Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade 2020, sp. nov.

Mycomystes nigriventris sp. nov.

Figs. 1–14

Material examined. Holotype. Mycomystes nigriventris holotype, sex undetermined, specimen not dissected (DZUP), “ Coleção M. Alvarenga [printed] \ Capão do Imbuia, CURITIBA, Paraná, Brasil, II–1966, R. Lange leg. [printed], \ DZUP 235198 [printed] \ HOLOTYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, red paper]”. Type locality. Capão do Imbuia, a quarter of the city of Curitiba, in the state of Paraná, South Brazil. Estimated coordinates: 25°25’40’’S, 49°16’23’’W.

Paratypes. A total of 21 specimens, as follows: 1 specimen, sex undetermined (CAMB) “ Coleção M. Alvarenga [printed] \ RIO GRANDE, R.G. SUL. BRASIL, VIII. 1979, L.C. ALVARENGA [handwritten] \ Coleção A.M. BELLO [printed] PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow pa- per]”; 1 ♀ (DZUP, dissected) “ Coleção M. Alvarenga [printed] \ Capão do Imbuia, CURITIBA, Paraná, Brasil, II– 1966, R. Lange leg. [printed], \ DZUP 235197 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 ♀ (DZUP, dissected) “ Coleção M. Alvarenga [printed] \ Capão do Imbuia, CURITIBA, Paraná, Brasil, II–1966, R. Lange leg. [printed], \ DZUP 235185 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MNRJ) “ Coleção M. Alvarenga [printed] \ B. Rico Anhembi, S. Paulo, Brasil [printed], II. 1982 [handwritten], W. Rokermann [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MNRJ) “ Brasil – S. Paulo, Est. S. Paulo [printed], & VIII [handwritten], Saude [printed], 1920 [handwritten], An Pilzen gefunden. 8 [?]. 6. 1920, Melmi [? handwritten, versus label] \ Mycotretus misellus Lac. [handwritten], J. Guerin. det. 194 [printed] 8[handwritten] \ UR [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undeter- mined (MNRJ) “ Brasil – S. Paulo, Est. S. Paulo [printed], & VIII [handwritten], Saude [printed], 1920 [handwritten], An Pilzen gefunden. 8. VIII [?]. 1920, [? handwritten, versus label] \ Mycotretus misellus Lac. [handwritten], J. Guerin. det. 194[printed]8[handwritten] \ UR [printed] \ 110 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 ♂ (MCNZ, dissected) “ Triunfo, RS, (Copesul), 30. XI. 2004, A. Barcellos col. [printed] \ Col. MCN 232832 [printed] \ PARATYPUS Mycomystes nigriventris Pecci- Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 ♂ (MCNZ, dissected) “ Est. Ecol. TAIM, Rio Grande, RS, 17/XII [handwritten] / 19[printed]85[handwritten], A. Lise leg. [printed] \ Col. MCN [printed] 62631 [handwritten] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “Tapes, RS (Faz. São Miguel), 17. XII. 2003, Equipe Probio col. [printed] \ Col. MCN 225584 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “Triunfo, RS, (Copesul), 30. XI. 2004, R. Ott col. [printed] \ Col. MCN 232829 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “Montenegro, RS, 15/XII [handwritten]/19[printed]77[handwritten], H. Bischoff [handwritten] leg [printed] \ Col MCN 26.913 [handwritten] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “ Est. Ecol. TAIM, Rio Grande, RS, 15/X [handwritten] / 19 [printed] 85 [handwritten], A. Lise leg. [printed] \ Col. MCN. [printed] 62852 [handwritten] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [print- ed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “Tapes, RS (Faz. São Miguel), 17. XII. 2003, Equipe Probio col. [printed] \ Col. MCN 225720 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “Tapes, RS (Faz. São Miguel), 17. XII. 2003, Equipe Probio col. [printed] \ Col. MCN 225655 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “Cambará do Sul, RS, 21/XII [handwritten] 19 [printed] 94 [handwritten], A. Bonaldo [handwritten] leg. [printed] \ Col. MCN 238432 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MCNZ) “Triunfo, RS, (Copesul), 6. I. 2005, A. Barcellos col. [printed] \ Col. MCN 232830 [printed] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 1 specimen, sex undetermined (MZSP) “N. Teutonia., S. Catarina. [printed], 10.950 [handwritten] \ Coll. J. Guerin. S. Paulo. Brasil. [printed], 17750 [handwritten] \ Mycotretus nigropunctatus var. D. Dup. [handwritten], J. Guerin. det. 19 [printed] 51 [handwritten] \ PARATYPUS Mycomystes nigriventris Pecci-Maddalena & Lopes-Andrade [printed, yellow paper]”; 4 specimens, sex undetermined (FSCA) “ Fazenda Bom Jesus das Ar- aucárias Reserva (PR, Brazil), Cultivo de Pleurotus sp., P. L. Lopes col. 18-19.II.2008 (noon) \ Mycotretus gemmula Lac., 1842, P. Lopez det. 2008”.

