Merosargus cingulatus Schiner 1868
Creators: name: Fachin, Diego Aguilar
name: Amaral, Edna Maria
name: Falaschi, Rafaela Lopes
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Stratiomyidae
Merosargus
Merosargus cingulatus

description: Merosargus cingulatus Schiner, 1868
(Figs 1–5, 12–27, 43)
Merosargus cingulatus Schiner, 1868: 62. Syntypes: 5 males, 1 female (NMW, examined in situ by the first author; according to Woodley, 2001: 195 it should be 1 male and 5 females). Type locality: “South America”.
Diagnosis of the adult (both sexes) (modified from James & McFadden (1971)). Dark body with green to bluish metallic reflections on head and scutum mainly; bluish reflections over abdominal tergites (Figs 1–3). Frontal callus on the lower frons entirely whitish, without a central dark brown band separating it into portions (as seen in Merosargus gracilis) (Figs 4–5); lower frons below frontal callus dark brown. Propleura brown to reddish brown (Fig. 3); meso- and metapleura mostly dark, shining blue to purple, except for a whitish spot on anepimeron distally, extending to the anterior portion of the katepisternum, and laterotergite withish anteriorly.
Material examined. Specimens with puparium. 1 ♂ (puparium without head), BRAZIL, Paraná, Carambeí, Alto do Carambeí, 24°55’30”S 50°04’51”W, 31.iii.2019 (emerged 11.iv.2019), emergence trap with fermented beans, Amaral, E.M. (MZUSP); 1 ♂ (puparium without head), 31.iii.2019 (emerged 17.iv.2019) (MZUSP); 1 ♀, 23.xi.2019 (emerged 12.xii.2019), abóbora podre [= in rotting pumpkin], Amaral, E.M. (MNRJ); 1 ♂ (puparium photographed), 23.xi.2019 (emerged 16.xii.2019) (MZUSP); 2 ♂ (puparia without head), 2 ♀ (1 without head; 1 coated with gold for SEM), 23.xi.2019 (emerged 17.xii.2019) (2 ♂, 1 ♀, MZUSP; 1 ♀, MNRJ, puparium without head); 3 ♂, 23.xi.2019 (emerged 18.xii.2019) (1 ♂, MZUSP; 2 ♂, MNRJ); 2 ♂, 23.xi.2019 (emerged 19.xii.2019) (MZUSP); 1 ♂ (puparium without head), 23.xi.2019 (emerged 20.xii.2019) (MZUSP); 1 ♀ (puparium coated with gold for SEM), 23.xi.2019 (emerged 21.xii.2019) (MZUSP); 4 ♂ (3 without head; 1 coated with gold for SEM), 23.xi.2019 (emerged 23.xii.2019) (MZUSP). Specimens from same locality, without puparium. 1 ♀ (genitalia dissected, stored in microvial with glycerin), BRAZIL, Paraná, Carambeí, Alto do Carambeí, 24°55’30”S 50°04’51”W, 31.iii.2019 (emerged 11.iv.2019), emergence trap with fermented beans, Amaral, E.M. (MZUSP); 1 ♂ (genitalia dissected, stored in microvial with glycerin), 31.iii.2019 (emerged 17.iv.2019) (MZUSP); 1 ♀, 23.xi.2019 (emerged 12.xii.2019), abóbora podre [= in rotting pumpkin], Amaral, E.M. (MZUSP); 1 ♀, 23.xi.2019 (emerged 13.xii.2019) (MZUSP); 3 ♂, 11 ♀, 23.xi.2019 (emerged 16.xii.2019) (1 ♂, 8 ♀, MZUSP; 2 ♂, 3 ♀, MNRJ); 1 ♂, 1 ♀, 23.xi.2019 (emerged 19.xii.2019) (MZUSP); 1 ♀, 23.xi.2019 (emerged 27.xii.2019) (MZUSP); 2 ♂, 23.xi.2019 (emerged 16.xii.2019), puçá [= sweeping net] (MZUSP). Other material, without puparium. 1 ♀, BRAZIL, Ceará, Ubajara, Parque Nac. [Nacional] de Ubajara, Cachoeira do Cafundó, 03°50’13”S 40°54’35”W, armadilha Malaise, 01–14.ii.2013, J.A. Rafael, F. Limeira-de-Oliveira cols. (CZMA). 1 ♀, Maranhão, Mirador, Parque Est. [Estadual] Mirador, Base da Geraldina, armadilha Malaise, 20.i.2007, F. Limeira-de-Oliveira (CZMA); 1 ♀, 30.ix.2007 (CZMA); 1 ♂, Mirador, Parque Est. Mirador, Base dos Cágados, 06°46’29”S 45°06’28”W, armadilha Malaise, 26.xi–03.xii.2011, F. Limeira-de-Oliveira & D.W.A. Marques cols. (CZMA); 1 ♀, Mirador, Parque Est. Mirador, Base da Geraldina, 06°37’25”S 45°52’08”W, armadilha Malaise, 11–16.i.2013, J.T. Câmara, L.L.M. Santos, L.S. Santos cols. (CZMA); 1 ♀, 10–16.v.2013, F. Limeira-de-Oliveira, L.L.M. Santos, L.S. Santos cols. (CZMA). 2 ♀, Mato Grosso do Sul, Bodoquena, Fazenda Califórnia, Transição, 20°41’53.5”S 56°52’55.7”W, Malaise 05, 06–21.v.2012, Lamas, Nihei & eq. cols. (MZUSP). 1 ♂, 1 ♀, Rio de Janeiro, Casimiro de Abreu, Reserva Biológica União, [22°25’41.77”S 42°2’8.32”W], Malaise (Biota Diptera Fluminense), 28.iv.