Motonerus obscurus Hansen, 1989

Ek, Martin Fiká Č & Short, Andrew Edward Z., 2006, A revision of the Neotropical genus Motonerus Hansen (Coleoptera: Hydrophilidae: Sphaeridiinae), Zootaxa 1268, pp. 1-38 : 26-35

Motonerus obscurus Hansen, 1989

( Figs. 1 , 17–18 , 28–29 , 38 , 48 , 61 )

Motonerus obscurus Hansen, 1989: 257 (pars.)

Type locality: EL SALVADOR, Montecristo near Metapán, 2300 m.

Type Material. Holotype ♂ ( CNC): “EL SAL., nr. Metapan / Montecristo, 2300 m / 8–10.V.1971, S. Peck [printed label] // Ber. 199 / cloud forest [printed label] // HOLOTYPE / Motonerus / obscurus / M. Hansen [red printed label] // HOLOTYPE / CNC No. 20749 [red printed label, number hand­written]”. Paratypes (8): EL SALVADOR: same data as holotype, only with “ PARATYPE ” on the first type label [both type labels yellow], 8 spec. ( CNC).

The original type series housed in CNC consists of two different species as the specimen from Costa Rica was found not to be conspecific with the holotype (this new species is described as M. hanseni sp. n. above). We did not have the opportunity to examine the paratype from Mexico (Hidalgo Prov.) mentioned in the original description. As both specimens from Oaxaca province in Mexico examined by us (see Additional material examined) are slightly aberrant from all other specimens of M. obscurus (see Discussion for details), we cannot conclude if the third Mexican paratype belongs to M. obscurus or not.

Additional material examined (46): HONDURAS: “ HONDURAS: FRANC. MOR. / P.N. La Tigra 23.2 lm N. / Tegucigalpa, 1950 m, 29.VI. / 1994 ­139C / oak/cloud forest litt. berl.”, ♂ ( CNMC); “ HONDURAS: FRANC. MOR. / Cerro Uyuca, ca. 10 km W. / Zamorano, 1840 m / 9.VI.1994 ­105, R. Anderson / cloud forest litter berlese”, 1 unsexed specimen ( CNMC); “ HONDURAS: LA PAZ / Titule, Res. Biol. Guajiquiro / N 14°10' W 87°50', 2130 m / 7.V.2002 R. Anderson cloud forest litter, 2002­010H”, 1 unsexed specimen ( CNMC); same data, only number of the sample “2002­010E”, 2 unsexed specimens ( AEZS, CNMC); “ HONDURAS: LA PAZ, Cord. / Montecillos, via 25 km S.E. & / 18 km N.W. La Paz, 21.VIII. / 1994 ­217C, 2000 m, R. Anderson / mixed pine/ hardwood forest litt. berl.”, 3ΨΨ ( CNMC); “ HONDURAS: STA BARBARA / Cerro Santa Barbara, 11 km S. / & 5.6 km W Penas Blancas / 1870 m, 24.VIII.1994 ­220D / R. Anderson cloud for. litt. berl.”, ♂, Ψ, 4 unsexed specimens ( AEZS, CNMC, MFPC); “ HONDURAS: SANTA BARBARA / Cerro Santa Barbara, 15 km S. E. Penas Blancas, 1850 m, 24.VIII.94 / S. Peck, 94­58, wet mont.for.litt.”, Ψ ( CNMC); “ HONDURAS: LEMPIRA / P.N. Celaque, nr. Gracias /Above Camp. Don Tomas / 2250 m, N 14°32.7' W 88°39.7' / 12–13.V.2002, R. Anderson / mixed oak for. litter 2002­021A”, 1 unsexed specimen; “ HONDURAS: STA. BARBARA / Cerro Santa Barbara, 11.5km, S. / & 5.6km W. Penas Blancas / 1870 m, 24.VIII.1994 ­220H / R. Anderson, cloud for. litt. berl.”, 1 unsexed specimen ( ZMUC); same data, but sample no. “220I”, 2ΨΨ ( ZMUC); same data, but sample no. “220J”, ♂ ( ZMUC). MEXICO: “ MEXICO: CHIAPAS: 8.9 / km E Rayon Elev. / 1500 m, cloud forest / litter R. Anderson / 91­109, 19­IX­1991 ”, Ψ ( CNMC); “ MEX. Rte. 131 / 187km. S. Oaxaca / Oax. V­12­1971 / J. M. Campbell, 5800’ “, 2♂♂ ( CNC); “ MEXICO: Hidalgo / 4.4 km N Tlanchinol / Hwy. 105, 6 July 1992 / 1420 m, J. S. Ashe / H. Frania #11 / ex. treefall litter”, ♂ ( ZMUC). NICARAGUA: “ NICARAGUA: MATAGALPA / 6 km N Matagalpa, Selva Negra / 1550 m, N 12°59.9' W 85°54.6' / 19.V.2002, R. Anderson, ridge– / top cloud for., litter, 2002­024H”, ♂ ( CNMC). EL SALVADOR: “EL SAL., nr. Metapan / Montecristo, 2300 m / 8.–10.V.1971, S. Peck”, ♂ ( CNC); “ EL SALVADOR: STA ANA / Cerro Montechristo, 21.7km / N. E. Metapan, 2100 m, 29.VIII. / 1994 ­228A, R. Anderson / hardwood forest litter, berlese” 3♂♂, Ψ, 16 unsexed specimens ( AEZS, MFPC, ZMUC).

