Pogonostoma (Microgeniatum) signifemorale, Moravec & Trýzna, 2021

Moravec, Jiří & Trýzna, Miloš, 2021, New or rare Madagascar tiger beetles- 24. Pogonostoma (Microgeniatum) signifemorale sp. nov. with revised key to species of the subgenus Microgeniatum Rivalier (Coleoptera: Cicindelidae), Zootaxa 5081 (4), pp. 524-534 : 527-532

Pogonostoma (Microgeniatum) signifemorale sp. nov.

( Figs 1–10 , 14 )

Type locality. Northwestern Madagascar: dry deciduous forest of the Ankarafantsika National Park, “Tour du Lac” ( Ambato Boeni Region , Province of Mahajanga) .

Type material. Holotype in NMPC (temporarily in JVCB), labelled: “NW Madagascar, 71 m, / Ankarafan- tsika N.P., Tour du Lac / S 16°18´13.0´´; E 46°48´49.1´´, / 23.- 26.i.2015, M. Trýzna leg.” [printed] // “Pogonos- toma / ( Microgeniatum ) / signifemorale sp. nov. ” / det Jiří Moravec / & Miloš Trýzna 2021 ” [red, printed].

Differential diagnosis. By its extremely small body and boomerang-bent aedeagus with similarly shaped apex, P. (M.) signifemorale sp. nov. may resemble P. (M.) infimum . The new species is immediately distinguished from it, however, and from other three species of the subgenus by its markedly bicoloured meso- and metafemora ( Fig. 1 ) with their basal third yellow, while their remaining, markedly dilated portions are black; moreover, also the basal area of all tibiae is yellow. Antennomeres of the new species are uniquely coloured as well: the scape is black dorsally, yellow-testaceous apically; antennomeres 2–4 ivory to yellow-testaceous ( Figs 1, 3–4 ). In contrast, the femora and tibiae, as well as the antennae of P. (M.) infimum are uniformly black or black-brown ( Moravec 2007, fig. 1819); the other two species also possess black femora, tibiae and antennae. In addition, the surface of the pronotal disc of the new species is covered with finer rugae ( Fig. 8 ) than the coarser and more almost subreticulateanastomosing ridges on the pronotum of P. (M.) infimum (see Moravec 2007, fig. 1621). Moreover, the aedeagus of the new species is more abruptly bent above the middle and wider in the point of the angle ( Fig. 5 ), while the angle is arcuate in P. (M.) infimum (see Moravec 2007, fig. 1622); the aedeagi of other two species are very differently shaped. For other differences see “Key to species” above, and the detailed redescriptions and illustrations in the monograph of the genus ( Moravec 2007).

It should be mentioned here that also P. (Microstenocera) sicardi W. Horn, 1927 may superficially resemble the new species by its yellow femoral bases; however, the yellow area is much less expanded and apart from the irregular elytral setal vesture (diagnostic for Microstenocera ), P. (Microstenocera) sicardi differs in a complex of other characters including the very different shape of its aedeagus (see Moravec 2007).

Description (male holotype). Body ( Fig. 1 ) extremely small, length 5.60 mm, width 1.50 mm, shiny-black; setae whitish.

Head ( Fig. 3 ) slightly narrower than body, width 1.20 mm; temples obliquely sloped, only indistinctly arcuate, 2 times shorter than eyes.

Frons anteriad-prolonged, merging with clypeus in middle and continuously confluent with vertex, surface rather finely, irregularly scabrous-rugulose and granulate to foveolate, much finer on anterior area; supra-anten- nal keels indistinct, merging with coarse surface sculpture. Vertex with indistinct anterior-sublateral impressions, median area moderately convex, occipital impression shallow, median area coarsely, irregularly scabrous-rugulose, passing posteriad into irregularly subreticulate-scabrous sculpture; limited occipital area with several very coarse, transverse-wavy rugae; temporal area irregularly sculptured by short, irregularly wavy ridges; whole surface ap- pears glabrous as covered with indistinct, sparse and extremely short, white microtrichia, which are barely notice- able in dorsal view.

Genae coarsely rugose nearly throughout their surface, glabrous or with few inconspicuous, short, white mi- crotrichia.

Clypeus black, convex in middle when merging with frons, finely wrinkled, with sparse, whitish microtrichia.

Labrum ( Fig. 2 ) 4–setose, rather short, length 0.32 mm, width 0.60 mm, basolateral margins arcuate towards right-angled lateral indentations, then obliquely narrowed anteriad towards rather distinct, right-angled anterolateral teeth, anterior margin shallowly emarginate between two blunt, yet well developed anterior teeth; surface blackbrown, with moderate basodiscal convexity, glabrous except for a few, barely noticeable whitish microtrichia.

Maxillae. Galea black (except for whitish apical orifice of penultimate galeomere); lacinia black with brown- ish-testaceous setae, 0.12 mm wide.

Palpi ( Fig. 3 ). Maxillary palpi with longest palpomere metallic black (only short basal palpomere testaceous), penultimate and terminal palpomere brown with faint reddish tinge; setae whitish; penultimate (longest) palpomeres of labial palpi notably long, their glabrous side black, while their uneven setose side is pale brownish with ivorytestaceous tinge and ivory-white apices; long setae pure white but irregularly interspaced with darker setae; terminal palpomeres brownish with mahogany tinge.

