Chrysomydas nitidulus ( Olivier, 1811 )

Calhau, Julia, Lima, Sheila, Rafael, José Albertino & Lamas, Carlos José Einicker, 2019, A taxonomic synopsis of Chrysomydas Wilcox, Papavero & Pimentel (Diptera: Mydidae: Mydinae), with first bionomic records for the genus and description of a new species from Brazil, Zootaxa 4664 (1), pp. 103-114 : 104-107

Chrysomydas nitidulus ( Olivier, 1811)

( Figs 1 A–H, 3A–G, 4A–E, 6)

Midas nitida Lichtenstein, 1796 :? (nom. nudum) (in auction-catalog of Holthuysen collection).

Mydas nitidulus Olivier, 1811: 82 , 83. Type-locality: “South America”. Type lost. Refs.— Wiedemann, 1830: 626 (cat.); Walker, 1854: 366; Gerstaecker, 1868: 94; Hunter, 1901: 154 (cat.); Kertész, 1909: 39 (cat.); d’Andretta, 1951: 8,72 (listed but not treated); Papavero & Wilcox, 1968: 9 (cat.).

Midas nitidulus Wiedemann, 1831: 36 , 41, pl. 52, fig. 4; Westwood, 1841: 51.

Chrysomydas nitidulus: Wilcox et al., 1989: 131 (n. comb.); Papavero & Artigas, 1990: 125 (cat.); Papavero, 2009: 15 (cat.).

Mydas claripennis Williston, 1898: 56 . Type-locality: Brazil, Mato Grosso, Chapada (dos Guimarães). Type ♂, AMNH. Refs.— Hunter, 1901: 154 (cat.); Kertész, 1909: 36 (cat.); d’Andretta, 1951: 8, 73 (only listed); Papavero & Wilcox, 1968: 7.

Mydas clarifumis Grossbeck, 1912: 373 (misspelling).

Diagnosis. Labellum about 1.1x longer than wide. T2–T5 with long dense golden recumbent setulae directed laterally. Scutum with distinct lateral white and golden posterior pruinose spots. Male cerci partially covered by epandrial lamellae; distal process of the gonocoxite-hypandrial complex apically wide, truncate, with both dorsal and ventral tips acute.

Redescription. Greatest length, excluding antennae 25–28 mm. Male terminalia ( Figs 3 A–D). Black, setulae black. Epandrial lamellae with distinct posterior spur, tip slightly curved. Cercus partially covered by epandrial lamella. Phallus short with bifid dorsal crest. Distal process of gonocoxite-hypandrial complex apically wide, truncate, with both dorsal and ventral tips acute. Female terminalia ( Figs 3 E–G). Black, setulae black. T9+10 anteroposteriorly narrowed. S10 with narrow membranous medial region. S8 distally with lateral and medial lobes; lateral lobes with oval sclerotized area, medial lobe largely membranous. Genital fork (S9) composed of two separated sclerites convergent anteriorly; anterior tips of sclerites bifid. Sclerite at base of spermathecal ducts slightly wider than cercus. Three spermathecae present; capsule of lateral spermathecae about as wide as spermathecal duct, with acute apex; capsule of medial spermatheca with roundish dilated apex.

