Saprinus Erichson, 1834

Lackner, Tomáš, 2010, Review of the Palaearctic genera of Saprininae (Coleoptera: Histeridae), Acta Entomologica Musei Nationalis Pragae (suppl.) 50, pp. 1-254 : 197-199

Saprinus Erichson, 1834

Saprinus Erichson, 1834: 172 . Type species: Hister nitidulus Fabricius, 1801 , designated by WESTWOOD (1838): 22.

Saprinus: LACORDAIRE (1854) : 274; J. E. LECONTE (1845):68; MARSEUL (1855): 327; MARSEUL (1857):154; JACQUELIN- DUVAL (1858): 111; THOMSON (1862): 235; HORN (1873): 312; SCHMIDT (1885a): 283, 302; GANGLBAUER (1899): 380; REITTER (1909): 290, 291; BLATCHEY (1910): 617; JAKOBSON (1911): 641; BICKHARDT (1916): 82, 84; GERMAIN (1917): 137; BICKHARDT (1921): 109; BRADLEY (1930): 95; PEYERIMHOFF (1936): 223; REICHARDT (1941):156, 176; MCGRATH & HATCH (1941): 54; BLACKWELDER & BLACKWELDER (1948):11; WENZEL (1962):374; DAHLGREN (1962): 237 –248; HATCH (1962): 257; HALSTEAD (1963): 9; DAHLGREN (1964): 152 –162; DAHLGREN (1967): 213 –224; DAHLGREN (1968a):82 –94; DAHLGREN (1968b):255 –268; HANSEN (1968):294, 320; DAHLGREN (1969b):257 –269; WITZGALL (1971):168 –172; MAZUR (1973): 26, 29; KRYZHANOVSKIJ & REICHARDT (1976):111, 125; VIENNA (1980): 116, 129; MAZUR & KASZAB (1980): 6, 25; MAZUR (1981a): 71, 72; MAZUR (1984): 44; ÔHARA (1994): 215, 226; DOWNIE & ARNETT (1996): 607; SECQ & SECQ (1997a): 10; KIM & LIM (1997): 60; MAZUR (1997): 218; ÔHARA & PAIK (1998): 28; BOUSQUET & LAPLANTE (1999): 141, 150; MAZUR (2001): 19, 31; KOVARIK & CATERINO (2001): 220, 223; YÉLAMOS (2002): 245, 255, 256; MAZUR (2004): 96; BOUSQUET & LAPLANTE (2006): 79, 81, 101.

Plesiosaprinus: HOULBERT & MONNOT (1923): 72 (nomen nudum). Synonymized by COOMAN (1947): 428.

Diagnosis. Body usually moderately-sized to rather large for the subfamily (2.50–10.00 mm); cuticle often metallic, occasionally black or light brown. Antennal club round, usually without visible articulation, although in some species, e.g. Saprinus (Phaonius) pharao , ventrally with 4 slit-like pits and dorsally with 2 slit-like pits roughly corresponding to sutures between antennomeres. Surface of antennal club in most cases, except for slit-like pits that are with sensilla basiconica, entirely covered with short dense sensilla and sporadic longer erect sensilla, occasionally with a large sensory area on apical part of club; sensorial patches usually present on ventral surface of club, variously shaped. Eyes convex, normally well visible from above. Frontal stria in most cases interrupted, only rarely complete, never cariniform, at times prolonged onto clypeus; lateral pronotal stria never present, marginal pronotal stria usually complete, sometimes interrupted or weakened behind head; pronotal hypomeron in most cases glabrous; in psammophilous species setose. Elytral humeri usually slightly prominent; elytra often with ‘mirrors’; dorsal elytral striae shortened, never reaching elytral apex (although in some species united inner subhumeral and humeral elytral striae can be almost nearing it); their configuration variable, but fifth dorsal elytral stria never present; humeral elytral stria in some taxa united with inner subhumeral stria creating thus a complimentary dorsal elytral stria parallel to first dorsal elytral stria; elytral disc in some cases with red or yellow maculae or transverse patch. Prosternal process with both sets of prosternal striae well developed, their configuration variable and useful in species determination, pre-apical foveae absent (present only in subgenus Hemisaprinus ); surface between carinal prosternal striae usually convex, rarely flattened; metaventrite in males flattened, often with longitudinal depression; males of some species with two tubercles near or on posterior margin of metaventrite. Protibia, except for psammophilous taxa, not particularly dilated, outer margin with 5–12 moderately sized to short teeth topped with short denticle; anterior margin not truncate; meso- and metatibiae in most cases not thickened or dilated; males of some species possess brush-like long sclerotized setae on their mesotarsi. Shape and structure of male terminalia very useful (and in numerous cases the only possible way) in species recognition.