Etymology. The specific epithet, from the Latin adjective “niger, nigra, nigrum” (= black, dark, dusky) and the Latin noun “venter, ventris (m.)” (= “belly”), refers to its black ventral coloration.

Diagnosis. Mycomystes nigriventris resembles its Mexican congener M. ferrugineus in the oval body shape and dilated tibiae. It differs in the black ventral coloration (yellowish to reddish-brown in M. ferrugineus), elytral punctation with rows of punctures uniformly longitudinal and not confluent (in M. ferrugineus these punctures are more irregular and confluent at disc), the lack of a conspicuous angle at the outer side of protibiae (present in M. ferrugineus) and the occurrence in the southern portion of the Neotropics (while M. ferrugineus occurs in the northern portion).

Description. TL = 4.27–6.12 mm (5.41± 0.59 mm, n = 9; length of the holotype = 5.65 mm). Body oval, widest at anterior third of elytra, TL/EW = 1.58–1.68 (1.63±0.03), GD/EW = 0.61–0.71 (0.66±0.034), glabrous, glossy; dorsal coloration homogeneously yellowish-brown or reddish-brown (Fig. 1). Ventral coloration yellowish-brown; prosternal process, meso- and metaventrite and legs blackish (Figs. 2, 3); head yellowish to reddish-brown (Figs. 1, 4); mouthparts yellowish to reddish-brown (Figs. 4–8), mentum plate subpentagonal, with a rounded outline (Fig. 8); antennae yellowish to reddish-brown, antennomeres VII to XI blackish.

Head. Glabrous; punctation fine, sparse; frontoclypeal suture interrupted at middle. Clypeus shallowly, arcu- ately emarginate. Antenna (left antenna measured in holotype given in mm): FL, 0.71, CL, 0.53, CL/FL 0.74; length of antennomeres I to XI as follows (in mm): 0.19, 0.12, 0.21, 0.14, 0.11, 0.10, 0.10, 0.08, 0.13, 0.12, 0.18. Eyes glabrous (GW 0.43 mm in holotype), finely granulate. Mouthparts (Figs. 4–8): Labrum free, sclerotized, pubescent, slightly emarginate at middle. Mandibles short, broad; outer apical edge with one distinct depression containing setae; apex with two teeth; mandibular base emarginate, with additional outgrowth above mola; inner edge of right mandible with conspicuous additional mesal teeth, glabrous, absent in left mandible (Fig. 6, arrow); mola well-de- veloped, naked, distinctly transversely costate; prostheca distal to mola, soft, with additional tuft of setae. Maxillae with cardo subtriangular, stipes elongated; galea shorter but wider than lacinia, somewhat widened towards densely pubescent apex; lacinia much longer and narrower than galea, densely pubescent at apex, with highly sclerotized inconspicuous pair of hooks; maxillary palp with four palpomeres, palpomere I almost as long as palpomeres II–III combined; apical palpomere semicircular (Fig. 7, mp), asymmetrical, approximately 3.46× wider than long and 5× wider than apical labial palpomere. Three labial palpomeres on each palp, palpomere III club-shaped (asymmetrical, Fig. 7, lp); mentum subpentagonal, with a rounded outline (Fig. 4, arrow and Fig. 8).

Thorax. Pronotum subtrapezoidal, edges bordered, sides moderately arcuate, convergent anteriorly. PW/PL = 0.43–0.60 (0.51±0.05), widest medially in both sexes; shiny, punctation single, interspaces microreticulate; punc- tures separated by about 3 puncture-widths at disc, each puncture bearing one very short minute seta (barely visible even at magnification of 150×); anterior edge slightly convex at middle, anterior angles sharp; lateral edge with one glandular pore on anterior angle and one on posterior angle. Scutellar shield BW 0.39 mm (in holotype), subpentagonal, nearly rounded laterally, glabrous, bearing few punctures. Elytra with weak anterior marginal bead; EL/EW = 1.16–1.23 (1.19± 0.02), EL/PL = 2.32–3.22 (2.73±0.35); moderately convex, with eight longitudinal rows of punctures; punctures separated by about 4 puncture-widths; interspaces between rows with fine, sparse punctures, each puncture bearing one minute seta (barely visible at magnification of 150×); elytral punctation with rows of punctures uniformly longitudinal and not confluent. Metathoracic wings developed. Prosternum convex; anterior margin smooth, pubescent; notosternal sutures distinct, entire; procoxal cavities ovate; prosternal process abruptly expanded apically, shallowly emarginate at apex; procoxal lines barely visible, short, nearly straight. Mesoventrite small, convex; mesocoxal lines straight to slightly arched; anterior edge slightly convex. Metaventrite convex, gla- brous, finely punctate; interspaces of punctures microreticulate; metacoxal lines conspicuous, approximately 0.69× as long as metaventrite; discrimen approximately 0.68× as long as metaventrite at midline. Metendosternite welldeveloped, sclerotized; laminae present, plate-like; anterior tendons thin, moderately separated. Legs: Procoxae oval; mesocoxae almost globular; metacoxae transverse, cigarette-shaped. Femora elongate, smooth, without spines or other outgrowths. Tibiae short, conspicuously widened apically and lacking a conspicuous angle at the outer side of protibia (present in M. ferrugineus) (Fig. 3, arrow); apex with crown of wide flat setulae and two apical spurs. Tarsi densely pubescent.

