Arctodium discolor ( Erichson, 1835 )

Hawkins, Shauna Joy, 2006, A revision of the Chilean tribe Lichniini Burmeister, 1844 (Coleoptera: Scarabaeidae: Melolonthinae), Zootaxa 1266 (1), pp. 1-63 : 34-37

Arctodium discolor ( Erichson, 1835)

( Figs. 5a , 9c , 11 )

Arctodium discolor ( Erichson 1835:269) (valid name).

Cratoscelis discolor Erichson 1835:269 (original combination).

Catalog

Arctodium discolor: Chapin 1938: 81 (transferred to Arctodium from Cratoscelis ); Hawkins 2004 (online catalog).

Cratoscelis discolor: Erichson 1835: 269 (original description); Laporte 1840: 155 (catalog); Burmeister 1844: 10 (catalog); Blanchard 1850: 52 (catalog); Solier 1851: 121 (redescription and diagnoses); Lacordaire 1856: 162 (checklist); Harold 1869: 1094 (catalog); Philippi 1887: 685 (catalog); Germain 1911: 68 (catalog); Arrow 1912: 6 (catalog); Blackwelder 1944: 216 (checklist); Hawkins 2004 (online catalog).

Type specimens

Cratoscelis discolor Erichson , neotype male at FMNH labeled: a) “Prov. ARAUCO / Palo Botado/ 1­Febr. 1953/ Co. ll. L.E. Pena ” (typeset), b) “ FMNH, 1986/ L. Peña Coll. / Acc. # 17­422” (typeset), c) “Southern Neotropical Scarabs/ database #SH75980854/ Arctodium discolor Erichson ♂ / DET: S.J. Hawkins 2005” (typeset, ♂ hand­drawn), d) “ Arctodium discolor / Erichson/ NEOTYPE ♂ / S.J. Hawkins ” (red label, typeset). Neotype here designated. The original type was deposited at ZMHB, but Dr. Johannes Frisch and Joachim Willers where unable to find it. Likewise, Dr. Andrew Smith, who searched specifically for Lichniini types, was unable to find Erichson’s C. discolor type at the ZMHB. Because I was unable to locate any specimens from the original type series in any other collection I visited or from which I borrowed specimens, I consider the type specimens to be lost. The total number of specimens in the original type series is unknown. Because no specimens from the original type series were located, and because the exact original type locality is unknown ( Erichson gave only “ Chile ” as the type locality), I chose a neotype that was in good condition and matched the original species description closely. Type locality: Palo Botado, Region IX (La Araucania), Chile.

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 ( Fig. 4b ). 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 ( Fig. 8c ). 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 ( Fig. 8d ).

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 square­like 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.

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.

Distribution Central Chile in Region VIII (Biobío) and Region IX (La Araucania) ( Fig. 11 ).

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) .

Temporal data January (29), February (112), December (21).

Figures

FIGURES 4a–c. Dorsal view of antenna showing length of club. a) Lichnia limbata male; b) L. limbata female; c) Arctodium mahdii male.

FIGURES 5a–b. Dorsal view of maxilla showing length of galea. a) Arctodium discolor; b) Lichnia limbata.

FIGURES 8a–d. Metatibial apex showing apical spine (arrow) and adjacent spur. a) Arctodium planum male; b) A. mahdii male; c) A. vulpinum male; d) A. vulpinum female.

FIGURES 9a–c. Caudal (i) and lateral (ii) views of parameres. a) Lichnia gallardoi; b) L. limbata; c) Arctodium discolor.

FIGURE 11. Map of central Chile showing distribution of Arctodium discolor and A. planum.