Euetheola humilis ( Burmeister, 1847 )

López-García, Margarita M., Gasca-Álvarez, Héctor J. & Amat-García, Germán, 2015, The scarab beetle tribe Pentodontini (Coleoptera: Scarabaeidae: Dynastinae) of Colombia: taxonomy, natural history, and distribution, Zootaxa 4048 (4), pp. 451-492 : 463-465

Euetheola humilis ( Burmeister, 1847)

( Figs. 33 – 39 )

Heteronychus humilis Burmeister, 1847: 93 . Ligyrus rugiceps LeConte, 1856: 21 .

Dyscinetus parvus Casey, 1915: 172 .

Dyscinetus hondurana Casey, 1915: 188 .

Description. Habitus as in Fig. 33 . Length 13.0 – 13.5 mm (♂), 13.0 – 14.0 mm (♀). Width 6.0 – 6.5 mm (♂), 6.0 – 7.0 mm (♀). Color black to reddish brown ( Fig. 33 ). Head: Frons transversely rugopunctate and grooved. Frontoclypeal suture present; carinate, elevated, and interrupted at middle ( Fig. 38 ). Clypeus subtrapezoidal with apex truncate; surface transversely grooved and rugose; apex with 2 small, reflexed teeth. Interocular distance equals 4.0 – 4.8 times the transverse ocular diameter. Mandibles strongly sinuate, with a sharp tooth and basal rounded lobe. Antennal club subequal in length to antennomeres 2 – 7. Pronotum: Surface with sparse, small punctures, most of them not larger than those on vertex. Scutellum: Surface with a few minute, sparse punctures. Elytra: Surface with 3 double rows of punctures, each small, deep and round ( Fig. 33 ). Lateral margin not thickened in females. Sutural stria complete, with contiguous punctures. Pygidium: Surface densely punctate, punctures larger and denser on the basal half. Legs: Protibia tridentate, basal tooth slightly removed from others. Protarsus simple ( Fig. 34 ). Metatibia with apex slightly crenulate and with 9 spinules of nearly equal length. Venter: Prosternal process long, apex truncate and subquadrate. Parameres: Basal half broad, apical half narrowed, with 2 curve and acute lateral projections, apex rounded ( Figs. 35 – 36 ). Spiculum gastrale: Base as long as lateral branches, apex broad, slightly truncate ( Fig. 37 ).

Diagnosis. Euetheola humilis and E. bidentata are similar species, but the former has sinuate mandibles, a cariniform frontoclypeal suture, and smaller, sparser pronotal punctation than in E. bidentata . The male protarsi are not enlarged, and females do not have elytral margin thickened as they are in E. bidentata .

Locality records. ( Fig. 39 ) 34 specimens, 12♂, 22♀. Specimens were seen from ANDES, CTI, ICN, MEFLG, MPUJ, UPN. Arauca (3): Arauca, Alred. río Arauca (3). Atlántico (3): Barranquilla (1). Juan de Acosta, Reserva Campesina La Montaña (1). Repelón, Reserva Bijibana (1). Bolívar (6): Mompox (5). Turbaco (1). Casanare (7): Hato Corozal, Caserío indígena Mochuelo, Selva de Galería (1). Trinidad, Fundación RN La Palmita (6). Magdalena (4): Sitio Nuevo, Los Cocos, Isla de Salamanca (4). Meta (6): Los Medios, Hda. La Cabaña (1). San Martín, RN El Caduceo (4). Villavicencio, Buena Vista (1). Sucre (1): San Marcos, Hda. Cocodrilia (1). Tolima (1): Ibagué (1). Valle del Cauca (1): Bugalagrande (1). Ambiguous data (2): Colombia (1). Costa Atlántica (1).

Temporal distribution. February (3), March (4), April (6), May (1), June (4), July (1), August (1), October (1), November (4), December (5). No data (6).

Distribution. Southern United States of America to Argentina ( Endrödi 1969; Ratcliffe & Cave 2006; Ratcliffe et al. 2013). In Colombia, besides the eight departments recorded here, the species was found in Antioquia and Córdoba by Restrepo-Giraldo et al. (2003).

Natural history. Several specimens were collected with light traps, between 4 – 600 m. Some individuals were found in dry forest and gallery forest. Adults are attracted to lights. They feed on stems of grasses, and larvae are found in the soil feeding on roots ( Ratcliffe & Morón 1997). This species can become a pest of rice, sugarcane, and tobacco ( Scavo & Joly 1998). Bernardi et al. (2006) reported adults attacking plants of Eucalyptus saligna Smith (Myrtaceae) in Brazil.

Figures

FIGURES 33 – 39. Euetheola humilis. 33) habitus in dorsal view, 34) habitus in frontal view, 35) parameres in frontal view, 36) parameres in lateral view, 37) spiculum gastrale, 38) head in dorsal view, 39) locality records in Colombia.