a. Dorsal view. b. Lateral view. c. Fronto-dorsal view, showing detail of dorsal pronotum (scale bar = 3 mm).

Family Scarabaeidae Latreille, 1802

Subfamily Dynastinae MacLeay, 1819

Tribe Phileurini Burmeister, 1847

Genus Oryctophileurus Kolbe, 1910

Oryctophileurus guerrai Perger & Grossi, 2013

(Figs. 1-3)

Distribution : BOLIVIA: Tarija, Reserva Nacional Tariquía.

Material examined: ARGENTINA: Jujuy, II-1915, 1 ♂, Bruch, C. col. [MACN_En 42057]. New Country Record (Fig. 2).

Description of parameres (Fig. 3): Phallobase 1.5 times longer than parameres; dorsal surface with a rounded constriction on the medial portion, strongly convex on the apex. Parameres symmetrical; basal portion with sides broadly separated and lateral margins sinuous; apical portion gradually narrowed, with convergent and straight sides; apex rounded, slightly dilated. In contrast, the parameres of O. armicollis and O. varicosus are abruptly narrowed on the apical region and have a strongly inflated apex, facilitating differentiation from O. guerrai. In lateral view, the parameres of O. guerrai are simply convex, with a slightly deflexed apex.

Figure 2.

Red circle indicates previously known (bibliographic) distribution. Open red circle indicates new record from Argentina (without locality data).

Figure 3.

Parameres: a. Frontal view, b. lateral view (scale bar = 1 mm).

Key to the Genera of Phileurini in Argentina

(Modified from Penco & Zubarán, 2013, Di Iorio et al., 2017 and Ratcliffe et al., 2023)

1. Outer side of mandibles simply curved....................... 2

1`Outer side of mandibles tridentate.............................. 3

2. Frons with 1‒2 horns or with tubercles........................ 4

2`Frons without horns or tubercles................................ 5

3. Apex of posterior tibia truncated, with many notches..... 6

3` Apex of posterior tibia poorly proyected, with 3 teeth; frons with 2 small tubercles; anterior tibia tridentate Goniophileurus Kolbe

4. Apex of posterior tibia truncated, lacking teeth............... Archophileurus Kolbe

4`Apex of posterior tibia with 1-3 teeth........................... 7

5. Anterior tibia cuatridentate........ Actinobolus Westwood

5` Anterior tibia tridentate.............................................. Argentophileurus Penco & Zubarán

6. Clypeal apex rounded; frons with 2 flattened horns......... Trioplus Burmeister

6` Clypeal apex obtusely acuminated; frons with 2 tubercles Microphileurus Kolbe

7. Frons with 1 horn.................... Oryctophileurus Kolbe

7` Frons with 2 horns or tubercles................................. 8

8. Apex of posterior tibia with 3 large teeth....................... Homophileurus Kolbe

8` Apex of posterior tibia with 1-2 large teeth................... 9

9. Tubercles or horns located near center of head.............. Hemiphileurus Kolbe

9` Tubercles or horns located near lateral margins of head.. Phileurus Latreille

Oryctophileurus guerrai was originally described from Reserva Nacional Tariquía in the department of Tarija, southern Bolivian Andes (Perger & Grossi, 2013). The specimen reported here represents the first record for Argentina, collected in the province of Jujuy in 1915, with no precise locality. Perger and Grossi (2013) suggested that this species is probably endemic to the Tucumán-Bolivian montane forest, and the discovery of this specimen confirms the authors' assumption.

The ecoregion spans approximately 56,000 km² from southern Bolivia into northwestern Argentina, where it is known as Province of the Yungas (Cabrera, 1971; Cabrera & Willink, 1973; Arana et al., 2021). The Yungas are characterized by piedmont and cloud forests with various layered vegetation, abundant epiphytes, lianas and high-altitude tree species (Arana et al., 2021). They play a crucial role in regional biodiversity and harbor a high number of endemics (Morrone, 2014; Arana et al., 2021).

With this new record, five of the ten genera of Phileurini found in Argentina now have species documented in the Yungas: Archophileurus (5 species), Goniophileurus, Microphileurus, Oryctophileurus (1 species each) and Phileurus (6 species). Some of these taxa are restricted to Salta and Jujuy provinces, while others have a wider distribution across the country (Ratcliffe et al., 2023). Considering the scarcity of Oryctophileurus specimens deposited in scientific collections and the vulnerability of the Yungas to anthropogenic impacts, comprehensive studies of the region’s entomofauna are essential for understanding and conserving its unique biodiversity.