Onthophagus transisthmius Howden and Young, 1981

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 : 563-565

Onthophagus transisthmius Howden and Young, 1981

( Figures 2 (a – d), 2(h – l), 5(b))

Onthophagus transisthmius Howden and Young, 1981: 106

Onthophagus transisthmius Howden and Young : Zunino and Halffter 1997: 161; Escobar 2000: 209; Medina et al. 2001: 140; Ratcliffe 2002: 17; Pulido-Herrera and Zunino 2007: 117; Delgado and Curoe 2014: 65

Diagnosis

Onthophagus transisthmius can be distinguished from O. chacoensis by the following combination of morphological characters: clypeus sub-trapezoidal, with sides rather straight and convergent, central margin transversely truncated to slightly depressed (clypeus widely curved in O. chacoensis ). Pronotal anterior angles with exterior margin straight to slightly curved (widely curved in O. chacoensis ); metasternal disc finely punctated (strongly and densely punctated in O. chacoensis (see Figure 1 (e))).

Redescription

Medium-sized species, body length 6 – 8.5 mm. Colour. Head and pronotum shining, metallic bronze, green, dark brown to black, sometimes with reddish or cupreous sheen on the head and sides of pronotum, elytra completely testaceous, tan brown or black, pygidium shining, metallic green, bronze or dark brown. Ventral side of the body dark brown with strong metallic-green sheen, scape, antennal articles I – V, mouthparts and tarsi brown, antennal club yellow to orange. Head. Clypeus of male sub-trapezoidal, with sides almost parallel near the clypeo-genal junction, straight and convergent towards the apex, transversally truncated at middle. Clypeal margin slightly reflexed, head margin clearly sinuated at the clypeo-genal junction. Fronto-clypeal carina absent, cephalic horns long, straight and parallel. Thorax. Anteromedial pronotal protuberance hump-like and not distinctly wide between cephalic horns, laterally with two weak excavations, pronotum polished and evenly punctated, punctures small, shallow and with a central pit. Elytra polished and dull, striae very shallow, interstriae weakly convex, lateral interstriae (VI – VII) slightly shinier, discal intervals finely microreticulated. Elytral punctation inconspicuous and sparse (only visible at high magnitude), easier to see in specimens with black elytra, interstria VII and base of VI with stronger punctures associated with short and straight setae. Abdomen. Pygidium completely bordered, at least basal region very finely microreticulated, weakly shining and almost sericeous, apical region shinier. Pygidial surface feebly convex, shallowly and evenly punctated, most of the points with a central pit. Legs. Foretibiae slender, with four external teeth, external and basal margin serrate, internoapical tooth obtuse, apical spur slightly curved downward. Middle and hind legs unmodified. Male genitalia. In dorsal view, distal-superior area of the paramerites obtusely acuminated at the apex, lateral margin straight to slightly curved. In lateral view, distal-inferior area straight to slightly sinuate near the apex, tips of the paramerites curved downward ( Figure 2 (h), 2(i)). Lamella copulatrix square-shaped, with superior margin slightly swollen on the right side, this part of the superior margin often indistinct. Superior left lobe usually shorter than inferior left lobe, narrow and obliquely oriented, apex larger with margin angled, external margin of the superior left lobe excavated. Inferior right lobe as long as the inferior left lobe, sometimes slightly longer, basolateral carina of the inferior left lobe very reduced. Secondary lamella quite narrow and longitudinally elongated, superior side narrower ( Figure 2 (j)). Female genitalia. Ventral sclerotization of the vagina distinct, central and inferior margin obtusely angled upward, infundibulum very short ( Figure 2 (i)).

Females have two cephalic carinae, frontal carina usually straight and strong at middle, fronto-clypeal carina straight to feebly curved forward ( Figure 2 (b)). Clypeal surface finely and transversally wrinkled. Anteromedial pronotal protuberance very weak and curved, pronotal punctation stronger than male and foretibiae larger. Minor males have short frontal horns or a frontal carina slightly elevated at both sides, pronotal protuberance weaker than major males, pronotal punctation similar to female.

Distribution and ecology

Panama, Colombia, western Venezuela, Ecuador, Peru and Bolivia ( Figure 5 (b)). Onthophagus transisthmius seems to be mostly associated with South American forest habitats, from dense to open ombrophilous formations. This species is often captured with human excrement, carrion and light traps (label data).

