Technical remarks

As illustrations are more useful than abstract text, the habitus and a set of details are depicted for each new species plus two close Moluccan relatives. Note that some species are strongly polymorphic (compare figs 13–16, 29, 35), and the identification of, for instance, minor singletons may encounter problems where reference to polymorphic series is impossible. Examine the figures in this paper, as references to them are limited to minimize cluttering the text with details. The sections “Identification” in the species accounts are tuned to the Moluccan context, not being overly explicit on extra-limital relatives, if any.

The term full-face view is applied where the surface of the element concerned is maximally parallel to the plane of the picture (as with the head). In the descriptions the qualification abundant for microsculptural units (like punctures) usually means: mostly separated by 2–5 diameters, dense: 1–2 diameters, crowded: less than 1 diameter; sparse: separated by at least 5 diameters, or limited to certain parts only. The type of punctation is usually qualified only if decidedly different from a simple punctation. The prefix micro- usually stands for sculpture and pilosity distinct at magnifications ×40 and higher; glabrous means that any pilosity is absent or indistinct at ×40.

Measurements of body parts of holotypes were estimated through a stereomicroscope using a calibrated ocular micrometer scale, rounded off to 0.1 mm. Total body lengths rounded off to 0.5 mm.

The species treated here are from all over the Moluccas, i.e. from Halmahera and Seram to the Tanimbar Islands, an area not fully congruent with administrative provincial borders; in the species list the island groups are clustered, smaller satellite islands not being mentioned separately. The Aru Islands and some marginal islands have different scarabeine faunas and are here excluded from treatment.

The specimen data of the new species and their close Moluccan relatives are all listed in Annex 1. Ecological label data are frequently abbreviated, like: multistr[atal] evergr[een] forest, human excr[ement] traps. The # symbol denotes a sample code. Paratypes will be distributed to other collections in due course.

Collections mentioned in the text:

Concise key to Moluccan Onthophagus species

This is a simple key to males, including all known Moluccan species. Males are recognized from their shorter (more compact) abdominal ventrites compared to females (measured over abdominal midline). The references to subkeys under the species group headings below are here flagged by q.v. – Consult the pictures.

1. 1. Protibia distally curved inward, with thumb-like apico-internal extension. Antennal scapus with finely serrate longitudinal crest. Large, body length usually 10–15 mm. (Subgenus Sunenaga Ochi, 2004.) .................. 13
2. – Protibia at most with slight apico-internal angle or spine. Antennal scapus unmodified .................. 2
3. 2. Frontovertex posteriorly with single transverse (plate-like) dentiform protrusion. Pronotum slightly trituberculate in front. Colourful, forebody with metallic lustre, dark elytra with symmetric pattern of yellow markings. Body length 5–8 mm .................. O. trituber
4. – Frontovertex posteriorly without or with different protrusion(s) .................. 3
5. 3. Pronotum virtually entirely closely reticulate-punctate. At least some elytral interstriae (sub)costate and strongly, closely (rugulate-) punctate. Head of major males with pair of vertexal horns .................. carinulatus group, q.v.
6. – Pronotum at most densely punctate and elytral interstriae different (at most median strip of interstriae slightly swollen and shiny) .................. 4
7. 4. Anterior side of clypeus remarkably broadly bilobate-bisinuate, median emargination simply rounded. Anterior pronotal declivity with slight longitudinal ridge between-behind basally dilated vertexal horns. Clypeofrontal ridge effaced. Body length 4–5 mm .................. O. ontosatu
8. – Anterior side of clypeus different; if bilobate, median emargination not simply rounded. Pronotum different .................. 5
9. 5. Clypeofrontal ridge (virtually) straight and on either side reaching clypeogenal edge. Frontovertex posteriorly with pair of simple unconnected tubercles .................. O. malasiacus group, q.v.
10. – Clypeofrontal ridge absent or different .................. 6
11. 6. Clypeus with T- or Y-shaped apico-median projection in broad emargination (minor males with simple apicomedian lobe). Body ovoid, pronotum shining, evenly convex. Small, body length 4–5 mm .................. O. alfuricus
12. – Clypeus different, without apico-median projection, or else other characters different .................. 7
13. 7. Clypeus with broad, reflexed apicomedian lobe. Clypeofrontal transition without ridge. Pronotum with flat anterior-central plane. Body length 7–9 mm .................. O. parryi
14. – Clypeal apex simply rounded, truncate, bidentate, or shallowly bisinuate .................. 8
15. 8. Protibia modified, apex more or less truncate, apico-external denticle usually not simply oblique and tapering, and/or other notable attributes present (like extra protrusion, hair pencil, modified spur) .................. 9
16. – Protibia unmodified, with simply oblique, tapering apico-external denticle, plus 3 more external denticles of proximally decreasing size, extra attributes absent .................. 10
17. 9. Protibia slender, evenly slightly curved, apex with fine pencil. Body length 3.5–4.5 mm. Dorsum not unicolour black or brown, elytra usually black with symmetric yellow to rufous markings, forebody may have metallic lustre. Frontovertex with low, more or less transverse protrusions. Pronotum simply convex .................. O. quadripustulatus
18. – Protibia robust, apex may be truncate, but lacking long pencil. Body length from 6 mm. Elytral interstriae of two species with median strip raised, shiny, more or less costate. Dorsum with numerous long, more or less erect setae .................. O. seramicus group, q.v.
19. 10. Pronotum with conspicuously long median concavity, flanked by crests with longer projections. Eyes widely elliptic in full-face view. Body length 10–11 mm .................. O. coprimorphoides
20. – Pronotum evenly convex, or with different ornamentation. Eyes more narrowly (sub)elliptic .................. 11
21. 11. Dorsal side unicolour black-brown, shining. Frontovertex posteriorly with pair of simple horns (gradually widened to base). Clypeofrontal ridge arcuate. Clypeal sides rounded, apex with short, triangular (tip rounded), reflexed lobe. Body length 5.5–6.0 mm .................. O. sciron
22. – Elytra with black-brown versus yellowish or rufous symmetric pattern .................. 12
23. 12. Frontovertex posteriorly with basally connected horns (joint outline more or less U-shaped). Clypeal apex rounded, broadly reflexed, (sub)lobate. Body length 5.0–7.5 mm .................. O. gestroi
24. – Frontovertex lacking pair of horns. Clypeal apex distinctly bidentate. Body length 3.5–4.5 mm .................. O. manguliensis
25. 13. Vertex with low crest over entire width. Pronotal surface strongly reticulate-punctate. Body length 10–12 mm .................. O. ribbei
26. – Vertex with median lamina bearing a slender horn. Pronotal surface with fine (non-reticulate) punctation. Body length 10–15 mm .................. O. wallacei

The Onthophagus malasiacus group

Males and females with transverse, (virtually) straight clypeofrontal ridge, running between both clypeogenal borders. Clypeal apex anteromedially truncate to bisinuate. Male frontovertex posteriorly with pair of short, at most slightly connected, upright (sub)conical protrusions. Pronotum simply convex, or anterior declivity topped by (variably pronounced) linear, transverse ridge (usually a very wide-legged V-shaped plica). Eye size varies, large in the two new species, narrow in the described one. Protibial apex unmodified. Body unicolour black or brown. Habitus rather robust, body length usually 6–10 mm.

Onthophagus malasiacus Gillet, 1927, like one of the new species, has a transverse plica topping the anterior declivity of its pronotum (Australasian species have a similar plica and extended clypeofrontal ridge, but different vertexal horns). O. sibela (described hereafter), however, lacks this pronotal plica and has a different aedeagus, although the males can, on overall similarity, hardly be excluded from the group; confusion with the two other species is certainly likely in the local context, and consequently, for comparison, sibela is here kept with the two others.

