Montesinus, Grossi, Paschoal Coelho, 2016

Grossi, Paschoal Coelho, 2016, A new brachypterous genus of Brazilian stag beetle (Coleoptera: Lucanidae: Lucaninae) with description of three new species, Zootaxa 4078 (1), pp. 218-229 : 219-220

Montesinus gen. nov.

( Figures 1–25 )

Type species: Montesinus monnei sp. nov., by present designation.

Description. Coleoptera , Lucanidae , Lucaninae . Body elongate, dorsally convex. Brachypterous species, wings half as long as elytra. Sexually dimorphic.

Male description ( Figs 1, 2 , 6–18 ). Mouthparts: Mandibles symmetrical, cylindrical in cross section with apex acute; abruptly upturned and somewhat inwardly curved, basal tooth cylindrical, sharp ( Figs 1 – 2 ). Maxillae with lacinia 2x shorter than galea with apex not hooked ( Figs 11 – 18 ). Labrum trapezoidal and transverse, about 3x wider than long. Mentum elliptical, wider than long with anterior margin setose. Gula width 1/3 as wide as head, with 2 longitudinal parallel sutures near anterior prosternal margin; gular sutures deep and incomplete, ending just before postlabium. Head: Shape trapezoidal. Frons projected, projection as wide as labrum, lateral edges above eyes convex. Eye canthus externally expanded, intruding into eyes in anterior half. Temporal process absent, with eyes far from pronotal anterior border. Antennae ten articulated; scape well curved and enlarged distally, three last antennomeres spongiose distally, the first and second only on anterior external portion and the third over the entire anterior half. Genae deeply impressed internally and posteriorly. Thorax: Pronotum transverse, convex, without any projections or tubercles; surface sparsely punctate; anterior and posterior margins almost straight, lateral margins slightly sinuous; anterior angles rounded, lateral and posterior angles almost absent. Border complete except at middle. Prosternum with a small pit near each pleural suture. Intercoxal process flat with sides subparallel; anteriorly with three convex constrictions, one at middle and two laterally. Posterior edge convex and barely projected. Mesosternum deeply depressed at middle, making a carina on each side. Metasternal discrimen weakly impressed, line shaped. Scutellum: Shape trapezoidal and glabrous with parallel sides; sparsely punctate. Elytra: Shape convex with sides subparallel, about 1.4 times longer than the width across humeri and as wide as prothorax; surface microreticulate. Humeri somewhat externally projected and slightly backwards directed. Surface totally punctate without a striate pattern; punctures deep, with single erect setae; setae longer than puncture diameter. Legs: Protibiae gradually expanded from base to apex with internal margins slightly incurved; external margin with 2 strong apical and somewhat forwardly directed teeth and 6-8 smaller teeth, sometimes decreasing, sometimes increasing in size towards base. Spurs downcurved, dorsally convex and ventrally flattened to concave. Mesotibiae gradually expanded from base to apex with 3–4 external middle teeth, the distal tooth larger. Metatibiae similar to mesotibiae but with only 1 large external middle tooth. Tarsi with 5 tarsomeres and arolia with 2–4 bristles. Abdomen: Sides of ventrites 1–4 with an elevated flange; distal margin of ventrite 5 not sexually dimorphic. Genitalia: Genital capsule simple, robust; tergite with lateral paired plates quadrate; mid line of sternite setose until discal area; distal margin rounded and translucent at middle; proximal portion with apical sides parallel. Aedeagus symmetrical; basal piece strongly sclerotized ventrally with lateral apices directed forward, being mostly membranous dorsally; paired struts present, as long as basal piece length. Parameres large, leaf-like in shape and broad apically; ventrally with a two-folded flange; internal ventral base with a curved process; dorsally with internal base projected. Medial lobe trapezoidal and strongly sclerotized and deeply emarginate apically and basally. Internal sac permanently everted, shorter than tegmen (basal piece plus parameres) in length, almost membranous, partly coated by dense and short setae. Middle expanded laterally and apex with 2 lateral projections covered by minute sclerotized spicules.

