Chalcionellus Reichardt, 1932

Lackner, Tomáš, 2010, Review of the Palaearctic genera of Saprininae (Coleoptera: Histeridae), Acta Entomologica Musei Nationalis Pragae (suppl.) 50, pp. 1-254 : 79-80

Chalcionellus Reichardt, 1932

Chalcionellus Reichardt, 1932: 15 , 16. Chalcionellus: REICHARDT (1941) :155, 262; DAHLGREN (1969a):59 –63, 66–68; DAHLGREN (1969b):230 –231; WITZGALL (1971): 172; MAZUR (1973): 27, 36; KRYZHANOVSKIJ & REICHARDT (1976): 111, 187; MAZUR & KASZAB (1980): 7, 48; VIENNA (1980): 116, 163; MAZUR (1981a): 71, 94; MAZUR (1984): 78; MAZUR (1997): 245; SECQ & GOMY (1999): 67; YÉLAMOS (2002): 245, 296; MAZUR (2004): 90.

Izpaniolus Mazur, 1972: 363 . Type species Saprinus condolens Marseul, 1864, original designation. Synonymized by SECQ & YÉLAMOS (1993): 338.

Type species: Saprinus amoenus Erichson, 1834 , original designation.

Diagnosis. Body variously colored, often metallic; frontal stria thin, often curved outwardly, never carinate, usually interrupted (in which case first curved inwardly, thence curved outwardly and prolonged onto clypeus); clypeus in several taxa (e.g. Chalcionellus decemstriatus ) depressed medially, laterally carinate; frontal disc punctate; eyes always convex. Pronotal foveae generally present, often a band of coarse punctation originates around them running parallel to pronotal margin; marginal pronotal stria always present and well visible, usually complete or slightly distanced on apical tenth from pronotal margin; lateral pronotal stria occasionally present (e.g. Chalcionellus tyrius ( Marseul, 1857) . If pronotal foveae are absent, clypeus usually distinctly carinate (except in some specimens of Chalcionellus amoenus ( Erichson, 1834) and C. ibericus Dahlgren, 1969 ); pronotal hypomeron glabrous, apart from Chalcionellus hauseri ( Schmidt, 1890) where the pronotal hypomeron is setose. Pre-apical foveae always present; both sets of prosternal striae present, seldom marginal prosternal stria connecting pre-apical foveae; outer margin of protibia with 5–8 moderately large teeth topped with denticle.

Differential diagnosis. Chalcionellus is most similar to the genera Hypocacculus , Zorius , Hypocaccus , or Pholioxenus , but differing from them: from Hypocacculus by the often present pronotal foveae (if these are absent, then clypeus is margined laterally) and more convex eyes; from Pholioxenus it likewise differs chiefly by the presence of pronotal foveae (if these are absent, then clypeus is margined laterally, whereas in Pholioxenus it is never margined laterally) as well as absence of microsculpture in-between elytral punctation (often present with Pholioxenus ), larger pre-apical foveae (usually tiny, occasionally even absent in Pholioxenus ); from Zorius it similarly differs by the presence of pronotal foveae (if these are absent, then the clypeus is margined laterally, whereas in Zorius it is never margined laterally) as well as by the present pre-apical foveae (always absent in Zorius ) and from Hypocaccus it again differs by the presence of pronotal foveae, often present microsculpture on the elytra (normally absent in Hypocaccus , present in several species of subgenus Baeckmanniolus ) and the absence of chevrons or rugae on the frontal disc.

Biology. Species of this genus are mostly found on carrion and in dung, with the exception of Chalcionellus hauseri ( Schmidt, 1894) , which lives within the desiccating stalks of Cistanche flava Fedtschenko & Fedtschenko, 1913 , as well as in the sand surrounding its roots ( REICHARDT 1941, KRYZHANOVSKIJ & REICHARDT 1976, KOVARIK & CATERINO 2005). Here, these beetles prey upon the fly larvae of the genus Eumerus Meigen, 1822 (Syrphidae) ( KRYZHANOVSKIJ & REICHARDT 1976).

Distribution. Chalcionellus currently comprises 33 described species worldwide; one species, Chalcionellus mersinae ( Marseul, 1857) , is regarded as incertae sedis. This genus is distributed mostly in the Palaearctic and Afrotropical Regions, with several representatives in the Indo-Malayan Region, too. Chalcionellus aeneovirens ( Schmidt, 1890) has been introduced into Australia. Chalcionellus is absent in North and South America and except for the abovementioned species it is normally absent in Australopacific Region, too ( MAZUR 1997).

Species examined. Chalcionellus aemulus ( Illiger, 1807) , C. amoenus ( Erichson, 1834) , C. blanchii blanchii ( Marseul, 1855) , C. blanchii tauricus ( Marseul, 1862) , C. decemstriatus decemstriatus (Rossi, 1792) , C. decemstriatus tingitanus Reichardt, 1932 , C. geminus Dahlgren, 1969 , C. hauseri ( Schmidt, 1894) , C. ibericus Dahlgren, 1969a , C. libanicola ( Marseul, 1870) , C. olexai Lackner, 2002 , C. orcinus Reichardt, 1932 , C. palaestinensis ( Schmidt, 1890) , C. persicus Lackner, 2002 , C. sibiricus Dahlgren, 1969a , C. suspectus ( Schmidt, 1890) , C. tunisius ( Marseul, 1876) , C. turcicus ( Marseul, 1857) , C. tyrius ( Marseul, 1857) , Chalcionellus sp. ( Iraq).

Discussion. Phylogenetic validity of this taxon is highly questionable, in authors’ opinion. It is probably a non-natural taxon, most likely paraphyletic, with respect to Hypocacculus and it is characterised by only few weak synapomorphies, especially the presence of pronotal foveae. However, even these are not present in all taxa and several of its species have been shifted between Hypocacculus and Chalcionellus . Therefore its validity should be tested in the future using modern phylogenetic methods. A species revision, an exciting and noble task in itself, would also be highly desirable in the case of Chalcionellus .