Liancalus Loew, 1857

Runyon, Justin B. & Hurley, Richard L., 2015, A revision of the Nearctic species of Liancalus Loew (Diptera, Dolichopodidae), ZooKeys 483, pp. 97-147 : 101-103

Taxon classification Animalia Diptera Dolichopodidae

Genus Liancalus Loew, 1857

Anoplomerus Rondani, 1856: Rondani 1856: 141. Type species: Dolichopus regius Fabricius, 1805 treated as type species, awaiting ruling by the International Commission on Zoological Nomenclature. Preoccupied by Anoplomerus Guérin-Méneville, 1844.

Anoplopus Rondani, 1857: Rondani 1857: 14. Replacement name for Anoplomerus Rondani 1856 [Not Guérin-Méneville 1844]. Type species taken as that of replaced name under ICZN Art. 67.8: Dolichopus regius Fabricius (pending ICZN ruling). Preoccupied by Anoplopus Wagler, 1830.

Liancalus Loew, 1857: Loew 1857: 22. Replacement name for Anoplomerus Rondani, 1856 [Not Guérin-Méneville 1844]. Type species taken as that of replaced name under ICZN Art. 67.8: Dolichopus regius Fabricius. Bigot 1859: 230; Loew 1861: 69-70; Loew 1864: 198-200; Osten Sacken 1877: 318; Gobert 1887: 33; Bigot 1890: 277; Aldrich 1893: 569; Becker et al. 1903: 343-344; Aldrich 1904: 271; Aldrich 1905: 298; Coquillett 1910: 561; Lundbeck 1912: 22, 352-356; Wahlgren 1912: 5, 48; Frey 1915: 74; Van Duzee 1917: 126; Becker 1917-1918: 160, 193; Becker 1922a: 117-119; Becker 1922b: 41; Curran 1926: 406-407; Parent 1932: 121-122; Curran 1934: 217; Parent 1938: 19, 268, 306; Parent 1939: 276; Harmston and Knowlton 1945: 55-56; Robinson 1964: 118, 182; Dyte 1967: 123; Cole 1969: 272, 282; Robinson 1970a: 59, 62; Robinson 1970b: 57; Dyte 1975: 241-242; D’Assis Fonseca 1978: 41; Negrobov 1978: 416-417; Negrobov 1979: 928; Robinson and Vockeroth 1981: 633, 635, 637; Hurley 1985: 3; Negrobov et al. 1987: 157-158; Negrobov 1991: 41; Wei and Liu 1995: 35; Yang 1998: 153; Masunaga 2001: 109, 117-118; Pollet et al. 2004: 52; Yang et al. 2006: 19, 246; Bickel 2009: 683; Evenhuis and Bickel 2011: 4-5; O’Hara et al. 2011: 30; Yang et al. 2011: 363; Kahanpää 2014: 203.

Notes.

The type species of Liancalus is involved in a convoluted nomenclatural issue resulting from an unpaginated correction page at the end of Rondani (1856) and interpretation of Loew’s (1857) creation of the name. If a straightforward use of the ICZN rules were to be followed, the genus here and previously considered Liancalus Loew would lack a valid generic name. However, the purpose of the ICZN is to "Promote stability and universality" (ICZN Preamble), and when strict application of the Code would act contrary to this purpose, the International Commission on Zoological Commission is empowered to set aside the rules using their Plenary Powers (ICZN Art. 78.1). Therefore, a petition has been prepared for the ICZN ( Runyon et al. submitted) asking that they use their Plenary Powers to preserve prevailing usage of Liancalus by setting aside the type species under the Rules, and replace it with a type species that retains established and universal usage. In the meantime, under ICZN Art. 82.1, prevailing use is to be maintained until such time as the Commission’s ruling is published. Therefore, Liancalus will be treated herein as if its type species is Dolichopus regius Fabricius, 1805.

Diagnosis.

Large flies of rather uniform general color and appearance (Figs 8-9) whose males and females can be recognized by the finger-like projection ventrally from proepimeron near base of coxa I (Fig. 1).

Description.

Male. Body length 6.5-12.0 mm, wing length 6.0-8.5 mm.