Differential Diagnosis. Body larger than 1.8 mm; elytra nearly evenly convex in lateral view; elytral intervals 2, 4 and 6 usually slightly higher than remaining ones basally; lateral margins of elytra with denticles usually not overlapping 0.66 of elytral length; anteromedian prosternal excision deep and narrow; preepisternal elevation 1.6–2.0× longer than wide, with deep concave median area; metaventrite with more or less developed depression; abdominal ventrite 1 with submedian longitudinal ridges; median lobe widened apicad, abruptly narrowing subapically, bearing small circular excision on apex.

This species, by the combination of a wider preepisternal elevation of mesothorax with median concave area, longer body size and abdominal ventrite 1 with submedian longitudinal ridges, somewhat resembles M. andersoni , M. hanseni and M. problematicus . From the latter two mentioned species it differs by having nearly evenly convex elytra in lateral view (they have distinctly depressed in the elytral midlength), moreover, from M. problematicus it can be easily distinguished by much wider preepisternal elevation with very distinctly developed median concavity. For comparison with M. andersoni see this species.

Description: Body elongate oval, maximum width on posterior margin of pronotum; elytra narrowed posteriad, evenly convex in lateral view, with only very indistinct depression in basal 0.2. Length: 1.8–2.3 mm (HT: 2.1 mm); width: 1.2–1.5 mm (HT: 1.35mm).

Coloration: Dorsal side brown, with slightly paler anterior margin of clypeus, lateral margins of pronotum and lateral margins of elytra. Ventral side reddish brown; mouthparts and antenna except antennal club paler, ferruginous.

Head: Clypeus with moderately coarse and not very densely setiferous punctation, interstices without microsculpture; anterior margin straight, finely rimmed. Lines dividing clypeus from vertex distinct even paramesally. Vertex with coarse and dense setiferous punctation, interstices smooth. Eyes quite small, divided by 9× width of one eye. Mentum slightly wider than long, anterior margin slightly bisinuate; surface with fine and sparse setiferous punctation, interstices smooth. Antenna with 9 antennomeres; scapus ca. as long as antennal club; antennomeres 2–6 shorter than scapus when combined; antennal club elongate oval, antennomere 7 slightly longer than antennomere 8; antennomere 9 slightly longer than antennomere 7, with acutely pointed apex and distinct subapical strangulation. Maxillary palpomere 2 ca. as long as palpomere 4, slightly widened apically; palpomere 3 shorter than palpomere 2, slightly swollen apically; palpomere 4 spindle­like.

Prothorax: Pronotum strongly arcuately narrowed anteriad, maximum width in posterior 0.25, Lateral margins slightly explanate; posterior margin slightly bisinuate; posterolateral corners only indistinctly pronounced. Posterior margin with slight but distinct impression in lateral 0.25 at posterior margin. Punctation coarse and dense, bearing long pubescence, interstices without microsculpture. Prosternum distinctly carinate medially; anteromaedian excision deep and narrow; lateral parts indistinctly divided from median area, dividing line nearly straight.

