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Scarabaeoidea of Southern South America Links |
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Scarab Guide Links
(goes to the University of Nebraska
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Classification |
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Arctodium discolor (Erichson, 1835)
Arctodium discolor (Erichson 1835:269) (valid name).
Cratoscelis discolor Erichson 1835:269 (original combination). |
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Figure 9c. Caudal (i) and lateral (ii) views of parameres
of Arctodium discolor. |
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Map of central Chile showing distribution of Arctodium discolor
and A. planum. |
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Description. Male. Length 7.0-9.5 mm; width 4.5-6.4 mm. Color: Head, pronotum, scutellum and
pygidium black; venter and legs black (dark red to reddish black under microscope); elytra
reddish brown. Head: Surface punctate; punctures small, dense, setose; setae long,
moderately dense to dense, orange to black. Labrum with surface punctate; punctures
small, dense, setose; setae short to moderately long, half as long as clypeal setae, dense,
black. Mandibular external surface with short to moderately long, dense, black setae.
Maxillary palpi with short, black, apical setae on all segments except last. Labial margins
with moderately long, dense, black setae. Labial palpi with short, black, setae at apex of all
segments except last. Eye canthus setose; setae long, dense, black. Antenna with pedicel
setose, elongate, segment 2 globular, 3-6 subequal in length, 7-9 lamellate; club shorter
than to subequal in length to segments 3-6. Pronotum: Surface punctate;
punctures small, moderately dense, with long, dense, bright orange setae. Anterior margin
setose; setae short, dense, golden yellow to orange. Lateral margins setose; setae long,
dense, white. Posterior margin setose; setae short to moderately long, dense, orange.
Scutellum: Surface setose; setae moderately long, moderately dense, orange. Elytron:
Form wide, half as wide as long. Surface depressed posteriorly, setosely punctate; punctures small, moderately dense medially, dense laterally, with short, black setae around
margins, long orange setae elsewhere. Propygidium: Surface exposed, covered with long,
dense, white setae; setae overlaying basal 1/5 of pygidium (covered by elytra in some
specimens), apices of setae forming straight row. Pygidium: Surface slightly concave
apically, setose; setae long, dense, black. Venter: Thorax, mes- and metepisternum
punctate; punctures small, dense, with black setae. Abdominal segments densely setose on
lateral margin, sparsely setose medially; setae long, black. Legs: Surface setose; setae
long, dense, black. Protibia slender, with 3 outer teeth and 2 inner teeth. Protibial spur
small, 3/4 length of first tarsal segment. Metafemur broadly expanded. Metatibial apex
with 2 spurs, 1 spine; spine between 2 spurs, longer than spurs, oblique at apex.
Parameres: Fig. 9c.
Female. Females differ from males in the following respects: length 7.9-9.0 mm;
width 4.4-5.5 mm. Elytron: Form moderately wide, less than half as wide as long. Surface
convex, not depressed posteriorly. Legs: Metafemur slightly expanded. Metatibial apex
with 1 spine; spine short, shorter than adjacent spurs, broadly attenuate at apex. |
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Diagnosis. Arctodium discolor is most similar to A. vulpinum. Arctodium discolor has brown
elytra, black legs (dark red to reddish black under microscope) with black setae, and bright
orange setae on the elytra and pronotum. Arctodium vulpinum has variable color of the
elytra, legs, and setae but is not as in A. discolor. Arctodium discolor is also characterized
by a square-like body form due to the elytra which are as wide as long when measured at the widest and longest points. Arctodium vulpinum is more elongate because its elytra are
longer than wide. |
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Distribution. Central Chile in Region VIII (Biobío) and Region IX (La Araucania) (see map). |
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Locality data.
164 specimens were examined from CASC, CMNC, CNCI, FMNH, HAHC, JMEC,
MNHN, MNNC, UCCC, UMRM, USNM, VMDC, ZMHB.
CHILE. REGION VIII (BIOBO) (93): Caete (4), Contulmo (76), Lanalhue (1),
Nahuelbuta (2), Rio Cayucupil (10). REGION IX (LA ARAUCANIA) (61): Palo Botado
(60), Puren (1). NO DATA (10). |
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Temporal data
January (29), February (112), December (21). |
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Remarks.
For reasons unknown to me, very few females have been collected relative to males.
Of the 163 specimens of A. discolor examined, only 6 were females. |
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Excerpt from:
Hawkins, S. J. 2006. A revision of the Chilean tribe Lichniini Burmeister, 1844
(Coleoptera: Scarabaeidae: Melolonthinae). Zootoaxa 1266:1-63. |
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