Strigocis vicosensis Lopes-Andrade

Lopes-Andrade, Cristiano, 2011, The first Strigocis Dury (Coleoptera, Ciidae) from the southern Neotropical region and a provisional key to world species, ZooKeys 81, pp. 27-37 : 29-33

Strigocis vicosensis Lopes-Andrade sp. n. Figs 17

Type-locality.

Viçosa, in the state of Minas Gerais, southeastern Brazil (20°45'S, 42°53'W).

Etymology.

The specific epithet is an adjective referring to the terra typica of the species.

Diagnosis.

Dorsal vestiture consisting of stout yellowish bristles, pronotal punctures coarse and separated from each other by 0.75 × to 1 × puncture-width, and sutural flange of elytra not diverging near apex. Males have both frontoclypeal ridge and anterior pronotal margin produced forward and emarginated at middle forming two small subtriangular plates (Figs 1, 2, 4, 5). Additionally, the abdominal sex patch of males is small, with around one-fifth the length of the first abdominal ventrite at the longitudinal midline.

Description.

Male holotype (Figs 1-3), measurements in mm: TL 1.70; PL 0.55; PW 0.68; EL 1.15; EW 0.73; GD 0.55. Ratios: PL/PW 0.81; EL/EW 1.59; EL/PL 2.09; GD/EW 0.76; TL/EW 2.34. Body elongate, moderately convex; dorsal and ventral surfaces mostly unicolored, almost black, with reddish brown appendages; dorsal vestiture consisting of stout suberect or decumbent yellowish bristles; ventral vestiture consisting of slender decumbent yellowish setae. Head barely seen from above; dorsal surface concave, glabrous; punctation sparse, consisting of course shallow punctures; frontoclypeal ridge slightly raised and produced, its anterior margin with an emargination at middle forming two short subtriangular plates with relatively rounded apices. Eyes coarsely facetted, each one bearing more than 60 ommattidia; greatest eye width 0.10 mm. Antenna (left antenna measured; FL 0.10 mm; CL 0.16 mm; CL/FL 1.63) with length of antennomeres (in mm) as follows: 0.06; 0.05; 0.04; 0.02; 0.01; 0.01; 0.01; 0.05; 0.05; 0.06; sensillifers of the antennal club whitish, conspicuous (seen in magnification of 50 ×). Pronotum densely punctate, the punctures being coarse and separated from each other by 0.75 × to one puncture-width; in between punctures somewhat microreticulate; the stout bristles of the pronotal disc are decumbent, so attached to the surface that they resemble small scales and are more easily visible in lateral view; anterior portion produced forward and almost concealing the head when seen from above; anterior margin bearing an emargination at middle, forming two small subtriangular plates that are slightly larger than those of the head (Figs 1-2, 4-5); anterolateral angles (corners) produced forward and rounded; lateral margins slightly crenulate, almost straight, barely visible from above except for their posterior portions. Scutellum very small, so close to the elytra that makes it barely discernible; posterior margin broadly rounded, so that the entire structure resembles a half-circle; surface bearing small punctures very close to each other, giving a creasy appearance to its surface; basal width 0.07 mm. Hind wings fully developed (macropterous species). Elytra with lateral margins subparallel at basal half, then gradually converging to the apex; punctation single and confused, the punctures being coarser than those on pronotum and closer to each other; bristles similar to those on pronotum, but suberect and a little bit bigger; in between punctures smooth and shiny; sutural flange not diverging near apex (slightly divergent when examined in SEM; see Fig. 6, arrows). Ventral sclerites with most of their surfaces finely granulate. Hypomera unpunctate and bearing a few sparse slender setae. Prosternum biconcave and distinctly tumid at the longitudinal midline, carinate. Each protibial with its outer apical angle expanded forming a small acute tooth; apex bearing a row of spines closest to the inner apical angle. Metaventrite with a few very shallow and coarse punctures, barely discernible; discrimen with one-third the length of the ventrite at the longitudinal midline. Abdominal ventrites bearing several slender setae; first abdominal ventrite twice as long as the second, bearing a small oval margined sex patch, with near one-fifth the length of the ventrite at the longitudinal midline.

Male terminalia in paratypes (Fig. 7).

Eighth sternite (Fig. 7) with its posterior margin membranous (tending to collapse during slide preparation), sinuous; corners bearing long setae. Aedeagus (Fig. 7) with near 0.3 mm of length; basal piece large, conspicuous, with two-fifths the length of tegmen; penis subcylindrical, membranous, 0.8 × the length of tegmen; tegmen with its posterior portion bearing a narrow emargination at middle (Fig. 7, small arrow) delimiting two lateral lobes, each lobe with a somewhat V-shaped concavity (dashed lines) ending in two sclerotized tips (large arrows).

Females.

Head with frontoclypeal ridge just slightly sinuous. Anterior margin of pronotum broadly rounded. Vertex of head with sparse suberect stout bristles. First abdominal ventrite devoid of sex patch.

Variation.

Males, measurements in mm (n = 10, including the holotype): TL 1.33-1.75 (1.59 ± 0.14); PL 0.50-0.70 (0.60 ± 0.07); PW 0.55-0.75 (0.66 ± 0.06); EL 0.80-1.15 (0.98 ± 0.10); EW 0.63-0.78 (0.70 ± 0.05); GD 0.50-0.60 (0.54 ± 0.04). Ratios: PL/PW 0.81-1.00 (0.92 ± 0.06); EL/EW 1.27-1.59 (1.40 ± 0.09); EL/PL 1.43-2.09 (1.64 ± 0.21); GD/EW 0.73-0.83 (0.77 ± 0.03); TL/EW 2.12-2.34 (2.26 ± 0.08). A few males were almost devoid of secondary sexual characters on frontoclypeal ridge and anterior margin of pronotum. However, the small abdominal sex patch was observed in all available males.

