Scapomegas auritus Marseul, 1855

Leivas, Fernando W. T., Bicho, Carla L., Degallier, Nicolas & Moura, Daniel P., 2012, Revision of the genus Scapomegas Lacordaire, 1854 (Coleoptera: Histeridae: Omalodini), Zootaxa 3482, pp. 33-46 : 42-43

Scapomegas auritus Marseul, 1855

Scapomegas auritus Marseul, 1855: 132 (original description); Degallier et al., 2010: 67 (distributional data); Mise et al., 2010: 321 –324 (ecological data); Mazur, 2011: 75 (catalogue).

Diagnosis. Pronotum with lateral stria complete, anterior margin sinuous behind the head; elytra with outer subhumeral stria present on the posterior half; propygidium with strong punctuation on the anterior half and with few strong points on the lateral and posterior margin, posterior region with a transversal elevation; 8th sternite in ventral view with two, sometimes three, long bristles and others small on lateral-posterior region.

Redescription. Length (pronotum+elytra): 3.40–4.83 mm; elytral width: 3.12–4.08 mm.

Color usually dark or dark-brown, sometimes metallic blue. Basal segment of the antennal club with a concave region on the inner side. Anterior margin of pronotum sinuous behind the head ( Figs. 1 A; 5A); marginal stria laterally discontinuous; lateral stria complete ( Fig. 5 A). Prosternal lobe with weak punctuation. Elytra with outer subhumeral stria present at the posterior half ( Fig. 2 A); inner subhumeral stria present or not; 1st dorsal stria complete, 2nd dorsal stria variable, 3th–5th dorsal striae present at the posterior margin, sutural stria complete ( Fig. 1 A). Mesosternum with marginal stria interrupted at the middle ( Fig. 1 B). Metasternum with lateral stria complete or not and postmesocoxal stria mostly present. Middle and hind tibiae, on the inner margin, with median submarginal stria interrupted at the extremities. Third visible abdominal sternite with a sulciform row of punctures ( Fig. 1 B). Propygidium with strong punctuation on the anterior half and few on the lateral and posterior margin, posterior region with a transversal elevation. Pygidium with variable punctuation ( Fig. 3 D).

Male terminalia. Eighth sternite in ventral view with two, sometimes three, long bristles and others short on lateral-posterior region ( Fig. 6 A). Basal margin of the parameres with an acuminate emargination in dorsal and ventral view, being shallower and sometimes rounded in dorsal view ( Fig. 7 A).

Remarks. A weak fovea at the frons was pointed out by Marseul (1855) but this character can be found in all species of the genus and with different levels of intensity. In some specimens studied the outer subhumeral stria is present on the posterior two thirds. Unlike what Marseul (1855) considered (2nd–5th dorsal striae present only on the apex), the third dorsal stria can be weakly indicated at the anterior region. Some specimens from Belém ( Brazil) present three long bristles on lateral-posterior region of the eighth sternite, but only in one of the sclerified plates. In populations from Ecuador and Peru the metallic blue color is more evident, the inner subhumeral stria is present, the 2nd dorsal stria can be well marked in its length and the punctuation of the pygidium can resemble S. gibbus , whereas, in populations from Brazil (excluding Belém), Venezuela and French Guiana the color is usually dark or dark-brown, the inner subhumeral stria is absent, the 2nd dorsal stria is marked only on the posterior margin, and the pygidium is equally punctuated except for an elevation where the punctuation is weaker. However, the structures of the terminalia for all the examined material were studied and we believe that there are no consistent differences in those structures to separate the populations in two species.

Distribution and ecological data. Currently known from elevations of 15–800 m in Amazon region from Ecuador, French Guiana, Suriname, Venezuela, Peru and Brazil.

Type material. The specimen labeled: “1 Scapomegas auritus m Cayenne …” (green round Marseul’s handwrited label) / “Museum Paris coll. De Marseul 2842-90 ” (printed label) / “ TYPE ” (red printed label) is herein designed as the LECTOTYPE of the species. L = 4.10 mm; l = 3.73 mm ( MNHN).

