuous ring), to varying degrees of reduction, such that the posterior part of the head comprises only some rods. The head may be retractile into the thorax, as in many Brachycera. The respiratory system is predominantly metapneustic, rarely apneustic. The posterior segment frequently bears elongate papillae around the margin of the plate that bears the posterior spiracles and the anus.
Distribution
The Tipulidae are cosmopolitan, from the Arctic to the subantarctic islands.