Eremophygus Ohaus, 1910

Mondaca, José, 2022, Revision of the high Andean genus Eremophygus Ohaus (Coleoptera: Scarabaeidae: Rutelinae: Rutelini), Insecta Mundi 2022 (905), pp. 1-11 : 3-7

Genus Eremophygus Ohaus, 1910

Eremophygus Ohaus 1910: 21–22 .

Type species. Eremophygus philippii Ohaus 1910: 22 , by monotypy.

Synonym. Heterocallichloris Gutiérrez, 1951 .

Heterocallichloris Gutiérrez 1951: 112–114 . [Type species. Heterocallichloris bicolor Gutiérrez, 1951 by original designation]. [syn. by Smith and Jameson 2001: 105].

Gender. Masculine.

Species. Two species.

Diagnosis. Within the Rutelini , members of Eremophygus are diagnosed by the following characters: male with head, pronotum, scutellar shield, part of the elytra, and ventral portion of the body finely and moderately to densely setose; setae pale yellow, long ( Fig. 4A, 4G , 5A, 5G ); female mostly glabrous, with sparse, dorsal setation ( Fig. 4D ). Antenna small with 9 antennomeres in both sexes ( Fig. 1A, 1B ). Mentum oval or semicircular in shape with apex narrow anteriorly ( Fig. 4L , 5F ). Maxilla with galea apically lobed, unarmed ( Fig. 1D ) or with a small, basal tooth. Male with internal protarsal claw thickened and greatly recurved, simple, not toothed ( Fig. 1F ); mesotarsus and metatarsus with long and thin internal and external claws, claws slightly curved, simple, not toothed in both sexes. Pronotum with marginal bead complete. Elytra variably striate or rugose ( Fig. 4A, 4D, 4G , 5A, 5G ).

Redescription (n = 18 males, 5 females). Body length: 8.9–11.0 mm (male), 8.0–14.0 mm (female); width: 5.5–8.0 mm (male), 6.0–8.0 mm (female). Color: Dorsally unicolorous pale yellow or brown opaque ( Fig. 5A, 5G ) or bicolored with pronotum dark brown and elytra shiny reddish brown ( Fig. 4A, 4D, 4G ), legs pale yellow or brown. Shape: Elongate oval, convex, with the sides diverging towards the posterior end of the body; elytral apex broadly rounded. Head: Clypeus rounded apically, with margins variably reflexed vertically; dorsal surface flat or transversely elevated at base near frontoclypeal region, densely punctate and moderately setose; punctures moderate to large, with some fused. Frontoclypeal suture absent, hinted laterally. Frons flat or slightly convex in lateral view, with moderate to large, dense punctures. Eye canthus simple, not carinate. Eyes small and reniform laterally, interocular distance equals 5–6 eye diameters ( Fig. 1C ). Antenna with 9 antennomeres in both sexes, apical 3 antennomeres forming club ( Fig. 1A, 1B ); scape claviform; pedicel submoniliform; antennomere 3 subcylindrical or cupiform; 4 subquadrate or moniliform; 5 spatuliform; 6 discoidal; club with 3 antennomeres subequal or slightly longer than the funicule. Labrum horizontal, projected beyond clypeal margin, with apex medially rounded or emarginate, dorsally punctate and setose. Mandibles exposed in dorsal view, externally rounded or angled at middle, with inner border entire; apex rounded or obtuse; molar region poorly developed, with surface not striate. Mentum longer than wide, oval or semicircular in shape, with apex narrow anteriorly; surface flat, punctate and microstriate, moderately setose ( Fig. 4L , 5F ). Labial palps short, with 3 palpomeres; palpomere 1 shorter than 2; 3 fusiform, subequal to 1–2 together. Maxilla with galea smooth and setose, with or without small basal tooth ( Fig. 1D ). Maxillary palps with 4 palpomeres; palpomere 1 shorter than 2; 2 and 3 subequal, cupiform; 4 fusiform, longer than 2–3 together ( Fig. 1D ). Pronotum: Convex, with base of similar width to elytral base; anterior angles angulose or round, posterior angles broadly rounded; posterior margin sinuate laterally and basomedially round, marginal bead complete; surface variably punctate and setose; setae long moderate to dense. Scutellar shield: Subtriangular, longer than wide, with apex rounded; surface variably punctate, glabrous or moderately setose. Elytra: Together longer than broad, with dorsal surface variably striate and finely punctate-rugose or rugose, glabrous, or setose at base and on sides; elytral suture apically rounded or angled; humeral umbone with prominent round tubercle. Pygidium: Subtriangular , wider than long, apex round or slightly curved; surface almost flat or convex, punctate, setose; lateral and caudal margins with complete marginal bead. Abdomen: Sternite 1 short, medially subtriangular; 2–4 subequal in width; 5 wider than previous sternite (1.5 times); propygidium subequal to 5 with the apex slightly emarginate in both sexes; surface finely, sparsely punctate, with setiferous punctures in transverse rows. Legs: Protibia with 3 external teeth unequally separated; distal tooth elongate, externally curved, medial large, basal small; subapical spur variable in length, straight or slightly curved. Protarsomeres subtriangular, gradually wider and shorter distally; ventral border of tarsomere 4 with striate stridulatory area. Pro-, meso-, and metatarsal onychia each with 2 setae. Meso- and metatibiae flat with contiguous, unequal apical spurs, slightly curved and somewhat flat, with round or acute apices; apical border of meso- and metatibia with numerous spinules, spinules also appear on external surface forming oblique carinae. Protarsi of male with large, unequal claws; internal claw thicker, greatly recurved, simple, not toothed, with apex acute or round; outer claw long, slightly curved, with apex acute ( Fig. 1F ); meso- and metatarsal claws similar in size, simple, not toothed. Male genitalia: Aedeagus with parameres fused dorsoventrally; apex separated or not at middle (dorsal view), sinuous in lateral view ( Fig. 4J, 4K ).