Three Moluccan species:

O. malasiacus Gillet, 1927

O. wayaua sp.n.

O. sibela sp.n.

Key to species (males, females)

1. 1. Antediscal pronotal plica distinct. Head surface distinctly rugulate-punctate. Males bituberculate between eyes, females with solid transverse ridge. Dorsum less shining .................. 2
2. – Antediscal pronotal plica absent, surface evenly convex. Head surface largely smooth. Both sexes bituberculate between posterior end of eyes (tubercles slight in females). Eyes very widely elliptic. Dorsum very shining. Body length 7.0–9.0 mm .................. O. sibela
3. 2. Eyes widely elliptic. Body length 6.0–10.0 mm .................. O. wayaua
4. – Eyes narrow. Body length 7.0–8.5 mm .................. O. malasiacus

Type material

Holotype male (RMNH), from Moluccas: Bacan: Sibela Range, 850 m, 28–04/vi–vii/1985, J. Huijbregts HH372, multistr evergr forest edge, 4 human excr traps. Paratypes listed in Annex.

Identification

Onthophagus species, habitus (1–7, oblique, 8, lateral), males. – 1, O. malasiacus, Ternate, 9 mm; 2, O. wayaua, holotype, 9 mm; 3, O. sibela, holotype, 8 mm; 4, O. carinulatus, Bacan, 5 mm; 5, O. biscarinatulus, holotype, 4 mm; 6, O. alfuricus, paratype, 5 mm; 7–8, O. coprimorphoides, holotype, 10.5 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species, habitus (1–7, oblique, 8, lateral), males. – 1, O. malasiacus, Ternate, 9 mm; 2, O. wayaua, holotype, 9 mm; 3, O. sibela, holotype, 8 mm; 4, O. carinulatus, Bacan, 5 mm; 5, O. biscarinatulus, holotype, 4 mm; 6, O. alfuricus, paratype, 5 mm; 7–8, O. coprimorphoides, holotype, 10.5 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species, habitus (1–7, oblique, 8, lateral), males. – 1, O. malasiacus, Ternate, 9 mm; 2, O. wayaua, holotype, 9 mm; 3, O. sibela, holotype, 8 mm; 4, O. carinulatus, Bacan, 5 mm; 5, O. biscarinatulus, holotype, 4 mm; 6, O. alfuricus, paratype, 5 mm; 7–8, O. coprimorphoides, holotype, 10.5 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species, habitus oblique (9–11), forebody dorsofrontal (12–16), males. – 9, O. frankrozendaali, holotype, 6.5 mm; 10, O. seramicus, holotype, 7 mm; 11–12, O. ontosatu, holotype, 4.5 mm; 13–14, O. carinulatus (13, major, 14, minor); 15–16, O. biscarinulatus (15, major, 16, minor). – Scale lines 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species, habitus oblique (9–11), forebody dorsofrontal (12–16), males. – 9, O. frankrozendaali, holotype, 6.5 mm; 10, O. seramicus, holotype, 7 mm; 11–12, O. ontosatu, holotype, 4.5 mm; 13–14, O. carinulatus (13, major, 14, minor); 15–16, O. biscarinulatus (15, major, 16, minor). – Scale lines 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species, habitus oblique (9–11), forebody dorsofrontal (12–16), males. – 9, O. frankrozendaali, holotype, 6.5 mm; 10, O. seramicus, holotype, 7 mm; 11–12, O. ontosatu, holotype, 4.5 mm; 13–14, O. carinulatus (13, major, 14, minor); 15–16, O. biscarinulatus (15, major, 16, minor). – Scale lines 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Onthophagus wayaua is very similar to O. malasiacus, sharing the development of a transverse antediscal pronotal plica, but the two differ strongly in the size of their eye foramina; O. malasiacus has narrow eyes (separated by 8–9 eye widths), while in O. wayaua they are widely elliptic (separated by 4–5 eye widths). Both species differ from O. sibela in having a transversely rugulate clypeogenal surface in both sexes, and the frontal surface being distinctly punctate, not nearly smooth, as in O. sibela. The male of O. wayaua has a pair of pointed postfrontal tubercles, the female has a transverse interocular ridge, as in O. malasiacus. Clypeal apex very slightly bisinuate. Fine clypeofrontal ridge extending from border to border at clypeogenal transition, the border being there at most slightly interrupted. Parameres tapering to transverse spatuliform tip, with distinct bulge on top. Dorsum virtually unicolour black-brown, shiny, but less so than in O. sibela. Body length 6–10 mm.

Onthophagus species 17–22, O. wauaya, holotype male and paratype female; 23–28, O. sibela, holotype male and paratype female. – Contours of head, full-face (12, 23, male, 22, 28, female paratype), pronotum, dorsal (18, 24, male), elytron, dorsal (19, 25, male); protibia, upper side (20, 26, male), metatibia, underside (21, 27, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species 17–22, O. wauaya, holotype male and paratype female; 23–28, O. sibela, holotype male and paratype female. – Contours of head, full-face (12, 23, male, 22, 28, female paratype), pronotum, dorsal (18, 24, male), elytron, dorsal (19, 25, male); protibia, upper side (20, 26, male), metatibia, underside (21, 27, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species 17–22, O. wauaya, holotype male and paratype female; 23–28, O. sibela, holotype male and paratype female. – Contours of head, full-face (12, 23, male, 22, 28, female paratype), pronotum, dorsal (18, 24, male), elytron, dorsal (19, 25, male); protibia, upper side (20, 26, male), metatibia, underside (21, 27, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Distribution

Halmahera and Bacan.

Description (holotype, male)

Body length ca 9 mm. Habitus convex, plump. Colour generally brown-black, shiny, slightly sericeous (part of surface with microreticulation); legs dark brown. Dorsum and pygidium virtually glabrous, punctation generally abundant, fine; underside and legs with seta-bearing punctures, setae pale brown.

Onthophagus species. 29–35, O. alfuricus, paratypes. 36–41, O. coprimorphoides, holotype male and paratype female. – Contours of head, full-face (29, 26, male, 34, 41, female), pronotum, dorsal (30, 37, male), elytron, dorsal (31, 38, male); protibia, upper side (32, 39, male), metatibia, upper side (21, 27, male); anterior clypeal margin, minor male (35). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Onthophagus species. 29–35, O. alfuricus, paratypes. 36–41, O. coprimorphoides, holotype male and paratype female. – Contours of head, full-face (29, 26, male, 34, 41, female), pronotum, dorsal (30, 37, male), elytron, dorsal (31, 38, male); protibia, upper side (32, 39, male), metatibia, upper side (21, 27, male); anterior clypeal margin, minor male (35). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species. 29–35, O. alfuricus, paratypes. 36–41, O. coprimorphoides, holotype male and paratype female. – Contours of head, full-face (29, 26, male, 34, 41, female), pronotum, dorsal (30, 37, male), elytron, dorsal (31, 38, male); protibia, upper side (32, 39, male), metatibia, upper side (21, 27, male); anterior clypeal margin, minor male (35). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species. 42–47, O. carinulatus, holotype male and paratype female; 48–53, O. biscarinulatus, holotype male and paratype female. – Contours of head, full-face (42, 48, male, 47, 53, female), pronotum, dorsal (43, 49, male), elytron, dorsal (44, 50, male); protibia, upper side (45, 51, male), metatibia, upper side (46, 52, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species. 42–47, O. carinulatus, holotype male and paratype female; 48–53, O. biscarinulatus, holotype male and paratype female. – Contours of head, full-face (42, 48, male, 47, 53, female), pronotum, dorsal (43, 49, male), elytron, dorsal (44, 50, male); protibia, upper side (45, 51, male), metatibia, upper side (46, 52, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species. 42–47, O. carinulatus, holotype male and paratype female; 48–53, O. biscarinulatus, holotype male and paratype female. – Contours of head, full-face (42, 48, male, 47, 53, female), pronotum, dorsal (43, 49, male), elytron, dorsal (44, 50, male); protibia, upper side (45, 51, male), metatibia, upper side (46, 52, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Clypeal border widely, evenly rounded to very weakly sinuate, slightly reflexed, marginate apex; clypeal surface entirely transversely rugulate; clypeogenal transition shallowly interrupted at border; clypeogenal suture obliterated by rugulate punctation on frons; clypeofrontal transition with transverse, almost rectilinear ridge between clypeogenal transitions at borders on each side. Genal border widely rounded, marginate, posteriorly reaching occipital side; genal and frontal surface rugulate-punctate, moderately shiny. Frons between posterior halves of eyes with pair of short, unconnected, upright, transverse, tapering (subconical) tubercles, their top surface smooth. Eye foramina large, broadly elliptic, with 16–18 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width ca 4.5.