–17.v.2013, Eq. col. (MNRJ). 1 ♂, Nova Iguaçu, Reserva Biológica do Tinguá, 22°34’34.9”S 43°26’06.5”W, Malaise, Bosque 2, 05–08.iii.2002, S.T.P, Amarante & eq. col. (MZUSP); 1 ♂, 22°34’27”S 43°26’10”W, Malaise, Trilha 6, 08–11.iii.2002, S.T.P, Amarante & eq. col. (MZUSP); 1 ♂, Moericke, Trilha 7, 09–12.iii.2002, S.T.P, Amarante & eq. col. (MZUSP). 1 ♀, São Paulo, Ribeirão Grande, Pq. Est. Intervales [Parque Estadual de Intervales]/ Barra Grande, Malaise, Ponto T 3, 10–13.xii.2000, M.T. Tavares & eq. col. (MZUSP); 1 ♂ Malaise, Ponto T 4, 10–13.xii.2000 (MZUSP). 1 ♀, Ubatuba, Pq, Est. [Parque Estadual da] Serra do Mar, 23°21’43”S 44°49’22”W, Malaise 5 - Trilha, 21.i.2002, N.W. Perioto & eq. cols. (MZUSP). 2 ♂, PANAMA, Colón Prov. [Province], Gamboa Pipeline Rd. Soberiana Nat’l Park, 05.ii.2014, 09°07’38.8”N 79°42’53.4”W, Larry G. Bezark coll. (CSCA).
Literature records. Carrera & Lane (1945), Lindner (1949), James & McFadden (1971), Fontenelle et al. (2012), Fachin & Amorim (2015), Fachin et al. (2022), and Riccardi et al. (2022).
Description. Puparium. Total length (n = 19): 9.5–12.0 mm. Cuticle with a well-defined zigzag appearance on ventral and dorsal surfaces (Figs 12–15). Head. Conical, somewhat convex dorsally, nearly straight ventrally, longer than wide, almost two times longer than wide, apical third, anteriorly to eyes, slender. Cuticle darker from the level of eyes to the posterior margin of head (Figs 12, 16). Maxillary palpus composed of a rigid, oval, and small structure, scarcely visible (Figs 12, 16–17), as much wide as antenna cavity, with three pairs of small setae posteriorly. Labrum subrectangular, rounded at apex (Fig. 12). Antenna (ant) small, apparently one-segmented; only one antennomere tapering towards apex (Fig. 22); antenna placed in a well-developed small circular cavity, dorsal-laterally arising from the anterior part of head (Figs 12, 16), posteriorly to the second pair of labral setae. Eye (e) prominent, rounded, arising slightly below the middle part of head (Figs 12, 16). Molar area (mo) distinct transversely ridged (Figs 14, 17), wider than the maxillary palpus in ventral view. Chaetotaxy: 2 pairs of labral setae (Lb), 2 pairs of clypeofrontal setae (Cf), 2 pairs of dorsolateral setae (Dl), 1 pair of lateral setae (L), 3 pairs of ventrolateral setae (Vl), 2 pairs of ventral setae (V), and 1 pair of ventroapical (Va) setae in the labral-molar area. Setae of head branched from a main axis, from broom-shaped to shrub-like (Fig. 21). Thorax. Rectangular; chaetotaxy: prothorax with 2 rows of setae in dorsal view, 2 pairs of anterodorsal setae (Ad), 3 pairs of dorsal setae (D), and 1 pair of dorsolateral (Dl); in ventral view, 1 pair of ventrolateral (Vl) and 2 pairs of ventral setae (V), (V1) simple and (V2) bipartite; prothoracic spiracle (prth spr) sclerotized, prominent. Meso- and metathorax with one row of setae each in dorsal view; mesothorax with 3 pairs of anterodorsal setae (Ad), 1 pair of dorsolateral setae (Dl), and 1 pair of lateral setae (L); in ventral view, 1 pair of ventrolateral setae (Vl) and 2 pairs of ventral setae (V), simple. Metathorax with 3 pairs of dorsal setae (D), 1 pair of dorsolateral setae (Dl), and 1 pair of lateral setae (L); in ventral view, 1 pair of ventrolateral setae (Vl) and 2 pairs of ventral setae (V), simple; apparently without lateral setae (Figs 12–15). Setae of thorax with shorter branches from a main axis, usually lanceolate (Fig. 18). Abdomen. Abdominal segments 1 to 7 similar in shape, slightly tapering from segment 5 to 7 (Figs 13, 15); segments 2 to 6 with small lateral abdominal spiracles (abd spr) (Figs 13, 15); chaetotaxy in segments 1 to 7 (Figs 13, 15, 24): each segment with a row of 3 pairs of dorsal setae (D) and 3 pairs of ventral setae (V); in segments 1 to 5, near the external margin of the body, 1 pair of ventrolateral setae (Vl), 1 pair of lateral setae (L), and 1 pair of dorsolateral setae (Dl), all three aligned, shorter setae in segments 2 to 5, longer in segment 1; in