Brachysternus Guérin­Menéville, 1831

Jameson, Mary Liz & Smith, Andrew B. T., 2002, Revision Of The South American Genus Brachysternus Guérin-Méneville (Coleoptera: Scarabaeidae: Rutelinae: Anoplognathini: Brachysternina), The Coleopterists Bulletin 56 (3), pp. 321-366 : 332-342

Genus Brachysternus Guérin­Menéville, 1831

( Figs. 1–38 ; see also Fig. 1 in Smith 2002)

Brachysternus Guérin­Méneville 1831:3 . Type species Brachysternus prasinus Guérin­Méneville, 1831 (by monotypy).

Description. Scarabaeidae , Rutelinae , Anoplognathini . Form ( Fig. 1 ): Elongate oval, sides subparallel, pygidium exposed beyond apices of elytra, apex of elytra broadly rounded. Length from apex of clypeus to apex of elytra 16.0–25.0 mm; width at base of elytra 7.0–12.0 mm. Dorsal color variable hues of green (metallic or opaque), castaneous with metallic green shine, or bluish­green. Head: Disc of frons and clypeus in lateral view nearly flat or weakly convex (more convex in males). Clypeal apex semi­

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circular to rectangular with broadly rounded corners, weakly constricted at base or not; margins and apex weakly or broadly reflexed (more reflexed in males). Frons and clypeus variably punctate, some punctures setose; setae short to long, slender or thick, white to orange, variable in density. Frontoclypeal suture complete, weakly bisinuate. Eye canthus narrow, poorly developed, not cariniform. Interocular width 2.0–6.0 transverse eye diameters. Region posterior to eye with or without thickened or scale­like setae. Mandibles ( Fig. 5 ) with external margin rounded, with 1 inner tooth; molar region broad. Labrum ( Fig. 2 ) vertically produced with respect to clypeus, with well­defined medial tooth, apex broadly rounded. Maxilla ( Fig. 4 ) with 6 poorly defined contiguous teeth in an arch, mesal side forming an inner concavity; palpus 4­segmented, terminal segment (in dorsal view) flattened, weakly or deeply sulcate, cylindrical or bean­shaped, 1.5 times longer than segments 2–3 or subequal to segments 2–3. Mentum ( Fig. 3 ) with well­defined medial tooth, apex quadrate; palpus 3­segmented. Antenna 10­segmented with 3­segmented club; club subequal to slightly longer than segments 1–7 combined (male) or subequal to segments 2–7 combined (female). Pronotum: Form widest at middle, weakly protuberant at mid­base, basolateral angle quadrate or feebly produced. Surface with variably impressed, median, longitudinal groove and variably punctate, some punctures setose; setae short to long, slender or thick, white to orange, variable in density. Marginal bead complete laterally, incomplete basally (to slightly beyond posteriolateral angle or