Additional examined material. VENEZUELA: Amazonas, Cerro de la Neblina Basecamp, 0°50’N, 66°10’W, 140m, 10-20/II/1985, FIT, P.J. & P.M. Spangler, R. A. Faitoute, W. E. Steiner colls. 3 ex. [ USNM]; Bolívar, Suapure, Caura River, 6/VII/1899, E. A. Klages col., 1 ex. ( SBMN). FRENCH GUIANA: Passoura, Coll. Le Moult, 1 ex.; idem, "JANVIER", 1 ex. ( BMNH); Gourdonville, march (H. Desbordes det., 1916), 1 ex. ( MNHN); Saint Laurent du Maroni, avril (H. Desbordes det., 1916), 1 ex. ( MNHN); Montagne des Chevaux (4°43' N; 52°24' W); Réserve Naturelle Nationale des Nouragues-Station de Saut Pararé (4° 02' 16" N; 52° 40' 21" W); Itoupé, Mont Tabulaire, 600–800 m (03°01’20’’N; 53°05’41’’ W - 03°01’19’’N; 53°05’03’’W); Saül, point de vue du Belvédère (unpublished, PCND). Detailed distributional and chronological data are available in Degallier & Kanaar (2001), Degallier et al. (2010) and herein cited papers. BRAZIL: Pará, Belém (Mocambo), 13/V/1978, N. Guimarães col., 1 ex.; Marajó, Breves (Rio Caruacá, área 2, margem NW), 20/II/1988, no collector data, 1 ex., ( MPEG); Belém ( IPEAN), XI/1984, N. Dégallier col. 1 ex. ( PCND); Tucurui, 16–29/VII/1985, N. Dégallier col. 1 ex. ( PCND); Santarém, Coll. G. Lewis, 1 ex.; Amazon, Bates col., 1 ex. ( BMNH); Jacareacanga, XII/1968, M. Alvarenga col., 1 ex. ( DZUP). Amazonas, Itacoatiara (Fazenda Aruana, AM 0 10, Km 215), 18/XI/1990, R. Andreazze col., 1 ex.; ZF-3 Km 23, Fazenda Esteio (60 km N de Manaus), 10/VI/1984, B. C. Klein col., 7 ex.; Manaus, Reserva Ducke, 06/IX/1978, Arias & Penny col. 4 ex.; 27/IX/1978, Arias & Penny col., 3 ex.; Reserva Ducke (010, Km 26), 20/IX/1977, no collector data, 1 ex.; Manaus, Reserva Ducke (Km 26), 27/IX/1977, B. C. Ratcliffe col., 1 ex.; Reserva Ducke (010, Km 26), 13/IX/1977, no collector data 1 ex.; 20/IX/1977, no collector data, 1 ex.; Manaus, Reserva Ducke (Km 26), 13/IX/1977, 1 ex.; 7/II/1978, 1 ex. B. C. Ratcliffe col. ( INPA); Manaus (Reserva Adolpho Ducke), 16/VII/2008, K. M. Mise col., 1 ex.. SURINAME: Sipaliwini, Arapahu, trail opposite Arapahu Island, FIT, 21/II-1/III/2011, Auke Hielkema col. (det. P. Kanaar) 6 ex. ( MHNL). EQUADOR: Napo, Tiputini Research Station, 220 m (0°38’0’’S 76°9’0’’W), BM 2000: 194, 5-25/IX/2000, D. J. Inward & K. A. Jackson col. (det. M. Caterino), 2 ex. ( BMNH); idem, 1 ex. ( SBMNH); Orellana, Tiputini Biodiv. Station, 0.6376°N, 76.1499°W, 2-9/VI/2011, AT1342, FIT, M. Caterino & A. Tishechkin colls., 5 ex.; 6/VI/2011 on mushrooms, M. Caterino & A. Tishechkin colls., 1 ex.; 4-9/VI/2011 AT1342, FIT, M. Caterino & A. Tishechkin colls., 5 ex.; 6/VI/2011 on mushrooms, M. Caterino & A. Tishechkin colls., 1 ex.; 4-9/VI/2011 AT1342, FIT, M. Caterino & A. Tishechkin colls. 1 ex. ( SBMN), 0°38.2’S, 76°8.9’W, 29/VII-03/VIII/2008, FIT, A. Tishechkin col., 1ex.; Yasuni Research Station, 0°40.5’S, 76°24’W, 11-18 /VII/1999, FIT, A. Tishechkin col., 1ex. ( AKTC). PERU: Huanuco, Tingo Maria, Monson Valley, XI.10.1954, E. I. Schlinger & E. S. Ross colls. ( CASC).

Figures

FIGURE 1. Dorsal and ventral habitus. A – B. Scapomegas auritus Marseul; C – D. Scapomegas gibbus Marseul; E – F. Scapomegas aurifer Marseul. Scale 1 mm.

FIGURE 2. Lateral habitus. A. Scapomegas auritus Marseul; B. Scapomegas gibbus Marseul; C. Scapomegas aurifer Marseul. Scale 1 mm.

FIGURE 3. Scapomegas auritus Marseul. A. Head in frontal view; B. Prothorax in ventral view; C. Detail of the last antennal segments of the funicle and antennal club. D. Propygidium and pygidium in posterior view.

FIGURE 5. Pronotum. A. Scapomegas auritus Marseul; B. Scapomegas gibbus Marseul; C. Scapomegas aurifer Marseul. Scale 1 mm.

FIGURE 6. Eighth sternite of the male terminalia with detail of the bristles on the sides of the posterior margin (A – C, scale 0.5 mm and 0.125 mm, respectively) and ninth sternite and tergite (D – F, scale 0.5 mm). A, D. Scapomegas auritus Marseul; B, E. Scapomegas gibbus Marseul; C, F. Scapomegas aurifer Marseul.

FIGURE 7. Aedeagus in ventral and dorsal view, respectively. A. Scapomegas auritus Marseul; B. Scapomegas gibbus Marseul; C. Scapomegas aurifer Marseul. Scale 0.5 mm.