Ontherus, Erichson, 1847

Chamorro, William, Lopera-Toro, Alejandro & Génier, François, 2024, A new species of Ontherus Erichson, 1847 (Coleoptera: Scarabaeidae: Scarabaeinae: Coprini) and new distributional records of Cryptocanthon humidus Howden, 1973 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini) for Ecuador, Zootaxa 5471 (1), pp. 56-66 : 60-62

Key to species of Ontherus from Ecuador

Modified from Génier (1996).

1. Mesometasternal suture angulate medially ( Fig. 2C ) (if junction appears straight then clypeofrontal suture carinate); median lobe of metasternum marginate anteriorly, similar to coxal margin, margin rarely atrophied; in some specimens, anterior edge lacks margin but anterior edge raised higher than mesosternum. Species usually restricted to lower elevations from 150–1200 m (subgenus Ontherus ) (see Figs. 1A–D , 3A–C for all species)................................................ 14

1’. Mesometasternal suture straight ( Fig. 2D ), in some specimens broadly arcuate, never angulate medially; median lobe of metasternum usually lacks margin anteriorly. Clypeofrontal suture always tuberculate medially. Species usually restricted to higher elevations from 150–3400 m (subgenus Caelontherus ).................................................. 2

2. Protibia with three teeth in males and four in females; male secondary sexual characters always located on head and pronotum; metafemur not modified; female head with pair of closely set tubercles or transverse horn (exceptionally in females of O. compressicornis Luederwaldt, 1931 process appears conical, but then minimum width of median lobe of mesosternum subequal to half maximum width of mesofemur).................................................................... 3

2’. Protibia with four teeth in males and females; male secondary sexual characters displayed in the shape and orientation of apical tooth of protibia, and/or shape of metafemur, or rarely on pronotal disc if apical tooth of protibia is similar to that of female; female with conical cephalic process or with clypeofrontal carina widely interrupted medially........................ 9

3. Anterior portion of median lobe of metasternum declivous on most of width; without vestigial longitudinal carina or sulcus medially; elytral striae with punctures simple on disc, punctures less than twice the width of connecting striae, punctures rarely deeper than connecting stria............................................................................. 4

3’. Anterior portion of median lobe of metasternum usually marginate, at least laterally; if anterior portion largely declivous, then usually with vestigial longitudinal carina or sulcus medially. Elytral striae with punctures rounded, impressed, usually umbilicate on disc, punctures more than twice width of connecting striae......................................... 6

4. Elytral striae similarly impressed on disc and apical declivity, feebly impressed on apical callus; evergreen lower montane forests, and montane cloud forests (Andean region).......................................................... 5

4’. Elytral striae more deeply impressed on apical declivity than on disc, normally impressed on apical callus; lowland evergreen forests of the Amazon region at around 230 m (Orellana)............ Ontherus (Caelontherus) tenuistriatus Génier, 1996

5. Inner edges of pronotal carinae raised higher than outer edges; distance between inner edges of carinae longer than width of carina in larger males; evergreen lower montane forests, and montane cloud forests ( Andean region in from 1540–2550 m) (Morona Santiago, Napo, Pastaza, Sucumbíos, Tungurahua and Zamora Chinchipe).............................................................................................. Ontherus (Caelontherus) incisus (Kirsch, 1871)

5’. Inner edges of pronotal carinae lower than lateral edges; distance between inner edges shorter than width of carina in larger males; montane cloud forests of the Andean region at 1800 m (Sucumbíos)..................................................................................................... Ontherus (Caelontherus) howdeni Génier, 1996

6. Male pronotum with transverse carina on each side of midline, carinae laterally reduced or much lower than internally, sometimes with small supplementary tubercle medially, or with at least single central minute tubercle in smaller individuals; female pronotum with three tubercles or single median tubercle in smaller individuals............................... 7