Onthophagus species. 54–59, O. frankrozendaali, holotype male and paratype female; 60–65, O. seramicus, holotype male and paratype female. – Contours of head, full-face (54, 60, male, 59, 65, female), pronotum, dorsal (55, 61, male), elytron, dorsal (56, 62, male); protibia, upper side (57, 63, male), metatibia, upper side (58, 64, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Onthophagus species. 54–59, O. frankrozendaali, holotype male and paratype female; 60–65, O. seramicus, holotype male and paratype female. – Contours of head, full-face (54, 60, male, 59, 65, female), pronotum, dorsal (55, 61, male), elytron, dorsal (56, 62, male); protibia, upper side (57, 63, male), metatibia, upper side (58, 64, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

Citation: Tijdschrift voor Entomologie 155, 1 (2012) ; 10.1163/221194312X651337

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Onthophagus species. 54–59, O. frankrozendaali, holotype male and paratype female; 60–65, O. seramicus, holotype male and paratype female. – Contours of head, full-face (54, 60, male, 59, 65, female), pronotum, dorsal (55, 61, male), elytron, dorsal (56, 62, male); protibia, upper side (57, 63, male), metatibia, upper side (58, 64, male). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Pronotum generally strongly convex, disc deplanate (lacking midline impression); anterior declivity abrupt, topped by transverse plica (medially slightly protuberant); shiny, disc abundantly, evenly micropunctate, anterior and lateral declivities more distinctly, more densely punctate; all borders, including basal sides, finely marginate; anterior section of lateral border virtually straight (full-face view), anterolateral angle shortly rounded, subrectangular; posterior section of lateral border very slightly sinuate, posterolateral angle rounded off; pronotal basal border evenly rounded.

Onthophagus species, 66–71, 74, O. ontosatu, 72, 82, O. frankrozendaali, 73, 83, O. seramicus, 75, O. malasiacus, 76, O. wauaya, 77, O. sibela, 78, O. alfuricus, 79, O. coprimorphoides, 80, O. carinulatus, 81, O. biscarinulatus. – Contours of head, full-face, O. ontosatu, holotype male and paratype female (66, male, 71, female), pronotum, dorsal (67, male), elytron dorsal (68, male); protibia, upper side (69, male), metatibia, upper side (70, male). – 72–73, parameral tips, full-face view, 74–83, parameres, lateral view (relevant scale line on top of picture). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Onthophagus species, 66–71, 74, O. ontosatu, 72, 82, O. frankrozendaali, 73, 83, O. seramicus, 75, O. malasiacus, 76, O. wauaya, 77, O. sibela, 78, O. alfuricus, 79, O. coprimorphoides, 80, O. carinulatus, 81, O. biscarinulatus. – Contours of head, full-face, O. ontosatu, holotype male and paratype female (66, male, 71, female), pronotum, dorsal (67, male), elytron dorsal (68, male); protibia, upper side (69, male), metatibia, upper side (70, male). – 72–73, parameral tips, full-face view, 74–83, parameres, lateral view (relevant scale line on top of picture). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Onthophagus species, 66–71, 74, O. ontosatu, 72, 82, O. frankrozendaali, 73, 83, O. seramicus, 75, O. malasiacus, 76, O. wauaya, 77, O. sibela, 78, O. alfuricus, 79, O. coprimorphoides, 80, O. carinulatus, 81, O. biscarinulatus. – Contours of head, full-face, O. ontosatu, holotype male and paratype female (66, male, 71, female), pronotum, dorsal (67, male), elytron dorsal (68, male); protibia, upper side (69, male), metatibia, upper side (70, male). – 72–73, parameral tips, full-face view, 74–83, parameres, lateral view (relevant scale line on top of picture). – Scale lines all 1 mm. This figure is published in colour in the online version of this journal, which can be accessed via http://www.brill.nl/tve.

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Elytra uniformly black-brown, disc subopaque due to stronger microreticulation, humeral area and sides more shiny; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; epipleuron smooth, irregularly micropunctate, with setae. Elytra broad, with 8 straight to slightly curved, narrow, distinct striae; stria 7 evenly, slightly curved in front, ending at humeral umbone; strial punctures minute, mostly indistinct. Interstrial surface slightly convex, interstriae abundantly micropunctate, punctures more pronounced on lateral declivity, elytral surface glabrous throughout.

Antennal club yellow and brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus posteriorly delimited by simple coxal-marginal ridge, postocular declivity steep. Proepisternal surface abundantly (hemi)punctate-setose, setae long, pale yellow. Anterior lobe of metasternum unmodified (evenly convex), disc smooth, with very shallow midline impression; metasternal flanks with numerous seta-bearing (ocellate) punctures. Abdominal ventrites opaque (microreticulate), smooth, with basal row of seta-bearing (ocellate) punctures. Pygidium black, evenly convex; base marginate; surface abundantly micropunctate, opaque.

Legs generally shiny dark brown. Protibia with 3 + 1 larger external denticles (distal 3 larger, acuminate), hardly separated by fine serration; proximal serration consisting of ca 4 smaller denticles; apico-external denticle oblique to tibial axis; apex with elongate-acuminate, distally curved spur; underside with low longitudinal crest; protarsus slender. Profemur robust, underside smooth, mainly with micropunctation, and with several longer setae. Meso- and metafemoral undersides smooth, mainly with micropunctation, and with numerous longer setae. Meso- and metatibiae robust, dilated distad to transversely subelliptic crest, which is fringed with fine fossorial spines; external side with 4–5 sets of slight, spine-bearing fossorial protrusions. Tarsi generally slender, with fine, sickle-shaped claws; meso- and metatarsomeres 1 robust, long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-acuminate. Approximate length proportions terminal spur // metatarsomeres 1–5: 26//27/12/8/5/9.

Parameres tapering to spatuliform tip, roof bulging, fig. 76.

Measurements in mm (dorsal view). Maximum width of head 2.8. Median length of pronotum 3.3, maximum width 4.7. Sutural length of elytra 3.8, maximum width 5.1.

Variation and sexual dimorphism

Female with well-developed transverse interocular ridge, crest at both ends (axial view) distinctly angular.

Variable in size, minors have reduced forebody protrusions, including an obsolescent antediscal pronotal ridge. Some specimens are lighter brown.

Etymology

Species named after a hospitable village near the Sibela Range on Bacan Island.

Type material

Holotype male (RMNH), from the Moluccas: Bacan: Sibela Range, 1000 m, 29–03/vi–vii/1985, J. Huijbregts, HH377A, multistr evergr forest, 2 human excr traps. Paratypes listed in Annex.

Identification

Contrary to the preceding species and Onthophagus malasiacus, this species lacks the antediscal pronotal plica. Its head microsculpture is much less pronounced than in the two others, more or less effaced, particularly in the male sex. The eyes of O. sibela are very large, the foramina being separated by 3–3.5 eye widths. Clypeal apex truncate-bisinuate. Both male and female have a pair of postfrontal, more or less pointed tubercles, not a transverse interocular ridge. Fine clypeofrontal ridge extending from border to border at clypeogenal transition, which is at most slightly interrupted. Parameres humped-recurved. Dorsum shining, virtually unicolour black-brown. Body length usually 7–9 mm.

Distribution

Halmahera and Bacan.

Description (holotype, male)

Body length ca 8 mm. Habitus convex, plump. Colour generally brown-black, shining (some parts with vague microreticulation, sericeous); legs dark brown. Dorsum and pygidium glabrous, punctation generally abundant, extremely fine; underside and legs with seta-bearing punctures, setae pale-brown.