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to long, slender or thick, white to orange, variable in density. Mesepimeron: Apex entirely hidden by base of elytra in dorsal view. Elytron: Surface with 4–6 weakly impressed, punctate striae; intervals variably punctate, some punctures setose; setae short to long, slender or thick, white to orange, variable in density. Epipleuron rounded or flat, expanded or not from metcoxa to sternite 2, region from base to sternite 2 with or without bead; region from metacoxa to apex setose or not. Apex of elytron weakly rounded. Sutural angle square or weakly rounded. Elytral sutural length 9.0–11.0 times length of scutellum. Propygidium: Hidden or weakly exposed; posterior margin with a fringe of setae; setae short to long, slender or thick, white to orangish. Supraspiracular ridge welldefined or indicated by a line ( Fig. 9 ). Pygidium: Variably sculptured and setose, disc of male convex, disc of female weakly convex or concave; setae short to long, slender or thick, white to orangish, variably dense; margins beaded; apex rounded or quadrate. Venter: Castaneous or testaceous in color, variably clothed with setae; setae short to long, slender or thick, white to orangish, variably dense. Prosternal keel broadly triangular; apex projecting anteriorly at about 458 with respect to ventral plane; apex produced to about level of protrochanter, blunt. Mesometasternum with apex weakly produced (quadrate or rounded) or not produced. Abdominal sternites 1–4 subequal in width in male and female. Last sternite of male with subapex weakly sinuate, with fringe of setae, apex quadrate. Last sternite of female moderately or deeply emarginated at middle ( Figs. 12–13 ). Legs: Profemur with apex weakly rounded and dilated ( Fig. 8 ). Protibia ( Fig. 8 ) with 3 teeth in apical half, basal tooth weakly removed from apical teeth, base with weak protibial notch, apical spur lacking. Larger claw of male slightly thickened, subequal in length to tarsomere 5, twice as thick as smaller claw, apex split or with a weak nib at subapex or apex in frontal view. Larger claws of female not thickened (both claws subequal in width), with or without ventral tooth. Unguitractor plate (all legs) laterally flattened, exposed beyond tarsomere 5, apex with 2 long setae. Tarsomere 5 of male with ( Figs. 22–24 ) or without ( Fig. 25 ) ventromedial tooth or swelling. Pro­ and mesotarsomere 4 with 2 apical spines, spines recurved at apex ( Figs. 22–27 ). Mesotibia with sides subparallel, apical 1/5 weakly divergent, external edge with 1–2 carinae; apex with 2 inner spurs, 10–14 spinulae, spinulae short to moderately long. Metacoxa with externolateral apex membranous, square or weakly acute. Metatrochanter with apex weakly produced beyond posterior border of femur. Metatibia ( Figs. 16–19 ) with inner edge straight or weakly bowed inwardly, outer edge straight or weakly bowed outwardly, with 1–2 carinae, apical 1/5 divergent (more so in females; e.g., Fig. 17 ) or not; apex with 2 inner spurs, 14–26 spinulae, spinulae short to moderately long. Hind wing ( Fig. 10 ): Precosta with poorly developed hooks present on ScA; setae present either side of RA 314. Vein AA 112 about 1/4 length of AA 314. AP 314 with bulbous, enlarged base. Male genitalia: Parameres and ventral plates symmetrical ( Figs. 28–34 ). Female gonocoxites: Simple, symmetrical.

middle of pronotum), lacking anteriorly. Scutellum: Shape parabolic, wider than long;

base declivous at elytral base. Variably punctate, some punctures setose; setae short to Diagnosis. In the Brachysternina , Brachysternus is separated from Hylamorpha by the following characters: 1) unguitractor plate with 2 setae (multisetose in Hylamorpha ), 2) protarsomere 4 with 2 recurved spines (not recurved in Hylamorpha ), 3) propygidium with supraspiracular ridge (lacking in Hylamorpha ), 4) last sternite of the female weakly or deeply emarginated at the middle (rounded in Hylamorpha ). Brachysternu s is separated from Aulacopalpus based on the following characters: 1) last sternite of the female weakly or deeply emarginated at the middle (rounded in Aulacopalpus ), 2) male parameres with well developed ventral and lateral sclerites (poorly developed in Aulacopalpus ).

Distribution ( Figs. 35–38 ). Southwestern South America.

Natural History. Species of Brachysternus are known to occur from sea level to 2,000 m elevation within southwestern South America. Their distribution corresponds to the distribution of Nothofagus species on which they

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feed. Adults are attracted to lights at night. Larvae are not known but probably feed on decaying wood or vegetation.

Comments. Some species in the genus Brachysternus were previously placed in the brachysternine genera Aulacopalpus , Sulcipalpus Harold (5 Aulacopalpus ), and Tribostethes Curtis (5 Aulacopalpus ). The following species were originally described in the genus Brachysternus but were subsequently transferred to other genera: Brachysternus castaneus Laporte (now Aulacopalpus castaneus ) and Brachysternus lamprimoides White (now Epichrysus lamprimoides [subtribe Anoplognathina ]).