6’. Male pronotum with four tubercles, lateral tubercles much larger than inner tubercles; if pronotum has transverse carinas on each side of midline, lateral portion always distinctly raised; smaller individuals with two minute tubercles medially, sometimes distal tubercles present, small; female pronotum with four tubercles, sometimes connected with carina, or with two low tubercles medially in smaller individuals.......................................................................... 8

7. Median lobe of metastemum with at least few setae similar to those on mesosternum, especially anteriorly, along mesocoxa; median lobe of metasternum completely marginate anteriorly, margin wide; coastal lowland evergreen forests and coastal evergreen foothill forests from 200–1250 m (Carchi, Imbabura, El Oro, Esmeraldas, Pichincha, Santo Domingo de los Tsáchilas)............................................. Ontherus (Caelontherus) trituberculatus Balthasar, 1938

7’. Median lobe of metastemum with minute, appressed pubescence only, setae much finer than those on mesosternum; median lobe of metasternum with anterior margin atrophied medially; coastal evergreen foothill forests from 420–1400 m (El Oro, Santo Domingo de los Tsáchilas).................................... Ontherus (Caelontherus) pilatus Génier, 1996

8. Male pronotum with transverse carina on each side of midline, carinae approximate, covering almost entire width of pronotum in larger individuals; carinae reduced to two transverse swellings with inner portion slightly tuberculate in smaller individuals; male cephalic horn laterally compressed and truncated apically in larger individuals; female with lateral portions of pronotum with punctures moderately large, separated by less than their diameter; evergreen foothill forests (coastal region from 550–1300 m), evergreen lower montane forests, and montane cloud forests ( Andean region from 1550–2300) (Cañar, Carchi, Cotopaxi, Imbabura, Loja, Pichincha, Santo Domingo de los Tsáchilas)..................................................................................................... Ontherus (Caelontherus) compressicornis Luederwaldt, 1931

8’. Male pronotum with four tubercles, outer tubercles much larger than inner tubercles, reduced to swellings in smaller individuals; male cephalic horn acuminate or forked apically in larger individuals; female with lateral portion of pronotum with punctures minute, only slightly larger on anterior angles; lowland evergreen forests and evergreen foothill forests of the Amazon region from 150–1300 m (Loja, Morona Santiago, Napo, Orellana, Pastaza, Sucumbíos, Tungurahua, Zamora Chinchipe).................................................................... Ontherus (Caelontherus) diabolicus Génier, 1996

9. Median lobe of metasternum with conspicuous setae similar to those on lateral lobes; male protibia with apical tooth triangular, similar to penultimate tooth in aspect; females with anterior angles of pronotum granulate........................... 10

9’. Median lobe of metasternum lacking conspicuous setae or setae shorter than those on lateral lobes; male protibia with apical tooth slender and pointing forward; females with anterior angles of pronotum punctate............................. 12

10. Genal surface with at least some coarse rugose areas; length less than 12 mm; lowland evergreen forests and evergreen foothill forests of the Amazon at around 220 m (Orellana).................. Ontherus (Caelontherus) laminifer Balthasar, 1938

10’. Genal surface smooth, with at most a few scattered, weakly impressed punctures anterior to the eye; length greater than 17 mm ............................................................................................... 11

11. Elytral striae distinctly crenulate; montane cloud forests and the evergreen high montane forests of the Andean region from 2700–2835 m (Morona Santiago, Napo, Pastaza)....................... Ontherus (Caelontherus) hadros Génier, 1996

11’. Elytral striae not crenulate, lacking distinct puncture; montane cloud forests of the Andean region at around 2600 m (Pichincha).................................................... Ontherus (Caelontherus) magnus Génier, 1996

12. Median lobe of metastemum marginate anteriorly, similar to lateral edge; elytra strongly alutaceous; montane cloud forests and the evergreen high montane forests of the Andean region from 2400–3000 m (Azuay, Cañar, Chimborazo, Napo, Pichincha, Sucumbíos)................................................. Ontherus (Caelontherus) aequatorius Bates, 1891

