Mycotretus chilensis Crotch, 1876

Pecci-Maddalena, Italo Salvatore De Castro & Lopes-Andrade, Cristiano, 2017, Redescription of two species and proposal of a new synonym in the genus Mycotretus Lacordaire, 1842 (Coleoptera: Erotylidae: Tritomini), Zootaxa 4282 (1), pp. 147-165 : 149-153

Mycotretus chilensis Crotch, 1876

Figs. 1 , 3 A–D, 4A–D, 5 and 7D.

Mycotretus chilensis Crotch 1876: 454 . Type locality: Chile (possibly mislabeled); Gemminger & Harold 1876: 3692 [distribution]; Kuhnt 1909: 75 [distribution]; Blackwelder 1945: 466 [distribution]; Guérin 1952: 182 [description by Crotch (1876) and distribution]; Alvarenga 1994: 22 [information on type series and distribution]; Skelley & Cekalovic 2001: 221 [comments on distribution].

Mycotretus bicinctus Guérin 1949: 236 , fig. 9, new synonym. Type locality: Brasil, São Paulo, Parque da Cantareira; Alvarenga 1994: 21 [information on type series and distribution]; Campaner et al. 2008: 242 [list of Erotylidae types deposited at MZUSP].

Adult diagnosis. There are two distinct color patterns in M. chilensis , a sexual dimorphism which works for most individuals. In the first pattern, observed in the lectotype and in most males, the pronotum usually has a small black band anteriorly ( Figs. 1 A and 1D, red arrow) instead of circular spots, and four circular free black spots on disc; the first transverse elytral black band reaches the anterior elytral edge ( Figs. 1 A and 1D); the second black band is more elongated and the posterior outline is less sinuate ( Figs. 1 A and 1D) in comparison to females; both the first and second transverse bands begin at mesal sutural edge but do not reach the elytral outer edges ( Figs. 1 B and 1E); the ventral coloration in fully pigmented males can be reddish-brown to blackish, mainly in the meso- and metaventrite ( Fig. 1 F). In the second color pattern, observed in most females, the pronotum usually has two circular black spots on the anterior portion and four circular free black spots on disc ( Figs. 1 G, 4A), which is similar to the pronotal color pattern of M. trifasciatus ( Figs. 2 A,D, 4E). The elytra have two wide and sinuate transverse black bands: the first on the anterior half, which reaches the anterior elytral edge close to scutellar shield ( Fig. 1 G, white arrow) and does not reach the outer elytral edges ( Fig. 1 H); the second transverse black band extends from the mesal sutural edge to the outer edges ( Figs. 1 G–H); the ventral coloration is homogeneously yellowish-brown even in fully pigmented females. Penis ( Fig. 5 A) with flagellum (in internal sac) well-developed and sinuate (length mean: 1.65 mm, n = 2, from the beginning of virga to the end of its head) with a median membranous portion containing a slight sinuosity (length mean: 0.15 mm, n = 2; Fig. 5 A, black arrow). Both flagellum and sinuosity are shorter compared to those of M. trifasciatus (compare to Fig. 6 A, sinuosity shown by black arrow).

Redescription. Length (in mm) = 3.73–5.71 (4.83 ± 0.53, n = 21). Body elongate, widest at the anterior third of elytra, TL/EW = 1.67–2.03 (1.77 ± 0.073), GD/EW = 0.63–0.82 (0.69 ± 0.04), glabrous and glossy, dorsal coloration whitish, yellowish or reddish-brown with transverse black bands. Ventral coloration homogeneously yellowish-brown (usually females) or blackish on the meso- and metaventrite (usually males) in fully pigmented individuals; head with the same background color of the remainder body but without black spots or marks; mouthparts usually yellowish to reddish-brown, mentum plate with an almost black outline; antennae yellowish to reddish-brown, antennomeres VI to XI blackish.

