Belongs within: Nerioidea.
The Taeniapterinae are a group of slender, long-legged flies whose larvae, where known, are found in dung and decaying vegetable matter. The genus Taeniaptera is widespread in the New World tropics with some species being synanthropic and common in disturbed areas. The genus Chaetotylus, known from Bolivia and Ecuador, is characterised by conspicuously thoracic bristles with four to six pairs of dorsoventral bristles; other genera usually have fewer dorsoventral bristles (Marshall 2010).
Flies on stilts
Published 18 March 2019
Flies deserve a much better rep than they’re usually given. They are animals of grace and poise that step lightly through the world. And perhaps few flies have an appearance that conveys that grace better than the stilt-legged flies of the Micropezidae. For today’s post, I wanted to look at one particular subfamily of micropezids, the Taeniapterinae.
Stilt-legged flies are found in most parts of the world but are particularly diverse in tropical regions. As their name indicates, they are light-bodied flies with notably long legs, the middle and hind legs being much longer than the fore legs. This legginess perhaps reaches its peak in the Madagascan genus Stiltissima, males of which have the hind femora alone at least 2.5 times the length of their thorax (Barraclough 1991). The adults are predators of small insects but are also attracted to decaying fruit or dung. Larvae of the family are little known but indications are that they feed on the aforementioned ordure or other rotting vegetation. Many of them are mimics of wasps such as ichneumons or ants with their slender figure resembling the narrow-waisted appearance of a wasp. Because micropezids belong to the brachyceran lineage of flies, in which the antennae are few-segmented and usually short, the front pair of legs is instead held out in front to imitate the wasp’s antennae.
The Taeniapterinae are the most diverse of three subfamilies recognised within the Micropezidae. Distinctive features of this subfamily include ocelli sitting relatively forward on the top of the head, a dense vertical fan of bristles on the sternopleuron (the sclerite on the side of the thorax just between the base of the fore and middle legs) and a vestigial subscutellum (Jackson et al. 2015). Though cosmopolitan in distribution, and the only micropezid subfamily known from sub-Saharan Africa (Barraclough 1991; the only non-taeniapterines known from the Afrotropical region are restricted to the Mascarene islands), taeniapterines are most diverse in the Neotropical region.
The Taeniapterinae have been divided into two tribes based on the length of the cup cell near the base of the fore wing, the short-celled Rainieriini and the long-celled Taeniapterini (Jackson et al. 2015). All taeniapterines found outside the Neotropical region belong to the Rainieriini, as well as a number of Neotropical genera. The Taeniapterini are restricted to the New World. Genera of Taeniapterinae are often poorly distinguished with the relationships between species obscured by the evolution of features related to mimicking their wasp models. A phylogenetic analysis of selected Taeniapterinae by Jackson et al. (2015) indicated many recognised genera were non-monophyletic. It also cast doubt on the tribal classification with the Taeniapterini rendering the Rainieriini paraphyletic.
Systematics of Taeniapterinae
Characters (from Marshall 2010): Katepisternum with dense, fanlike, vertical row of posterior bristles; subscutellum not developed; cells bm and dm separate (crossvein bm-cu present); upper calypter with tightly packed comb of short bristles; male with surstyli absent.
<==TaeniapterinaeM10 |--ChaetotylusM10 |--CardiacephalaM10 |--Hoplocheiloma fabriciiM10, S87 |--Parasphen frontalisM10 |--Ptilosphen viriolatusM10 |--Tenthes citatusM10 |--Grallomyia tarsataM10 |--Poecilotylus similisM10 |--Mesoconius hemithoraxM10 |--ZelatractodesM10 |--Globopeza ecuadorensisM10 |--PhaeopterinaM10 |--PseudeurybataM10 |--CalosphenM10 |--PlanipezaM10 |--CliobataM10 |--MimegrallaCM91 |--GrallipezaM10 | |--G. nebulosaS87 | `--G. unifasciataM10 |--ScipopusM10 | |--S. belzebulM10 | `--S. limbativertexM10 |--RainieriaM10 | |--R. alternataM10 | `--R. antennaepesM10 |--CalobatinaS87 | |--C. geometraS87 | `--C. geometroidesM10 |--PlocoscelusM10 | |--P. arthriticusM10 | |--P. coniferM10 | `--P. harenosusM10 |--Metasphen [incl. Globomyia]M10 | |--*M. vigilansM10 | |--M. gilvimanaM10 | `--M. obscuraM10 `--TaeniapteraM10 |--T. albibasisM10 |--T. annulataM10 |--T. lascivaM10 |--T. trivittataM10 `--T. vulgataM10
*Type species of generic name indicated
References
Barraclough, D. A. 1991. Review of the Madagascan Taeniapterinae (Diptera: Micropezidae), with the description of a remarkably elongate-legged new genus and first record of Rainieria Rondani from the subregion. Annals of the Natal Museum 32: 1–11.
[CM91] Colless, D. H., & D. K. McAlpine. 1991. Diptera (flies). In: CSIRO. The Insects of Australia: A textbook for students and research workers 2nd ed. vol. 2 pp. 717–786. Melbourne University Press: Carlton (Victoria).
Jackson, M. D., S. A. Marshall & J. H. Skevington. 2015. Molecular phylogeny of the Taeniapterini (Diptera: Micropezidae) using nuclear and mitochondrial DNA, with a reclassification of the genus Taeniaptera Macquart. Insect Systematics and Evolution 46: 411–430.
[M10] Marshall, S. A. 2010. Micropezidae (stilt-legged flies). In: Brown, B. V., A. Borkent, J. M. Cumming, D. M. Wood, N. E. Woodley & M. A. Zumbado (eds) Manual of Central American Diptera vol. 2 pp. 805–813. NRC Research Press: Ottawa.
[S87] Steyskal, G. C. 1987. Micropezidae. In: McAlpine, J. F. (ed.) Manual of Nearctic Diptera vol. 2 pp. 761–767. Research Branch, Agriculture Canada.