Opisthencentrus dentipennis ( Germar, 1843 )

Moravec, Jiří, 2016, Taxonomic and nomenclatorial revision within the Neotropical genera of the subtribe Odontocheilina W. Horn in a new sense — 15. The genus Opisthencentrus W. Horn (Coleoptera: Cicindelidae), Zootaxa 4097 (3), pp. 332-340 : 334-339

Opisthencentrus dentipennis ( Germar, 1843)

Oxygonia dentipennis Germar, 1843: 3 .

Type locality. Brazil.

Opisthencentrus dentipennis: Horn 1893: 196 .

Type material. Lectotype (designated here), ♀ deposited in MFNB, labelled: “42560” [printed] // “ Oxygonia / dentipennis / Germ. / Brasil ” [greenish label, handwritten] // “ Lectotype / Oxygonia / dentipennis Germar, 1843 / design. Jiří Moravec 2014” [red, printed] // “ Opisthencentrus / dentipennis Germar, 1843 / det. Jiří Moravec 2014”.

Other material examined. Following five specimens in SDEI: 1 ♂, 1 ♀: “Angra dos Reis / Rio de Janeiro / XII.1913 ” [head of a male glued on the pronotum of the female!]. 1 ♀: “Coll. Weber / Brasilia ” // “Coll W. Horn / DEI Eberswalde” // “ dentipennis / Germ”. 1 ♂: “ Oxygonia / dentipen- / nis / Germ” // “ Brasilia / Ex Cab. Thomson” // “Coll. V. de Poll” // “Coll W. Horn / DEI Eberswalde”. 1 ♂: “ Brasilia / Coll. Baden Ruge” // “ Opisthencentrus / dentipennis / Germ. / Dr. W. Horn det. 1936”.

Redescription. Body ( Figs 1–3 ) small, 7.90–9.00 (LT 8.90) mm long, 2.40–2.65 (LT 2.60) mm wide, mostly (also in LT) metallic black-copper, sometimes with faint, rarely more intense greenish or blue lustre, elytral surface of rather matt appearance.

Head ( Figs 4–5 ) with large eyes, but narrower than body, 2.00– 2.30 mm wide, black-copper with faint greenish or blue lustre; all head portions glabrous.

Frons moderately sloped towards clypeus, cupreous with strong green lustre, almost smooth, with several fine longitudinal striae in middle; supraantennal plates irregularly triangular, cupreous with strong green lustre.

Vertex cupreous with greenish lustre (also in LT), green coloration in one male prevailing; surface irregularly finely vermicular-rugulose in middle, lateral areas with coarser and parallel striae which are partly fragmented on anterior area of juxtaorbital plates; posteriad-divergent parallel rugae passing onto temples; occipital area irregularly rugulose to finely tuberculate.

Genae glabrous, finely parallel-striate.

Labrum in male ( Figs 6–7 ) ochre-testaceous, transverse, sinuous anterior margin only moderately prolonged anteriad towards blunt, only indicated median tooth; female labrum ( Figs 8–9 ) brownish-darkened, sinuous anterior margin more distinctly prolonged anteriad, forming wide, blunt median tooth.

Clypeus comparatively large, bright iridescent green or with reddish-cupreous areas, surface glabrous, finely irregularly wrinkled.

Palpi ( Figs 4–5 ) in male yellow, terminal palpomeres with black-brown darkened apical area, normally shaped (moderately and gradually dilated), palpi in female usually darker, ochre to testaceous, whole terminal palpomeres blackened.

Mandibles ( Figs 4–5 ) almost symmetrical, lateral margins arcuate, each mandible with four teeth (and basal molar), the inner teeth become gradually smaller towards the basal molar; coloration in male reddish-brown with wide, pale ochre basolateral areas; in female much darker, almost black-brown except for testaceous basolateral areas.

Antennae filiform, rather slim and short, in male barely reaching elytral third, in female somewhat shorter; scape and pedicel and mostly also antennomeres 3-4 in male testaceous, occasionally partly black-brown darkened and with indistinct metallic green lustre particularly on scape, generally darker in female; remaining antennomeres brownish, gradually smoky-blackened.