Females, measurements in mm (n = 10): TL 1.30-1.65 (1.52 ± 0.13); PL 0.43-0.63 (0.54 ± 0.06); PW 0.53-0.70 (0.62 ± 0.06); EL 0.83-1.10 (0.99 ± 0.08); EW 0.60-0.75 (0.69 ± 0.06); GD 0.45-0.58 (0.54 ± 0.05). Ratios: PL/PW 0.75-0.96 (0.86 ± 0.06); EL/EW 1.38-1.54 (1.44 ± 0.06); EL/PL 1.60-2.18 (1.85 ± 0.17); GD/EW 0.75-0.81 (0.78 ± 0.02); TL/EW 2.14-2.30 (2.22 ± 0.05).

Type series.

Male holotype(MZSP) "BRASIL: MG Viçosa; Campus UFV 18.vi.2006 C.B. Oliveira leg. ex Phellinus sp." " Strigocis vicosensis Lopes-Andrade HOLOTYPUS" [printed on red paper]. Paratypes: one male (LAPC), same data as holotype; six females, three males (LAPC) "BRASIL: MG Viçosa; 2° Represa UFV; 20.ii.2006 leg. CB Oliveira"; one female (LAPC) "BRASIL: MG Viçosa 16.ii.2002 leg. C. Lopes-Andrade"; 13 females, five males (LAPC) "BRASIL: MG; Viçosa Campus UFV, 3° represa, próx. supermercado 18.vii.2007; colônia II leg C. B. Oliveira". All paratypes distinguished labeled " Strigocis vicosensis Lopes-Andrade PARATYPUS" [printed on yellow paper].

Host fungus.

Possibly a single species of an undetermined Phellinus Quél. ( Hymenochaetaceae ). It’s important to emphasize that only adult ciids were found and they were not observed breeding in the collected basidiomes.

Natural history.

All the known specimens were collected in open areas of the Federal University of Viçosa’s campus. It was not found in either forested or urban areas of Viçosa, although ciids were continuously collected there from September 1998 until recently. Adults could not be maintained in laboratory for much longer, which suggests that it colonizes and consumes the basidiomes just after sporulation and before basidiomes’ decaying. Another possibility is that the Phellinus sp. is not a host for Strigocis vicosensis sp. n., and adults were incidentally collected in the fungus. The latter explanation is supported by the fact that all the other Strigocis species are known to feed on fungi in the Trametes host-use group and were never found in association with fungi of the Phellinus host-use group ( Orledge and Reynolds 2005). Xylographus gibbus Mellié were found in basidiomes possibly conspecific to the ones inhabited by Strigocis vicosensis sp. n., in the same open areas. However, these two ciid species have not been collected together.

Comparative notes.

Among the examined Strigocis , the most similar to Strigocis vicosensis sp. n. is the Mexican Strigocis bilimeki . The latter specieshas pronotal and elytral punctation comparatively denser, subtriangular plates of the frontoclypeal ridge in males usually with acute apices and anterior pronotal margin with a short and relatively narrow lamina bearing a small emargination at middle (Fig. 8). Additionally, in Strigocis bilimeki the male sex patch in the first abdominal ventrite is very large (Fig. 9, arrow), its diameter being at least 0.55 × the length of the sclerite at its longitudinal midline. Male terminalia of both species are similar in form, mainly in the subcylindrical membranous penis (Figs 7, 10) and the shape of the posterior portion of tegmen. However, the whole aedeagus of Strigocis bilimeki (Fig. 10) has around 0.8 × the length of the one of Strigocis vicosensis sp. n., a proportionally smaller basal piece (Fig. 10, dashed lines) and is less sclerotized. Moreover, the posterior margin of the eighth sternite has a broad U-shape emargination (Fig. 10) similar to that of Strigocis bicornis , Strigocis opacicollis and Strigocis opalescens .

Strigocis opalescens has a vestiture of minute setae barely visible even in high magnifications (50 ×), sparse pronotal and elytral punctation, and broad lateral margins of pronotum forming a raised lip. The tegmen of its male terminalia is subquadrate, with a deep U-shaped emargination at middle delimiting two lateral lobes, each lobe bearing a small emargination at apex. Strigocis bicornis is a small blackish species with shallow pronotal and elytral punctation, irregular elytral surface with in between punctures finely granulate, and dorsal vestiture of fine setae. Its tegmen is elongate, with a rounded posterior margin bearing a very narrow V-shape emargination at middle. It is similar to the examined named specimens of Strigocis opacicollis , in which the elytral margins are not so parallel and elytral punctation is coarser and denser. Additionally, the tegmen in Strigocis opacicollis is quite different, with an almost straight posterior margin bearing a small U-shaped emargination at middle. I could not examine any named specimen of Strigocis tokunagai , but data and drawing provided by Nobuchi (1960) show that it is similar to Strigocis vicosensis sp. n. in the vestiture of yellowish bristles, pronotal and elytral punctation. However, the abdominal sex patch of Strigocis tokunagai is described as being large.