Mesothorax: Scutellar shield in form of equilateral triangle, bearing a few coarse, setiferous punctures, interstices smooth. Elytron with 9 punctural series; series 1–5 and 8–9 reaching elytral base; series 7 and 8 arising subbasally. Intervals strongly elevate, costate, bearing very fine and sparse hair­bearing punctation. Intervals lowly costate, evenly elevate at elytral base; intervals 2, 4 and 6 becoming slightly higher than adjacent intervals posteriad. Lateral margins with moderately large obtuse denticles basally, becoming finer and more distant apicad, reaching 0.75 of elytral length. Epipleura wider than pseudepipleura basally, reaching posterior margin of metaventrite; pseudepipleura narrowing posteriad, reaching elytral apex. Preepisternal elevation with subrhomboid plate 2.0× longer than wide, with elevate narrow lateral edge and deeply concave median area. Grooves for reception of procoxae shallow and wide.

Metathorax: Metaventrite with pentagonal elevate median area bearing very sparse and fine setiferous punctation, interstices without microsculpture; median part with very distinct circular depression. Lateral parts of metaventrite with fine microreticulation and sparse, very fine hair­bearing punctures. Postcoxal ridges bent posteriad medially, forming a longitudinal ridge reaching anterior 0.2 of metaventrite length. Femoral lines missing. Hind wings present.

Legs short; femora with moderately strong but very sparse setiferous punctation, interstices without microsculpture; tibiae bearing small and fine spines; tarsi distincly shorter than femora, bearing numerous hairs ventrally.

Abdominal ventrite 1 carinate medially, bearing additional longitudinal ridges paramesally. Ventrites 2–5 finely microsculptured in apical part, smooth and very indistinctly and sparsely punctured on posterior margins.

Male genitalia: Parameres ca. 1.5× longer than phallobase, continuously narrowing apicad, apices slightly bent outwards, bearing two small setae. Median lobe slightly widened apicad, with wide and obtusely angulate apical part; apex with small circular excision.

Variability. Moderately variable species in some external characters. Pronotum bears very shallow median longitudinal furrow in some specimens. Elytra are quite constant in most characters, only with lateral denticulation reaching to the subapical area (then small and rather distant denticles can be observed near elytral apex). Preepisternal elevation 1.6–2.0× longer than wide. Median depression on the metaventrite can have two much smaller lateral impressions without any punctures on their bottom, or can be slightly elongate rather than circular in some specimens; it is very shallow in some specimens. The shape of elytra in lateral view is constant in all examined specimens except of two males from Mexico (see discussion below).

Discussion. Two males from prov. Oaxaca ( Mexico) listed under the Additional material examined above differ from the other examined specimens of M. obscurus by slightly depressed elytra in lateral view and slightly more elongate apex of the median lobe. As both these differences from usual specimens of M. obscurus are very slight, we decided to treat these Mexican specimens as M. obscurus for the time being. However, as the lateral shape of elytra is very constant in all Motonerus species, these Mexican specimens may represent a separate species closely allied to M. obscurus . More material from Mexico needs to be examined before a determination can be made with confidence.

Biology: The type series including the holotype was collected in a broadleaf cloud forest with Cyathea tree ferns and Podocarpus conifers, in which the litter was sifted and carrion and dung baited pitfall traps were set (S. Peck, pers.comm.).

Distribution: Confirmed from Nicaragua, Honduras and El Salvador; its occurrence in Mexico requires further confirmation.

Motonerus oosternoides Fiká č ek & Short, sp. n. ( Figs. 7–8 , 22 , 33 , 46 , 55, 64 )

Type Locality. PANAMA, Chiriqui Prov., 5.6 km N Boquete, 1800 m.