Head. Glabrous; punctation single, fine and sparse; frontoclypeal suture present but interrupted at middle. Clypeus. Shallowly and arcuately emarginated. Antennae. Left antenna measured in one individual: FL 0.65 mm, CL 0.5 mm, CL/FL 0.77; length of antennomeres (in mm), from antennomere one to eleven, as follows: 0.18, 0.1, 0.18, 0.1, 0.1, 0.07, 0.07, 0.11, 0.12, 0.16. Eyes. Glabrous (GW 0.36 mm), finely granulate. Mouthparts. ( Figs. 3 A–D) Labrum free, highly sclerotized, pubescent, slightly emarginated at middle. Mandibles short and broad, outer apical edge with a distinct depression containing setae; apex with two teeth; mandibular base emarginated, with an additional outgrowth above mola; mola well-developed, horseshoe-shaped, naked and distinctly costate; there is a soft and pubescent prostheca above mola with an additional tuft of setae. Maxillae with cardo subtriangular and stipes elongated; galea shorter but wider than lacinia, somewhat widened towards apex, which is densely pubescent; lacinia much longer and narrower than galea, densely pubescent at apex, with a highly sclerotized but barely visible hook; basal maxillary palpomeres almost as long as the next two together, apical palpomere semicircular and approximately 2.4× wider than long. Labium with apical palpomere of labial palps club-shaped (asymmetrical); mentum pentagonal, strongly sclerotized and bearing setae at middle; paraglossae slightly sclerotized and pubescent; glossa strongly sclerotized.

Thorax. Pronotum. ( Fig. 4 A) Subtrapezoidal with edges bordered and sides moderately arcuate, convergent anteriorly. PW/PL = 2.08–2.76 (2.31 ± 0.16), widest anteriorly in both sexes; shiny, punctation single and interspaces microreticulate; punctures separated by a distance of about 3–6 puncture-widths at disc, each puncture bearing a very short minute seta (barely visible even at a magnification of 150×); anterior edge slightly convex at middle and anterior angles sharp; color pattern: with a small and narrow anterior black band instead of circular spots ( Figs. 1 A and 1D) (n = 15; seven individuals were dissected, six being males and one a female) or with two circular anterior black spots and four circular free black spots on disc ( Figs. 1 G and 4A) (n = 9; four individuals were dissected and were females). Scutellar shield. (BW 0.29 mm), subpentagonal, glabrous, bearing a few punctures. Elytra. EL/EW = 1.27–1.60 (1.38 ± 0.07), EL/PL = 3.18–4.06 (3.66 ± 0.28); strongly margined anteriorly, moderately convex, with seven conspicuous longitudinal rows of punctures ( Fig. 4 B, counted from the elytral suture toward elytral outer edges); punctures separated by about 2–4 puncture-widths; interspaces between rows microreticulate and with fine and sparse punctures, each puncture bearing a minute seta (barely visible at magnification of 150×); color pattern of males and females as in the diagnosis. Hind wings. Developed, apparently functional. Prosternum. Convex; anterior margin smooth and pubescent; notosternal sutures distinct and entire; procoxal cavities ovate; prosternal process abruptly expanded apically, shallowly emarginated at apex; procoxal lines shorter and nearly straight; there is a pair of secretory pores on the prosternal process ( Fig. 4 C). Mesoventrite. Small, convex, mesocoxal lines straight to slightly arched; anterior edge sinuate, medially lobed. Metaventrite. Convex, glabrous, finely punctate, interspaces of punctures microreticulate; approximately 2.32× as long as mesoventrite; metacoxal lines conspicuous, approximately 0.73× as long as metaventrite; discrimen ( Fig. 1 F, arrow) approximately 0.79× as long as metaventrite. Metendosternite well-developed ( Fig. 4 D), hardened but still translucent, convex; central sclerotization of the anterior processes ( Fig. 4 D, red arrow) approximately 0.21× as long as the central sclerotization of the stalk ( Fig. 4 D, big black arrow); inner outline of laminae with a conspicuous ear-shaped extension ( Fig. 4 D, small black arrows). Legs. Procoxae oval, mesocoxae almost globular and metacoxae transverse, cigarette-shaped. Femora elongated, smooth, without spines or other outgrowths. Tibiae long, somewhat widened apically; apex with a crown of wide flat setulae, two apical spurs on meso- and metatibiae and one reduced apical spur on protibiae. Tarsi densely pubescent.