12’. Median lobe of metastemum declivous anteriorly, margin atrophied medially; elytra smooth, at most slightly alutaceous.... 13

13. Elytral striae with punctures deeply foveolate on apical declivity (especially striae 1 and 2); metacoxa with median sulcus foveolate; montane cloud forests and evergreen high montane forests of the Andean region from 2000–3400 m (Carchi, Napo, Sucumbíos, Tungurahua, Zamora Chinchipe).......................... Ontherus (Caelontherus) politus Génier, 1996

13’. Elytral striae with punctures similarly impressed on apical declivity and disc; metacoxa with median sulcus not foveolate; high montane forests of the Andean region (Carchi)...................... Ontherus (Caelontherus) brevicollis Kirsch, 1871

14. Clypeofrontal suture tuberculate medially................................................................. 15

14’. Clypeofrontal suture with strong subquadrate carina ( Figs. 3B , 4 ); lowland evergreen forests and evergreen foothill forests of the Amazon region from 250–1020 m (Loja, Napo, Morona Santiago, Orellana, Zamora Chinchipe .................................................................................... Ontherus (Ontherus) edentulus Génier, 1996

15. Male protibia with apical spur ( Fig. 3A, C ); parameres tapered or rounded distally in lateral view; female head with vertex coarsely granulopunctate (in O. pubens Génier, 1996 ) or weakly punctate (except on small area posteriorly in O. azteca ); Amazonian region................................................................................... 16

15’. Male protibia lacking apical spur ( Fig. 1A, C ); parameres distinctly widening distally in lateral view ( Fig. 2A ); female head with vertex punctate throughout (punctures transverse along posterior surface); matorral dry montane forests of the Andean region at around 1150 m ( Ecuador: Loja)................................. Ontherus (Ontherus) araujoi new species

16. Posterior edge of metacoxa finely serrate (character best seen when metacoxa rotated forward to expose posterior margin); most punctures on lateral lobes of metasternum rounded, clearly delimited; lowland evergreen forests and evergreen foothill forests of the Amazon region from 250–1200 m (Napo, Orellana, Pastaza, Sucumbíos)...... Ontherus (Ontherus) azteca Harold, 1869

16’. Posterior edge of metacoxa without fine serration; most punctures of lateral lobes of metasternum weakly-defined posterolaterally; lowland evergreen forests and evergreen foothill forests of the Amazon region from 150–1200 m (Loja, Morona Santiago, Napo, Orellana, Pastaza, Sucumbíos, Zamora Chinchipe)..... Ontherus (Ontherus) pubens Génier, 1996

Figures

FIGURE 1. Ontherus araujoi new species. A, Ontherus araujoi (male, dorsal view); B, Ontherus araujoi (female, dorsal view); C, Ontherus araujoi (male, ventral view); D. Ontherus araujoi (male, lateral view).

FIGURE 2. Ontherus diagnostic characters. A, Ontherus araujoi new species, aedeagus; B, Ontherus araujoi, endophallites. C, Ontherus araujoi, mesometasternal suture; D, Ontherus compressicornis Luederwaldt, 1931, mesometasternal suture.

FIGURE 3. Ontherus and Cryptocanthon species. A, Ontherus azteca Harold, 1869, male in dorsal view; B, Ontherus edentulus Génier, 1996, female in dorsal view; C. Ontherus pubens Génier, 1996, male in dorsal view; D, Cryptocanthon humidus Howden, 1973, male in dorsal view.

FIGURE 4. Distribution of Ontherus araujoi new species (red pentagon); Ontherus azteca Harold, 1869 (purple square); Ontherus edentulus Génier, 1996 (blue triangle); Ontherus pubens Génier, 1996 (green circle); and Cryptocanthon humidus Howden, 1973 (yellow octagon).