Thorax. Pronotum ( Figs 10–12 ) black-copper with faint green lustre (also in LT) rarely with stronger green or blue-green lustre, oblong in shape, slightly longer than wide, 1.50–1.65 mm long, 1.30–1.50 mm wide; anterior lobe almost as wide as the posterior one, surface rather coarsely but sparsely wavy-rugose; lateral margins of disc moderately convex to almost parallel, mostly slightly dilated posteriad, formed by distinct notopleural sutures which are clearly visible from above; surface of disc rather densely but distinctly irregularly transversely striaterugulose; median line thin but usually distinct; posterior lobe with distinct dorsolateral bulges, surface very irregularly rugulose; lateral and ventral thoracic sterna glabrous, metallic black with blue, green and gold-bronze reflections; female mesepisternal coupling sulci in form of longitudinal furrow impressed in its dorsal area to deep, rather wide pit with indistinctly defined margins.

Elytra ( Figs 15–18 ) elongate, humeri rounded to subquadrate, lateral margins subparallel, anteapical angles arcuate, then sinuous towards conspicuously long, slightly bent or straight lateral-median spine (the length of the spine varies in both sexes), then truncate in middle towards shorter but distinct sutural spine; elytral surface almost even, lacking deep impressions, matt, densely irregularly punctate throughout; more isolated punctures are only on anterior area, then punctures become irregularly anastomosing with bumpy to tuberculate intervals ( Fig. 19 ); elytral maculation consisting of three distinct ivory-white maculae: mostly rounded humeral macula clearly visible from above, rounded sublateral-median macula, and anteapical macula which is prolonged towards the lateralmedian spine, but not covering the truncate elytral apex; surface glabrous except for usual, a few hairlike sensory setae; elytral coloration black-copper (also in LT) to cupreous, sometimes with faint, rarely more intense blue or cyaneous tinge.

Legs with metallic-green coxae, pro- and mesocoxae setose; lateral margins of metacoxae widely fringed with dense setae; trochanters testaceous with apical seta on pro- and mesotrochanters; femora brownish in male, blackbrown in female, in both sexes with yellow to testaceous basal area which in male extends to basal half, and limited testaceous subapical area; femoral apices with two distinct spines ( Fig. 13 ); whitish semierect setae on femora rather sparse, more dense on profemora, sparser on metafemora; tibiae in male brownish with testaceous basal half, much darker in female, covered with sparse, short but rather stiff semierect setae, pro- and mesotibiae with usual denser greyish setose pad on their apical third; tarsi thin and long, brown in male, almost black in female, often with faint metallic lustre; protarsomeres sexually dimorphic: first three protarsomeres in male moderately, but distinctly dilated, with usual whitish pad.

Abdomen metallic-black with blue reflections, ventrites glabrous, except for usual hairlike sensory setae at their margins.

Aedeagus ( Fig. 20 ) elongate, 2.60 mm long, 0.40 mm wide, apical half conically attenuated towards elongate, moderately ventrally bent, subclavate-rounded apex; internal sac ( Fig. 21 ) with conspicuous, longitudinal, distinctly serrate dorsal sclerite; other sclerites comprise thick spike-like arciform piece, thin, longitudinal, doubled central piece, distinct ventral spur with thin, rather short, acute projection and stiffening rib, and three basal sclerites: dorsally placed small ellipsoidal piece, and elongate, almost transverse sclerite covered with a horseshoeshaped piece.

Variability. The original diagnosis given by Germar (1843) was: “ O. supra obscure aenea, subtus viridiaurea, nitida, capite thoraceque transversim strigosis, elytris punctatis, apice truncatis exctus spinosis, maculis tribus albis, pedibus fuscis, femoribus basi testaceis”, thus describing the dorsal surface as obscure copper. In the original description Germar also described the dorsal coloration of the elytra as “ densius et profundis punctata, aeneo-nigra, opaca ” (= densely and deeply punctate, black-copper, dull), which well corresponds with the lectotype in MFNB ( Figs 1 and 16 ) and other specimens examined here; all have the same matt elytral appearance due to the irregularly and densely arranged punctures with bumpy intervals (fig 19). Only one female ( SDEI) has the elytra with deep blue tinge ( Fig. 17 ), and it was probably the same female illustrated in colour aquarelle by Horn (1910: T. 13, fig. 6) —the illustration was adopted by Erwin and Pearson (2008: Pl. 26). The male published by Huber (2012) has bluish tinge on its elytra which are of the same matt appearance as in all other specimens examined (R. Huber, pers. com).

Biology and distribution. Opisthencentrus dentipennis is a very rare tiger beetle, known only from seven specimens, all collected in a comparatively large area of the Atlantic Rainforest in Brazil. ( Horn 1926) also mentioned the locality Alto da Serra, Sao Paulo, but no specimens labelled as such were found in the collection of Walther Horn (now in SDEI), nor in other collections.