Clypeal border widely, evenly rounded to truncate (very weakly sinuate), slightly reflexed, marginate apex; clypeal surface finely, abundantly punctate; clypeogenal transition shallowly interrupted at border; clypeogenal suture very vague, curving widely onto frons; clypeofrontal transition with very widely curved (anteriorly concave) ridge between clypeogenal suture at borders on each side. Genal border widely rounded, posteriorly reaching occipital side; genal and frontal surface sparsely micropunctate, moderately shiny due to microreticulation. Frons between posterior ends of eyes with pair of short, unconnected, upright, transverse, tapering (subconical) tubercles, their top surface smooth. Eye foramina large, broadly elliptic, with 20–23 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width ca 3.

Pronotum evenly moderately convex, disc deplanate (lacking midline impression); anterior declivity gradual, without ridge or other protrusions; pronotal surface shiny, abundantly, evenly micropunctate (two size classes, secondary punctation hardly distinct); all borders, including basal sides, finely marginate; anterior section of lateral border virtually straight (full-face view), anterolateral angle shortly rounded, subrectangular (adjacent surface deplanate); posterior section of lateral border very slightly sinuate, posterolateral angle rounded off; pronotal basal border evenly rounded.

Elytra uniformly black-brown, shiny; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; epipleuron smooth, irregularly micropunctate, glabrous. Elytra broad, with 8 straight to slightly curved, narrow, distinct striae; stria 7 evenly, very slightly curved in front, ending at humeral umbone; strial punctures simple, small, moderately distinct, on disc mostly separated by 3–8 puncture diameters, punctures hardly crenulating interstrial edges. Interstrial surface slightly convex, all interstriae abundantly micropunctate, glabrous.

Antennal club light yellow-brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus posteriorly delimited by simple coxal-marginal ridge, postocular declivity steep. Proepisternal surface abundantly (hemi)punctate-setose, setae long, yellowish. Anterior lobe of metasternum unmodified (evenly convex), disc smooth, with very shallow midline impression; metasternal flanks with sparse seta-bearing (ocellate) punctation. Abdominal ventrites opaque (microreticulate), smooth. Pygidium black, evenly convex; base marginate; surface abundantly micropunctate, shiny.

Legs generally shiny dark brown. Protibia with 3 + 1 larger external denticles (distal 3 larger, acuminate), separated by some fine serration; proximal serration consisting of ca 6 small denticles; apico-external denticle oblique to tibial axis; apex with elongate-acuminate spur; underside with low longitudinal crest; protarsus slender. Profemur robust, underside smooth, mainly with micropunctation and with numerous longer setae. Meso- and metafemoral undersides smooth, mainly with micropunctation, and with several longer setae. Meso- and metatibiae robust, dilated distad to transversely subelliptic crest, which is fringed with fine fossorial spines; external side with 4–5 sets of slight, spine-bearing fossorial protrusions. Tarsi generally slender, with fine, sickle-shaped claws; meso- and metatarsomeres 1 robust, long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-acuminate. Approximate length proportions terminal spur // metatarsomeres 1–5: 23//27/11/7/5/8.

Parameres humped, tips downward (in profile), fig. 77.

Measurements in mm (dorsal view). Maximum width of head 2.5. Median length of pronotum 2.6, maximum width 4.0. Sutural length of elytra 3.6, maximum width 4.5.

Variation and sexual dimorphism

Female with transversely rugulate clypeogenal surface, postfrontal tubercles smaller than in male. Type series showing little variability, mainly in size and postfrontal horn development.

Etymology

Species named after the type locality, a high mountain area on Bacan Island.

Nomenclatural note

Onthophagus danumicus Krikken & Huijbregts nom.n.

Replacement name for Onthophagus danumensis Krikken & Huijbregts, 2011 non Onthophagus danumensis Ochi, Kon & Barclay, 2009.

Institutional reorganization and consequent limited access to library services produced a nomenclatural oversight during the preparation of our paper on Southeast Asian members of the deflexicollis group (Krikken & Huijbregts 2011), i.e. a homonymy, which is corrected here.

Type material

Holotype male (RMNH), from Moluccas: Bacan: Sibela Range, 450 m, 04–08/vii/1985, J. Huijbregts HH380, multistr evergr forest, 2 human excr traps. Paratypes listed in Annex.

Identification

Onthophagus alfuricus is different from all known Moluccan congeners by the following combination of characters: clypeal apex of male with projection, in majors T-shaped and set in a deep emargination, simply mono-lobate in minor males; female clypeal apex bidentate; pronotum evenly convex (no protrusions, no deplanation); colour generally shining brown-black, forebody frquently has metallic (bronzy) lustre, dorsum lacking light markings. A close relative of Onthophagus alfuricus, different, for instance, in the presence of well-defined, clear yellow, symmetrical elytral markings, is O. lorianus Gillet, 1930 from New Guinea. Males of that species agree with alfuricus in having the apico-median clypeal projection also set in an emargination. Body length of O. alfuricus usually 4–5 mm.

Distribution

Halmahera and Bacan.

Description (holotype, male)

Body length ca 5 mm. Habitus convex, plump, body generally ovoid. Colour generally brown-black, with metallic lustre, shiny; legs yellow-brown. Dorsum and pygidium glabrous, punctation generally abundant to dense, fine; underside and legs with punctures bearing pale-yellow setae.

Clypeal border laterally almost straight, anterolaterally evenly rounded to broadly emarginate anterior section, which has T-shaped, reflexed median projection (base narrow, tip dilated, in axial view subtriangular, apex transverse, straight, with slight extra transverse ridge behind); lobes bordering emargination broad, their apex rounded, surface behind anterior emargination concave; clypeal surface anteriorly sparsely, finely punctate; clypeogenal transition not interrupted at border; clypeogenal suture vague, curving onto frons; clypeofrontal transition without ridge. Genal border very widely rounded, finely marginate; genal, postclypeal and frontal surface finely, distinctly, abundantly punctate, interspersed with almost indistinct micropunctation, interpunctural surface shiny. Interocular surface flat, central part finely, sparsely punctate; vertex lacking protrusion. Eye foramina narrow, subelliptic, with ca 8 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width 8–9.

Pronotum uniformly black-brown, generally evenly, strongly convex, lacking any protrusions (also lacking midline impression), anterior declivity low; pronotal surface abundantly, evenly punctate, sides more densely punctate (micropunctation almost indistinct); all borders, including basal sides, finely marginate; anterior section of lateral border virtually straight (full-face view), anterolateral angle shortly rounded, subrectangular; posterior section of lateral border also virtually straight, posterolateral angle rounded off; basal border evenly rounded.

Elytra uniformly black, shining; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; epipleuron convex, shining, irregularly, sparsely, finely punctate, glabrous. Elytra broad, with 8 straight to very slightly curved, narrow, well-delineated striae; stria 7 almost straight in front, ending at humeral umbone; strial punctures medium-sized, distinct, mostly separated by 4–6 diameters, crenulating interstriae. Interstrial surface slightly convex; interstriae abundantly, minutely, somewhat irregularly punctate, glabrous throughout.

Antennal club pale yellow-brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus posteriorly delimited by sinuate coxal-marginal ridge reaching lateral border. Proepisternal surface sericeous (shagreened), finely punctate-setose. Anterior lobe of metasternum unmodified (evenly convex), disc smooth, with micropunctation and shallow midline impression; metasternal flanks with numerous seta-bearing (subocellate) punctures. Abdominal ventrites shiny, smooth, sides with basal row of seta-bearing (subocellate) punctures. Pygidium shining brown, distinctly convex; base marginate; surface densely, evenly, finely punctate.

