Operclipygus simplistrius, Caterino, Michael S. & Tishechkin, Alexey K., 2013

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Operclipygus Marseul (Coleoptera, Histeridae, Exosternini), ZooKeys 271, pp. 1-401 : 34-35

Operclipygus simplistrius sp. n. Fig. 7DMap 1

Type locality.

BRAZIL: Santa Catarina: Nova Teutonia [27°11'S, 52°23'W].

Type material.

Holotype female: "Nova Teutonia, Sta. Catharina, BRAZ. I:14:1958 Fritz Plaumann leg." / "FMNH-INS 0000 069 297" / “♀” (FMNH).

Diagnostic description.

While this species shares most of the characters of the group, it is relatively unmodified in terms of sculpturing. Pronotal and elytral striae are all relatively shallowly depressed, with little exaggeration of interstrial intervals. This brief description will distinguish it from other species: length: 2.43 mm, width: 1.53 mm; body rufo-brunneus; anterior submarginal pronotal stria recurved slightly more than one-fourth pronotal disk length; lateral submarginal pronotal stria slightly abbreviated at base; pronotal disk with short, sublinear prescutellar impression, disk relatively impunctate with only small elongate group of punctures near sides, not at all depressed along inner edges of submarginal striae; elytra with outer subhumeral stria present only in apical half, inner subhumeral stria absent, dorsal striae 1-4 complete, 5th present in apical third, sutural very slightly abbreviated at base; prosternal striae nearly reaching presternal suture anteriorly, joined in a broad arch; propygidium evenly convex with large punctures separated by about their widths at the base becoming smaller and more widely separated apically; pygidium with fine ground punctation throughout, with larger scattered punctures confined to basal third. Male: unknown.

Remarks.

This species is unique in the group in having rather simple pronotal striation, without any depression in the anterolateral corners, and in having the outer subhumeral and 5th dorsal elytral striae abbreviated from base.

Etymology.

This species is named for its relatively simple sculpturing and striation compared with other members of the group.

Operclipygus mirabilis group

The Operclipygus mirabilis group includes eight species, most of which exhibit a unique sexual dimorphism in which the median pair of pronotal discal glands differs in placement and elaboration between the sexes. The name of the only described species is based on the male condition, which is quite remarkable; in males of this species the median gland opening is easily visible atop a pronounced tubercle, which itself sits within a moderately broad anterolateral pronotal depression (Fig. 9A). This is in fact the most pronounced of these dimorphisms present in known species, but most of the species in the group exhibit comparable conditions to varying degrees (Figs 9 B–D). Other external characters shared by these species include: frons generally broad, flat to moderately convex; anterior part of frontal stria generally transverse, complete, not sinuate over antennal bases (with one notable exception, Operclipygus schlingeri , where the frontal stria is abruptly bent at the sides and strongly sinuate across the front); lateral submarginal pronotal striae not extending far inward along anterior margin, generally ending at anterolateral corner; pronotal plicae present; apical elytral punctures present, generally associated with apical disruption and abbreviation of the 4th and 5th elytral striae (e.g. Fig. 8C). The aedeagus of most of these species is distinctly ‘hooked’ apically, with the tip abruptly curved (Fig. 10 F–H), moreso than in nearly any other Operclipygus . Two of the species we place here are known from females only, but other characters strongly support their assignments here. The real outlier is Operclipygus schlingeri , in which only a single pair of pronotal glands is apparent in the female, and those of the male are not visible dorsally. It appears that they have been displaced beneath the lateral pronotal margin, through a visible and unique anterolateral groove, onto the hypomeron, but it is very difficult to see a distinct opening at the terminus of this groove, and it is not easily visible in any of the available specimens. The aedeagus of Operclipygus schlingeri also does not conform well with the general diagnosis above (Fig. 10H). However, in most other characters it seems to fit well here.