Abdomen. Elongated; punctation coarse, shallow; interspaces, granulate; vestiture of sparse, slender setae. Coxal lines conspicuous and not continuous around coxae (approximately 0.75× the length of the first abdominal ventrite). Length of ventrites one to five as follows (in mm, from base to apex of each ventrite at the longitudinal midline): 0.72, 0.42, 0.26, 0.28, 0.42. Male terminalia. ( Figs. 5 A–C) Penis elongate, slightly curved ( Fig. 5 A, pen); basal portion with a short sclerotized projection that is linked to the apophyses; internal sac with a welldeveloped flagellum ( Fig. 5 A, “fla”) (length mean: 1.65 mm, n = 2, from beginning of virga to end of head), with a short sinuosity at middle that is accompanied by a membranous enlargement ( Fig. 5 A, black arrow; length mean: 0.15 mm, n = 2); the flagellum and sinuosity are shorter than those of M. trifasciatus (compare to Fig. 6 A–B). Apophyses ( Fig. 5 A, “apo”) approximately 1.5× longer than penis (n = 2). Tegmen ( Fig. 5 B) strongly sclerotized, with a membranous portion on its dorsum; parameres reduced and strongly sclerotized, with densely pubescent outgrowths, dilated and then acute at apex ( Fig. 5 B, arrows). Tergite IX and segment X well sclerotized ( Fig. 5 C); anteroventral edge of segment IX with a truncate subgenital plate ( Fig. 5 C, black arrow). Female terminalia. ( Figs. 5 D–F) Resembles that of M. trifasciatus . Gonostyli and gonocoxites strongly sclerotized ( Fig. 5 D, black and red arrow, respectively). Spermatheca ( Fig. 5 E) oval, membranous to strongly sclerotized; bursa copulatrix developed. Tergite VIII sclerotized and sternite VIII with a conspicuous median strut ( Fig. 5 F, arrow; displaced to the right during dissection).

Lectotype, here designated (UMZC). ( Figs. 1 A–C) “TYPE [blue label, printed] \ TYPE [printed], chilensis Reiche [handwritten] \ LECTOTYPE [red label, printed], Mycotretus chilensis Crotch, 1876 [handwritten]”.

