Malalcahuello ocaresi gen. & sp. n. (Elateridae, Campyloxeninae)

Abstract Malalcahuello ocaresi gen. n. & sp. n., from Chile, is described and compared with Campyloxenus pyrothorax Fairmaire & Germain, 1860.


Introduction
Fairmaire and Germain (1860) described Campyloxenus pyrothorax. Costa (1975) transferred the species to his newly erected monotypic subfamily Campyloxeninae based on the following character states: claws lacking setae near base, hind wings with a wedge cell, female genitalia with a stylus and a very elongate baculum. Stibick (1979) placed it within the Agrypninae based on the presence of prothoracic luminous organs. All authors (Golbach 1994;Lawrence et al. 2010a;Bouchard et al. 2011;and Arias-Bohart and Elgueta 2012) have followed Costa (1975) in retaining Campyloxenus pyrothorax within its monotypic subfamily Campyloxeninae. During an ongoing canopy forest fogging surveys over the last decade in Chile Richardson and Arias-Bohart 2011) we collected an unknown click beetle which I describe here and place within the Campyloxeninae.
The following procedure as detailed by Becker (1958) was used for examining male and female genitalia: The last few abdominal segments were removed and placed overnight in in a Petri dish with soapy in order to soften the tissues. Male genitalia were extracted, examined and stored in small genitalia vials with 90% alcohol, or glued to a card pinned under the specimen. Measurements using a calibrated ocular micrometer are as follows: total body length from the frontal margin to elytral apex; pronotal length and maximum width of the pronotum and elytral length and maximum width of elytra. Adult morphology follows Gur'yeva (1974), Platia (1994), Calder (1996), Arias (2008), Arias (2009), Lawrence et al. (2010b), Arias-Bohart (2013, 2014. Wing vein nomenclature follows that of Dolin (1975), Kukalova-Peck and Lawrence (1993Lawrence ( , 2004. Locality data were taken directly from labels where / = line separation and // = new label. Approximate GPS, when not available, its provided underlined. Locality data for JEB material can be accessed at http://www.coleoptera-neotropical.org. Drawings were made using a camera lucida on a Leica MZ7 dissecting scope. Drawings were made using a camera lucida on a Leica MZ7 dissecting scope. Type material has been databased with a unique number indicated on the label information consisting of the acronym EMEC and the identification number. For example, the holotype of Malalcahuello ocaresi sp. n. has the unique number EMEC117539 that can be accessed at http://essigdb.berkeley.edu.
Etymology. The generic name Malalcahuello (gender masculine) is derived from the type locality of origin of the genus, Malalcahuello, in southern Chile. The word Malalcahuello derives from Mapudungun language malal = barnyard and kahuellu horse (Musigraf 2003).
Diagnosis. This genus differs from all other elaterid genera by the following combination of characters: strongly serrate antennae from antennomere 3 onwards, antennomere 2 very small, length about 0.4 times as long as antennomere 3; pronotum 0.76-0.99 as long as wide, convex, without deep impressions basally, lacking bioluminescent organs; stout, and protruding posterior angles with apex truncate; mesocoxal distance about 0.16 times mesocoxal cavity; wing venation with R cell elongate 4.2 times its width and wedge cell length 4 times its maximum width.
Description. Body about 3.27-3.87 times as long as wide; pronotal sides slightly sinuated, narrower than elytral sides. Elytral maximum width at posterior third; elytral apices softly rounded, not meeting at mid-line. Dorsal vestiture short, spare, fine, with some erect and decumbent short, well distributed hairs (Fig. 1).
Scutellum not elevated, flat, anteriorly simple, posteriorly rounded, notched on the sides, all borders well defined, tongue-shaped. Elytra about 2.81-2.54 times as long at midline as greatest width and 4.43-5.02 times as long as pronotum; anterior edge carinate; humeri well developed; parallel-sided at anterior third, gradually enlarging towards posterior third, converging posteriorly, apices rounded, not meeting and central midline. Disc with 10 defined puncture rows.
Hind wing about 2.63-2.66 times as long as wide; apical field about 0.6 times as long as total wing length, with 2 pigmented oblique linear sclerites; radial cell well developed, elongate, length 4.1 times as long as wide, with inner posterobasal angle acute; cross-vein r3 long, length about 2.2 times length of radial cell, horizontal and arising away from r4, which is slightly straight and complete; base of RP very long, extending to wing base; R-M loop forming narrowly acute angle; medial spur arise and then straight; medial field with five free veins; MP3+4 branching in 2 long veins; wedge cell length about 2.8 times its width (Fig. 9).
Members of the Elateridae generally exhibit a hard body, but members of the subfamily Campyloxeninae exhibit a soft-body trait that is also found within the Elateriformia, in Dascillidae, Elmidae, Ptilodactylidae and Psephenidae (Bocakova et al. 2007). Within the subfamily Campyloxeninae, only Campyloxenus exhibits bioluminescent organs. These are lacking in Malalcahuello. Bioluminescence is limited to the tribes Pyrophorinae and Hapsodrilini within the Elateridae (Colepicolo-Neto et al. 1986), and the genus Balgus (Costa, 1984) that has been placed in Thylacosterninae (Vahtera et al. 2009). Most species of Coleoptera possessing bioluminescent organs exhibit soft bodies are members of the cantharoid section of Elateriformia. Kundrata et al. (2014) indicated multiple origins for the soft-bodied trait and bioluminescent organs. Malalcahuello lacks bioluminescent organs and its body is harder than Campyloxenus. Future molecular studies of endemic Campyloxeninae may elucidate their systematic position within the Elateriformia.