Brachysternus angustus (Philippi and Philippi, 1864) ( Figures 2–5 , 12, 17–18 , 23 , 28a–c , 35 ; see also Fig. 1 in Smith 2002)

Aulacopalpus angustus Philippi and Philippi 1864:322 . Holotype male at MNNC with label data: a) ‘‘361’’ (handwritten), b) ‘‘HOLOTIPO?’’ (orange label, typeface), c) ‘‘ Aulacopalpus ? angustus Ph. ’’ (handwritten), d) ‘‘angustus P.G. monogr. g. aulacopalpus Phili. 1494’’ (handwritten), e) ‘‘ Chile M.N.H.N. Tipo No 2909’’ (typeface), f) ‘‘ AULACOPALPUS ANGUSTUS PHILIPPI & PHILIPPI ? HOLOTYPE’’ (our red holotype label), g) Brachysternus ANGUSTUS (PHILIPPI AND PHILIPPI) ? DET:JAMESON & SMITH 2000.’’ Male genitalia card­mounted. Philippi and Philippi (1864) stated that there was only one specimen in the type series, therefore the holotype is fixed by monotypy.

Description. Length: 15.8–20.3 mm. Width: 7.2–9.7 mm at base of elytra. Color: Dorsally light to dark shiny apple green (occasionally bluish­green or tan), elytral margins metallic brassy­green, apical umbone metallic green; apex of clypeus and pronotal margin tan or green; femora, tibiae, and sternites testaceous with metallic green sheen (occasionally entirely testaceous); pygidium metallic dark green (occasionally entirely testaceous); propygidium and tergites castaneous. Head: Clypeal apex rectangular with broadly rounded corners, not constricted at base; margins and apex weakly reflexed (male) or flat (female). Frons densely punctate; punctures moderately large (0.07–0.12 mm), some setose; setae hair­like laterally and at base (sparse, short to moderately long, tawny) and scale­like posterior to eye (dense, short, white). Clypeus confluently punctate to rugopunctate, punctures moderate. Interocular width 3.5–6.0 transverse eye diameters. Terminal segment of maxillary palpus (dorsally) with moderately impressed groove from base to near apical third, segment subequal in length to segments 2–3. Antennal club subequal in length to segments 1–7 (male) or segments 2–7 (female). Pronotum: Surface with weakly impressed, median, longitudinal groove; disc confluently punctate, margins confluently punctate or rugopunctate; punctures moderate in size, some setose; setae hairlike, short to moderately long, tawny, moderately or sparsely dense. Basal bead complete to just beyond posteriolateral angle. Elytron: Surface with 5 weakly impressed, poorly defined, punctate, longitudinal striae between suture and humerus; punctures moderate and small, sparse (disc), moderately dense (base), or dense (margin at apex), some setose; setae hair­like (short to moderately long, sparse, tawny) or thickened (moderately long, sparse, white). Intervals with similar sculpturing. Humeral and apical umbone well­developed. Epipleuron flat, not expanded, marginal bead present; region from metacoxa to apex setose; setae thickened, short and moderately long, dense, white. Sutural angle square. Propygidium: Posterior margin with fringe of setae; setae thickened, short, white. Supraspiracular ridge well­defined. Pygidium: Male: disc and middle apex with hair­like setae (moderately long and long, moderately dense, tawny) and punctures (small, sparse); margins with scale­like setae (dense, white). Female: disc weakly bituberculate, punctate at margins and at middle apex; punctures moderate in size, setose; setae on disc hairlike, tawny, moderately long and long, sparse (at margins) or moderately dense (at middle apex), margins with scale­like setae (dense, white). Venter: Setose; male clothed with dense, white, scale­like setae; female with sparse (disc) and dense (lateral margins),