Other examined specimens. 1 specimen ( MZUSP) “HOLOTIPO [red label, printed] \ Cantareira., S. Paulo. [printed], 1938 [handwritten] \ Coll. J. Guérin., S. Paulo., Brasil. [printed], 18336 [handwritten] \ Mycotretus bicinctus J. Guer [handwritten], J. Guerin det. [printed] 1949 [handwritten]” ; 3 specimens ( MZUSP, on the same pin, including two dissected female) “PARATIPO [red label, printed] \ Cantareira. S. Paulo [printed], 1938 [handwritten] \ Coll. J. Guérin., S. Paulo., Brasil. [printed], 17030 [handwritten] \ Cantareira, S. Paulo, 4.I.38, Coll. Zellibor-Hauff [printed] \ Mycotretus bicinctus J. Guer [handwritten], J. Guerin det. [printed] 1949 [handwritten]” ; 2 specimens ( MZUSP) “PARATIPO [red label, printed] \ Cantareira. S. Paulo [printed], 11937 [handwritten] \ Coll. J. Guérin., S. Paulo., Brasil. [printed], 17198 [handwritten] \ Cantareira, S. Paulo, 30.11.37, Coll. Zellibor-Hauff [printed] \ Mycotretus bicinctus J. Guer [handwritten], J. Guerin det. [printed] 1949 [handwritten]” ; 1 specimen ( MZUSP) “PARATIPO [red label, printed] \ Cantareira. S. Paulo [printed], 10936 [handwritten] \ Coll. J. Guérin., S. Paulo., Brasil. [printed], 0 526 [handwritten] \ Mycotretus bicinctus J. Guer [handwritten], J. Guerin det. [printed] 1949 [handwritten] \ 33 [orange label, handwritten]” ; 1 specimen ( MZUSP) “PARATIPO [red label, printed] \ Hansa. S. Catarina. [printed], 11943 [handwritten] \ Coll. J. Guérin., S. Paulo., Brasil. [printed], 16338 [handwritten] \ Mycotretus bicinctus J. Guer [handwritten], J. Guerin det. [printed] 1949 [handwritten]” ; 1 specimen ( MZUSP) “ Jabaquara., S. Paulo. [printed], 4949 [handwritten] \ Coll. J. Guérin., S. Paulo., Brasil. [printed], 18433 [handwritten] \ Mycotretus bicinctus J. Guer [handwritten], J. Guerin det. [printed] 1949 [handwritten]” ; 1 male ( MZUSP, dissected) “CANTAREIRA [handwritten], S. Paulo – SP, Brasil [printed], 31-viii- 1960 [handwritten], Col: E. Amante [printed]” ; 1 specimen (MZUSP) “Est. biol. Boraceia, Salesópolis SP, 14- 18.XI.1973, Exp. Mus. Zool.”; 1 specimen ( MZUSP) “ BRASIL, Rio Vermelho , Est ° Sta. Catar., Col.: DIRINGS [printed], DEZ 1950 [date printed on label back]” ; 1 specimen ( MZUSP) “ BRASIL, Itatiaia, Est ° R. Janeiro., Col.: DIRINGS [printed], JAN 1960 [date printed on label back]” 1 specimen ( MCNZ) “ Tenente, Portela, RS, 11/IX/ 1990 [handwritten], leg. [printed] \ Col. MCN [printed], 155021 [handwritten]” ; 1 male ( UFPR, dissected) “ Coleção M. Alvarenga [printed] \ BRASIL, Rio de Janeiro, D.F. CORCOVADO [printed], 12.XII.1955 [handwritten], D. Zajclw leg. [printed] / Mycotretus bicinctus [handwritten] C. Lopes-Andrade det. [printed] / DZUP 279313 [printed]” ; 1 specimen ( UFPR) “ Coleção M. Alvarenga [printed] \ REPRESA RIO GRANDE, Guanabara Brasil [printed], X.1965 [handwritten], F.M. Oliveira [printed] / DZUP 279318 [printed]” ; 1 female (UFPR, dissected) “Coleção M. Alvarenga [printed] \ Amparo, S. Paulo, P. Rech [handwritten] / DZUP 235894 [printed]”; 1 female ( UFPR, dissected) “ Coleção M. Alvarenga [printed] \ REPRESA RIO GRANDE, Guanabara Brasil [printed], X.1966 [handwritten], F.M. Oliveira [printed] / DZUP 279320 [printed]” ; 2 specimens ( CELC, including one dissected male) “ Brasil: MG, Viçosa, " Mata do Paraíso ", 26.xi.2014, leg Pecci-Maddalena, Í.S.C. [printed] \ ex Lentinus brumalis ” ; 6 specimens ( CELC, including one dissected male) “ Brasil: MG, Viçosa, " Mata do Paraíso ", 02.xii.2014, leg. Pecci-Maddalena, Í.S.C. [printed] \ Fungo 1 Bicho 1 [printed] \ ex Lentinus brumalis ” ; 2 males ( CELC, both dissected) “ Brasil: MG, Viçosa, " Mata do Paraíso "; xii.1999, leg. C. Lopes- Andrade & FZ Vaz-de-Mello ” ; 2 females ( CELC, both dissected) “ Brasil: MG, Viçosa, " Mata do Paraíso ", 08.xii.2014, leg. Pecci-Maddalena, Í.S.C & Lopes-Andrade, C. \ Bicho 9 Fungo 9 \ ex Mycena sp.”.