Legs slender, generally shiny brown. Protibia with 3 + 1 larger external denticles (distal 3 larger, subacuminate), widely separated by fine serration; proximal serration consisting of ca 10 small denticles; apico-external denticle oblique to tibial axis; apex with slightly curved, elongate, distally acuminate spur; underside with low longitudinal crest; protarsus slender. Femora slender, undersides smooth, mainly with very fine punctation and with few longer setae. Meso- and metatibiae slender, dilated distad to transversely subelliptic crest, which is fringed with fine fossorial spines, externally with some very slight, spine-bearing fossorial protrusions. Tarsi generally slender, with fine, sickle-shaped claws; meso- and metatarsomeres 1 robust, long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-acuminate. Approximate length proportions terminal spur // metatarsomeres 1–5: 26//27/14/8/6/8.

Parameres tapering to spatuliform tip, fig. 78.

Measurements in mm (dorsal view). Maximum width of head 1.5. Median length of pronotum 1.6, maximum width 2.6. Sutural length of elytra 2.0, maximum width 2.8.

Variation and sexual dimorphism

Female has bidentate clypeal apex, with sides widely, evenly rounded; clypeal surface densely, transversely rugulate. Clypeofrontal ridge slight, straight, not reaching lateral borders. Pygidium less convex than in male.

The shape of the male clypeus varies strongly, the longer apico-median projection not perfectly T- or Y shaped, minor males having only a short, reflexed lobe, with a truncate or slightly rounded tip, lacking the adjacent emarginations (fig. 35). The clypeogenal margin (at the suture) may be slightly indented. Elytra and other parts may be lighter in some specimens, brownish.

Etymology

Species named after the Alfur, a forest people of Halmahera and other Moluccan islands.

Key to species (males)

1. 1. Pygidium and other body parts at least partly yellowish(-brown). Major males with pair of long, slender, evenly curved, tapering vertexal horns, their broad base extending laterad over eyes. Body length 3–5 mm .................. O. carinulatus
2. – Pygidium and rest of body (including elytra) dark, usually unicolour black. Major males with pair of upright, in basal half internally slightly dilated vertexal horns, tip abruptly narrowed. Body length 3.5–4.5 mm .................. O. biscarinulatus

Type material

Holotype male (RMNH), from Moluccas: Halmahera: Akelamo, 3 km NNE of, 50 m, 25–29/vii/ 1985, J. Huijbregts HH395, multistr evergr forest, 2 human excr traps. Paratypes listed in Annex.

Identification

The body of Onthophagus biscarinulatus is usually completely black (dorsum occasionally dark-brown, but always uniform), with brown legs; lacking the (partly) pale yellow to brown colouration common in O. carinulatus. Major males of O. biscarinulatus between posterior end of eyes with pair of upright, in basal half internally slightly dilated horns (reticulate microsculpture on adjacent pronotal declivity more or less effaced); tip of these horns abruptly narrowed. Clypeal apex shallowly bisinuate-bidentate in both sexes. Dorsum usually strongly microsculptured, with numerous fine micro-stubbles – O. carinulatus has a denser cover of short but more distinct whitish setae and scales. Anteromedian pronotal protrusion usually distinct in both sexes. Elytral interstrial costae usually with fine midline crest, extending to distal declivity. Parameral tip in O. biscarinulatus (in lateral view) more slender than in O. carinulatus. Body length usually 3.5–4.5 mm.

Distribution

Halmahera and Bacan.

Description (holotype, male)

Body length ca 4 mm. Habitus distinctly convex-raised. Colour generally black, somewhat opaque due to heavy microsculpture, shiny between microsculptural units, legs dark brown; forebody with slight metallic lustre. Pronotum, elytra and pygidium with inconspicuous whitish micro-stubbles in distinct, crowded punctures, abdominal venter also with numerous micro-stubbles, only propectus with longer pale-brown setae.

Clypeal border widely, evenly rounded to bidentate-sinuate, broadly reflexed apex, (median emargination slight); clypeal surface finely, densely, somewhat transversely punctate; clypeogenal transition very shallowly interrupted at border; clypeogenal suture vague, curving widely onto frons; clypeofrontal transition gradual, without ridge or suture. Genal border rounded, lateral tip rounded; genal and frontal surface crowdedly ocellate-punctate. Frons between posterior ends of eyes with pair of horns, i.e. straight, unconnected, more or less upright, subtransverse plates, thick basal part subparallel, abruptly narrowed, slightly tapering tip very slightly sinuate, plate surface virtually smooth (sparsely micropunctate). Eye foramina very narrow, with 4–5 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width ca 13.

Pronotum strongly, generally evenly convex (disc lacking distinct midline impression near base); anterior declivity steep, medially with blunt longitudinal ridge (top subangular), behind vertexal projections deplanate, shiny, impunctate; all borders, including base, finely marginate; anterior section of lateral border virtually straight (full-face view), anterolateral angle very shortly rounded, subrectangular; posterior section of lateral border very slightly sinuate, posterolateral angle rounded off; pronotal basal border evenly rounded. Pronotal surface with crowded subocellate punctation, most punctures bearing micro-stubble, their length not exceeding puncture diameter.

Elytra uniformly black, shiny; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; posterior outline (in dorsal view) broad, due to raised interstria 7 being curved inward along margin; epipleuron rugulate-punctate, not distinctly setose. Elytra broad, with 8 straight to slightly curved, narrow, more or less distinct striae; stria 7 evenly curved in front, ending at humeral umbone; strial punctures simple, variably distinct, on disc mostly separated by 4–8 puncture diameters, more or less crenulating interstrial edges. Interstrial surface distinctly convex (of interstria 1 less so), interstria 7 distinctly raised, apically curved inward; all interstriae coarsely, irregularly rugulate-punctate, with numerous, fine, very short setae (locally serially arranged).

Antennal club light grey-brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus posteriorly delimited by simply arcuate coxal-marginal ridge. Proepisternal surface abundantly punctate-setose, setae long, yellowish. Anterior lobe of metasternum unmodified (evenly convex), disc smooth, with shallow midline impression; metasternal flanks crowdedly (arcuate-)ocellate, with micro-stubbles. Abdominal ventrites 1–2 more or less smooth, shiny, 3–6 matt, with numerous ocellate punctures and microreticulation (hypo-elytral sides of ventrites yellow-brown). Pygidium black, base slightly depressed, convex near apex; base marginate; surface crowdedly ocellate-punctate, opaque.

Legs generally shiny brown. Protibia with 3 + 1 larger external denticles (distal 3 larger, subacuminate), separated by fine serration (1–2 denticles); proximal serration consisting of ca 6 small denticles; apico-external denticle oblique to tibial axis; tibial apex slightly angulate internally, and with elongate-acuminate spur; underside with low longitudinal crest; protarsus slender. Profemur robust, underside with numerous punctures. Meso- and metafemoral undersides with generally finer, sparser punctures. Meso- and metatibiae dilated distad to transversely subelliptic crest, which is fringed with short fossorial spines; external side with 4–5 sets of slight fossorial, spine-bearing fossorial protrusions. Tarsi generally slender, with very fine, sickle-shaped claws; meso- and metatarsomeres 1 robust, long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-acuminate. Approximate length proportions terminal spur // metatarsomeres 1–5: 19//21/8/5/4/7.

Parameres generally tapering, tip shortly rounded, fig. 81.

Measurements in mm (dorsal view). Maximum width of head 1.5. Median length of pronotum 1.6, maximum width 2.4. Sutural length of elytra 1.9, maximum width 2.7.

Variation and sexual dimorphism

Female never with pair of horns; protibia without accrete apico-internal protrusion. Clypeus with bidentate apex. Clypeofrontal transition in some females with fine, feebly arcuate ridge and frontovertex posteriorly at most with obsolescent tubercles.

Variation strong, both in size and more specific morphological attributes, like the development of vertexal and pronotal protrusions (figs 15–16) and elytral microsculpture (cf. note on aberrant specimens under group heading). Discrete tip of some long-horned males more distinctly sinuate.

Etymology

Species name expresses similarity to Onthophagus carinulatus, the prefix meaning: again, or twice.