Mandibles ( Fig. 3 ) metallic black with mahogany-reddish teeth; with moderately arcuate margins, subsymmetrical, with terminal tooth in left mandible notably shorter than that in right mandible; second tooth of left mandible shorter than third one, while inner teeth of right mandible of approximately equal size; distinct basolateral portions arcuate, with very sparse indistinct microtrichia.

Antennae ( Figs 1, 3–4 ) shorter than body, reaching anteapical elytral angles (when completed), notably pale, scape black dorsally, while ventrally and apically yellow-testaceous; antennomeres 2–4 ivory to yellow-testaceous with darkened apices, antennomeres 5–6 with ivory base, then gradually testaceous-darkened towards brownish apex, remaining antennomeres pale brownish-testaceous.

Thorax. Pronotum ( Fig. 8 ) elongate, length 1.35 mm, width 0.85 mm; anterior lobe narrower then posterior one, irregularly rugulose and with coarse, irregularly transverse ridges; disc oblong, lateral margins only moderately arcuate; notopleural sutures invisible from above; sculpture of discal surface consisting of coarse but rather dense transverse-wavy ridges which are irregularly anastomosing on anterior area, while more continuous, wavy and coarser on median area of posterior discal half, and more irregular and commonly anastomosing on lateral areas; rugae passing over notopleural sutures on proepisterna; median line indistinct, partly merging with surface sculpture; posterior lobe rather finely and irregularly transverse rugulose, its posterior half ochre-testaceous; whole pronotal surface appears glabrous; proepisterna covered with coarse but rather dense ridges (passing from lateral discal areas over notopleural sutures), glabrous; prosternum, mesosternum and metasternum rather sparsely covered with long and short, hairlike setae; mesepisterna with uneven surface and sparse microtrichia; metepisterna nearly glabrous.

Elytra elongate, 3.30 mm long, humeri arcuate, then obliquely sloped towards posterior pronotal suture; outer margins subparallel with slightly arched dilatation above the middle and slightly dilated towards rather distinct anteapical convexity; apex arcuate and shallowly emarginated towards small sutural spine; surface moderately convex, basodiscal convexity and discal impression rather distinct, coarsely punctate throughout, punctures notably large and deep with shiny intervals, often anastomosing with declined lateral intervals, often forming irregularly elongate caverns; setal vesture regular, microsetae confined to punctures, very short and therefore barely visible and easily abraded to the measure that particularly posterior elytral third appears glabrous.

Abdomen. Ventrites black, except for last ventrite and pleurite which are testaceous, their surface rather sparse- ly covered with short, whitish microtrichia.

Legs ( Fig. 1 ). Coxae black, trochanters testaceous; profemora voluminous, black, except for yellow base; meso- and metafemora with basal third yellow, remaining portion black and subclavate-dilated towards constricted apex; basal quarter or third of all tibiae yellow; tarsi brownish to black-brown, claws testaceous; setal vesture of legs inconspicuous: femora glabrous, tibiae and tarsi covered with usual, rather dense microsetae.

Aedeagus ( Fig. 5 ) abruptly boomerang-bent above middle, length 1.10 mm, width 0.20 mm, apical portion rather wide, notably dilated in the dorsal angle, conical-constricted towards blunt apex which is ventrally arcuate, dorsally very slightly emarginate, thus slightly directed dorsad; in its dorsal (and ventral) aspect the apical portion appears gradually conical-constricted towards blunt apex.

Distribution and habitat ( Figs 9–10 , 14 ). Known only from the male holotype caught by the second author in the dense, dry deciduous forest of the Ankarafantsika National Park (previously known as Ampijoroa Forest Station, see Viette 1991) near Marovoay, northwestern Madagascar (Ambato Boeni Region, district of Mahajanga). The only male was caught along the tracking path “Tour du Lac” in a margin between primary and secondary forest when running along a surface of an almost horizontal fallen twig of about 10 cm in diameter ( Fig. 9 , bottom). No other adult was observed in the area despite an intense search. Unfortunately, due to serious bushfires which have recently afflicted some of the Madagascan protected areas, including the Ankarafantsika National Park (see Bezain 2021, Vyawahare 2020), the chance of finding other adults of the new species appears even more improbable.

Etymology. Derived from Latin signo [signum] = marked, referring to the markedly bicoloured femora of the new species.

Figures

FIGURES 1–8. Pogonostoma (Microgeniatum) signifemorale sp. nov., male holotype from type locality. 1—habitus; 2—la- brum; 3—head; 4—antennomeres 1–6; 5—aedeagus; 6—elytral apices; 7—elytron; 8—pronotum. Bars = 1 mm.

FIGURE 9–10. Pogonostoma (Microgeniatum) signifemorale sp. nov., Ankarafantsika National Park. 9—collecting site; 10— habitat of the new species.

FIGURES 11–14. Distribution of Pogonostoma (Microgeniatum) in Madagascar. 11—P. (M.) pseudominimum W. Horn; 12— P. (M.) infimum Rivalier; 13—P. (M.) flavopalpale Jeannel; 14—P. (M.) signifemorale sp. nov.