Ecology. Mycotretus chilensis has been collected in basidiomes of Lentinus brumalis (Pers.) Zmitr. ( Fig. 7 A– D; Polyporaceae ) and Mycena sp. ( Fig. 7 F; Mycenaceae ). Mycotretus chilensis and M. trifasciatus are sympatric in Cantareira and Jabaquara, in the state of São Paulo; Rio Vermelho, in Santa Catarina; and Viçosa, in Minas Gerais. They were also found to be syntopic in Viçosa, where they were caught together on the same fungi in two field collections (see examined material). Like M. trifasciatus , M. chilensis has usually been collected during summer (see examined material).

Distribution. Southern and southeastern Brazil and a doubtful record from Chile ( Fig. 8 , green diamonds and black question mark).

Remarks. The lectotype was not dissected but we think it is probably a male, because its color pattern was observed in mostly males with gender confirmed by dissection. Likewise, the holotype of M. bicinctus (junior synonym of M. chilensis ) was not dissected but we think it is a female. It is worth mentioning that one paratype of M. bicinctus with the same color pattern as the holotype was dissected and it is a female. The body of the lectotype is slightly more elongated than that of other specimens examined by us. The visibility of elytral rows of punctures on different specimens studied depends on the degree of pigmentation of specimens and the exact number of rows may be hard to establish. As we discuss below, the record of M. chilensis for Chile is probably a case of a mislabeled specimen.

Figures

FIGURE 1. Adult Mycotretus chilensis Crotch, 1876: A – C lectotype from Chile (doubtful record), (A) dorsal view, with arrow showing anterior pronotal band; (B) lateral view; (C) labels. D – F male M. chilensis Crotch, 1876 from Viçosa (MG, Brazil), (D) dorsal view, with arrow showing anterior pronotal band; (E) lateral view; (F) white arrow showing discrimen. G – I holotype of M. bicinctus (syn. n. of M. chilensis) from Cantareira (SP, Brazil). This color pattern was observed in most females, (G) dorsal view, with arrow showing the first black band reaching the anterior edge of elytra close to scutellar shield; (H) lateral view; (I) labels. Scale bars: A = 1 mm, D – F, G – H = 0.5 mm.

FIGURE 2. Adult Mycotretus trifasciatus Guérin, 1956: A – C holotype of M. trifasciatus from Nova Teutônia (SC, Brazil), (A) dorsal view, with black arrows showing yellowish-brown coloration, big white arrow showing a scutellar bilobed and elongate black spot, small white arrow showing a spot close to the humerus, red arrow showing a prominent “ pick ” at middle of the first band; (B) lateral view; (C) labels. D – F M. trifasciatus from Viçosa (MG, Brazil), (D) dorsal view, with arrow showing the scutellar spots reaching the anterior edge of elytra; (E) lateral view; (F) ventral view, with white arrow showing discrimen. (G) female M. trifasciatus from Obidos (PA, Brazil), arrow showing yellowish-brown coloration. (H) female M. trifasciatus from Viçosa (MG, Brazil). (I) male paratype of M. trifasciatus from Nova Teutônia (SC, Brazil). Scale bars: A – B, D – F, H – I = 0.5 mm, G = 1 mm.

FIGURE 3. (A – D) Mouthparts of a male Mycotretus chilensis Crotch, 1876 from Viçosa (MG, Brazil) (A) labrum; (B) mandibles; (C) right maxilla; (D) labium. (E – G) Mouthparts of a male M. trifasciatus from Viçosa (MG, Brazil), (E) labrum; (F) mandibles; (G) left maxilla. (H) labium of a male M. trifasciatus from Canela (RS, Brazil), with separated mentum plate. Scale bars: A – H = 0.1 mm.

