Arctodium planum ( Blanchard, 1850 ), 2006

Hawkins, Shauna Joy, 2006, A revision of the Chilean tribe Lichniini Burmeister, 1844 (Coleoptera: Scarabaeidae: Melolonthinae), Zootaxa 1266 (1), pp. 1-63 : 46-51

Arctodium planum ( Blanchard, 1850)

( Figs. 8a , 11 )

Arctodium planum ( Blanchard 1850: 52) . New combination.

Cratoscelis plana Blanchard 1850: 52 (original combination).

Cratoscelis canicapilla Philippi & Philippi 1864: 326 . New synonymy.

Catalog

Cratoscelis plana: Blanchard 1850: 52 (original description); Solier 1851: 120 (redescription and diagnoses); Lacordaire 1856: 162 (checklist); Philippi & Philippi 864: 326 (comparison with Cratoscelis canicapilla ); Philippi 1887: 685 (catalog); Redtenbacher 1868: 61 (catalog); Harold 1869: 1094 (catalog); Germain 1911: 68 (catalog); Arrow 1912: 6 (catalog); Blackwelder 1944: 216 (checklist); Hawkins 2004 (online catalog).

Cratoscelis canicapilla: Philippi & Philippi 1864: 326 (original description); Philippi 1887: 685 (catalog); Harold 1869: 1094 (catalog); Arrow 1912: 6 (catalog); Blackwelder 1944: 216 (checklist); Hawkins 2004 (online catalog).

Type specimens

Cratoscelis plana Blanchard , lectotype male at MNHM labeled: a) “ M. Gay / 18?9./ Chili” (round green label, handwritten on underside, third digit of date on line two of label is obscured by pinhole), b) “ C. plana ./ Cat. mus./ Chili / M. Gay. ” (large green label, handwritten), c) “ Southern Neotropical Scarabs / database #SH75981044/ Arctodium planum Blanchard ♂ / DET: S.J. Hawkins 2005” (typeset, ♂ hand­drawn), d) “ Arctodium planum / Blanchard/ LECTOTYPE ♂ / S.J. Hawkins ” (red label, typeset). Lectotype here designated. Blanchard (1850) stated that he based his concept of C. plana only on males, but he did not indicate how many specimens were in the type series. The location and existence of other paralectotypes is unknown. Type locality: Chile.

Cratoscelis canicapilla Philippi & Philippi , neotype male at USNM labeled: a) CHILE: Valpo./ P.N. Penuelas/ 28 Oct. 1969./ O.S. Flint Jr., b) “Southern Neotropical Scarabs/ database #SH75980999/ Arctodium planum Blanchard ♂ / DET: S.J. Hawkins 2005” (typeset, ♂ hand­drawn), c) Cratoscelis canicapilla / Philippi and Philippi/ NEOTYPE ♂ / S.J. Hawkins” (red label, typeset). Neotype here designated. The original type was deposited in the MNNC. The curator, Mario Elgueta, and I searched together in the collections at the MNNC but did not find any specimens from the original type series of C. canicapilla . Unfortunately, many Philippi (1887) and Philippi & Philippi (1864) types in Santiago were lost or are unidentified because they were not properly labeled. No Philippi & Philippi types of Lichniini were found in any other collections I visited or from which I obtained loans. A neotype was chosen that was in condition that closely matched Philippi & Philippi’s description, and which was from the coast of Valparaíso, a typical locality for the species. See remarks for an explanation of synonymy with A. planum . Type locality: Parque Nacional Peñuelas, Region V (Valparaíso), Chile.

