Villarrica Volcano, southern Chile
The Mecoptera fauna of Chile is small, but is striking unique. There are only six species in three families found west of the Andes Mountains in South America, all in Chile south of the Atacama Desert. They display some fascinating biogeographical patterns. The small austral family Nannochoristidae, considered to be among the most primitive of Mecoptera families and the only family with aquatic larvae, contains only eight species in two genera worldwide. One genus and species, Microchorista philpotti (Tillyard, 1917) is endemic to the south island of New Zealand. The other genus, Nannochorista, contains four species from southeastern Australia (mostly Tasmania), and three species from the Andean Region of Chile and Argentina. The family Eomeropidae has only a single living species, Notiothauma reedi McLachlan, 1877, from the Nothofagus forests of southern Chile. The third family, Bittacidae, contains two representatives in Chile, Anabittacus iridipennis Kimmins, 1929, and Bittacus chilensis Klug, 1838. The first genus is endemic to Chile, and has some morphological traits in common with Tytthobittacus from Australia. The other genus, Bittacus, is cosmopolitan. However, even this Chilean representative of Bittacus displays some distinctive features. It is among the largest species of Bittacus in the world, and appears to be most frequently associated with caves, unlike other species of this genus (McLachlan, 1894). The Mecoptera fauna of this region have clearly been isolated for a long time to develop such interesting biogeographical and behavioral patterns.
The family Nannochoristidae, although small, appears to have a long geological history. Some early fossils from the upper Permian of southeastern Australia have been attributed to this family (Riek, 1953), although this view has more recently been questioned (Grimaldi & Engel, 2005). Earliest fossil records of Nannochorista have been reported from the Middle Jurassic of Russia (Novokshonov, 1997). The aquatic larva may have helped this family survive the fluctuating climatic changes that occurred over geological time.
Nannochorista andina Byers, 1989
Nannochorista edwardsi Kimmins, 1929
Nannochorista neotropica Navás, 1929
The family Eomeropidae has a single living representative and five fossil species. There are three species known from the Cenozoic: Eomerope asiatica Ponomarenko & Rasnitsyn, 1974 from the late Paleocene; Eomerope pacifica Ponomarenko & Rasnitsyn, 1974 from the late Eocene/early Oligocene; and Eomerope tortriciformis Cockerell, 1909 from the late Eocene (Archibald et al., 2005). The oldest known eomeropid fossils are from the Middle Jurassic of Inner Mongolia: Typhotha yixianensis Ren & Shih and Tsuchingothauma shihi Ren & Shih (Ren & Shih, 2005). These creatures are flattened and cockroach-like with many bristles. They can be collected at night by setting oatmeal trails in the Nothofagus forests.
Notiothauma reedi McLachlan, 1877
The family Bittacidae, or hanging-flies, look superficially like four-winged crane flies (Tipulidae). They hang from the vegetation by their forelegs, and capture small insects with their hindlegs. Legs are modified for predation by having only a single, large, raptorial tarsal claw that folds against the tibial segments. This is the only family of Mecoptera known from South America east of the Andes Mountains. In Chile, two genera are known: Anabittacus and Bittacus.
Anabittacus iridipennis Kimmins, 1929
Bittacus chilensis Klug, 1838
Acknowledgments: I would like to thank Rachel Diaz-Bastin for the Auto-Montage© images, Charles E. Griswold for the photo of the Villarrica Vulcano, and Amanda Kershaw for organizing the text and images on the California Academy of Sciences web site.
Archibald, S.B., A.P. Rasnitsyn, and M.A. Akhmetiev. 2005. Ecology and distribution of Cenozoic Eomeropidae (Mecoptera), and a New Species of Eomerope Cockerell from the Early Eocene McAbee Locality, British Columbia, Canada. Annals of the Entomological Society of America 98(4):503-514.
Grimaldi, D & Engel, M.S. (2005) Evolution of the Insects. Cambridge University Press, New York, 755 pp.
Novokshonov, V.G. (1997a) New and little known Mesozoic Nannochoristidae (Insecta: Mecoptera). Herald of Perm State University [Vestnik Permskogo Universiteta], 4, 126–135. (In Russian, with English abstract.).
Ren, D. and C.-k. Shih. 2005. The first discovery of fossil eomeropids from China (Insecta, Mecoptera). Acta Zootaxonomica Sinica 30(2):275-280.
Riek, E.F. (1953) Fossil mecopteroid insects from the Upper Permian of New South Wales. Records of the Australian Museum, 23, 55–87.