FIGURE 4. (A – D) Parts of thorax of Mycotretus chilensis Crotch, 1876 from different localities, (A) female, pronotum showing punctation; (B) male, longitudinal elytral striae; (C) pair of secretory pores on prosternal process; (D) metendosternite, red arrow showing central sclerotization of the anterior processes, big black arrow showing central sclerotization of the stalk, small black arrows showing inner outline of laminae. (E – I) parts of thorax of M. trifasciatus from different localities, (E) male, pronotum showing punctation; (F) longitudinal elytral striae in two specimens; (G) pair of secretory pores on prosternal process; (H) and (I) metendosternites of two specimens, red arrow showing central sclerotization of the anterior processes, big black arrow showing central sclerotization of the stalk, small black arrows showing inner outline of laminae. Scale bars: A – B and F = 0.5 mm, C – D and G – I = 0.1 mm, E = 1 mm.

FIGURE 5. (A – C) Male terminalia of a Mycotretus chilensis Crotch, 1876 from Cantareira (SP, Brazil), (A) penis (pen), flagellum (fla), apophyses (apo), arrow showing the median sinuosity in flagellum; (B) tegmen, arrows showing the parameres; (C) tergite IX and segment X, with arrow showing anteroventral edge of segment IX. (D – F) female abdominal terminalia of a paratype of M. chilensis from Cantareira (SP, Brazil), (D) genitalia in two views, with black arrow showing a gonostylus and red arrow showing a gonocoxite; (E) spermatheca (hardened structure at left) and part of the bursa copulatrix; (F) sternite VIII with a median strut (arrow; the strut was displaced to the right during dissection). Scale bars: A – D and F = 0.5 mm, E = 0.1 mm.

FIGURE 6. (A – D) male terminalia of a paratype of Mycotretus trifasciatus Guérin, 1956 from Cerro Azul (PR, Brazil), (A) penis (pen), flagellum (fla), apophyses (apo), with arrow showing the median sinuosity of flagellum; (B) detail of the sinuosity, with arrow showing a sclerotization not observed in M. chilensis; (C) tegmen, with arrow showing parameres; (D) tergite IX and segment X, with arrow showing anteroventral edge of segment IX. (E) female genitalia of a paratype of M. trifasciatus from Rio Vermelho (SC, Brazil), with arrows showing the gonostyli; (F) female genitalia of a M. trifasciatus from Obidos (PA, Brazil), with red arrows showing gonocoxites; (G) female genitalia of a M. trifasciatus from Viçosa (MG, Brazil), with black arrow showing the spermatheca and red arrow showing an expanded portion of the bursa copulatrix; (H) spermatheca of a paratype of M. trifasciatus from Rio Vermelho; (I) sternite VIII with a median strut (arrow) of a paratype of M. trifasciatus from Rio Vermelho. Scale bars: A – G and I = 0.5 mm, H = 0.1 mm.

FIGURE 7. Host fungi, (A – C) Lentinus brumalis, basidiomes from Viçosa (MG, Brazil); (D) Two male specimens of M. chilensis on a basidiome of Lentinus brumalis from Viçosa (MG, Brazil); (E) One female M. trifasciatus on a basidiome of Lentinus tricholoma from Viçosa (MG, Brazil); (F) Mycena sp. basidiomes from Viçosa (MG, Brazil). Scale bars: A – B = 5 mm.

FIGURE 8. Distribution map for Mycotretus chilensis Crotch, 1876 (green diamonds) and M. trifasciatus Guérin, 1956 (red circles). The blue question mark indicates the doubtful record of M. trifasciatus from northern Brazil. The black question mark indicates the doubtful record of M. chilensis from Chile.