Tomarus gyas Erichson, 1848

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 : 484-485

Tomarus gyas Erichson, 1848

( Figs. 132 – 143 )

Tomarus gyas Erichson, 1848: 561 .

Ligyrus amazonicus Arrow, 1914: 273 .

Description. Habitus as in Figs. 132–133 . Length 23.5–27.0 mm (♂), 22.0–26.0 mm (♀). Width 12.0– 13.5 mm (♂), 11.0–13.0 mm (♀). Color black to dark reddish brown. Head: Frons flat; surface strongly rugose and grooved; base nearly smooth, with sparse, deep punctures. Frontoclypeal suture visible only on sides and interrupted by 2 frontal tubercles. Tubercles transverse and triangular, separated by about 4.5–5.0 times a tubercle diameter. Clypeus strongly rugose and grooved; shape triangular, apex narrowed with 2 reflexed teeth, separated by one or less a tooth diameter. Interocular distance equals 3.4–3.9 times the transverse ocular diameter. Antennal subequal in length to antennomeres 2–7. Mandibles with 2 apical teeth and one basal rounded lobe. Pronotum: Surface with shallow, small punctures, denser and deeper on anterior and posterior angles. Apical tubercle inconspicuous to prominent, apex strongly acute and slightly recurved. Subapical fovea rounded, deep to shallow ( Figs. 134–135 ), rugose and finely punctate. Scutellum: Surface with small to minute, sparse punctures. Elytra: Surface with deep, large punctures, some smaller between intervals; 3 pairs of double rows of punctures; elytral suture present. Pygidium : Basal third strongly punctate and rugose. Disc with sparser punctures. Surface weakly convex in males, nearly flat in females. Legs: Protibia tridentate or with a fourth basal tooth; teeth subequally spaced. Male protarsus simple, not enlarged. Apex of metatibia slightly crenulate; apical margin with 22–25 spinules. Apex of first slightly triangular expanded. Venter: Prosternal process long, extending beyond procoxae; apex flat, longitudinally oval, bordered by long yellow setae. Parameres: Base broad; lateral teeth large, long and strongly arcuate; apex strongly narrowed; apex with 2 small lobed or triangular projections on each apex ( Figs. 136, 139, 140 ). Spiculum gastrale: Base larger than lateral branches, apex broad ( Figs. 138, 142 ).

Diagnosis. Tomarus gyas and T. bituberculatus are similar in the shape of the pronotal fovea and frontal tubercles. However, T. gyas tends to be a smaller species, the distance between the frontal tubercles is smaller, and the pronotal fovea is narrower and rounded, whereas it is wider and transversally oval in T. bituberculatus . Moreover, some specimens of T. gyas have the protibia with a fourth small basal tooth. The general appearance of some specimens of T. gyas is similar to that of T. maternus and T. pullus . However, T. pullus is a much smaller species (16–18 mm) and its frontal and pronotal tubercles are inconspicuous. Tomarus maternus can be distinguished by having a longitudinal pronotal fovea and the scutellum with deep punctures forming lines that converge apically, and by having fewer number of spinules on the apex of the metatibia (14–17).

Locality records. ( Fig. 143 ) 53 specimens, 31♂, 22♀. Specimens were seen from BCRC, CEUN, CTI, HJG, IAvH, ICN, LEUC, MEFLG, MLS, MPUJ, UNSM, UPN, UPTC. Amazonas (9): Leticia (5). Leticia, Parque Orellana (1). Leticia, Pureté, T. San Juan (1). Puerto Nariño, Sector Macedonia (2). Antioquia (7): Medellín (7). Arauca (1): Arauquita, Campamento Caño Limón (1). Boyacá (1): Puerto Boyacá (1). Caldas (2): Manizales (1); Ecoparque Los Alcázares (1). Caquetá (7): Florencia (7). Casanare (3): Aguazul, Periferia urbana (1). Yopal, Parque Central, P. Urbano (1). Caño Mocuare (1). Huila (1): Acevedo, W. Acevedo-Suaza, ribera de Río Guaza (1). Meta (12): Acacías, W. Villavicencio-Acacías, Vda. Benposta (1). Granada (1). Restrepo (3). Restrepo, Vda. Caney Alto (1). Villavicencio, Río Ocoa (3). Villavicencio, Vda. La Vanguardia (1); W. Villavicencio-Catama, Alred. Barrio Bosques de Abajam (2). Nariño (2): Pasto (2). Norte de Santander (1): Cúcuta (1). Quindío (1): Quimbaya, RN La Montaña del Ocaso (1). Santander (1): Río Carare (1). Tolima (1): Espinal (1). Vichada (2): Gaviotas (2). Ambiguous data (2): Colombia (1). St. Br. (1).

Temporal distribution. January (8), February (5), March (1), April (11), May (3), June (3), August (3), October (3), November (9), December (2). No data (5).

Distribution. Mexico to Argentina ( Endrödi 1969; Ratcliffe 2003; Ratcliffe & Cave 2006). In Colombia, the species was previously recorded from Cauca ( Pardo-Locarno et al. 2005), and Chocó (identified as T. fossor in Neita-Moreno 2011).

Natural history. Specimens were collected with light traps between 140–2,500 m.

Taxonomic remarks. Tomarus gyas is the most variable species in the genus. The pronotal fovea can be small and shallow or wide and deep. Specimens with larger fovea generally have the protibia with a small fourth basal tooth. Three different shapes of parameres are found ( Figs. 136, 139, 140 ), but the variation is continuous and it could not be associated to the geographical distribution.

Figures

FIGURES 132 – 143. Tomarus gyas. 132 – 133) habitus in dorsal view, 134 – 135) pronotum in dorsal view, 136,139 – 140) parameres in frontal view, 137, 141) parameres in lateral view, 138, 142) spiculum gastrale, 143) locality records in Colombia.