Female ( Figs 3–5 , 12 , 19–25 ). As male in general aspect except in the following.

Mouthparts: Mandibles 1.5x shorter than head, slightly incurved, somewhat concave bellow dorsal margin; internally with 1 forwardly directed tooth. Maxillae with hooked lacinia and sometimes with 1 hooklet on lacinia or galea. Galea shorter than in males. Labrum quadrate, not transverse as in male. Mentum more punctate and setose; punctures not as deep as in male. Gula wider than in male and less punctate. Genal disc not concave. Antennae with segments smaller than in male. Head: Surface densely punctate with many coalescent punctures, smaller than pronotum; canthi rounded. Thorax: Surface shinier than that of male, with irregular obsolete reddish spots; posterior angles more pronounced. Prosternum with intercoxal process less constricted and almost concave. Mesosternum slightly concave. Scutellum : smaller than in male. Elytra: Shape more elongate and at least 1.5 times longer than pronotum. Posterior wings: Wings vestigial with veins obsolete and with groups of setae on costa (C), radius (R), medial recurrent (Mr) and cubitus (Cu); these veins also more sclerotized ( Fig. 25 ). Legs: Coxae, trochanters and femora almost reddish brown. Protibiae shorter and more flattened with 4 well developed external teeth, 2 distal and 2 proximal. Meso- and metatibiae smaller with less well-developed teeth. Tarsomeres less setose.

Etymology. The name Montesinus is derived from the junction of the Portuguese word “ monte ” meaning mountain and the suffix “- inus ”, from the Greek, meaning “belonging to”, in reference to its species, that are all small mountaineers. Montesinus is masculine in gender.

Remarks. Montesinus gen. nov. is allied to Altitatiayus , with which it has in common the flightless condition, male upturned mandibles, simple genital capsule and internal base of the parameres with an acute outcurved prolongation. They differ in the aspects listed in Table I.

TABLE I. List of the main characters to differentiate the genera Altitatiayus Weinreich and Montesinus gen. nov.

Figures

FIGURES 1 – 5. Habitus of Montesinus species. 1 – 3. Montesinus monnei sp. nov., holotype male in dorsal (1) and lateral views (2), and allotype female in dorsal view (3); 4. M. tatula sp. nov., holotype female in dorsal view; 5. M. machadoi Grossi sp. nov., holotype female in dorsal view. Scale bars = 4 mm.

FIGURES 6 – 12. Montesinus monnei sp. nov. 6. ventral view of aedeagus; 7. dorsal view of parameres and internal sac; 8. internal sac in ventral view; 9 – 10. genital capsule in dorsal view (9) and ventral view (10); 11 – 12. left maxillae in dorsal view of male (11) and female (12). scale bars = 1 mm.

FIGURES 13 – 17. Montesinus monnei sp. nov. aedeagus. 13. ventral view; 14. dorsal view; 15. lateral view with internal sac omitted; 16. apex of internal sac in ventral view; 17. internal sac in dorsal view with setae omitted. Scale bars = 1 mm.

FIGURES 18 – 21. Left maxillae in dorsal view: 18 – 19. M. monnei sp. nov., male (18) and female (19); 20. M. tatula sp. nov.; 21. M. machadoi sp. nov. Scale bars = 1 mm.

FIGURES 22 – 27. Details of morphology of Altitatiayus Weinreich and Montesinus gen. nov. 22 – 24. right female protibiae (punctures and setae omitted); 26 – 27. wings in dorsal view; 22. Montesinus monnei sp. nov.; 23. M. tatula sp. nov.; 24 – 25. M. machadoi sp. nov., 25. right wing; 26. Altitatiayus ruficollis (Lüderwaldt); 27. A. rotundatus (Boileau).