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white, scale­like setae. Prosternal keel broadly triangular; apex projecting anteriorly at about 458 with respect to ventral plane; apex produced to about level of protrochanter,

blunt. Mesometasternum with apex rounded, not produced. Apex of terminal sternite in female deeply emarginated at middle ( Fig. 12 ). Legs: Larger pro­ and mesotarsal claw of male weakly bifurcate at apex. Pro­ and mesotarsomere 5 of male with well developed ventromedial tooth, apex rounded or quadrate (not acute) ( Fig. 23 ). Metatibia ( Figs. 17– 18 ) with inner and outer edges straight, with 2 weak carinae; 1 at middle (poorly developed), 1 in apical third (moderately developed), carinae more developed in females; apical 1/5 weakly divergent (more so in females). Male genitalia: Figs. 28a–c .

Diagnosis. Brachysternus angustus is separated from other species of Brachysternus by the well­developed humeral and apical umbones on the elytron, the form of the male genitalia (ventral and lateral sclerites and form of the parameres in lateral view), and the form of the pygidium in the female (surface of disc weakly bituberculate). The species is most similar to B. spectabilis , but differs by the green coloration on the meso­ and metafemora (castaneous or castaneous with weak green reflections in B. spectabilis ); the dense, scale­like setae on the sternites (moderately dense, thickened setae in B. spectabilis ); and the scale­like setae posterior to the eye (setae thickened in B. spectabilis ).

Brachysternus angustus bears an overall similarity to Hylamorpha elegans (Burmeister) based on the well­developed humeral and apical umbones, distribution of scale­like setae on the venter and pygidium, and overall coloration. These taxa differ by several features including: larger claw split (simple in Hylamorpha ), female with apex of the last sternite emarginate ( Fig. 12 ) (simple in Hylamorpha ), form of the male genitalia ( Fig. 28 ), and bisetose unguitractor plate (trisetose in Hylamorpha ) (see Ratcliffe and Ocampo 2002 for a detailed description of Hylamorpha ).

Distribution ( Fig. 35 ). Recorded from 100–1,800 m elevation from O’Higgins to Llanquihue, Chile and east to Neuquén, Argentina.

Locality Data. 85 specimens examined from AMNH, BCRC, CASC, CMNC, CMNH, FMNH, GASC, LACM, MGFT, MNNC, PVGH, SEMC, USNM, VMDM .

ARGENTINA (6). NEUQUÉN (6): Lago Lácar, Parque Nacional Lanín, Tromen.

CHILE (78). BÍO­BÍO (1): Cerro Pemehue . CAUTÍN (7): Volcán Villarrica. CURICÓ (1): Las Trancas. LLANQUIHUE (5): Hornohuinco ( 11 km SW Lago Chapo ), Los Muermos (12 km S) . MALLECO (38): Lonquimay, Malalcahuello, Manzanar, Manzanar (9.2 km E), Parque Nacional Nahuelbuta, Río Chanchuco , Villa Portales (15 km W) . ÑUBLE (10): Las Trancas (72 km SE Chillán), Los Lleuques, Nevados de Chillán, Shangrila (SW side Volcán Chillán ) . O’HIGGINS (1): Las Cabras. OSORNO (2): Parque Nacional Puyehue. VAL­ DIVIA (13): Lago Pirehueico, Las Lajas (W La Unión), Pirihueico, Valdivia .

NO DATA (1).

Temporal Data. January (9), February (10), March (1), November (17), December (41).

Natural History. Brachysternus angustus has been collected in Nothofagus forests (including Nothofagus swamp and a mixed forest with Nothofagus pumilio Krasser , Araucaria araucana [C. Koch], and Chusquea species ). Specimens were collected at ultraviolet lights at night, at flight intercept traps, and under logs.

Remarks. Philippi and Philippi (1864) described B. angustus based on one male specimen. They were dubious about the generic placement of the taxon

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and referred to the species as ‘‘ Aulacopalpus ? angustus .’’ Based on the characters that seemed to be indicative of the prevailing generic concepts of

Brachysternus and Aulacopalpus (claws, mesosternum, femora), Philippi and Philippi placed the taxon in the genus Aulacopalpus . However, they queried the reader, ‘‘... wouldn’t it be most sensible to combine Brachysternus and Aulacopalpus again?’’ This comment reflected the confused state of the brachysternine generic concepts at that time.

