Merodon angustiventris MACQUART 1855
Creators: name: Ricarte, Antonio
name: Marcos-García, M. Ángeles
name: Hancock, E. G.
name: Rotheray, Graham E.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Syrphidae
Merodon
Merodon angustiventris

description: MERODON ANGUSTIVENTRIS MACQUART, 1855: 110   
 HELOPHILUS AURATUS WALKER, 1857: 153 QUICHUANA AURATA (WALKER, 1857: 153) SYN. NOV.   
FIGURES 5-7  
 Macquart (1855) described angustiventris, placing it in the genus Merodon from an unspecified number of males from ‘Patrie inconnue’. Hull (1946) transferred the species to the genus Quichuana as Q. auratus, without agreement in gender. A lectotype was designated by Thompson (1988) from a group of three apparent syntypes in the collection of the NHM. The lectotype is labelled as follows: co-type/ Merodon angustiventris Macq. /Ex. coll. Bigot/ BM 1901.14. On the other hand, Walker (1857) described auratus placing it in Helophilus from material collected in the ‘Valley of the Amazon’ in the William Saunders’ collection (NHM). Hull (1946) examined Walker’s type and redescribed the species based on Colombian and Peruvian (middle Río Ucayali) material. This material was revised by FCT in 1978 and a male was labelled as lectotype to fix the auratus name (FCT, unpubl. data). The lectotype is labelled as follows: LECTO-TYPE/Type/Amaz (handwritten)/ S. America/Amazon (handwritten)/ Helophilus auratus Wlk. (handwritten by E.E. Austen)/ auratus Wlk (probably handwritten by Walker)/ LECTOTYPE Helophilus auratus Walker desig. FCT 1978. Based on the examination by FCT in 1978, and on the recent examination of images of this specimen by Antonio Ricarte, Q. aurata is made a junior synonym of Q. angustiventris.   
 Diagnostic features   
Male  
Frontal triangle with a conspicuous mat of adpressed, usually golden yellow hairs obscuring the background colour (this mat of hairs varies from silver white to bright brown and, unusually, pink); face pollinose except for a central stripe; abdomen densely pale haired, mainly with golden yellow hairs; terga II – IV with a posterior triangular area bearing hairs in lower density than on the rest of the tergum (the triangular area may extend until the mid part of the tergum or more, and is conspicuous, at least, on tergum II); tergum II only with yellow hairs; tergum III usually only with yellow hairs, but sometimes with a few black hairs posteriorly; tergum IV with a semi-circular band of black hairs on the posterior third or less; genitalia as illustrated in Figures 5–7.  
Female  
Vertex with black hairs in and around the ocellar triangle; frons with posteriorly directed golden yellow hairs; frontal prominence, dorsally, with anteriorly directed golden yellow hairs, and sometimes with dark-brown to black hairs near the antennae; basoflagellomere longer than scape plus pedicel; face pollinose, with a central, shiny stripe not reaching the antennae, and two lateral, shiny stripes; the lateral, shiny, facial stripes are usually well defined on the upper half of the face, and taper downwards (sometimes these stripes extend to the lower half of the face, but then they become densely pollinose and very inconspicuous); PAPT posterodorsally, NP and PC with tufts of golden yellow hairs; scutum with two medial, pollinose stripes extending on the anterior three-quarters of the scutum, and slightly diverging posteriorly; pro- and mesoleg with pale hairs except for a few black hairs at the apex of the femora dorsally, at the apex of the tibiae ventrally, and on the tarsi; metaleg with pale hairs except for scattered black hairs on the apical quarter of the femur dorsally, and a few spiny black hairs at the apex of the femora ventrally; metatibia with black hairs along the full ventral length, these hairs circumventing the apical third to quarter; wing brown-pigmented anteriorly (pigmented area decreasing towards the wing apex); tergum I with a moustache arrangement of golden yellow hairs, which comprises two lateral, dense groups of laterally directed hairs and a central area with a lower density of hairs; terga II – IV yellow haired except for the posterior margin, which usually has a semicircular band of black hairs (at least some of these terga sometimes with only a few black hairs posteriorly): on tergum II the maximum length of this band is up to about a fifth of the tergum length; on tergum III the maximum length is up to a third and on tergum IV it is up to a half of the tergum length; tergum V with long, black hairs, except for yellow hairs on the lateral margins.  
 Material examined   
 Lectotypes of Q. angustiventris and Q. aurata (see data above).   