Description

Male. Length 6.5–9.3 mm; width 3.9–6.2 mm. Color: Head, pronotum, scutellum , and pygidium black; venter and legs brown; elytra brown. Head: Surface obscured by setae; setae long, dense, pale yellow. Labrum with surface obscured by setae; setae short to moderately long, half as long as clypeal setae, dense, pale yellow. Mandibular external surface with short to moderately long, dense, pale yellow setae. Maxillary palpi with short, pale yellow, apical setae on all segments except last. Labial margins with moderately long, dense, pale yellow setae. Labial palpi with short, pale yellow setae at apex of all segments except last. Eye canthus setose; setae long, dense, pale yellow. Antenna with pedicel setose, elongate, segment 2 globular, 3–6 subequal in length, 7–9 lamellate; club subequal in length to segments 2–6 or to 3–6 ( Fig. 4b ). Pronotum: Surface setosely punctate, obscured by setae; setae, long, moderately dense to dense, pale yellow. Anterior margin setose; setae short, dense, pale yellow to golden yellow. Lateral margins setose; setae long, dense, white to pale yellow. Posterior margin setose; setae moderately long to long, dense, pale yellow. Scutellum: Surface setose; setae long, moderately dense, pale yellow. Elytron: Form moderately wide, less than half as wide as long. Surface strongly depressed, obscured by setae; setae long, dense laterally, moderately dense medially, pale yellow. 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 obscured by setae; setae long, dense, pale yellow. Venter: Thorax, mes­ and metepisternum setose; setae dense, long, pale yellow. Abdominal segments densely setose; setae long, pale yellow. Legs: Surface setose; setae long, dense, pale yellow. 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, narrow, attenuate at apex ( Fig. 8a ). Parameres: Fig. 9c .

Female. Females of A. planum are unknown.

Diagnosis

Arctodium planum is characterized by its long, dense, pale yellow setae covering all parts of the body. While some specimens of A. vulpinum may also have pale colored setae on some parts of the body, the setae are not usually as long, dense, or pale yellow. Setae of A. vulpinum are typically more golden brown. Other species of Arctodium do not have pale setae. Arctodium planum is the only species that has pale colored setae on the apices of the segments of the maxillary and labial palps and a fringe of pale yellow setae along the eye canthus. All other species of Lichniini have dark colored (brown, gray, or black) setae on the mouthparts and eye canthus. Arctodium planum males are also characterized by the metatibial apex, which is modified into a spine that is slender and attenuate and is longer than the adjacent spurs ( Fig. 8a ). Males of A. vulpinum and A. discolor also have a long spine that is longer than the adjacent spurs, but the shape is different. The metatibial spine of males of A. vulpinum and A. discolor is much broader and oblique towards the apex ( Figs. 8c ). Males of A. mahdii have a metatibial spine that is shorter than the adjacent spur ( Fig. 8b ).

Remarks

While the original Philippi & Philippi type series of Cratoscelis canicapilla is lost (see Type Specimens section), there is evidence in the original description to indicate that C. canicapilla is a junior synonym of Arctodium planum . First, Philippi & Philippi characterize C. canicapilla by the pale setae covering the body and particularly by the “white lash­like hairs on the side of the head, while that of other species is black.” These pale setae are also what Blanchard (1850) used to characterize C. plana . Also, according to Philippi & Philippi’s description, C. canicapilla , like A. planum , is of a distinctly small size, being four German lines long (approximately 8.8 mm including the head). Furthermore, the type locality for C. canicapilla is Valparaíso, which is where most specimens of A. planum are found. All other characters used by Philippi & Philippi to describe C. canicapilla match characters of A. planum , and no characters were provided that differ from A. planum . I conclude that C. canicapilla is conspecific with A. planum . See the Taxonomic History section for an explanation of authorship of C. canicapilla .

Distribution

Central Chile in Region V (Valparaíso), Region VI (O’Higgins), and Region Metropolitana de Santiago ( Fig. 11 ) .

Locality data

99 specimens were examined from BMNH, FMNH, HAHC, JMEC, LEMQ, MNHN, MNNC, UCCC, USNM .

CHILE. REGION METROPOLITANA DE SANTIAGO (13): Leyda (1), Macul (1), Peumo (2), Pilay (8), Santiago (1). REGION V (VALPARAỈ SO) (66): Algarrobo (2), El Quisco (3), LloLleo (17), Malvilla (1), Peuelas (38), Quebrada Verde (1), Rodelillo (1), San Antonio (3). REGION VI (O’HIGGINS) (2): Matanza (1), Rinconada de Idahue (1). NO DATA (18).

Temporal data January (14), September (1), October (37), November (21), December (6).

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 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.