Ateuchus earthorum Kohlmann & Solís, 2009

Kohlmann, Bert & Solis, Angel, 2009, New species of Ateuchus and Canthidium (Coleoptera: Scarabaeidae: Scarabaeinae) from Costa Rica, Zootaxa 2219, pp. 31-37 : 31-34

Ateuchus earthorum Kohlmann & Solís , sp. nov.

( Figs. 1–2, 4 )

Diagnosis: This species is distinguished from other Costa Rican species by the following combination of characters: head disc finely punctured with coarse punctures at anterior margin; pronotum finely punctured with coarse punctures at the base of the pronotal midline; anterior pronotal margin incomplete; eyes viewed from above 3 times longer than wide; head and pronotum with coppery red reflections; body oval; profemur coarsely punctured; proepimeron without punctures; elytra not shagreened; pygidium very convex; last abdominal segment broad; internal sac with three hooks.

Holotype description: Male ( Figs. 1–2). Total length 6.7 mm. Elytral width 4.4 mm. Body slightly ovoid and convex, dorsum dark brown, head and pronotum with strong cupreous red reflections; venter dark brown.

Clypeal margin coarsely punctate and broadly V-shaped, tooth on each side rounded, lateral margin arcuate, dorsal surface of head finely punctate and granulate, frons and vertex feebly tumid, eye dorsally small (ten times the interocular distance).

Pronotum finely punctate and granulate, moderately punctate at posterior end of midline, midline impressed only one-third pronotal length, anterior pronotal margin incomplete. Proepisternum finely wrinkled, proepimeron granular.

Elytral surface smooth and shiny; striae slightly impressed, more strongly so anteriorly; striae feebly punctate, intervals slightly convex. Pygidium very convex, surface slightly granulate and minutely punctate, completely grooved.

Protibia quadridentate, basal tooth small, protibial spur oval; apical one-half of profemur ventrally coarsely punctate, punctures extending along posterior margin to base of femur, punctate area black; mesofemur and metafemur short, thick, with minute punctures near apex.

Internal sac of the aedeagus ( Fig. 2) with three hooks, one small, two large; three apical lamellae; and a well-developed, spiny fascies.

Allotype: Female. Total length: 7.2 mm. Elytral width: 4.9 mm. Differs from the holotype by the following characters: Clypeal margin anteriorly moderately V-shaped, anterior clypeal border moderately punctate, protibia with acute, slender spur slightly bent apically; last abdominal segment broader, pygidium less convex.

Variation: Total length: 6.3–7.2 mm. Elytral width: 4.1–4.9 mm. The color intensity varies of the cupreous-red head and pronotum.

Material Examined (11 specimens): Holotype, male: COSTA RICA: Est. Cacao, 2 km SW del Cerro Cacao, Prov. Guanacaste, 1100 m, 12–14SET1995, C. Scarabaeidae , caca de caballo. L_N _323100_375800, #6292. Allotype, female: ibidem. Paratypes. ibidem, 5 males, 3 females; ibidem, caca de mono, 1 female.

Remarks: This species will key to A. ginae in Kohlmann’s (1997) key. These species are cryptic and cannot be separated on the grounds of external morphology; only the internal sac differences will distinguish them. In both species there are three hooks, two are long and similar and the third is long and like a simple bar in A. ginae , whereas it is short and spine-like in A. earthorum ( Fig. 2). These sac-hooks morphological differences are not only consistent (external morphology can be very variable and misleading) and geographically circumscribed to Cacao volcano, but also typical for separating Ateuchus species ( Kohlmann 1984, 1997, 2000). Moreover, the ecology and geology are also critical; the Guanacaste volcanoes are a wellknown species generating area for small-sized dung beetle taxa like Ateuchus , Canthidium , and Onthophagus ( Kohlmann 1997, Kohlmann & Solís 2001, Kohlmann & Wilkinson 2007, Kohlmann et al. 2007, Solís & Kohlmann 2004) and for plants ( Araceae , Arecaceae , and Bromeliaceae ) as well (Kohlmann et al. accepted).

Habitat: The new species lives in mountain tropical forest at 1100 m and has been collected in September in horse manure and from monkey’s dung.

Geographical distribution ( Fig. 4 ): The new species is so far only known from the Pacific slope of Cacao volcano, in the province of Guanacaste.

Chorological affinities: The new species is found at the same altitude, in the Guanacaste Cordillera, as its sister species, A. ginae Kohlmann , in the Central Cordillera ( Kohlmann 1997).

Taxonomic relationships: Ateuchus earthorum is hypothesized to be the sister species to A. ginae Kohlmann based on shared morphological characters discussed above.

Etymology: The name is a Latinized noun in the genitive case. This species is dedicated to EARTH University in Costa Rica, an institution committed to the sustainable development of the humid tropics, to celebrate its 20th anniversary.

Figures

FIGURE 4. Known distribution of the new species in Costa Rica: A. earthorum (․) and C. darwini (˔).