 Additional material: COSTA RICA: 5m & 1f with puparia, Braulio Carillo, 550 m, 22.vii.2006 (2m), 25.vii.2006 (1m), and 31.vii.2006 (2m & 1f) (CR87, 88, 91 to 93, 97 and 146) (CEUA); 1m with puparium, Tausito Jiménez, Cartago, 1300 m, 20.viii.2007, leg. MAM (CR146) (CEUA); 1f with puparium, Prov. Cartago, Tapantí forest, 16–19.ii.1999, ex liquid contained between bracts of Heliconius, leg. EGH (HM); 10m & 4f, Puntarenas, Rincón de Osa, Tropical Sciences Center Field Station, leg. Richard P. Seifert, det. FCT 1978 (USNM ENT 00036217, 00036221, 00036223 to 00036229, 00036231, 00036238 to 00036241) (USNM); 1m, Prov. Limón, Talamanca, Estación Gandoca, 0–50 m, 19.v.2004, leg. W. Porras, collected by ‘red con aguamiel’, L S 392600 615500#77094 (INB0003845226) (INBio); 1m with puparium, leg. GER, det. CPB & EGH 2001 (HM).   
 TRINIDAD: 56m with puparia & 15m without puparia, reared from larvae collected in Arima Valley, Chaguaramas, El Tucuche, Guanapo Rd, Lopinot, Maracas Bay Rd, Simla, Tamana Hill, Trinity and W. I. Northern Range nr Mt St Benedict, in 22.vii.1994, 8.vii.1996, 27.viii.1996, 4.vii.1997, 16–25.vii.1998, vii-viii.1999, and 27.vii-9.viii.2008, ex liquid contained between the bracts of Heliconia bihai, leg. EGH and Sharon Kennedy, collected by ‘ Glasgow Univ. Epdtn’, det. CPB & EGH 2001 or EGH (HM); 54f with puparia & 17f without puparia, reared from larvae collected in Hollis Dam and the same localities as the males except for Simla, Trinity and ‘W. I. Northern Range nr Mt St Benedict’, on 4, 22, and 25.vii.1994, 7, 15, and 17.vii.1996, 16–31.vii.1998, vii–viii.1999 and 27.vii/ 9.viii.2008, ex liquid contained between the bracts of Heliconia bihai, leg. EGH, collected by ‘ Glasgow Univ. Epdtn’, identification data as in males (HM).   
 VENEZUELA: 39m & 45f, reared from larvae collected February 2007 in ‘ Edo. Aragua. P.N. Henri Pittier, Estación Biológica Rancho Grande, 1183 m’ and ‘ Edo. Yaracuy. San Felipe, Hacienda Guáquira, 90 m’, leg. CPB (CEUA).   
 Range   
Brazil, Colombia, Costa Rica, Peru Trinidad, Venezuela, and Surinam (specimens from Menno Reemer).  
 Taxonomic notes   
 Small to medium size species (7.5–11.5 mm; N = 100+) with slender abdomen; males are unequivocally distinguished from any other species by the presence of a thick mat of adpressed hairs obscuring the background colour of the frontal triangle; males of the similar species Quichuana quixotea Hull, 1946 never have such a thick mat of hairs, and the background colour of the frontal triangle is not obscured; females of Q. angustiventris have two lateral, shiny stripes restricted to the upper half of the face, whereas in Q. calathea, Quichuana picadoi Knab, 1913, Quichuana subcostalis (Walker, 1860), and Q. sylvicola the bottom of the frontal prominence to the mouth edge; facial pollinosity white and restricted to a narrow line at the eye margins and a stripe extending from the eye margin to the mouth edge laterally; occiput white pollinose, with long hairs mostly white but, on the upper third of occiput, with a line of intermixed black hairs.   
 these stripes are complete (from the frontal prominence to the mouth edge or nearby); examining the proportion of black hairs on terga II – IV in females of Q. angustiventris can also help to separate them from females of all the above species (see ‘diagnostic features’ under each species or key). Females of Q. angustiventris and Q. quixotea cannot be separated, see ‘taxonomic notes’ under Q. quixotea.
description: Published as part of Ricarte, Antonio, Marcos-García, M. Ángeles, Hancock, E. G. & Rotheray, Graham E., 2012, Revision of the New World genus Quichuana Knab, 1913 (Diptera: Syrphidae), including descriptions of 24 new species, pp. 72-131 in Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) (Zool. J. Linn. Soc.) 166 (1) on pages 74-77, DOI: 10.1111/j.1096-3642.2012.00842.x, http://zenodo.org/record/5408533