Genus Euligyrus Casey, 1915 new status

Euligyrus Casey, 1915: 185 (as subgenus).

Type species: Scarabaeus ebenus De Geer, 1774: 317 by original designation.

Description. (n = 555). Length 24–30 mm. Humeral width 12.5–15.1 mm. Head: Clypeus trapezoidal (Fig. 1A). Apical clypeal teeth transverse and widely separated (3 tooth diameters). Ocular canthus rounded; without ventral or dorsal setae. Frons with 2 transverse, high tumescences. Mentum subrectangular; strongly narrowed at apex (Fig. 2G–H). Mentum and ligula separate by a suture. Ligula wide; covered with long, dense setae; ligular lobes not fused, with a narrow emargination. Maxillar apical palpomere 1.3 times longer than the second. Maxilla with galea rectangular (2.5 times longer than wide); with 6 teeth (Fig. 4A). Mandible tridentate (2 apical and 1 lateral triangular large tooth); apical teeth equal in shape (Fig. 5A). Labrum rectangular (2.5 times wider than long); apex straight to slightly bilobed; with long, dense setae. Antenna with 10 antennomeres, club short (1.2 times longer than antennomeres 2–7). Pronotum: Apical marginal bead complete. Apex with a rounded tubercle and an oval to triangular fovea. Elytra: Inner surface of apex with irregular small tubercles. Wings: RA with dense, large peg-like setae on medial ventral region; with peg-like setae on dorsal surface (Fig. 7A, C). Edge of RA 3 with dense setae. Abdomen: Apex of tergite IV with irregular granules like scales, not forming lines. Sternite VIII emarginate in males; entire in female. Propygidium without stridulatory area. Venter: Prosternum very wide, convex. Propleura with short, sparse setae on anterior and posterior surface, medial surface glabrous. Apex of prosternal process flat, with a deep sulcus, without dorsal setae. Metepisternum with complete carina; inner surface smooth and glabrous; outer surface homogeneously rugose, glabrous. Metasternum with large, deep, confluent punctures, without setae. Legs: Male protarsus enlarged (tarsomeres 2–4 2 times wider than long, tarsomere 5 1.5 longer than wide); tarsomere 4 with a lateral flat, striate projection (Fig. 10A); inner claw bifid (Fig. 10B). Protibia tridentate, basal tooth distant from others (Fig. 11A). Apical margin of mesotibia and metatibia crenulate (Fig. 12A, G). Female genitalia: Subcoxite 1.5 times wider than long. Coxite subquadrate (as long as wide); surface flat (Fig. 13A). Subcoxite wider than and as long as coxite. Male genitalia: Phallobase 1.6 times longer than parameres. Parameres without dorsal teeth, with ventral tooth (Fig. 17A). Internal sac without copulatory lamella nor lamellar spiny belt; accessory lamella long with an apical brush of setae (Fig. 21A).

Diagnosis. Euligyrus can be differentiated from other Pentodontini by the following: frons concave at middle; clypeus trapezoidal, clypeal teeth widely separated (Fig. 1A); frontoclypeus with tumescences (Fig. 1A); mentum subrectangular; galea with 6 teeth (Fig. 4A); pronotum with apical marginal bead complete; pronotal tubercle rounded; fovea deep, oval to triangular; metasternum glabrous; protibia tridentate; protarsus of male enlarged, inner claw wide and bifid (Fig. 10B); protarsomere 4 with a lateral flat, striate projection (Fig. 10A); internal sac without copulatory lamella nor lamellar spiny belt, with an apical brush of setae (Fig. 21A); surface of coxite flat (Fig. 13A); and stridulatory apparatus consisting of an area with irregular granules like-scales on apex of sternite IV and apical inner surface of elytra with irregular small tubercles.

Composition. Two species: Euligyrus ebenus and E. similis .

Geographic distribution. It is apparently a South American genus that dispersed to Central America and some islands of the West Indies (Fig. 31).

Phylogenetic relationships. According to the phylogenetic analysis of Tomarus (sensu lato), Euligyrus is not closely related to any of the analyzed genera but shares some characters with species of Cyclocephala and Oxyligyrus (i.e., the shape of the protarsus and inner claw in males, and the shape of the prosternal process). Although its relation to other Dynastinae groups is uncertain, it is probably closer to Cyclocephalini, as suggested by Casey (1915).

Taxonomic remarks. Casey (1915) described Euligyrus, which included only E. ebenus, as a subgenus of Ligyrodes due to its shared characters, such as the anterior tarsus modified in the male, the apex of the prosternal process without setae, and the transverse shape of the abdominal spiracles of segments I–III. Although the subgenus Euligyrus was not used since Cartwright (1959) synonymized the genus Ligyrus with Ligyrodes, Endrödi (1969) revalidated this subgenus but as part of the genus Ligyrus and included E. similis . Morón & Grossi (2015) placed these two species in “Group A” of the genus Tomarus, but the species of Euligyrus are not closely related to Tomarus and are clearly a different genus with affinities to the tribe Cyclocephalini .

Key to males of the genus Euligyrus

1 Parameres wide, basal 3rd widened, apical 3rd strongly contracted and apex dilated (Fig. 15A). Brazil to Mexico (Fig. 31)........................................................................... Euligyrus ebenus (De Geer, 1774)

- Parameres slender and long, apical 3rd not strongly contracted, sides nearly parallel (Fig. 15B). Brazil to Costa Rica (Fig. 31)........................................................................ Euligyrus similis (Endrödi, 1968)