Onthophagus steinheili Harold, 1880

Rossini, Michele, Vaz-de-Mello, Fernando Z. & Zunino, Mario, 2018, A taxonomic revision of the New World Onthophagus Latreille, 1802 (Coleoptera: Scarabaeidae: Scarabaeinae) of the osculatii species-complex, with description of two new species from South America, Journal of Natural History 52 (9 - 10), pp. 541-586 : 571-573

Onthophagus steinheili Harold, 1880

( Figures 3 (e – h), 3(n – r), 5(a))

Onthophagus steinheili Harold 1880: 34

Onthophagus steinheili Harold : Boucomont and Gillet 1927: 208; Boucomont 1932: 305; Blackwelder 1944: 212; Vulcano and Pereira 1967: 563; Zunino and Halffter 1997: 161; Escobar 2000: 209; Medina et al. 2001: 140; Pulido-Herrera and Zunino 2007: 116; Concha-Lozada et al. 2010: 47; Pardo-Locarno and Camero 2014: 210, 223 Diagnosis

Pronotal and elytral surface completely sericeous, with strong silver iridescence. Male with fronto-clypeal carina and frontal horns. Superior metasternal keel strong and sharp. Female with two cephalic carinae, frontal carina distinctly interrupted at middle or entire, and always slightly elevated at both sides. Anteromedial protuberance of female callus-like and transverse.

Redescription

Medium-sized species, body length 6 – 7 mm. Colour. Body completely black, opaque to very feebly shining, anterior side of pronotum often with a weak metallic green sheen, body sericeous with silver iridescence. Ventral side of the body dark brown to black, middle-, metafemurs, sides of metasternum (on the inferior side and close to the inner margin of mesocoxae), mouthparts, scape and antennal articles I – V reddish brown, antennal club tan-brown. Head. Clypeus sub-trapezoidal, with sides very weakly curved, clypeal margin widely truncated at middle, clypeo-genal junction barely indicated. Fronto-clypeal carina thin and distinct at middle, carina curved forward, frontal horns long and slightly convergent at the apex, more distinctly curved at the base, surface of head finely punctated, punctures evenly distributed. Thorax. Anteromedial pronotal protuberance narrowly and obtusely triangular between the cephalic horns, superior side of pronotum flattened (in lateral view), dorsal and medial region with a very shallow, wide and longitudinal sulcus. Pronotal punctures obsolete, discal punctures only visible at high magnification (40× – 50×). Elytral striae large and shallow, interstriae flattened, lateral interstriae (VI – VII) with setiferous punctures, setae very short and straight, discal interstriae more opaque and sericeous, punctation inconspicuous. Propleuron with an acuminated tubercle in proximity of the anterior angles of pronotum. Superior side of metasternum with a strong, sharp and longitudinal keel between mesocoxae, metasternal punctation very fine and sparse. Abdomen. Pygidium flat, basal region sericeous and dull, apical half usually shinier, distinct punctures evenly distributed, basal half of pygidium with stronger punctures, apex with smaller points. Legs. Foretibiae slender, internoapical margin with an obtuse to more acuminate tooth, apical spur curved downward, tip obtuse. Male genitalia. In dorsal view, distal-superior area with apical margin transversally truncate, lateral margin acuminated. In lateral view, distal-inferior area widely excavated, tips of the paramerites distinctly curved downward. Lamella copulatrix square-shaped, superior margin transversally straight. Superior left lobe of the lamella copulatrix narrow and obtusely acuminated at the apex. Apical part of the superior left lobe clearly bent outward, external margin widely excavated. Inferior right lobe slightly longer than inferior left lobe. Secondary lamella quite rounded, with left margin curved and right margin distinctly notched at middle ( Figure 3 (n – q)). Female genitalia. Ventral sclerotization of the vagina wide, central and inferior margin of the sclerotization widely and evenly curved upward ( Figure 3 (r)).