Morphological variation

Individuals from Panama, Colombia and Venezuela show a different pattern of colours compared to specimens collected farther south ( Ecuador, Peru and Bolivia). Indeed, northern specimens usually have the pronotum metallic bronze and elytra alutaceous to light brown, while southern specimens have the pronotum darker (metallic green, brown or black) with elytra black to tan-brown. Nonetheless, the external morphology and shape of the genital organs of the specimens here examined did not show any significant variation to justify the taxonomic separation of these populations.

Remarks

Pulido-Herrera and Zunino (2007) reported O. transisthmius from Panama (type locality) and Colombia. The Colombian distribution of this species is very vague, as the authors relied upon two inventories in which O. transisthmius was mentioned without exact localities ( Escobar 2000; Medina et al. 2001). The examination of multiple specimens deposited in several collections allowed us to update the geographical distribution of this species. Onthophagus transisthmius is indeed widely distributed across the eastern side of the Andes, from north-western Venezuela to central Bolivia. It has also been collected in central and eastern Ecuador, as well as central and southern Peru ( Figure 5 (b)). According to these data, it is therefore very probable that this species occurs also in south-western Colombia and north-western Peru.

Type specimen examined

Holotype (♂ USNM): 1: Canal Zone , Gamboa, 23,24- X-1975, TAPIR FECES TRAP, Col. O. P. Young, LIMBO HUNT CLUB (printed and handwritten on white label). 2: Type Number, 104485, U. S. N. M. (printed and handwritten on light-red label). 3 : HOLOTYPE, Onthophagus transisthmius, H. Howden & O. Young (printed and handwritten on darkred label). Allotype (♀ USNM): 1: Canal Zone , Gamboa, 23,24- X-1975, TAPIR FECES TRAP, Col. O. P. Young, LIMBO HUNT CLUB (printed and handwritten on white label). 2 : ALLOTYPE, Onthophagus transisthmius, H. Howden + O. Young (printed and handwritten on red label). Paratypes (♂ CMNC): 1: Canal Zone , Frijoles, 2,3- XI-1975, TAPIR FECES TRAP, Col . O . P . Young , BUENA VISTA P. (printed and manuscripted in white label) . 2: H. & A. Howden collection (printed in white label) . 3: H. & A. Howden collection, ex . A. Martínez coll. (printed in white label). 4: PARATYPE, Onthophagus transisthmius, H. Howden & O. Young (printed and manuscripted in yellow label). 5: Canadian Museum of Nature barcode (printed in white label). (1 ♂, 2 ♀♀ CMNC) : 1: Canal Zone , Gamboa, 23,24- X-1975, TAPIR FECES TRAP, Col . O . P . Young , LIMBO HUNT CLUB (printed and manuscripted in white label) . 2: H. & A. Howden collection (printed in white label) . 3: PARATYPE, Onthophagus transisthmius, H. Howden & O. Young (printed and manuscripted in yellow label). 4: Canadian Museum of Nature barcode (printed in white label). (1 ♂, 1 ♀ CMNC) : 1: Canal Zone , Gamboa, 23,24- X-1975, HUMAN FECES TRAP, Col . O . P . Young (printed and manuscripted in white label) . 2: H. & A. Howden collection (printed in white label) . 3: SEM (printed in yellow label). 4: PARATYPE, Onthophagus transisthmius, H. Howden & O. Young (printed and manuscripted in yellow label). 5: Canadian Museum of Nature barcode (printed in white label) .