Type Material. Holotype ♂ ( ZMUC): “ PANAMA: Chiriqui / 5.6km N Boquete, / La Culebra Trail, 1800 m / 15.Jun.1996 R. Anderson / wet cloud forest litt. 96­131B”. Paratypes (47): PANAMA: same data as holotype, 2♂♂, Ψ, 41 unsexed specimens ( AE ZS, CMNC, CUIC, MFPC, NMW, USNM, ZMUC); PANAMA: CHIRIQUI / 5.6 km N. Bouquete / La Culebra Trail / 1800 m / 15.VI.1996 / R. Anderson, 96­131A / wet cloud forest litter”, 1 unsexed specimen ( CNMC); PANAMA: Chiriqui / P. Int. La Amistad, Las Nubes / 5.3 km W Cerro Punta, 2150 m / 15.Jun.1995 R.Anderson / cloud forest litter 95­ 026”, 2 unsexed specimens ( ZMUC).

Differential Diagnosis. Body smaller than 1.8 mm; elytra evenly rounded in lateral view; elytral intervals almost evenly elevate thoughout; lateral margins with fine denticulation reaching elytral apex; anteromedian prosternal excision with obtuse “tooth” medially; preepisternal elevation of mesothorax lamellar, longer than metaventrite, without median concave area; metaventrite without median depression; abdominal ventrites without additional submedian longitudinal ridges; hind wings absent; median lobe with slightly widened serrate apex with apical excision.

Very similar to M. apterus (see under this species for comparison with it as well as with other Motonerus species) The combination of lamellar preepisternal elevation of mesothorax and missing longitudinal submedian ridges on abdominal ventrites can resemble M. depressus , however both M. oosternoides and M. apterus are easily distinguishable from it by evenly and highly convex elytra, much smaller body size, paler general coloration, distinctly developed anteromedian prosternal elevation, missing coarse crenulation on anterior part of the abdominal ventrite 1 and by the male genitalia.

Description. Body elongate oval, maximum width closely before posterior margin of pronotum; elytra narrowing posteriad, evenly highly convex in lateral view; pronotum slightly convex in lateral view. Length: 1.5–1.8 mm (HT: 1.8 mm); width: 1.0– 1.1 mm (HT: 1.1 mm).

Coloration: Dorsal side brown; clypeus and lateral margins of pronotum and elytra slightly paler. Ventral side reddish brown; mentum, gula and legs slightly paler. Mouthparts and antennae yellowish brown, terminal antennomeres of antennal club whitish.

Head: Clypeus with fine and sparse punctation, interstices without microsculpture; anterior margin straight, narrowly rimmed. Lines dividing clypeus from vertex distinct even paramesally. Vertex with setiferous punctation much coarser and denser than on clypeus, interstices without microsculpture. Eyes small, separated by 10× width of one eye. Mentum slightly wider than long, with deeply bisinuate anterior margin; punctation coarse and moderately dense, interstices without microsculpture. Maxillary palpomere 2 as long as palpomere 4, distinctly swollen apically; palpomere 3 shorter than palpomere 2, short, stout, slightly swollen apically; palpomere 4 rather stout, spindle­like. Antenna with 9 antennomeres; scapus slightly longer than antennal club; antennomeres 2–6 small, slightly shorter than antennal club when combined; antennal club compact, elongate oval; antennomere 8 slightly shorter than antennomere 7; antennomere 9 slightly longer than antennomere 7, obtusely pointed, without distinct subapical strangulation.

Prothorax: Pronotum strongly arcuately narrowing anteriad, maximum width closely before posterior margin. Lateral margins slightly explanate; posterior margin bisinuate, posterolateral corners slightly pronounced. Sublaterally on posteior margin with very weak impression. Punctation moderately strong, sparse, consisting of setiferous punctures; interstices without microsculpture. Prosternum weakly carinate medially; anteromedian excision shallow and wide, with obtuse “tooth” medially; lateral parts indistinctly divided from median area, dividing line convex laterad.

Mesothorax: Scutellar shield in form of equilateral triangle, bearing a few fine punctures. Elytron with 9 punctural series; series 1–5 and 8 reaching elytral base; series 6, 7 a 9 arising subbasally. Elytral intervals weakly costate, evenly elevate basally; intervals 2 and 4 slightly narrower than adjacent intervals apically. Intervals with fine punctation bearing protruding bent hairs. Lateral margin of elytron with fine, equidistant denticles reaching elytral apex. Epipleuron slightly narrower than pseudepipleuron basally, reaching level of metathorax; pseudepipleuron narrowing posteriad, reaching elytral apex. Preepisternal elevation as an elevate bulge with narrow longitudinal carina medially, distinctly developed in anterior 0.5, weakly developed posteriorly. Grooves for reception of procoxae deep and not very wide.