Differential diagnosis. Species of the genus Saprinus can be confused with several externally similar genera, especially Styphrus , Zorius , or Euspilotus (Neosaprinus) perrisi . They differ from the most other Palaearctic genera by the combination of widely interrupted frontal stria (only rarely complete), absent pre-apical foveae (but present in subgenus Hemisaprinus , see below) and usually present pronotal foveae. Likewise, species of this genus are larger in general than members of other genera. From the only Palaearctic representative of the genus Styphrus , S. corpulentus , they differ chiefly by the punctate frontal disc (impunctate in Styphrus ) and shorter, curved meso- and metatarsal claws (longer and almost straight in Styphrus ). Furthermore, lateral parts of all visible abdominal sternites are setose in Styphrus whereas they are normally asetose in Saprinus . From members of the genus Zorius the species of Saprinus differ chiefly by the form of the sensory structures of the antenna (see LACKNER 2009b) and the complete frontal stria (in most cases widely interrupted in Saprinus ), more flattened eyes, absent pronotal foveae (often present in Saprinus ) as well as the elevated anterior margin of clypeus. From the sole Palaearctic representative of the subgenus Neosaprinus of the genus Euspilotus , E. (Neosaprinus) perrisi , the members of Saprinus chiefly differ by the present supraorbital stria and absent pre-apical foveae (present and vaguely connected with the marginal prosternal stria in E. (N.) perrisi ); furthermore, females of E. (N.) perrisi possess curious pygidial sulci. Species of the subgenus Hemisaprinus possess pre-apical foveae and as such could be confused with several Palaearctic genera, e.g. Hypocaccus , Chalcionellus or Pholioxenus , but differs from them chiefly by the largely interrupted frontal stria (usually complete in the afore-mentioned taxa) and anteriorly divergent and ‘open’ carinal prosternal striae (usually anteriorly convergent and often united apically in Hypocaccus , Chalcionellus or Pholioxenus ). Some species of the genus Chalcionellus have similarly widely interrupted frontal stria, but their carinal prosternal striae are usually convergent and not ‘open’ anteriorly.

Biology. Most species of this genus prefer open xerophilous landscapes; only few species inhabit mesic biotopes. They are most frequently collected on the carrion, less so in dung; in both cases they prey on eggs or larvae of soft-bodied insects, especially flies; according to REICHARDT (1941) several central Asian species are even able to capture adult flies on dung. Some species are even attracted to flowers (THÉROND 1931; REICHARDT 1941; KRYZHANOVSKIJ & REICHARDT 1976; VIENNA 1980; Lackner, pers. observ.). Some species, e.g. S. (Saprinus) rugifer ( Paykull, 1809) , live in the nests of birds; another taxa are fond of rotting fungi where they probably prey on fly larvae (e.g. S. (Saprinus) lautus Erichson, 1839 ) ( KRYZHANOVSKIJ & REICHARDT 1976; Lackner, pers. observ.).

Distribution. With 150 species occurring around the world ( MAZUR 1997; VIENNA 1996 a,b; GOMY & VIENNA 1998; GOMY 2000; THÉRY et al. 2009), the genus Saprinus is the most species-rich genus of the Saprininae ; most of its species occur in the Palaearctic and Afrotropical Regions. Only about 10 species are known from the Nearctic Region (8 from Canada – BOUS- QUET & LAPLANTE (2006)), only 4 occur in South or Central America, 7–9 species occur in Australia, 1–2 species in New Caledonia, 4 in New Guinea, and 2 in New Zealand. Some species, e.g. S. (Saprinus) chalcites ( Illiger, 1807) , S. (Saprinus) cupreus Erichson, 1834 or S. (Saprinus) splendens ( Paykull, 1811) , are widespread, other species, like S. (Saprinus) caerulescens ( Hoffmann, 1803) and S. (Saprinus) subnitescens Bickhardt, 1909 , were probably introduced into Peru or North America, respectively ( MAZUR 1997).

Discussion. Saprinus is the most species-rich genus of the Palaearctic Saprininae , most likely polyphyletic with the respect to other smaller genera. Sensory strurctures of antennal club undergo remarkable transition among its subgenera (especially Phaonius ), but also among the members of the nominotypical subgenus (for more details see DE MARZO & VIENNA (1980 a)), and the task for the future research would be to delineate the phylogenetically most valuable characters and define the monophyly of this taxon, or monophyletic groupings within it. The current concept of this genus implies that it is not well defined by synapomophies and the characters that are currently used for the taxonomic classification of this taxon are merely phenetic. The task of revising this genus on species level is enormous, given the number of species and their geographical distribution. Many species are geographically scattered, but very similar morphologically, which may imply cryptic genetic variation. Among the putative synapomorphies that characterise this taxon can be listed the sensory structures of antennal club (but see above!), absence of pre-apical foveae (but present in the subgenus Hemisaprinus !), interrupted frontal stria (but occasionally complete, e.g. in S. (S.). ruber Marseul, 1855 ). The presence of slit-like pits on the ventral side of the antennal club present in several of its members (e.g. S. (P.) pharao ) is considered a plesiomorphic character.