Revision of the genus Hemisaprinus Kryzhanovskij, 1976 (Coleoptera, Histeridae, Saprininae)

Abstract The monophyletic genus Hemisaprinus Kryzhanovskij in Kryzhanovskij & Reichardt, 1976 is revised herein. All three species Hemisaprinus subvirescens (Ménétries, 1832), H. lutshniki (Reichardt, 1941) and H. cyprius (Dahlgren, 1981) are found to be correctly assigned to the genus and their monophyly is supported by the synapomorphy of the presence of prosternal foveae. The three species are re-described and supplemented with colour photographs as well as SEM micrographs outlining their differences. Male genitalia drawing of H. subvirescens and H. lutshniki are provided and a key to the species is given. Hemisaprinus subvirescens (Ménétries, 1832) is newly reported from Armenia, Azerbaijan, Kyrgyzstan, Uzbekistan, Turkmenistan, Tajikistan, Jordan, Cyprus and Mongolia. The lectotypes and paralectotypes of the following species are designated herein: Saprinus foveisternus Schmidt, 1884, Saprinus syriacus Marseul, 1855 and Saprinus viridulus Marseul, 1855.


Introduction
The genus Hemisaprinus was established by Kryzhanovskij in Kryzhanovskij and Reichardt (1976)  Abbreviations. Abbreviations of morphological measurements follow Ôhara (1994) and are used throughout the text as follows: APW width between anterior angles of pronotum EL length of elytron along elytral suture EW maximum width between outer margins of elytra PEL length between anterior angles of pronotum and apices of elytra PPW width between posterior angles of pronotum.
Differential diagnosis. By the presence of prosternal foveae Hemisaprinus can be readily differentiated from members of the genus Saprinus, which it otherwise strongly resembles, by the absence of complete frontal stria as well as general appearance. The sensory structures of the antenna (Figs 3,15) are typically Saprinus-like as well, with four oval sensory areas on ventral side of the club with a corresponding vesicle situated under internal distal sensory area. The reader is referred to the Key to the genera of the Palaearctic Saprininae by the author (Lackner 2010: 60) for more information.
Biology. Hemisaprinus subvirescens is found chiefly on carcasses in arid regions while H. lutshniki is found in decomposing vegetable matter, and has not been found on carcasses so far (Lackner 2010). The biology of Hemisaprinus cyprius Dahlgren, 1981 is completely unknown.
Antennal scape (Fig. 2) not particularly thickened, with shallow sparse punctures and two short setae; club round, without visible articulation, entire surface with dense short sensilla intermingled with sparser longer erect sensilla; sensory structures of antennal club (Fig. 3) in form of four ovoid sensory areas on ventral side and one vesicle situated under internal distal margin.
Mouthparts: mandibles ( Fig. 2) with rounded outer margin, laterally with deep dense punctures, moderately curved inwardly, mandibular apex pointed; sub-apical tooth obtuse, inconspicuous; labrum (for fig. see Lackner 2010, fig. 69) convex, densely punctate, anterior margin medially with a small convexity interrupting concavity; labral pits deep, each with two well-sclerotized long setae; terminal labial palpomere elongated, its width about one-third its length; mentum sub-trapezoid, anterior margin (for fig. see Lackner 2010, fig. 135) medially with deep notch surrounded with sparse short setae, lateral margins with single row of sparse shorter setae, several setae present also on disc of mentum; cardo of maxilla with few short setae; stipes triangular, with three short setae; terminal maxillary palpomere elongated, its width about onefourth its length, approximately 2.5 times as long as penultimate.
Propygidium and pygidium densely and coarsely punctate, punctures separated by about half their own diameter.
Intercoxal disc of the first abdominal sternite laterally with incomplete stria; except for median part with coarse round punctures, becoming finer along posterior margin.
Protibia (for fig. see Lackner 2010, fig. 651) slightly dilated, outer margin with 5 moderately large triangular teeth topped with short rounded denticle, diminishing in size in proximal direction, followed by 4 tiny denticles; setae of outer row regular, rather short; protarsal groove deep, strigulate; anterior protibial stria complete apically; setae of intermedian row about as long as those of outer row, becoming more sclerotized apically; two tarsal denticles present near tarsal insertion; protibial spur short, bent, growing out from apical margin of protibia; apical margin of protibia posteriorly with 3 tiny denticles abutting each other; outer part of posterior surface (for fig. see Lackner 2010, fig. 651) obscurely variolate, separated from glabrous median part of posterior surface by vague boundary and row of short sclerotized setae; posterior protibial stria complete, with a row of tiny sclerotized setae becoming thicker apically; inner row of setae double, setae dense and short.