Additional material examined

BOLIVIA: Beni: Ballivián . Rio Negro . 13°45 ’ S, 67°17 ’ W. 140 m. Bosque várzea. 20-XI-2004 (1 ♂, 1 ♀ OUMNH) . Rurrenabaque (1 ♂ MSNM) . Cochabamba: Parque Dep. Altemachi. 16°02 ’, 66° 40 ’ W. 700 m. Bosque pie de monte. 20-IX-2004 (1 ♂ OUMNH) . Valle Sacta. 17°07S, 64°45 ’ W. 230 m. Bosque Amazónico. 1-III-2005 (1 ♂, 1 ♀ OUMNH) . Chiapare. Chimoré. 250 m . 1952-1972 (6 ♂♂, 3 ♀♀ CMNC). 124 Km E Cochabamba. Rio Espirito Santo . 17°03 ’ 45 ” S, 65°38 ’ 38 ” S. 700 m . 01-06-II-1999 (3 ♂♂, 7 ♀♀ CMNC). 117 Km E Cochabamba. Lagunitas. 17°06 ’ 22 ” S, 65°40 ’ 57 ” S. 1000 m. 01-06-II-1999 (1 ♀ CMNC). Yungas. Cochabamba-Villa Tunari road. 17°06 ’ 32 ” S, 65° 41 ’ 12 ” W. 1040 m. 10-12-II-1999 (1 ♀ CMNC). 67.5 Km E Villa Tunari. Estacion Biologica Valle Sajta. Universidad San Simon. 17°06 ’ 19 ” S, 64°46 ’ 57 ” S. 300 m . 07-09-II-1999 (4 ♂♂, 5 ♀♀ CMNC). 16.7 Km E Cochabamba. Villa Tunari. Avispas. 17°01 ’ 13 ” S, 65°32 ’ 46 ” S. 500 m . 10-12- II-1999 (3 ♂♂, 4 ♀♀ CMNC). Villa Tunari. Hotel El Puente. 16°59.02 ’ S, 65°24.5 ’ W. 357 m . 15-27- XII-2005 (1 ♂, 1 ♀ CMNC). La Paz: Parque Nacional Madidi. 13°38 ’ S, 68°44 ’ W. 260 m. Bosque Amazónico. 27-VIII-2004 (4 ♂♂, 2 ♀♀ OUMNH) . Santa Cruz: 5 Km Buena Vista Hotel Flora y Fauna. 17°29.925 ’ S, 63°39.128 ’ S. 440 m (1 ♂ CMNC) . Los Fierros. 14°46 ’ S, 61°02 ’ W. X-1994 (1 ♂ BGc). COLOMBIA: Antioquia: San Luis . Rio Claro . 1440 m. 02-III-1994 (1 ♂, 3 ♀♀ CMNC) . Santander: Serrania de las Quinches. Reserva El Paujíl. IX-2006 (1 ♂, 2 ♀♀ CEMT) . Meta: Mozambique. Franja de bosque de galeria. IV-1996 (1 ♂ CEMT) . Norte de Santander: 3 Km N Chinacota . 1000 m. 10-V-1974 (4 ♂♂, 6 ♀♀ CMNC) . 30 Km S Cúcuta. Quebrada Honda. 13-V- 1974 (3 ♀♀ CMNC). La Garita. 07°45 ’ 0 ” N, 72°32 ’ 0 ” W. 08-V-1974 (1 ♀ CMNC). ECUADOR: Pastaza: Villano . VII-1996 (3 ♂♂, 3 ♀♀ CEMT) . Morona Santiago: Via Mendez-Paute. 23- VIII-1997 (1 ♀ CEMT). Sucumbíos: Limoncocha. 250 m . 18-24-VI-1976 (1 ♂ CMNC). Napo: La Joya de los Sachis . 290 m . 18-19-I-1986 (15 ♂♂, 23 ♀♀ MZc). Jatun Sacha Biological Station . 01°04 ’ S, 77°37 ’ W. 450 m . 24-26-VII-1998 (1 ♂ CMNC). Same locality. 21 Km E Puerto Napo. 400 m . 09-VII-1994 (2 ♂♂, 5 ♀♀ CMNC). Tena. 400 m (2 ♂♂, 2 ♀♀ CMNC) . Tungurahua: 6 Km W Rio Negro . 1200 m. 18-VII-1994 (1 ♂, 1 ♀ CMNC) . PANAMA: Colón: 14 Km N junction Escobal Road and Piña Road . 20 m . 02-13-VI-1996 (1 ♂, 3 ♀♀ CMNC). San Lorenzo Forest . 09°17 ’ N, 79° 58 ’ W. V-2004 (1 ♂, 1 ♀ CEMT) . 2 Km Pipeline Road. 80 m. 29-31-V-1995 (5 ♀♀ CMNC). Panamá-Colón: Parque Nacional Soberania. 12-15-II-1999 (1 ♂, 1 ♀ CMNC) . Darién: Estacion Ambiental Cana. 07°45.32 ’ N, 77°41.07 ’ W. 500 m . 07-10-VI-1996 (3 ♂♂, 4 ♀♀ CMNC; 1 ♂, 1 ♀ OUMNH). Canal Zone: 4.1 mi NW Gamboa . Rio Frijoles . 19-II-1976 (2 ♀♀ MCZ) . 6.1 Km Pipeline Road. Near Gamboa . 40 m . 07-21-VI-1995 (3 ♂♂, 7 ♀♀ CMNC). Pipeline road. K 1-12 (5 ♂♂, 3 ♀♀ FSCA) . PERU: Ayacucho: Sivia . 520 m . 15-V-1936 (1 ♂, 1 ♀ NMPC). Huánuco: Pachitea (1 ♂, 2 ♀♀ NHRS) . Junín: 11°8 ’ S, 75°17 ’ W . 1000 m. 03-21-X-06 (2 ♂♂, 1 ♀ ZMHB) . Madre de Dios: Rio Tambopata . Ccolpa de Guacamayos . 13°8,5 ’ S, 69°36,4 ’ W. 300 m X-1995 (1 ♂ BGc). 15 Km NE Puerto Maldonado. Reserva Cuzco Amazonica. 12°33 ’ S, 69°03 ’ W. 200 m . 24- VI-1989 (5 ♂♂, 7 ♀♀ CMNC). Manu National Park . 15-30-VIII-1986 (16 ♂♂, 11 ♀♀ CMNC; 1 ♂, 1 ♀ BGc) . Cocha Salvador. Reserved Zone. Manu National Park . 12°00 ’ 13 ” S, 71°31 ’ 36 ” W. 310 m . 20-21-X-2000 (4 ♂♂, 3 ♀♀ CMNC). Cocha Cashu Biological Station . Manu National Park . 11° 53 ’ 45 ” S, 71°24 ’ 24 ” W. 350 m . (6 ♂♂, 2 ♀♀ CMNC; 3 ♂♂, 2 ♀♀ BGc). Ucayali: Boca Rio Tarahuacá . Rio Aguaytía . 15-VIII-1984 (1 ♀ CMNC). No Department: Callanga (2 ♂♂, 4 ♀♀ SMTD; 1 ♀ NMPC) . VENEZUELA: Táchira: Rio Frio . 500 m . 11-18-VIII-1983 (1 ♂, 1 ♀ CMNC; 4 ♂♂, 1 ♀ BGc). San Cristobal. 1200 m. 10-18-VIII-1983 (2 ♂♂, 1 ♀ BGc). 42 Km SE San Cristobal. 700 m . 19-V-1974 (3 ♂♂, 4 ♀♀ CMNC). Navay. 200 m . 30-X-1978 (3 ♂♂, 5 ♀♀ MZc). Parque Nacional Tamá. Rio Negro . 600 m . 30-VII-1984 (1 ♀ MZc). Santo Domingo. 300 m. 11-16-VIII- 1983 (1 ♂ BGc). Portuguesa: Guanare. 400 m . 15-X-1975 (3 ♂♂, 1 ♀ MZc). Zulia: Macniques. El Tucuco. 400 m . 21-XI-1984 (3 ♂♂ MZc).