Key to species (males)

1. 1. Frons with pair of tubercles between eyes, usually connected by transverse saddle. Pronotal paramedian plates broad at base (in profile). Anterolateral surface of pronotum punctate. Parameres simply curved (in profile) three New Guinea species .................. Krikken & Huijbregts forthcoming
2. – Interocular protrusions absent, vertex with low, long, transverse ridge. Pronotal paramedian plates narrow, strongly tapering, recurved (forward, in profile). Median depression of pronotum shallow, evenly concave, basomedian surface lacking projection. Anterolateral surface of pronotum impunctate. Parameres humped, tips downward, under hump (in profile). Moluccas. Body length 10–11 mm .................. O. coprimorphoides

Type material

Holotype male (RMNH), from Moluccas: Halmahera: Akelamo, 8 km NNE of, 100 m, 30–01/vii–viii/1985, J. Huijbregts HH399, multistr evergr forest, 1 human excr trap, HH399c, 20:15–06:15 [night], flight activity study. Paratype listed in Annex.

Identification

Onthophagus coprimorphoides differs from its New Guinea relatives by having a low transverse vertexal ridge (medially protuberant in single available female), while lacking any interocular protrusions. The tapering plates flanking the median concavity of the pronotum are recurved forward, narrow (prong-like) compared to the other species, and there are no extra protrusions, for instance, along the pronotal midline. Anterolateral surface of pronotum smooth, impunctate. Parameres very strongly curved, with characteristic details (in lateral view). Female generally similar to male, but protrusions and concavities of pronotum less developed. Body length 10–11 mm.

Distribution

Halmahera.

Description (holotype, male)

Body length ca 10.5 mm. Habitus distinctly convex-raised, pronotal armature dominant. Colour generally black, legs dark brown, dorsum shining, virtually glabrous (micro-stubbles hardly distinct); underside with longer pale-yellow setae, sides somewhat sericeous, due to microreticulation.

Clypeal border with sides evenly, widely rounded to very slightly reflexed, submarginate, rounded apex; clypeal and genal surfaces entirely rugulate-punctate; clypeogenal transition slightly interrupted (incised) at border, clypeogenal transition with low, almost straight ridge to arcuate ridge on clypeofrontal transition. Genal border widely rounded, posteriorly reaching occipital side; frontal surface with numerous fine punctures, abundant in front, sparser and even finer between eyes, with vague indication of genal suture. Vertex with low, sinuate ridge between posterior ends of eyes. Eye foramina very broadly elliptic, with ca 30 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width ca 3.3.

Pronotum strongly, generally raised, convex, with broad median longitudinal concavity over virtually entire length, its surface slightly wrinkled; concavity flanked by pair of long, erect, distally inward curved, tapering projections, their base broad in lateral view; lateral declivities convex; most of pronotal surface sparsely, evenly micropunctate; borders, except base, distinctly marginate; anterior section of lateral border virtually straight (full-face view, surface shallowly depressed), anterolateral angle very distinct, rectangular; posterior section of lateral border slightly sinuate, posterolateral angle very obtuse, rounded off; pronotal basal border evenly rounded.

Elytra uniformly black, shining; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; epipleuron smooth, convex, glabrous. Elytra broad, with 8 straight to slightly curved, narrow, distinct striae; stria 7 straight in front, ending at humeral umbone; strial punctures simple, fine but distinct, mostly separated on disc by 4–6 puncture diameters, very slightly crenulating interstrial edges. Interstrial surface slightly convex, all interstriae with scattered, mostly sparse micropunctation.

Antennal club yellowish, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus posteriorly delimited by simple coxal-marginal ridge. Proepisternal surface opaque, with sparse punctures, several bearing setae. Anterior lobe of metasternum unmodified (evenly convex), disc smooth, with shallow midline impression; metasternal flanks opaque, with sparse, fine (annulate) punctures, several bearing seta. Abdominal ventrites largely smooth, shiny, laterally with sparse, fine (annulate) punctures bearing short seta. Pygidium slightly convex, black, shiny, with evenly scattered, sparse, fine punctation; base marginate.

Protibia with 3 + 1 robust external denticles, some separated by fine serration (1–2 small denticles); proximal serration consisting of ca 6 small denticles; apico-external denticle oblique to tibial axis; terminal spur long, acuminate, distally curved; underside with slight longitudinal crest; protarsus slender. Femora robust, undersides all mainly with scattered micropunctation, few larger seta-bearing punctures present. Meso- and metatibiae strongly dilated distad to transversely subelliptic crest, which is fringed with fine fossorial spines and longer setae; external side with ca 4 sets of slight, spine-bearing fossorial protrusions. Meso- and metatarsi generally robust, with, sickle-shaped claws; meso- and metatarsomeres 1, long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-tapering, metatibial spur broad, tip slight curved, blunted. Approximate length proportions terminal spur // metatarsomeres 1–5: 60//64/30/19/11/22.

Parameres peculiarly humped, rounded (in lateral view), without lateral paramerite, fig. 79.

Measurements in mm (dorsal view). Maximum width of head 3.5. Median length of pronotum 4.1, maximum width 5.8. Sutural length of elytra 4.8, maximum width 6.3.

Variation and sexual dimorphism

Female with shallower concavity and smaller prongs on pronotum; clypeofrontal ridge straight, vertexal ridge medially with low, blunt tubercle; clypeal surface transversely rugulate. Otherwise generally similar to male. Body length female ca 11 mm. Only one pair of O. coprimorphoides available.

Etymology

Species name expresses similarity to Onthophagus coprimorphus.

The Onthophagus seramicus group

Parameral shape characteristic, distally quasi-sinuate, with lateral paramerite (a short sclerotized protrusion). Male protibial apex modified, more or less truncate-transverse, apico-external denticle dilated, apico-internal accrete protrusion small but distinct. Head surface at most with slight, arcuate clypeofrontal ridge (not reaching clypeogenal borders), frontovertex lacking projections (but cf. Onthophagus laratinus, in next paragraph). Clypeal apex bisinuate-bidentate. Pronotum and elytra with numerous moderately long but inconspicuous setae; surface of elytral interstriae more or less sericeous, medially they may be uneven or have a swollen (shiny) strip. Body length usually 6–8 mm.

Shiny interstrial swellings like those on the elytra of O. seramicus (fig. 62) occur also in O. laratinus Arrow, 1916 from the Tanimbar Islands, but that species differs by having a pair of upright vertexal horns or tubercles. Protibia of laratinus with truncate apex and only three external denticles (photographs of male and female syntypes BMNH seen; note listing of holotype in Bacchus 1978). This species might well belong in the Onthophagus seramicus group, certainly if it would prove to have matching parameres (we had no opportunity to study O. laratinus in detail). For convenience, the species is included in the key hereafter.

Two or three species in this group:

O. frankrozendaali sp.n.

O. seramicus sp.n.

O. laratinus Arrow, 1916

Key to species (males)

1. 1. Elytral interstriae all evenly, very slightly convex, without medial swelling or costa. Elytral sides, pygidium, and other parts distinctly pale yellow. Vertex without protrusions. Eyes narrow. Parameral tip dilated, spatuliform (full-face view). Protibia with 3 + 1 external denticles. Body length 6.5–7 mm .................. O. frankrozendaali
2. – At least some elytral interstriae with swollen, more or less costiform median strip. Elytra unicolour black-brown .................. 2
3. 2. Vertex without distinct protrusions. Protibia with 3 + 1 external denticles. Parameral tip dilated, sharply angulate laterally (full-face view). Body length 6–7 mm .................. O. seramicus
4. – Vertex with pair of horns (or tubercles). Protibia with 3 external denticles. Body length 8–9 mm .................. O. laratinus

Type material

Holotype male (RMNH), from [Indonesia:] Tanimbar Is: Yamdena, 6 km NW of Bomaki, 7 53′S - 131 15′E, 10–15/ix/1985, F. Rozendaal, prim[ary] mons[oon] forest, human faeces. Paratypes listed in Annex.