Head: Face and frons broadly separated with distinct frontoclypeal suture near mid-face (Fig. 1). Eyes with short hairs between facets. Vertical setae on small elevation; ocellar tubercle prominent with 2 large setae, without hairs; with 2 postocellar setae. Gena absent. Proboscis somewhat sclerotized, slightly enlarged, covered with sparse gray-brown pollen; each labellar lobe with 6 geminately sclerotized pseudotracheae. Antenna of rather uniform shape, size, and color (Figs 1, 8-9); black, scape without dorsal setae; pedicel with apical ring of setae/setulae, longest setae dorsally and ventrally; first flagellomere about as long as wide, broadly pointed apically, arista inserted near midpoint of dorsal edge.

Thorax: Scutum metallic green to green-blue with silver-gray pollen and bronze-red stripes; 0-14 acrostichal setae in a single row; usually 6 dorsocentral setae (6-10 in Liancalus pterodactyl ), 2 notopleural setae; 1-3 strong, black postpronotal setae (often with some smaller white hairs), usually 2 presutural intra-alar setae (1 in Liancalus genualis ), 1 presutural seta, 2 postsutural supra-alar setae, and 1 postalar seta per side; scutellum usually with 6 large marginal setae (8-9 in Liancalus pterodactyl ), no additional hairs; proepisternum with 1 dorsal and 1 ventral tuft of white hairs. Pleura metallic bronze-green, covered with dense silver-gray pollen, without setae or hairs (Fig. 1).

Legs: Legs very long, slender, dark metallic green (Figs 8-9). Coxa I uniformly covered with white hairs on anterior surface; coxa II with white hairs on anterior surface and black ad seta near middle; coxa III with a black dorsal seta near middle (Fig. 1). Femur II and III with a slender preapical ad seta near 3/4. Tarsus I either with tarsomere 1 long and tarsomere 2 short (Figs 3 A–E), or with tarsomere 1 short and tarsomere 2 long (Figs 3 F–G).

Wing: Modified with dark brown markings and spots, sometimes enclosing a white apical spot and sometimes with lobes and setae (Figs 4-7). Calypter yellow with a fan of long, pale yellow setae. Halter pale yellow.

Abdomen: Cylindrical, elongate, and slightly broadened at apex (Fig. 2). T5 prolonged ventrally into two lateral flap-like projections that form a hood or pocket for the apex of the hypopygium. Hypopygium (Figs 10-12) nearly round, capping apex of abdomen. Phallus arched to rather sharply bent dorsally just before apex, with apical margin minutely serrate. Hypandrium rather broad, thin, arched anteriorly near apex with lateral lobe bearing setulae and a larger seta at or near apex. Epandrium with large, apical, thin, nearly transparent lobe that is hinged and can be raised or lowered dorsoventrally; at rest, this lobe sits against and covers the surstylus and base of cerci. Surstylus somewhat pointed, strongly sclerotized, directed medially, with large spatulate seta near apex. Cerci broad basally, with either very short (Figs 2 E–F, 12) or very long filaments that project anteriorly below abdomen (Figs 2 A–D, 8).

Female. Body length 5.0-9.0 mm, wing length 5.5-7.5 mm. Lacking typical male secondary sexual characters and similar to male except: face broader, nearly parallel-sided; palpi larger; fore tarsi unmodified; wings unmodified, but with diagnostic dark brown spots in most specimens (Fig. 16); abdomen shorter and somewhat flattened dorsoventrally.

Immatures. Larvae twelve segmented, cylindrical, truncate posteriorly and tapered anteriorly, opalescent with transparent cuticle; antenna with basal ring bearing sensilla; mouthparts dark brown to black, labrum large with pointed tip (sometimes hooked and/or with tooth-like projections), mandibular hook well developed; metacephalic rods enlarged at caudal tips, longer than tentorial arm. Pupa with prothoracic respiratory horns about 2 mm long, sharply pointed at tips; frontofacial sutures distinct, brown; abdominal segments 2-7 with rows of posteriorly-directed spines. Coccon elliptical, externally composed of sand grains and sometimes moss and mud, inner surface smooth; respiratory horn tips exposed. See Vaillant (1948), Corpus (1986) and Masunaga (2001) for illustrations and photographs of immature stages.

Remarks.

Cerci of male specimens sometimes shrivel upon drying. In teneral specimens, the spots on the wings can be very faint which can render them, particularly females, difficult to identify.