Reserva Biológica do Alto da Serra de Paranapiacaba is located at Paranapiacaba district (municipality of Santo André, São Paulo Metropolitan Region), near the Industrial Center of Cubatão, which is one of the most polluted industrial area in the world; interestingly, the preserve still includes remnants of the Atlantic rainforest and its associated biodiversity.

Apart from the male lectotype in MFNB, only five historical specimens have been found in SDEI (two males and three females), two of them from the locality Angra dos Reis which lies in the southern coastal part of the Brazilian state of Rio de Janeiro. The hilly area of the Atlantic Rainforest also comprises several forested islands.

The most recent record for this species was published by Huber (2012) with a colour imagine of the habitus of a single male with the following label data: “ Brazil: Rio de Janeiro / Rio Macacú” // On RJ 116, Km 65 / 22°22.786'S / 42°33.945'W, elev. 933m / 17-iii-1996 ”, collected during an intensive survey by the University of Minnesota team of Holzenthal, Rochetti and Oliveir; the specimen is deposited in RLHC.

The Guapi-Macacú River Basin is located within the Brazilian state of Rio de Janeiro, northeast of Guanabara Bay and the city of Rio de Janeiro. The Cachoeiras de Macacu is a lowland area of Atlantic Rainforest, close to the Serra dos Órgãos Mountain Range. It was severely deforested in most of its territory, but there are still some sites of well preserved forest and its valuable biodiversity(André Sylva Roza, pers. com).

Little is known of the biology of this very rare tiger beetle. Huber (2012) mentioned that the biotope of the male from Macacú was described by the collectors as: “forested slopes at upper reaches of Macacú basin; wet, rich with epiphytes, steep slopes”.

Erwin and Pearson (2008) mentioned that the only recently collected specimen was captured in a flight interruption trap in forested vegetation along a mountain stream, referring to “Huber, pers. com.”, so, the record was probably the same as published by Huber (2012). These authors ( Erwin and Pearson 2008: Pl. 26) published a photograph of a “forested coastal mountain stream landscape in which members of the genus may dwell (Salto Morato Nature Reserve, Mata Atlântica, Paraná, Brazil, ca 100 m. altitude)”. While the Salto Morato Nature Reserve in Guaraquecaba, Paraná, is a well preserved area of the Atlantic Rainforest, its phytogeographic profile may be different from the other localities where Opisthencentrus dentipennis has been recorded; thus considering that Erwin and Pearson (2008) did not provide evidence of a specimen collected in this locality, there is no proof of the occurrence of this rare tiger beetle in the Paraná area.

As discussed by Roza and Mermudes (2015), the Atlantic Rainforest is one of the most threatened biomes of the world, with only 11−12 % of its original cover.

Remarks. Opisthencentrus dentipennis was described by Germar (1843) probably from only one female (MFNB), but as no number of specimens was given in the original description, the female is here designated as a lectotype to assure stability of the taxon.

Figures

FIGURES 1 – 3. Habitus of Opisthencentrus dentipennis (Germar). 1 — ♀, 8.3 mm, Brasil, LT (MFNB); 2 — ♀, 8.9 mm, “ Brasilia ” (SDEI); 3 — ♂, 7.9 mm, “ Brasilia ” (SDEI).

FIGURES 4 – 14. Opisthencentrus dentipennis (Germar). 4 – 5 — head, “ Brasilia ” (SDEI): 4 — ♂; 5 — ♀; 6 – 9 — labrum: 6 — ♂, “ Brasilia ” (SDEI); 7 — ♂, Angra dos Reis (SDEI); 8 — ♀, “ Brasilia ” (SDEI); 9 — ♀, Brasil, LT (MFNB); 10 – 12 — pronotum: 10 — ♂, “ Brasilia ” (SDEI); 11 — ♀, LT (MFNB); 12 — ♀, “ Brasilia ” (SDEI); 13 — apex of posterior femur, ♀ “ Brasilia ” (SDEI); 14 — original labels of LT (MFNB). Bars = 1 mm.

FIGURES 15 – 21. Opisthencentrus dentipennis (Germar). 15 – 18 — elytron; 15 — male, “ Brasilia ” (SDEI); 16 — ♀, Brasil, LT (MFNB); 17 — ♀, Angra dos Reis (SDEI); 18 — ♀, “ Brasilia ” (SDEI); 19 — detail of elytral sculpture, ♀, LT (MFNB); 20 — aedeagus, “ Brasilia ” (SDEI); 21 — ditto, internal sac. Bars = 1 mm.