9. Family LYGISTORRHINIDAE
[Originally by] F. Christian Thompson
Lygistorrhinidae is a small family of fungus gnats (Sciaroidea) that are rather homogenous and easily recognized by elongate mouthparts and reduced wing venation. Overall size is ca. 4 to 5 mm; mouthparts are greatly elongate, at least 3x as long as height of head, and consist of 5 filaments, a pair of one-segmented palpi, a pair of labellae, and a hypopharynx. Wings are ca. 2 mm long, with Sc short and ending in the costal cell, R1 and R5 ending in C and separately extending to the base of the wing, M1 and M2 present only as apical fragments, CuAl (M4 of earlier authors) also present only as an apical fragment, CuA2 is entire, and the anal veins are absent or indistinct.
Lygistorrhine fungus gnats are considered to belong to a single genus, Lygistorrhina. This genus has usually been recognized as representing a separate entity in the higher classification of fungus gnats, either as a subfamily (Edwards 1925b, Tonnoir 1929b, Okada 1937, Shaw & Shaw 1951, Laffoon 1965, Vockeroth 1981) or as a family (Hennig 1948, 1954, 1966, 1968b, 1969b, 1973; Brauns 1954a,b; Rohdendorf 1964; Stackelberg 1969; Thompson 1975; Papavero 1977b; Matile 1981, 1986a, 1988a). Only Tuomikoski (1966b) has combined lygistorrhine fungus gnats with another group (Keroplatidae), but Thompson (1975) demonstrated that his arrangement was based on symplesiomorphy. Pragmatically, Thompson recognized only 1 genus, divided into 3 subgenera: Probolaeus Williston (New World spp.); Palaeognoriste Meunier (a fossil sp. in Baltic amber); and Lygistorrhina s. str. (Old World spp.).
Although lygistorrhine fungus gnats are extremely rare in collections,
they can be locally abundant and are found in the warmer parts of all biotic
regions: Nearctic (1 sp.), Neotropical (6), Palaearctic (1), Oriental (2),
Afrotropical (1), and Australasian/Oceanian (2). Since Thompson (1975),
only 2 additional species have been described [Matile, 1979: 254 (nassreddinei
from the Comoro Is, Africa), 1986a (vide infra)].
Ref.: Thompson (1975, syst., key, checklist).
Genus LYGISTORRHINA Skuse
LYGISTORRHINA Skuse, 1890d: 598. Type species: Lygistorrhina
insignis Skuse, 1890, mon.
carayoni Matile, 1986a: 286. New Caledonia (New Caledonia).
insignis Skuse, 1890d: 600. Australia (NSW).
This page last revised 17 August 1996