Metathorax: Metaventrite shorter than preepisternal elevation, without median depression, bearing fine setiferous punctation, interstices without microsculpture.

Postcoxal ridges bent posteriad medially, forming ridge reaching 0.25 of metaventrite length. Hind wings absent.

Legs short; femora bearing very sparse and fine setiferous punctures, interstices shiny, without microsculpture. Tibiae slightly longer than tarsi, bearing numerous very fine spines. Tarsi densely pubescent ventrally.

Abdominal ventrite 1 bearing median longitudinal carina, additional submedian longitudinal ridges missing on all ventrites; fine crenulation of anterior part of ventrite 1 missing.

Male genitalia: Parameres ca. 1.6 longer than phalobase, gradually narrowing apicad, slightly bent outwards subapically, bearing a few small setae apically. Median lobe slightly longer than parameres, considerably narrowing in apical 0.15, slightly widened and bearing serrate rim apically; the rim interrupted by a distinct incision at apex.

Variability. Very uniform species in most external characters. The only observed variability concerns the morphology of the preepisternal elevation of the mesothorax and the metaventrite. In some specimens, the posterior part of the preepisternal elevation is vaguely defined and the median ridge (formed by postcoxal ridges bent posteriad mesally) reaches nearly the posterior margin of metaventrite. The aedeagus of these specimens is, however, completely identical to that of the holotype. Moreover, intermediate specimens with the metasternal median ridge only slightly protracted posteriad and only indistinctly narrowed preepisternal elevation were found. Thus, we consider this variability as intraspecific, without any taxonomic importance.

Etymology. Oosternoides = resembling Oosternum , reflecting the small size and Oosternum ­like habitus of the species. This name was originally given to this species in notes written by the late Michael Hansen.

Habitat. All specimens examined were sifted from the cloud forest litter in elevations between 1800 and 2150 m a.s.l.

Distribution. The species is known from two closely situated localities in western Panama.

Motonerus problematicus Fiká č ek & Short, sp. n. ( Figs. 19–20 , 27 , 39 , 50 , 59 )

Type locality. COSTA RICA, Puntarenas Prov., Monteverde Cloud Forest Reserve.

Type Material. Holotype ♂ ( ZMUC): “ COSTA RICA: Puntarenas / Monteverde Reserve / 25 May 1993, C. Michalski / ex; flight intercept trap // Motonerus n.sp. / M. Hansen det.”. Paratype: COSTA RICA: “Quebrada Segunda, P.N. Tapanti A. C. / Amistad, Prov. Carta COSTA RICA 1150 / m, Jul. 1994, G. Mora, L.N. / 194000­559800 # 3010”, female ( INBIO).

Differential Diagnosis. Body larger than 2.0 mm; elytra depressed, not abruptly elevate behind pronotum in lateral view; elytral intervals evenly elevate throughout; elytral margin with fine and more or less equidistant denticles reaching elytral apex; preepisternal elevation of mesothorax 3.0–4.0× longer than wide; metaventrite with shallow median depression; abdominal ventrites 1–3 with longitudinal ridges (not as distinct on ventrites 2–3 as on ventrite 1); apex of median lobe gradually narrowing apicad from apical 0.25, with only minute incision on apex.

Most easily recognized by the combination of depressed elytra in lateral view (in contrast to M. andersoni and M. obscurus ) not abruptly elevate behind pronotum (in contrast to M. nublado ), elytral intervals evenly elevate thoughout (in contrast to M. obscurus and M. hanseni ), preepisternal elevation 3.0–4.0× longer than wide and in some cases with weak, very shallow median concavity, and denticulation of elytral margins equidistant or nearly so and reaching elytral apex (in contrast to M. hanseni , M. obscurus and M. nublado ).