Brachysternus germaini (Ohaus, 1909) NEW COMBINATION ( Figs. 6 , 25, 27 , 29a–c , 35 ; see also Fig. 1 in Smith 2002)

Tribostethes germaini Ohaus 1909:9 , 14. Neotype male at the MNNC, labeled a) ‘‘ CHILE TALCA La Vega (E Carrizal) 3­Noviembre­1991 leg. M. Elgueta’’, b) ‘‘ TRIBOSTETHES GERMAINI OHAUS ? NEOTYPE A. B. T. SMITH 2000’’ (red type label), c) ‘‘ Brachysternus GERMAINI (OHAUS) ? DET: Jameson & Smith 2000’’ (white determination label). Neotype here designated. It is necessary to designate a neotype for B. germaini because the original holotype has been lost. Ohaus (1909) remarked that the ‘‘type is in the collection of the museum in Santiago.’’ We have searched numerous collections for the holotype (see ‘‘Specimens and Taxonomic Material’’). According to Mario Elgueta of the Museo Nacional de Historia Natural, Santiago, Chile (which houses Germain’s collection and types) and Hella Wendt of the Museum für Naturkunde der Humboldt­Universität zu Berlin, Germany (which houses Ohaus’s types) the type of B. germaini is not in either collection. The original holotype was a male labeled ‘‘Chile, Curico, IX. 97, Ph. Germain S.’’ We selected a male neotype from the neighboring province of Talca. The neotype was collected less than 100 km away from the original holotype and closely matches the original description by Ohaus (1909). Mario Elgueta, who collected the neotype, stated that the coordinates for La Vega in Talca, Chile are 358179S and 728099W.

Description. Length: 19.5–20.3 mm. Width: 8.3–10.3 mm at base of elytra. Color: Dorsally shiny apple green to olive green; eltyral margins metallic brassy green or green; apex of clypeus castaneous (females) or green (males); pronotal margin testaceous suffused with green or green; legs, sternites, pygidium, and propygidium coppery­brown to castaenous. Head: Clypeal apex rectangular with broadly rounded corners, not constrict­ ed at base; margins and apex weakly to moderately reflexed. Frons moderately densely punctate (occasionally confluent at apex); punctures moderate to moderately large; setae short to moderately long, hair­like, tawny to reddish; region posterior to eye with or without sparse, thickened, short, white setae. Clypeus densely punctate (disc) and confluently punctate (base and apex); punctures moderate to moderately large. Interocular width 4.6–5.4 (male) or 4.8–7.2 (female) transverse eye diameters. Maxilla with terminal segment of maxillary palpus (dorsally) deeply impressed from base to apex ( Fig. 6 ), segment 1.4 (male) or 1.3 (female) times longer than segments 2 and 3. Antennal club subequal in length to segments 1–7 (male) or segments 2–7 (female). Pronotum: Surface with weakly impressed, median, longitudinal groove; disc moderately densely to densely punctate (occasionally confluent), margins sparsely to moderately densely punctate; punctures moderate to large, few setose at posteriolateral angle and anteriolateral angle; setae hair­like and thickened, moderately long, tawny. Basal bead complete to just beyond posteriolateral angle. Elytron: Surface with 1–5 poorly defined, punctate, longitudinal striae between suture and humerus; punctures moderate and small (mixed), sparse (disc), lacking setae. Intervals with similar sculpturing. Humeral umbone poorly developed, apical umbone poorly developed. Epipleuron flat, not expanded, marginal bead present; region from metacoxa to apex setose; setae thickened, short and moderately long

