Chiasognathus jousselinii Reiche, 1850

Paulsen, M. J. & Smith, Andrew, 2010, Revision of the genus Chiasognathus Stephens of southern South America with the description of a new species (Coleoptera, Lucanidae, Lucaninae, Chiasognathini), ZooKeys 43 (43), pp. 33-63 : 50-53

Chiasognathus jousselinii Reiche, 1850

Figs 5, 18, 20, 22, 27

Chiasognathus jousselinii Reiche, 1850: 259 , original combination. Type material: holotype male (MNHN) labeled: a) bordered label “Ex-Musaeo / Mniszech”; b) handwritten “ Jousselini / Reiche”; c) handwritten “ Chiazognathus / Jousselini”; d) “MUSÉUM PARIS / [2810]”; e) red paper, “TYPE”; f) handwritten “ Chiasognathus . / jousselini. Reich. / Det: JP. LACROIX.”; g) handwritten “Figure I. 1969 / JP. LACROIX.”; h) bordered label “Southern Neotropical Scarabs / database # AS 2618225 / Chiasognathus jousselinii / Reiche, 1850 [male symbol] / DET: A.B.T. SMITH 2009”; i) red label “ Chiasognathus / jousselinii [male symbol] / Reiche, 1850 / HOLOTYPE / Det. M.J. Paulsen”. The holotype was fixed by monotypy when Reiche (1850a, b) explicitly indicated that only one specimen was used to describe this species. Type locality: “versant oriental des Andes du Chili ” ( Reiche 1850b).

Description. Length: 22.0– 33.9 mm. Width: 10.0– 13.1 mm. Color: Reddish brown, with weak metallic reflections, appearing lighter from dense covering of lightbrown, scale-like setae. Head: Form subquadrate. Surface punctate; punctures fine to coarse, generally setose with short to long setae, especially laterally. Anterior margin of head roundly produced beyond anterior angles and with median nasus; nasus composed of 2 rounded teeth. Anterior angles obtusely rounded in dorsal view. Male mandible (Fig. 20) setose, cylindrical, robust, 2–3× as long as head, weakly rounded externally until abruptly, internally curved at apex; apex curved weakly upward, lacking patch of setae. Dentate carina with 4–10 obtuse teeth; teeth variably reduced, almost obsolete. Base of mandibles without ventral tooth. Galeal brush long, longer than first and second labial palpomeres combined. Antennal scape in males with sparse area of long setae at apex. Pronotum: Posterior and lateral angles subdentate (angulate in small males). Lateral margins distinct, crenulate. Disc with central area raised and with strong transverse ridge either side of broad median longitudinal depression; depressed areas variably setose, setae moderately long in males (shorter than length of distal antennomere of antennal club), lacking scattered longer setae. Elytra: Surface rough, slightly wrinkled, generally obscured by dense cover of short scale-like setae. Apex rounded to subdentate, lacking spine; elytral margin thickened, without bead. Epipleuron flat. Legs: Protibiae elongate, dentate basally with 4–6 small teeth (Fig. 18); ventral surface along internal margin with teeth well developed. Male genitalia: Flagellum moderately long, longer than length of parameres and basal piece together (Fig. 5). Females unknown.

Distribution. Only known from the west side of the Nahuelbuta Cordillera (Fig. 27).

CHILE (9): Biobío (5): Cañete, “Concepción”. No data (4).

Temporal distribution. December (4). No data (5).

Diagnosis. This species can be readily distinguished from the other squamose species, C. mniszechii , by the shorter, more robust and less strongly dentate mandibles in males (Fig. 20), dentate rather than serrate protibiae (Fig. 18), flat epipleuron, pronotum lacking long scattered setae, and thickened elytral apices that lack a marginal bead apically. The flagellum of the male genitalia is nearly twice as long in C. jousselinii as it is in C. mniszechii (Figs 5–6). With only nine male specimens located in collections, the female of this species remains unknown.

Remarks. The fact that the holotype of C. jousselinii is clearly not conspecific with the more common C. mniszechii was recognized by Lacroix (1979), but this species has otherwise been confused with C. mniszechii ( Krajcik 2001; Molino-Olmedo 2001, 2002; Chalumeau and Brochier 2007). The two species are easily separated when the appropriate characters are examined. Very few specimens of C. jousselinii are known, which has not helped to alleviate the confusion. We were able to study specimens graciously loaned by Alfredo Ugarte Peña that were collected in Cañete, and they

Figures Ι8–24. Ι8–Ι9 Right protibia of males. Ι8 C. jousselinii , and Ι9 C. mniszechii . Scale bar = 2mm. 20–2Ι Right mandibles of males. 20 C. jousselinii , and 2Ι C. mniszechii . Scale bar = 5mm. 22–24 Dorsal habitus of Chiasognathus species. 22 C. jousselinii , male, 23 C. mniszechii , male, and 24 C. mniszechii , female.

remain the only specimens known with reliable locality information. It is likely that this species is restricted to the western side of the Nahuelbuta Cordillera, where other rarely encountered and potentially threatened stag beetles are also found: Pycnosiphorus franzae (Weinreich) and Hilophyllus penai (Martínez) . Very little of this habitat is currently protected, and it is instead being logged at an alarming rate ( Smith-Ramirez 2004). Thus, the future of these three species is in doubt, and their need for conservation should be studied in detail.