Pupa ( Figs 4 A–E). Greatest length, not including anterior antennal or dorsal posterolateral processes 21.3 mm. Greatest width of thorax 4.9 mm. Greatest width of abdomen 5.2 mm. Body yellowish brown. Spines reddish brown. Anterior antennal processes spiniform, reddish on proximal two thirds, black on distal third, rugose, curved outwards. Posterior antennal processes reddish, rugose, with two separate posteriorly curved spines. Maxillary sheath rugose. Proboscidal sheath short, rugose, truncate. Prothoracic spiracle laterally at anterior margin of thorax on highly rugose, raised area. Anterior lateral mesothoracic callosity reddish, flat, rugose. Wing sheath with small basal reclinate spine. Thoracic area above wing sheath smoothly transversely rugose. Leg sheaths rugose. Leg sheath 3 reaching to middle of abdominal segment 2. Spiracles of abdominal segments 1–7 situated along midline laterally, raised, shining, reddish. Spiracle of segment 8 not as conspicuous as remaining abdominal spiracles. Abdominal segment 1 anteriorly with 13 flattened proclinate spines, posterolaterally with 8–9 reclinate spines, some of them bifid. Abdominal segments 2–7 each with 39–58 posterior flattened erect to reclinate spines. Abdominal segment 2 with 58 posterior flattened erect to reclinate spines, with 21 dorsal, 9–10 on each lateral, and 18 ventral. Abdominal segment 3 with 52 posterior flattened erect to reclinate spines, with 19 dorsal, 7–8 on each lateral, and 18 ventral. Abdominal segment 4 with 52 posterior flattened erect to reclinate spines, with 18 dorsal, 7–8 on each lateral, and 19 ventral. Abdominal segment 5 with 49 posterior flattened erect to reclinate spines, with 17 dorsal, 7–8 on each lateral, and 17 ventral. Abdominal segment 6 with 46 posterior flattened erect to reclinate spines, with 15 dorsal, 7–8 on each lateral, and 16 ventral. Abdominal segment 7 with 39 posterior flattened erect to reclinate spines, with 14 dorsal, 6 on each lateral, and 13 ventral. Abdominal segment 8 dorsally with 7 reclinate short spines, laterally with 1 long and 1–2 minute reclinate spine on each of two raised tubercular areas on each side, and 10 erect ventral spines. Abdominal segment 9 with pair of divergent long posterior spiniform processes, ventrally curved.

Type material examined. Mydas nitidulus : holotype lost (type depository not stated by Olivier; see the Remarks section below).

Mydas claripennis: Images of the male holotype of C. claripennis taken by Dr. Torsten Dikow. BRAZIL, Mato Grosso: Chapada [dos Guimarães, 15°27′S, 55°44′W], no date, H.H. Smith ( AMNH).

Additional material examined. BRAZIL, Amazonas: Manaus, Rodovia AM 010 , km 35, Ramal Água Branca II, Sítio Vida Tropical , 2°51′53″S, 59°56′’00″W, 10.iv.2017 (larva collected in coconut trunk), 29.v.2017 (emergen- ce of female imago in laboratory), (1 ♀, INPA) . Minas Gerais: Santa Bárbara, Fazenda Bocaina , pomar [orchard], 20°00′00″S, 43°28′16″W, 19.xi.2016, alt. 750 m, M.F. Vasconcelos leg. (1 ♂, 1 ♀, UFMG) . São Paulo: Arujá [23°24′S, 46°18′W], 18.i.2015, G. Ide col. (1 ♂, MZUSP) .

Distribution ( Fig. 5 ). Brazil (Amazonas, Mato Grosso, Minas Gerais, São Paulo), French Guiana (Cayenne), Guyana ( Demerara, Georgetown, Warratuk), Suriname.

Bionomics. Two third-instar larvae (L3) were collected on the same decaying trunk of a coconut palm ( Cocos nucifera L.), and one of those larvae completed its development in the laboratory. The mydid larva was fed Elateridae and Scarabaeidae larvae ( Fig. 5 ) and also earthworms. The larva pupated after about 30 days, with the pupal stage lasting 19 days. The pupa underwent color change in the pre-emergence period, from light yellow to brown. On the nineteenth day, the pupa became immobile and rigid, non-responsive to mechanical stimulation, with ventral portion upward, and the female imago emerged (Video: https://www.youtube.com/watch?v=j18XUCOkMSQ). The adult remained motionless for about thirty minutes, and grew darker, eliminating the meconium and stretching its wings to make its first flight. The adult fly was then preserved and added to the INPA collection.