Abdomen. Slightly elongate; punctation coarse, shallow; interspaces microreticulate; vestiture of sparse, slen- der setae. Coxal lines conspicuous, not continuous around coxae (approximately 0.64× length of first abdominal ventrite). Length of ventrites 1 to 5 as follows (in mm, from base to apex of each ventrite at the longitudinal mid- line): 0.85, 0.52, 0.26, 0.28, 0.48. Male terminalia (Figs. 9–12): penis (Fig. 9, pen) elongate, slightly curved; basal portion with short sclerotized projection linked to the apophyses; internal sac with well-developed, elongate flagel- lum (Fig. 9, fla), 1.88× as long as penis, slightly sinuous, with membranous portion (Fig. 10, arrow) between virga and head of flagellum; head of flagellum (Fig. 10, head) horseshoe-shaped, inner contours widely separated, ante- rior borders laterally rounded, shallowly fused medially. Apophyses (Fig. 9, apo), approximately 1.7× longer than penis. Tegmen sclerotized (Fig. 11); parameres reduced, sclerotized, with densely pubescent outgrowths, slightly dilated. Tergite VIII sclerotized, with sparsely distributed bristles. Sternite VIII slightly sclerotized. Laterotergite IX sclerotized, pubescent, posteriorly elongate, slightly narrowed; outer contours angulate; anteroventral edge with paired, subparallel lateral struts, connected at their anterior tips by small, transverse, slightly sclerotized sclerite. Posterior edge of sternite IX sclerotized; outer contour rounded; weakly membranous anteriorly. Tergite X sclero- tized; posterior edge with sparsely distributed bristles. Female terminalia: genitalia (Figs. 13–14) with gonostyli and gonocoxites strongly sclerotized; vagina elongate at level of gonostyli (Fig. 14, arrows); baculi of paraprocts sclerotized, slightly arcuate; spermatheca oval, sclerotized; spemathecal duct sclerotized, slightly sinuous. Tergite VIII sclerotized, with sparsely distributed bristles. Sternite VIII with conspicuous median strut.

Remarks. The exact location of “Cerro de Plumas”, the type locality of M. ferrugineus cited by Gorham (1888), is unknown. It may refer to “Cerro de Palmas” in Veracruz, introduced as a correction to “Cerro de Plumas” in a subsequent issue of Biologia Centrali-Americana (Selander & Vaurie 1962). The type locality is certainly in Mexico, which places it far from the species described herein. Mycomystes nigriventris fits well in the genus because it has conspicuously dilated tibiae, an oval body, and a subpentagonal mentum plate, with a rounded outline and very elongate maxillary palpomeres in relation to labial palpomeres. All of these features are uncommon in Neotropical Tritomini and, as discussed below, they may also be found in at least four species of Mycotretus. Based on the original description, Mycotretus misellus Lacordaire is similar to M. nigriventris in the black ventral coloration. The type of M. misellus has not been located by either Alvarenga (1994) or the senior author of the present work. However, we think Mycotretus misellus is not conspecific to M. nigriventris based on the examination of a specimen identified as M. misellus from the Reiche collection, housed in the University Museum of Zoology Cambridge (Camdridge, UK). This specimen fits Lacordaire’s description well in the slightly elongate body and the coarse elytral punctation (features not observed in M. nigriventris). Aside from that, Lacordaire (1842) did not mention dilated tibiae, a conspicuous feature of M. nigriventris.

Host fungi. There is a record of four specimens collected in Pleurotus sp. (Pleurotaceae) (see above the list of examined specimens).

Distribution. South and Southeast Brazil (Fig. 15).