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Scarabaeoidea of Southern South America Links
 

 
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Scarab Guide Links
(goes to the University of Nebraska web site)
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Classification
Superfamily...
Family...........
Subfamily......
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Scarabaeoidea
Scarabaeidae
Rutelinae
Anoplognathini
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Brachysternus germaini
(Ohaus, 1909)
Tribostethes germaini Ohaus 1909:9, 14.
 
 
Figure 29a-c. Form of the male genitalia in Brachysternus germaini (lateral view of parameres and apex of phallobase, caudal view of parameres, and ventral view of ventral and lateral sclerites).
 
Map showing the distribution of B. germaini.
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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 coppery-brown to castaenous. Head: Clypeal apex rectangular with broadly rounded corners, not constricted 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, hair-like, 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, 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 hair-like 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 (mixed), dense, whitish. Sutural angle square. Propygidium: Posterior margin with fringe of setae; setae thickened, short, white. Supraspiracular ridge poorly defined. Pygidium: Male: disc and middle apex with hair-like 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 crescent-shaped (moderately dense) and transversely wrinkled, setose; setae on hair-like 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, hair-like, 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. Legs: Larger protarsal claw of male with or without weak nib at apex. Claws of female simple, subequal in width. Tarsomere 5 without ventromedial tooth. 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.
   

 

Diagnosis. This species is separated from all other species in the genus Brachysternus by the following combination of characters that are unique for the genus: all tarsal claws appearing simple in male and female (male with weak, apical nib in some specimens); protarsomere 5 without ventromedial tooth; pygidium of the female simple (lacking discal concavity); terminal segment of the maxillary palp with deeply impressed sulcus from base to apex; and 1.3-1.4 times as long as segments 2 and 3 combined (male and female).
   

 

Distribution (see map). Andes from Curicó to Concepción, Chile.
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  Locality Data. 9 specimens examined from BMNH, CMNC, CNCI, FMNH, MNNC.

CHILE (9). CONCEPCION (3): Concepción, Penco. CURICO (2): El Coigo, no data. LINARES (1): Estero Leiva, Cord Parral. NUBLE (1): Cachapoal. TALCA (2): Canelillos (E. Carrizal), La Vega (E. Carrizal).
   
  Temporal Data. February (1), October (1), November (4), December (3).
   
  Remarks. Brachysternus germaini has an unusual combination of primitive and derived character states compared to other species of Brachysternus. Some character state reversals include: all tarsal claws appearing simple in both sexes (shared with Hylamorpha), sulcate terminal maxillary palp that is longer than the two preceding segments (shared with some species of Aulacopalpus), pygidium in the female that lacks a discal concavity (shared with some species of Aulacopalpus), supraspiracular ridge not welldeveloped (shared with species of Aulacopalpus), and fifth protarsomere that lacks a ventromedial tooth (shared with species of Aulacopalpus). In addition, B. germaini shares many derived character states with other species of Brachysternus including: form of the maxillary teeth, male parameres with well developed lateral and ventral sclerites (Fig. 29a-c), and apex of the terminal sternite moderately emarginate in the female. Transfer of this species from Aulacopalpus to Brachysternus is justified based on these derived character states. Smith's (2002) phylogenetic analysis of the subtribe Brachysternina also corroborates transfer of this species to Brachysternus. Although Brachysternus germaini has been collected in several Chilean provinces, it is rare in collections.
   
  Literature cited:
Smith, A. B. T. 2002. Revision of the southern South American endemic genus Aulacopalpus Guérin-Méneville with phylogenetic and biogeographic analyses of the subtribe Brachysternina (Coleoptera: Scarabaeidae: Rutelinae: Anoplognathini). Coleopterists Bulletin 56:379-437.
   
  Excerpt from:
Jameson, M. L. and A. B. T. Smith. 2002. Revision of the South American genus Brachysternus Guérin-Ménville (Coleoptera: Ruteliinae: Anoplognathini: Brachysternina). Coleopterists Bulletin 56: 321-366.
 

Authors: Mary Liz Jameson (University of Nebraska State Museum) and
Andrew Smith ( Canadian Museum of Nature)
This website is based upon work supported by the National Science Foundation under Grant No.0342189.
Generated on: 09/OCT/07.....Last modified: 09/OCT/07

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