segments 6 to 7, 1 pair of ventrolateral setae (Vl), 2 pairs of lateral setae (L), and 1 pair of dorsolateral setae (Dl), all longer setae and lateral setae lower in the external margin of the body compared to the other two. Segment 6 with a well-developed oval-shaped sternal patch, half the length of the segment 6 (Figs 15, 19–20, 23–25). Segment 8 semicircular, tapering towards posterior margin (Figs 13, 15, 24); posterior margin somewhat concave (Fig. 13); cleft of posterior spiracle placed dorsally on segment 8, somewhat straight, with lower lip of opening bordered by flat and pinnate setae; anal slit with more than one-third the length of segment 8, placed in the basal half (Figs 15, 24); chaetotaxy: 1 pair of dorsal setae (D), 1 pair of lateral setae (L), 4 pairs of ventral setae (V), 1 pair of subapical setae (Sa), and 2 pairs of apical setae (Ap).
Notes on natural history. Larvae of Merosargus cingulatus have been collected from a variety of substrates. Viana & Xerez (2002) found larvae of the species in a composter and stated that the species was also found in rooting fruits of Couroupita guianensis Aubl. (Lecythidaceae), known as the cannonball tree, referring to Pujol-Luz & Leite (2001). However, this finding was not mentioned in this study. More recently, Fontenelle et al. (2012) found larvae developing in stems of Astrocaryum aculeatissum (Schott) Burret (Arecaceae) and Thoracocarpus bissectus (Vell.) Harling (Cyclanthaceae), as well as in pseudostems of Heliconia episcopalis Vell. (Heliconiaceae) and in leaves of A. aculeatissum. As the new records of larvae in rotting beans and a pumpkin may suggest, M. cingulatus seems to be attracted to the decomposing commercial varieties as well. Additionally, it is not uncommon to find adults flying over fruits in supermarkets and farmer markets/fruit stands in Brazil.
Geographic distribution. Brazil (Ceará, Maranhão, Mato Grosso do Sul, Minas Gerais, Paraná, Roraima, Santa Catarina 1, São Paulo), Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Trinidad & Tobago, Venezuela (Fig. 43). 1 Likely occurring in the state of Santa Catarina, as indicated by James & McFadden (1971), but a formal record for the state has not been published yet.
Comments. Merosargus gracilis Williston, 1888 is possibly a synonym of M. cingulatus. Both species are widespread in the Neotropical Region (Woodley 2001) and they are morphologically similar. They are dark metallic species with green to bluish metallic reflections on the head and thorax and they have a dark abdomen with purple metallic shining and hind femur with basal half white and apical half black or with the extreme base of the femur black, then white up to the middle, and then apical half black. According to James & McFadden (1971: 26, 65), both species can be distinguished by the coloration of the frontal callus (on the lower frons) and prothorax. In M. cingulatus, the frontal callus is entirely white (as in our Figs 4–5) or nearly so, and the prothorax is orangish to brown (as in our Fig. 3), while in M. gracilis, the frontal callus is divided into two whitish spots by a central dark brown marking and the prothorax is much darker (Iide & Pujol-Luz 1999; Zeegers et al. 2022). We have examined dozens of specimens of, supposedly, both species and the limits are not so clear. Particularly, the intensity of coloration of the frontal callus central marking and prothorax varies between specimens from distinct localities. The use of molecular markers can be an interesting source of data to give a new perspective on the limits of both species.
description: Published as part of Fachin, Diego Aguilar, Amaral, Edna Maria & Falaschi, Rafaela Lopes, 2024, Puparium of Merosargus cingulatus Schiner, 1868 and Ptecticus lanei James, 1941 (Diptera: Stratiomyidae: Sarginae), with new geographical records for the species and a list of all known immatures of the subfamily, pp. 421-440 in Zootaxa 5406 (3) on pages 424-427, DOI: 10.11646/zootaxa.5406.3.2, http://zenodo.org/record/10628050