Description. Body elongate oval, maximum width closely before posterior margin of pronotum; elytra slightly narrowed posteriad, depressed in lateral view, not abruptly elevate behind posterior margin of pronotum. Length: 2.1–2.4 mm (HT: 2.1 mm); width: 1.5–1.6 mm (HT: 1.5 mm).

Coloration: Dorsal side black, with anterior margin of clypeus, lateral margins of pronotum and lateral margins of elytra paler, reddish brown. Ventral side pitchy brown, lateral portions slightly paler; mouthparts, antennae, mentum, gula and legs reddish brown.

Head: Clypeus with fine but rather dense punctation, interstices without microsculpture; anterior margin slightly convex, narrowly rimmed. Lines dividing clypeus from vertex distinct also paramesally. Vertex with coarse and rather dense setiferous punctation, interstices narrow, without microsculpture. Eyes small, separated by 10× width of one eye. Mentum slightly wider than long, anterior margin shallowly bisinuate; surface with moderately coarse and not very dense punctation, intertices with fine mesh­like microsculpture. Maxillary palpomere 2 ca. as long as palpomere 4, strongly swollen apically; palpomere 3 shorter than palpomere 2, slightly swollen apically; palpomere 4 spindle­like. Antenna with 9 antennomeres; scapus ca. as long as antennal club; antennomeres 2–6 shorter than scapus when combined; antennal club elongate oval; antennomere 7 slightly longer than antennomere 8; antennomere 9 slightly longer than antennomere 7, with acute apex and distinct strangulation subapically.

Prothorax: Pronotum strongly arcuately narrowed anteriad, maximum width in posterior 0.25. Lateral margins slightly explanate; posterior margin slightly bisinuate, with weakly pronounced posterolateral corners. Punctation moderately coarse but very dense, interstices very narrow, without microsculpture. Prosternum with fine median carina; anteromedian excision deep and narrow; lateral parts indistinctly divided from median area, dividing line nearly straight.

Mesothorax: Scutellar shield in form of equilateral triangle, slightly depressed in the middle, with a few fine punctures. Elytron with 9 punctural series; series 1–7 reaching elytral base, series 8–9 arising slightly subbasally. Intervals lowly costate, evenly elevate basally; intervals 2, 4 and 6 slightly more elevate than adjacent intervals posteriorly; intervals with fine pubescent punctation, interstices without microsculpture. Elytral margin with moderately large blunt denticles basally, becoming finer and more distant apicad, nearly reaching elytral apex. Epipleuron wider than pseudepipleuron basally, reaching posterior margin of metaventrite; pseudepipleuron narrowing posteriad, reaching elytral apex. Preepisternal elevation with plate 4.0× longer than wide, bearing slightly elevate narrow lateral edges and not very distinct median concave area. Grooves for reception of procoxae shalow, wide.

Metathorax: Metaventrite with elevate median pentagonal area bearing moderately strong and not very dense punctation, interstices without microsculpture; medially with quite deep elongate depression. Lateral portions with pubescent microsculpture. Postcoxal ridges bent medially, forming median longitudinal ridge reaching apical 0.15 of metaventrite length. Femoral lines absent. Hind wings present.

Legs short. Femora with very fine and sparse setiferous punctation. Tibiae longer than tarsi. Tarsi with dense pubescence ventrally.

Abdomen: Abdominal ventrite 1 with strong median longitudinal carina and with additional submedian longitudinal ridges. Ventrites 2 and 3 with distinct but not so strong additonal longitudinal ridges. Ventrites 4–5 smooth.

Male genitalia: Parameres 2.0× longer than phallobase, gradually narrowing apicad, apices slightly bent outwards, bearing two long setae. Median lobe considerably longer than parameres, rather wide subapically, narrowing apicad from apical 0.25. Apical grooved rim present in apical 0.25, apex with minute incision.

Variation. Because only two specimens are known to us, we cannot discuss the variability of this species. We observed a slight variability in the preepisternal elevation of mesothorax—this can be 3.0–4.0× longer than wide.