Figures

Figure 1. Onthophagus osculatii. (a, b) Dorsal habitus of male (neotype) and female (scale bar: 1 mm). (g, h) 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. osculatii. (m) Female genitalia (scale bar: 0.02 mm); arrow indicating the slight medial excavation of the ventral sclerotization of O. osculatii. Onthophagus chacoensis sp. nov. (c, d) Dorsal habitus of male (holotype) and female. (e) Metasternal punctuation (scale bar: 1 mm). (f) Detail of the pronotal punctuation. (i, j) Lateral and dorsal view of the parameres (scale bar: 0.05 mm). (n, o) Lamella copulatrix and accessory lamellae; arrow indicating the deep excavation of the external margin of the left lobe of O. chacoensis. (p) Female genitalia (scale bar: 0.02 mm).

Figure 2. Onthophagus transisthmius. (a, b) Dorsal habitus of male and female. (c, d) Dorsal habitus of the holotype and original labels (scale bar: 1 mm). (h, i) Lateral and dorsal view of the parameres (scale bar: 0.05 mm). (j, k) Lamella copulatrix and accessory lamellae. (l) Female genitalia (scale bar: 0.02 mm). Onthophagus basicarinatus sp. nov. (e, f) Dorsal habitus of male (holotype) and female. (g) Detail of the male horns (scale bar: 1 mm). (m, n) Lateral and dorsal view of the parameres (scale bar: 0.05 mm). (o, p) Lamella copulatrix and accessory lamellae (scale bar: 0.02 mm). (q) Female genitalia (scale bar: 0.02 mm).

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