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(

of Male: disc and middle apex with hair­like setae (moderately long and long [mixed], moderately dense, white) and punctures (small, moderately dense); margins and base with moderately dense, white, thickened setae. Female: disc lacking concavity, punctate; punctures crescent­shaped (moderately dense) and transversely wrinkled, setose; setae on hair­like and thickened, white, moderately long and long (mixed). Venter: Sternum densely (male) or moderately densely (female) clothed with long, tawny, setae; sternites with setae moderately dense, hair­like, white setae (less dense in female). Prosternal keel broadly triangular; apex projecting anteriorly at about 458 with respect to ventral plane; apex produced to about middle of protrochanter, blunt. Mesometasternum with apex rounded or weakly quadrate, not produced. Apex of terminal sternite in female moderately emarginated at middle (e.g., Fig. 13 ). Legs: Larger protarsal claw of male with or without weak nib at apex ( Fig. 25 ). Claws of female simple, subequal in width ( Fig. 27 ). Tarsomere 5 without ventromedial tooth ( Figs. 25, 27 ). Metatibia with inner and outer edges straight, with carinae: 1 at middle, 1 in apical third, carinae more developed in females; apical 1/5 weakly divergent (more so in females). Male genitalia: Fig. 29a–c .

Figures

Fig. 1. Dorsal habitus of Brachysternus prasinus Guérin­Méneville, female.

Figs. 2–10. Generic characteristics of Brachysternus. Mouthparts of B. angustus: 2) Frontal view of the labrum; 3) ventral view of the mentum; 4) ventral view of left maxilla and mesal view of maxillary teeth; 5) dorsal view of left mandible; 6) dorsal view of maxillary palpus of B. germaini (male) and 7) B. spectabilis (male); 8) prothoracic leg of B. prasinus (male) showing femur with apex weakly rounded and dilated, base of tibia with weak protibial notch, and form; 9) lateral view of the apex of the abdomen in B. prasinus (male) showing supraspiracular ridge and elytral membrane; 10) hind wing of B. patagoniensis showing distribution of wing pegs, setae, and venation.

Figs. 11–21. Characteristics of Brachysternus species. Setal types in Brachysternus species: 11a) scale­like setae (pygidium of B. prasinus); 11b) thickened setae (pygidium of B. olivaceus); 11c) hair­like setae (pygidium of B. patagoniensis). Apex of the terminal sternite in the female (ventral view): 12) deeply emarginate (B. angustus); 13) moderately emarginate (B. olivaceus). Elytral epipleuron (ventral view) showing: 14) margin expanded from metacoxa to second sternite (B. marginatus); 15) margin not expanded (B. prasinus). Metatibia (ventral view) of: 16) B. spectabilis (male); 17) B. angustus (female); 18) B. angustus (male); 19) B. patagoniensis (male). Head (dorsal view) showing: 20) clypeus not constricted at the base and scale­like setae posterior to the eye (B. prasinus); 21) clypeus weakly constricted at the base and hair­like setae posterior to the eye (B. patagoniensis).

Figs. 22–27. Form of the fourth and fifth protarsomeres (dorsomedial view) with inset of the apex of male larger claw (frontal view): 22) B. olivaceus (male); 23) B. angustus (male); 24) B. patagoniensis (male); 25) B. germaini (male); 26) B. spectabilis (female); 27) B. germaini (female).

Figs. 28–34. Form of the male genitalia in Brachysternus species (lateral view of parameres and apex of phallobase, caudal view of parameres, and ventral view of ventral and lateral sclerites). 28a–c) Brachysternus angustus; 29a–c) B. germaini; 30a–c) B. marginatus; 31a–d) B. olivaceus; 32a–d) B. patagoniensis; 33a–g) B. prasinus; 34a–c) B. spectabilis.

Fig. 35. Map showing the distribution of B. angustus and B. germaini in southern South America.

Fig. 36. Map showing the distribution of B. marginatus, B. olivaceus, and B. patagoniensis in southern South America.

Fig. 37. Map showing the distribution of B. prasinus in southern South America.

Fig. 38. Map showing the distribution of B. spectabilis in southern South America.