Discussion. Distinguishing of this species from Motonerus sp. B ( Bolivia) is possible only on the basis of a slight difference in the shape of the preepisternal elevation (3.0–4.0× longer than wide in M. problematicus and 5.5× longer than wide in Motonerus sp. B). Because of the low number of examined specimens of both species, we cannot exclude that this difference refers the intraspecific variability of both species. In this case, M. problematicus would be externally indistinguishable from Motonerus sp. B for the time being. However, because of the large distance of localities where both species were found, we decided to treat them as two different species until the male of the putative separate Bolivian species is found.

Etymology. Problematicus (Lat.) = problematic, referring the fact that the solution of the status of this species remained as the last and most difficult problem during preparation of this paper.

Habitat. One specimen was collected at light, the collecting circumstances of the second are not known to us. The elevation 1150 m a.s.l. is mentioned for the paratype.

Distribution. The species is known from two ca. 130 km distant cloud forest localities in Costa Rica (Cordillera de Talamanca and Cordillera de Guanacaste).

Figures

FIGURES 1 – 4. Dorsal habitus of Motonerus. 1: M. obscurus Hansen; 2: M. apterus sp. n.; 3: M. andersoni sp. n.; 4: M. depressus sp. n. Scale bar = 1 mm.

FIGURES 13 – 20. Male genitalia of Motonerus. 13 – 14: M. andersoni sp. n., paratype; 15 – 16: M. hanseni sp. n., holotype; 17 – 18: M. obscurus Hansen, paratype; 19 – 20: M. problematicus sp. n., holotype. 13, 15, 17, 19 — aedeagus (scale bar = 0.1 mm); 14, 16, 18, 20 — apical part of median lobe (scale bar = 0.05 mm).

FIGURES 21 – 31. Lateral habitus of Motonerus. 21: M. apterus sp. n.; 22: M. oosternoides sp. n.; 23: M. depressus sp. n.; 24: M. nublado sp. n.; 25: M. andersoni sp. n.; 26: M. hanseni sp. n.; 27: M. problematicus sp. n.; 28: M. obscurus Hansen (El Salvador); 29: M. obscurus Hansen (Oaxaca prov., Mexico); 30: M. sp. B; 31: M. sp. A. Scale bar = 1 mm.

FIGURES 32 – 40. Preepisternal elevation of mesothorax and median part of metaventrite of Motonerus. 32: M. apterus sp. n.; 33: M. oosternoides sp. n.; 34: M. depressus sp. n.; 35: M. andersoni sp. n.; 36: M. hanseni sp. n.; 37: M. nublado sp. n.; 38: M. obscurus Hansen; 39: M. problematicus sp. n.; 40: M. sp. A. Scale bar = 0.2 mm.

FIGURES 41 – 53. Details of of Motonerus. 41, 49: M. sp. B; 42, 52: M. andersoni sp. n.; 43, 53: M. apterus sp. n.; 44: M. depressus sp. n.; 45: M. hanseni sp. n.; 46: M. oosternoides sp. n.; 47: M. nublado sp. n.; 48: M. obscurus Hansen; 50: M. problematicus sp. n.; 51: M. sp. A. 41 — preepisternal elevation of mesothorax and median part of metaventrite (scale bar = 0.2 mm); 42 – 51 — median part of prosternum; 52 – 53 — sternite 9 of male.

FIGURES 54 – 64. Details of Motonerus. 54, 60, 63: M. apterus sp. n.; 55, 64: M. oosternoides sp. n.; 56: M. depressus sp. n.; 57, 62: M. nublado sp. n.; 59: M. problematicus sp. n.; 61: M. obscurus Hansen. 54 – 59 — epipleuron and lateral part of elytron; 60 – 62 — abdominal ventrites; 63 – 64 — head, lateral view. Scale bar = 0.5 mm (54 – 59), 0.25 mm (60 – 62); 0.1 mm (63 – 64).

FIGURES 5 – 12. Male genitalia of Motonerus. 5 – 6: M. apterus sp. n., paratype; 7 – 8: M. oosternoides sp. n., paratype; 9 – 10: M. depressus sp. n., holotype; 11 – 12: M. nublado, holotype. 5, 7, 9, 11 — aedeagus (scale bar = 0.1 mm); 6, 8, 10, 12 — apical part of median lobe (scale bar = 0.05 mm).