Female ( Fig. 4D, 4E ). Slightly longer and wider than male, with oval and convex body. Clypeus semicircular with margins moderately reflexed vertically. Antenna with 9 antennomeres; club with 3 antennomeres. Protibia wide with large, rounded teeth; tarsi shorter with tarsomeres short and thick; pretarsal claws small, not toothed; inner protarsal claws smaller than outer; meso- and metatarsal claws subequal. Meso- and metatarsal spurs unequal, short, wide, flat, distally round. Pygidium wide, distinctly convex in lateral view.

Distribution and habitats. Eremophygus species live at high elevations (3300–4100 m) in the altiplano (highlands) of Argentina, Chile, Bolivia, and Peru ( Fig. 3 ). This distribution corresponds to the biogeographic province of the Puna of the Andean Region proposed by Morrone (2015). These scarabs occupy high-elevation, semiarid environments comprised of shrubby steppe vegetation and grasslands characteristic of the dry puna of South America ( Fig. 2 ). The Rutelini fauna present in this region is unique and is composed of other endemic taxa such as Microogenius arrowi (Ohaus) , Microogenius puna Mondaca , and Peruquime arequipensis Mondaca and Valencia , which are adapted to living under extreme biological and climatic conditions.

Natural history. Due to the difficulty in observing the species of Eremophygus in their natural environment, little is known about their immature stages, life cycles, and conditions of the habitat they occupy. Like other altiplanic rutelines (e.g., Microogenius arrowi , M. puna , and Peruquime arequipensis ), the adults are diurnal and emerge during the rainy season (highland winter) that occurs between the months of December and April. Males have been observed flying during the morning at ground level among bushes and high grasslands. The adults live for a few weeks, during which they appear in large numbers to mate with the females that usually remain half-buried in the ground. The immature stages of these rutelines are unknown, possibly their larvae feed on roots and detritus as has been described and hypothesized for some species of Oogenius Solier and Microogenius Gutiérrez (Mondaca 2016, 2019).

Remarks. Eremophygus antennae are small with nine antennomeres in both sexes and the protarsal claws simple (not toothed) in both sexes. These characters are also present in the females of Microogenius (males with ten antennomeres and protarsal claws toothed), which caused Gutiérrez (1952) to erroneously place the female of Microogenius arrowi (described originally as Eremophygus calvus ) in the genus Eremophygus .

Tribal classification. Eremophygus were placed in Rutelini by previous authors ( Ohaus 1925, 1934, 1952; Gutiérrez 1950, 1951, 1952; Machatschke 1972; Smith and Jameson 2001; Krajcik 2008; Ratcliffe et al. 2015; Mondaca and Valencia 2016; Mondaca 2019), and this tribal-level classification has been maintained with some doubts by Moore et al. (2017). Eremophygus species were placed in Rutelini because the labrum is horizontally produced with respect to the clypeus, without a medial projection; antennae with 9 antennomeres (10 antennomeres in Lasiocala Blanchard , Microogenius (except the female), Peruquime , and Oogenius ); protibia tridentate, with inner protibial spur apical; protarsomeres not enlarged or densely setose ventrally; elytral margin simple, without a membranous border; and terminal spiracle positioned in pleural suture ( Smith and Jameson 2001).

All valid species in the genus Eremophygus (except E. pereirai = Cyclocephala pereirai ) have independently movable claws that are diagnostic of Rutelinae, also the apex of meso- and metatarsomere 5 have two weak, longitudinal slits (contrary to what was observed by Moore et al. 2017). Based on these morphological characters, Eremophygus must be classified in the tribe Rutelini until more detailed morphological and molecular studies are conducted.

Figures

Figure 1. Detailed morphology of the genus Eremophygus Ohaus, 1910. A–B) Antenna. A) Female. B) Male. C) Head in dorsal view. D) Left maxilla, lateral view. E) Mentum, ventral view. F) Protarsus of male, lateral view.

Figure 2. Andean habitat of Eremophygus philippii Ohaus in the Antofagasta Mountain range, Chile. Photo courtesy of Andrés Ramírez C.

Figure 3. Geographical distribution of Eremophygus Ohaus species in the Andean region.

Figure 4. Eremophygus lasiocalinus Ohaus. A–C) Male holotype of Eremophygus bicolor (Gutiérrez) (=E. lasiocalinus). A) Habitus, dorsal view. B) Habitus, lateral view. C) Labels. D–F) Female lectotype of Eremophygus pachyloides Ohaus (=female E. lasiocalinus). D) Habitus, dorsal view. E) Habitus, lateral view. F) Lectotype labels, egg, and mouthparts. G–L) Male lectotype of Eremophygus lasiocalinus Ohaus. G) Habitus, dorsal view. H) Habitus, lateral view. I) Labels. J–K) Aedeagus. J) Lateral view. K) Dorsal view. L) Mentum.

Figure 5. Eremophygus philippii Ohaus. A–F) Male lectotype of Eremophygus philippii Ohaus. A) Habitus, dorsal view. B) Habitus, lateral view. C) Labels. D–E) Aedeagus. D) Dorsal view. E) Lateral view. F) Mentum, ventral view. G–I) Male holotype of Eremophygus leo Gutiérrez (= E. philippi). G) Habitus, dorsal view. H) Habitus, lateral view. I) Labels.