Identification

The elytral colour pattern in combination with the following characters should usually distinguish Onthophagus frankrozendaali from its Moluccan congeners. Elytral interstriae all virtually flat, medially slightly uneven but not with swollen, shiny median strip. Elytral sides, pygidium, and other ventral parts, distinctly yellowish. Clypeal apex of male slightly bisinuate, of female distinctly bidentate. Clypeofrontal ridge distinct in both male and female. Eyes narrowly elliptic in full-face view, posteriorly with narrowly open dorso-ventral potsgenal transition. Parameral tip dilated, spatuliform (full-face view). Male protibia with 4 larger external denticles, apico-external denticle short, tip rounded. Vertexal protrusions obsolescent. Pronotum and elytra laterally with long, fine setae. Body length 6.5–7 mm.

Distribution

Tanimbar Islands.

Description (holotype, male)

Body length ca 6.5 mm. Habitus convex, dorsum slightly deplanate. Colour generally brown-black, slightly shiny (part of surface sericeous, less shiny); legs dark brown, elytral margins, pygidium, parts of abdominal venter yellow(-brown). Pilosity generally inconspicuous, numerous on dorsal side, pale yellow; underside with numerous longer pale-yellow setae.

Head generally with dense, distinct, evenly scattered punctation. Clypeal border widely, evenly rounded to slightly bidentate-bisinuate, slightly reflexed apex; clypeogenal transition continuous at border; clypeogenal suture distinct, extending onto frontal sides; clypeofrontal transition with transverse, slightly arcuate ridge. Genal border rounded, finely marginate, lateral tip rounded off, posteriorly just not reaching occipital side. Vertex with pair of obsolescent swellings. Eye foramina narrowly elliptic, with 7–8 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width ca 9.

Pronotum generally moderately convex, disc deplanate (lacking midline impression near base); anterior declivity gradual; shiny, entirely densely, distinctly, quite evenly punctate, anterior and lateral declivities with punctures slightly smaller; all borders finely marginate; anterior section of lateral border virtually straight (full-face view), anterolateral angle distinct, subacute; posterior section of lateral border also virtually straight, posterolateral angle rounded off; pronotal basal border evenly rounded.

Elytra black, margins (interstria 8 behind humeral area and posterior declivity) yellow(-brown), opaque due to microreticulate surface; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; epipleuron smooth, blackish, sparsely punctate-setose. Elytra broad, with 8 straight to slightly curved, narrow, distinct striae; stria 7 almost straight in front, ending at humeral umbone; strial punctures fine, mostly separated by 4–6 diameters, slightly crenulating interstriae. Interstrial surface very slightly convex, medially slightly uneven, sparsely, finely punctate, pilosity very sparse, longer setae only on lateral and posterior surfaces.

Antennal club yellow-brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus slightly convex, posteriorly delimited by simple coxal-marginal ridge reaching border. Proepisternal surface sparsely punctate-setose, setae long. Anterior lobe of metasternum unmodified, slightly convex, smooth, shiny, with micropunctation; disc similar, also smooth, shiny, with very shallow midline impression running onto anterior lobe and shallow central impression; metasternal flanks opaque, with numerous (some ocellate) punctures, sparsely setose. Abdominal ventrites also opaque, along base of 1–5 with sparse (some ocellate, some seta-bearing), mostly fine punctures; anal ventrite brownish. Pygidium (and propygidium) yellow-brown, opaque; base marginate; pygidial surface slightly, evenly convex, sparsely, finely punctate, numerous punctures with variably long seta.

Legs generally shiny brown. Protibia with 3 + 1 larger external denticles (distal 3 larger, apical one broad, with rounded tip), separated by some fine serration; proximal serration consisting of ca 6 small denticles; apico-external denticle almost perpendicular to tibial axis; apical edge with short, acuminate spur, internal side with short accrete spine; underside with low longitudinal crest; protarsus relatively long, robust. Profemur robust, underside smooth, mainly with fine, scattered punctation, posteriorly with numerous longer setae. Meso- and metafemoral undersides smooth, mainly with fine, scattered punctation, generally with few longer setae. Meso- and metatibiae dilated distad to transversely subelliptic crest, which is fringed with fossorial spines and setae; external side with 4–5 sets of slight, spine-bearing fossorial protrusions. Tarsi generally slender, with fine, sickle-shaped claws; meso- and metatarsomeres 1 long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-acuminate. Approximate length proportions terminal spur // metatarsomeres 1–5: 15//21/8/5/4/7 (paratype male).

Parameres down-curved to spatuliform tip (full-face view), sides near apex with short paramerite, figs 72, 82.

Measurements in mm (dorsal view). Maximum width of head 2.0. Median length of pronotum 2.3, maximum width 3.5. Sutural length of elytra 2.9, maximum width 4.1.

Sexual dimorphism and variation

Female protibial apex unmodified, with acuminate apico-external denticle, without accrete apico-internal spine; clypeal apex distinctly bidentate. In other characters very similar to male. Dorsal colour occasionally lighter brown, but lateral-distal yellowish zone on elytra remaining distinct.

Etymology

Named after the collector of this species, F.G. Rozendaal (The Netherlands); he organized the trip with J. Huijbregts to Halmahera and Bacan.

Type material

Holotype male (BMNH), from Indonesia: Seram: Manusela NP: Wae Mual Plain, viii/1987, M.J.D. Brendell, pitfall 4 dung 2. Paratypes listed in Annex.

Identification

This species is easily separable from the known Moluccan congeners by the combination of subcostate elytral interstriae, narrowly elliptic eyes (in full-face view), and absence of vertexal projections. Parameral tip dilated, (sub)angulate laterad (full-face view), distal-lateral paramerite small but distinct. Clypeal border evenly, widely rounded, apex at most slightly bisinuate-bidentate. Male without, female with slight clypeofrontal ridge. Eyes posteriorly with narrowly open dorso-ventral postgenal transition. Male protibia with 4 external denticles, apico-external denticle short. Dorsum unicolour (brown-) black, elytra lacking colour pattern. Pronotum and elytra laterally with long, fine setae. Body length 6–7 mm.

Distribution

Seram.

Description (holotype, male)

Body length ca 7 mm. Habitus convex, dorsum slightly deplanate. Colour largely brown-black, slightly shiny (part of surface with microreticulation, sericeous); legs dark brown. Pilosity generally inconspicuous, numerous on dorsal side, pale yellow; punctation abundant, locally dense, mostly very distinct.

Clypeal border widely, evenly rounded to truncate (or indistinctly bisinuate), slightly reflexed, marginate apex; clypeal surface largely distinctly, somewhat irregularly, densely punctate; clypeogenal transition hardly interrupted at border; clypeogenal suture fine, extending onto frons; clypeofrontal transition lacking ridge. Genal border widely rounded, posteriorly just not reaching occipital side; genal punctation slightly effaced, surface opaque; frontal surface finely, distinctly, abundantly punctate, moderately shiny. Vertex with pair of obsolescent swellings. Eye foramina narrowly elliptic, with ca 8 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width ca 7.

Pronotum moderately convex, disc deplanate (lacking midline impression); anterior declivity gradual, unmodified; surface shiny, abundantly, evenly punctate throughout, lateral declivities with numerous erect setae; all borders finely, distinctly marginate; anterior section of lateral border very slightly convex (full-face view), anterolateral angle shortly rounded, subrectangular; posterior section of lateral border virtually straight, posterolateral angle rounded; pronotal basal border evenly rounded.

Elytra uniformly black, largely sericeous, interstriae sparsely punctate-setose; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; epipleuron smooth but wrinkled, irregularly punctate. Elytra broad, with 8 straight to slightly curved, narrow, well-defined striae; stria 7 evenly, very slightly curved in front, ending at humeral umbone; strial punctures moderately distinct from their interstrial crenulations, mostly separated by 3–5 diameters. Interstrial surface opaque, discal interstriae with raised, shiny, median longitudinal zone (surface of these costae uneven, lower on interstriae 2 and 4 than on other interstriae); setae on interstriae 7–8 longer than on others, erect.