Remarks. The species C. nitidulus has a confusing history, and its holotype has been considered lost for decades ( Wilcox et al. 1989; Papavero 2009; Papavero & Artigas 1990; Papavero et al. 2002). Lichtenstein was the first to study a specimen of this species at the Holthuysen collection; however, in the Holthuysen collection catalog ( Lichtenstein 1796) edited in Hamburg, he referred to this species as Midas nitidus (nom. nud.). This species was only formally described by Olivier (1811), who did not designate type specimens. It is possible that he described the species based on the same specimen studied by Lichtenstein, since Olivier named the species almost with the same name: Mydas nitidula (instead of M. nitudus ). The short original description by Olivier is translated below:

“The antennae are black. The head and the thorax are black, and covered, in some places, with red hair. The abdomen is black, with a golden-green spot on each side of the second, third, fourth, and fifth segments; a few red hairs are seen on the first. The wings are transparent, with a slight brown tint on the outer edge. The legs are black, the hind legs are little enlarged, and have short spines on their inner surface. It is found in South America” ( Olivier 1811: 83).

Decades later, Wiedemann (1830) redescribed the species based on the specimen studied by Lichtenstein, an “Exemplum vetustissimum” from Suriname. He cites the name given by Olivier with two corrections: the spelling of the genus name ( Midas for Mydas ) and the gender concordance of the specific epithet ( nitidula for nitidulus ). The description by Wiedemann fits the specimen formerly studied by Lichtenstein in all details mentioned in the description, even the abdominal color, and absence of the abdominal sternites (J. Pohl, pers. comm.). This specimen is now deposited in the Museum für Naturkunde, Berlin, Germany, and the labels are as follows (no type label present) (J. Pohl, pers. comm.):

“ Surinam /?”; “1178”; “nitidulus / Ol. Wd. / nitidus Licht * / Mus Holth. / Kirst. ” [line breaks in the labels are indicated with /].

Although there is a good possibility that this specimen is indeed the holotype of C. nitidulus , the status of the specimen remains unclear because there are no labels indicating that it was actually examined by Olivier (there are only labels by Lichtenstein and Wiedemann). We believe that this fact, more than the lack of type labels, prevents us from determining the type status of the specimen until new evidence emerges.

Figures

FIGURE 1. Chrysomydas nitidulus. A–D: male (UFMG). A. Dorsal habitus; B. Lateral habitus; C. Head, frontal view; D. wing; E–H. female (INPA); E. Dorsal habitus; F. Lateral habitus; G. Head, lateral view.

FIGURE 3. Male and female terminalia of Chrysomydas. A–D. Chrysomydas nitidulus (male, UFMG); A. Epandrium and proctiger, dorsal view; B. Gonocoxite-hypandrial complex and associate structures, dorsal view; C. same, ventral view; D. same, lateral view; E–G. Chrysomydas nitidulus (female, INPA); E. Sternite 8; F. Female terminalia, dorsal view; G. same, ventral view; H–K. Chrysomydas phoenix sp. nov. (male holotype, MNRJ); H. Epandrium and proctiger, dorsal view; I. Gonocoxite-hypandrial complex and associate structures, dorsal view; J. same, ventral view; K. same, lateral view. Abbreviations: cerc, cercus; ph, phallus; phc, phallic crest; sps, sclerite of spermathecal ducts; S, sternite; S9, genital fork; T, tergite.

FIGURE 4. Pupal exuviae of Chrysomydas. A–E. Chrysomydas nitidulus (female, INPA). F–J. Chrysomydas phoenix sp. nov. (male, MNRJ). Abbreviations: aap, anterior antennal process; abs, abdominal spiracles; amsp, anterior mesothoracic spines; dpp, dorsal posterolateral process; ls, labral sheath; ls1, leg sheath 1; ls2, leg sheath 2; ls3, leg sheath 3; ms, maxillary sheath; pap, posterior antennal processes; pmc, posterior mesothoracic callosity; prs, proboscidal sheath; ps; palpal sheath; pths, prothoracic spiracle; vc, ventral callosity; vpp, ventral posterolateral process; ws, wing sheath.

FIGURE 5. Distribution map for species of Chrysomydas in South America.