Females have two distinct cephalic carinae, the fronto-clypeal carina is slightly curved forward and low, while the frontal carina is often interrupted at middle, with both sides elevated. Foretibiae of females are slightly larger than male, while the anteromedial pronotal protuberance is callus-like. Minor males are very similar to females but can be distinguished in having two small frontal horns and last abdominal sternite distinctly narrower at middle.

Distribution

Known from Colombia and Ecuador ( Figure 5 (a)).

Remarks

Onthophagus steinheili is a fairly rare species in collections and so far it is known only from a few Colombian localities, such as Fusagasugá, San Antonio and Cauca. We report here a new Colombian locality and a first record from southern Ecuador ( Figure 5 (a)). This latter finding led us to suggest that O. steinheili might also occur in central and northern Ecuador.

As specified in Harold ’ s (1880) title, the type series of O . steinheili was collected by the German naturalist Eduard Steinheil (1830 – 1879) during his trip to Colombia between 1872 and 1873 ( Papavero 1973). Two females housed at the MNHN are clearly part of the syntypic series, as they bear labels indicating they were part of Steinheil ’ s collection and they were collected in the Colombian town of Fusagasugá (Cundinamarca), which perfectly matches the type locality given by Harold (1880) .

To maintain the nomenclatural stability, we designate a well-preserved female as the lectotype of O. steinheili (ICZN 1999, Art. 74). The other female of the type series has been properly labelled as paralectotype. Label data are provided below.

Type specimens examined

Lectotype here designated (♀ MNHN): 1: Ex Musaeo E.Steinheil (printed on cream label with black border). 2: Steinheili, Harold (handwritten in italics on cream label). 3: Fusagasugá (handwritten in italics on cream label). 4: Muséum Paris, 1952, Coll. R. Oberthur (printed on light-green label with black border). 5 : LECTOTYPE: Onthophagus steinheili Harold , des. F.Z. Vaz-de-Mello, 2014, ♀ (printed and handwritten on red label with black border). Paralectotype (♀ MNHN): 1: Ex Musaeo E .Steinheil (printed on cream label with black border). 2: Fusagasugá (handwritten in italics on cream label). 3: Muséum Paris, 1952, Coll . R . Oberthur (printed on light-green label with black border). 4: PARALECTOTYPE: Onthophagus steinheili Harold , des. F.Z. Vaz-de-Mello, 2014, ♀ (printed and handwritten on yellow label with black border)

Additional material examined

COLOMBIA: Caquetá: PNN Picachos . 02°47 ’ 51 ” N, 74°51 ’ 18 ” W. 1560-1770 m. XI-XII-1997 (2 ♂♂, 1 ♀♀ CMNC) . Cauca: 16 Km E Silvia . 22-II-1970 (1 ♂ CMNC) . No data: (1 ♂ NHRS) . Tolima: San Antonio (1 ♂ NMPC; 1 ♂ MZc) . No department: Rio Cauca (1 ♀ NMPC) . ECUADOR: Zamora-Chinchipe: Chito . Rio San Francisco . 723925E-9457364N. 1540 m. 17-II-2008 (2 ♂♂ CEMT) .

Figures

Figure 3. Onthophagus nyctopus. (a, b) Dorsal habitus of male and female. (c, d) Dorsal habitus of the lectotype and original labels (scale bar: 1 mm). (i, j) Lateral and dorsal view of the parameres (scale bar: 0.05 mm). (k, l) Lamella copulatrix and accessory lamellae; arrow indicating the basolateral carina of the inferior left lobe of O. nyctopus. (m) Female genitalia (scale bar: 0.02 mm). Onthophagus steinheili. (e, f) Dorsal habitus of male and female. (g, h) Dorsal habitus of the lectotype and original labels (scale bar: 1 mm). (n, o) Lateral and dorsal view of the parameres (scale bar: 0.05 mm). (p, q) Lamella copulatrix and accessory lamellae. (r) Female genitalia (scale bar: 0.02 mm).

Figure 5. Geographic distribution of the species of the osculatii complex.