Antennal club light brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus posteriorly delimited by simple coxal-marginal ridge. Proepisternal surface abundantly (hemi)punctate-setose, setae long. Metasternum shiny, anterior lobe unmodified (evenly convex); metasternal lobe and disc smooth, with very shallow midline impression, sparsely punctate-setose and with numerous fine secondary punctures; metasternal flanks with numerous seta-bearing (ocellate) punctures. Abdominal ventrites also shiny, each with basal row of seta-bearing (ocellate) punctures. Pygidium yellow-brown, opaque, evenly convex; base marginate; surface with abundant, seta-bearing (ocellate) punctures (diameter variable).

Legs generally shiny dark brown. Protibia with 3 + (1) external denticles (distal 3 larger, subacuminate), separated by some fine serration; proximal serration consisting of ca 6 small denticles; apico-external denticle short, with anterior edge almost perpendicular to tibial axis; apex with short, internal accrete spine and with fine, slightly curved spur; underside with low longitudinal crest; protarsus slender. Profemur robust, underside shiny, coarsely punctate-setose, interspersed with finer punctation. Meso- and metafemoral undersides shiny, with few coarse, seta-bearing punctures and with sparse finer punctation. Meso- and metatibiae dilated distad to transversely subelliptic crest, which is fringed with fossorial spines and setae; externally with ca 5 sets of slight, spine-bearing fossorial protrusions. Tarsi generally slender, with fine, sickle-shaped claws; meso- and metatarsomeres 1 long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-acuminate. Approximate length proportions terminal spur // metatarsomeres 1–5: 15//20/8/5/4/8.

Parameres down-curved to laterally produced tip (full-face view), sides near apex with short paramerite, figs 73, 83.

Measurements in mm (dorsal view). Maximum width of head 2.1. Median length of pronotum 2.2, maximum width 3.5. Sutural length of elytra 3.1, maximum width 3.8.

Variation and sexual dimorphism

Female protibial apex unmodified, with acuminate apico-external denticle, without accrete apico-internal spine; clypeal apex bisinuate-bidentate; clypeofrontal ridge present, slightly arcuate. In other characters very similar to male. The dorsal sculpture in this species varies slightly, particularly in the development of the elytral interstrial costae.

Etymology and note

Named after the home island of this species. This is species #4 in Hanski & Krikken (1991, Table 10.4).

Type material

Holotype male (RMNH), from Moluccas: Bacan: Sibela Range, 850 m, 28–04/vi–vii/1985, J. Huijbregts HH373, multistr evergr forest, window trap [= flight interception trap]. Paratypes listed in Annex.

Identification

General shape of the head of Onthophagus ontosatu unique in the Moluccan context and beyond: anterior margin of clypeus strongly, broadly bisinuate-bilobate (less so in female; no median projection in emargination, as in O. alfuricus, q.v.); pair of male vertexal horns long, dilated in basal part, much shorter in female; clypeofrontal transition of male without ridge, in female with arcuate ridge. Male pronotum with anteromedian protrusion (short longitudinal ridge), somewhat angular, flanked by slight impression on either side, all less pronounced in female. Eye foramina narrow. Head and pronotum largely densely punctate. Male protibial apex with small accrete internal spine, otherwise unmodified, external denticles slender, acuminate. Small (body length 4–5 mm), but forebody relatively robust compared to other Moluccan Onthophagus species. Dorsum shining black and/or brown. Body length usually 4–5 mm.

Distribution

Halmahera and Bacan.

Description (holotype, male)

Body length ca 4.5 mm. Habitus distinctly convex-raised. Colour generally black-brown, elytra, underside and legs slightly lighter (dark-brown), all shining. Forebody and pygidium abundantly to crowdedly punctate, virtually glabrous (with inconspicuous almost indistinct whitish micro-stubbles); underside with longer pale-yellow setae.

Head large relative to pronotum. Clypeal border with sides almost straight to broadly bilobate, reflexed apex; separating median emargination strong, rounded; preclypeal surface smooth, with few fine punctures only; clypeogenal transition uninterrupted at border; clypeogenal suture indistinct; clypeofrontal transition slightly convex, gradual, without ridge or suture. Genal border rounded, lateral tip rounded; postclypeal, genal and frontal surface very densely punctate, punctation multi-sized. Vertex with pair of separated, upright, transverse horns, broad basal part of horn with angulate internal plate, tip of horn tapering, plate surface smooth. Eye foramina narrow, with ca 8 facet rows across widest point. Ratio interocular distance / maximum (transverse, single) eye width ca 10.

Pronotum strongly, generally evenly convex (disc lacking distinct midline impression near base); anterior declivity steep, medially with blunt longitudinal ridge (top subangular in lateral view), surface behind vertexal projections depressed, largely impunctate; all borders, including basal sides, finely marginate; anterior section of lateral border virtually straight (full-face view), anterolateral angle very shortly rounded, subrectangular; posterior section of lateral border very slightly sinuate, posterolateral angle rounded off; pronotal basal border evenly rounded. Pronotal surface densely punctate, finer and less dense on disc.

Elytra uniformly chocolate-brown, shiny; scutellum indistinct; shape of base and apex unmodified; apicosutural angle distinct; epipleuron smooth, convex, glabrous. Elytra broad, with 8 straight to slightly curved, narrow, more or less distinct striae; stria 7 evenly, slightly curved in front, ending at humeral umbone; strial punctures simple, distinct, separated on disc by 3–6 puncture diameters, slightly crenulating interstrial edges. Interstrial surface slightly convex, all interstriae with sparse, scattered micropunctation.

Antennal club light grey-brown, scapus unmodified. Mentum shallowly emarginate in front. Postocular area of propectus posteriorly delimited by straight coxal-marginal ridge reaching lateral border. Proepisternal surface with numerous superficial (ocellate) punctures. Anterior lobe of metasternum unmodified (evenly convex), disc smooth, with shallow midline impression; metasternal flanks with numerous (ocellate) punctures, some bearing setae. Abdominal ventrites largely smooth, shiny, 1–5 with basal row of subocellate punctures. Pygidium slightly convex, brown, shiny, crowded with irregular, shallow punctation; base marginate.

Legs generally shining brown. Protibia with 3 + 1 large external denticles (distal 3 larger, slender, acuminate), separated by fine serration (1–2 denticles); proximal serration consisting of ca 6 small denticles; apico-external denticle oblique to tibial axis; tibial apex with fine accrete spine internally, next to fine terminal spur; underside with very slight longitudinal crest; protarsus slender. Profemur robust, underside mainly with micropunctation. Meso- and metafemoral undersides mainly with scattered micropunctation. Meso- and metatibiae dilated distad to transversely subelliptic crest, which is fringed with fine fossorial spines; external side with 3–4 sets of very slight, spine-bearing fossorial protrusions. Tarsi generally slender, with very fine, sickle-shaped claws; meso- and metatarsomeres 1 robust, long, straight, unmodified. Terminal spurs on meso- and metatibiae elongate-acuminate. Approximate length proportions terminal spur // metatarsomeres 1–5: 21//23/11/6/5/8.

Parameres generally tapering, without distinct distal-lateral paramerites, fig. 74.

Measurements in mm (dorsal view). Maximum width of head 1.6. Median length of pronotum 1.6, maximum width 2.5. Sutural length of elytra 2.1, maximum width 2.7.

Variation and sexual dimorphism

Female with relatively short clypeal lobes, arcuate clypeofrontal ridge, and short vertexal tubercles, connected by slight saddle; pronotal anteromedian protrusion slight (rounded in lateral view), lacking distinct impressions on either side. Female protibia without accrete apico-internal spine.

Colour of O. ontosatu usually black, but brown may become predominant – separate parts always uniform. The curvature of the clypeal lobes varies – they may be a bit sharper than in the holotype.

Etymology

The name of this species is a blend of the simplified genus name and the Indonesian word satu, meaning (number) one.