Austroascia segersi Thompson & Marnef, 1977

Barahona-Segovia, Rodrigo M., Riera, Pamela, Pañinao-Monsálvez, Laura, Guzmán, Vicente Valdés & Henríquez-Piskulich, Patricia, 2021, Updating the knowledge of the flower flies (Diptera: Syrphidae) from Chile: Illustrated catalog, extinction risk and biological notes, Zootaxa 4959 (1), pp. 1-178 : 22-23

Austroascia segersi Thompson & Marnef, 1977

Figs 16–19

Austroascia segersi Thompson & Marnef, 1977: 4

Type locality and data. “ Quintero , Bosque Relicto, Chile ” (HT, ♂, USNM) .

Material examined. Coquimbo: 2♂, 3♀, El Naranjo, Tilama , no data, Leg. L.E. Peña ( MEUC) ; Valparaíso: Bosque relicto, Quintero ( Thompson & Marnef 1977); El Salto, I.1959, Leg. H. Toro ( Thompson & Marnef 1977) ; Biobío: 1♂, Concepción, 7.XI.1973, Leg. E. Krahmer ( MZUC) ; La Araucanía: 1♂, Termas de Palguín , 14–22.II.1966, Leg. Etcheverry ( MNHNCL) ; Los Ríos: 1♂, 1♀, Santo Domingo , 6.XII.1987, Leg. E. Krahmer ( UACH) ; 2♂, same locality, 20.I.1974, 30.XII.1979, Leg. E. Krahmer ( UACH) ; 2♀, Valdivia , 21.XII.1980, Leg. E. Krahmer ( UACH) ; Los Lagos: 3♂, 6♀, Senda Darwin Biological station , 14.I.2015, Leg. L. Vieli & C. Smith-Ramírez ( CSD) ; 1♂, 2♀, Caulín, Chacao , II.2016, Leg. C. Smith-Ramírez ( CSD) .

References. Thompson & Marnef, 1977: 4 (desc.); Thompson, 1999a: 330 (key).

World distribution. Chile.

Chilean distribution. From Coquimbo to Los Lagos region ( Fig. 28 ).

Altitudinal range. From coastal to inland valley ecosystems (5– 450 m.a.s.l.).

Biology and notes. Austroascia segersi is associated with native trees such as Drimys winteri J.R. Forst. & G. Forst. , Eucryphia cordifolia Cav. and Myrceugenia planipes (Hook. & Arn.) O. Berg (Thomspon & Marnef 1977; C. Smith-Ramírez pers. obs.). Throughout its distribution range, many ecosystems have been negatively affected by plantation forestry, croplands and urbanization ( Alaniz et al. 2016; Miranda et al. 2017). Both males and females are dichoptic ( Figs 16–19 ) and sexual dimorphism is generated by the maculae pattern and color of the abdomen. Males present enlarged and yellowish maculae located near the abdominal margin. Females do not present maculae and the abdominal color is reddish.

Conservation status. VU under B2ab (iii) using AOO = 28 km 2 and seven localities (or subpopulations); EOO = 41,336 km 2.

Genus Chamaesphegina Shannon & Aubertin, 1933

Chamaesphegina Shannon & Aubertin, 1933: 145 . Type-species, argentifacies Shannon & Aubertin (orig. des.).

Desmetrum Enderlein, 1938: 194 . Type-species, macrum Enderlein (orig. des.).

Figures

FIGURE 28. Distribution map of Austroascia segersii Thompson & Marnef, 1977 (red circles); Chamaesphegina argentifascies Shannon & Aubertin, 1933 (blue circles); Notiocheilosia nitescens Shannon & Aubertin, 1933 (black circles); Orthonevra chilensis Thompson, 1999 (green circles) and Sphiximorpha barbiger (yellow circles) in Chile.

FIGURES 16–19. Austroascia segersii Thompson & Marnef, 1977: (16) male, dorsal view; (17) male, lateral view; (18) male, frontal, view; (19) female, dorsal view. Scale bars = 1 mm (all photos by Vicente Valdés).