Mesotibia slender, outer margin with two rows of short denticles; setae of outer row regular, dense, shorter than denticles; setae of intermedian row shorter and finer than those of outer row, regular; posterior mesotibial stria almost complete; anterior surface of mesotibia (for fig. see Lackner 2010, fig. 645) strigulate-punctate; anterior mesotibial stria complete, terminating in single tiny inner anterior denticle; mesotibial spur short; apical margin of mesotibia anteriorly with two short denticles; claws of apical tarsomere slightly bent, shorter than half its length; metatibia slenderer and longer than mesotibia, in all aspects similar to it, but denticles on outer margin much sparser and claws of apical tarsomere slightly longer than half its length.
Pronotal sides (Fig. 13) on basal half moderately narrowing anteriorly, strongly narrowing on apical half; apical angles obtuse; median emargination for head shallow; pronotal depressions absent; marginal pronotal stria complete, somewhat weakened behind head; pronotal disc shining on most part, with sparse punctures separated by several times their diameter, laterally and behind head more coarse and dense punctures appear, punctures form a depressed band of confluent punctuation, between it and pronotal margin a narrow band with simple punctuation present; several rows of ovoid punctures present along pronotal base; pronotum with faint ante-scutellar depression; pronotal hypomeron asetose, in fine scattered punctures; scutellum well visible.
Propygidium and pygidium densely and coarsely punctate, punctures separated by about half to their own diameter; interspaces with microsculpture.
Anterior margin of median portion of prosternum (Fig. 16) rounded; marginal prosternal stria present laterally and as short anterior fragment; prosternal process on apical sixth distinctly elevated in respect to the remaining part; surface between carinal prosternal striae slightly convex, with scattered fine punctation, punctures surrounded by microsculpture; carinal prosternal striae well-impressed, parallel on prosternal apophysis, thence divergent anteriorly, terminating in deep and large prosternal foveae; lateral prosternal striae carinate, sub-parallel, apically terminating near the point where carinal prosternal striae enter prosternal foveae.
Intercoxal disc of first abdominal ventrite incompletely striate laterally; on basal third with irregular scattered fine punctures separated by several times their own diameter; rest of first visible abdominal ventrite with scattered microscopic punctuation.
Protibia slightly dilated, outer margin apically with single low tooth topped by tiny denticle, in proximal direction three low triangular teeth topped by short rounded denticle appear, all three approximately of the same size, followed by another low tooth (occasionally bearing two tiny denticles), followed by a single tiny denticle growing out directly from outer margin of protibia; setae of outer row regular, rather short; protarsal groove rather deep; anterior protibial stria very shortened (absent?); setae of intermedian row situated on ridge delimiting proximal margin of protarsal groove; single tarsal denticle present near tarsal insertion; protibial spur short, bent, growing out from apical margin of protibia; apical margin of protibia posteriorly with three tiny denticles almost abutting each other; outer part of posterior surface obscurely variolate, punctate, separated from imbricate median part of posterior surface by vague boundary and row of short sclerotized setae; posterior protibial stria complete, bearing a row  (Reichardt, 1941) paratype, 8 th sternite and tergite, ventral view 18 ditto, dorsal view 19 ditto, lateral view 20 Hemisaprinus lutshniki (Reichardt, 1941) paratype, 9 th + 10 th tergites, dorsal view 21 ditto, lateral view 22 Hemisaprinus lutshniki (Reichardt, 1941) paratype, spiculum gastrale, ventral view 23 ditto, lateral view 24 Hemisaprinus lutshniki (Reichardt, 1941) paratype, aedeagus, dorsal view 25 ditto, lateral view. of fine sparse setae along its length, terminating in two tiny inner denticles; inner row of setae double, setae dense and short.
Mesotibia slender, outer margin with a single row of short denticles situated on low teeth; setae of outer row regular, sparse, about as long as denticles themselves; setae of intermedian row shorter and finer than those of outer row, regular; posterior mesotibial stria almost complete; anterior surface of mesotibia imbricate, with another row of approximately seven shorter denticles than those of outer row; anterior mesotibial stria complete, terminating in single tiny inner anterior denticle; mesotibial spur short; apical margin of mesotibia anteriorly with three short denticles; claws of apical tarsomere slightly bent, shorter than half its length; metatibia slenderer and longer than mesotibia, outer margin with approximately five short denticles situated on even lower teeth than those of mesotibia; apical-most tooth bearing two denticles; setae of outer row distinctly longer than denticles themselves; anterior face of metatibia punctate, with a row of approximately five tiny denticles; claws of apical-most metatarsomere longer than half of its length; metatibia otherwise similar to mesotibia.
Remarks. This species is very similar to H. cyprius, differing from it chiefly by the presence of a second dorsal elytral stria, absent with H. cyprius and aciculate elytral punctuation, as well as shining pronotum (matt in cyprius).
Antennal scape (Fig. 27) slightly thickened, densely punctate, lower margin carinate, with few short setae; club round, pointed apically, without visible articulation, entire surface with dense short sensilla intermingled with sparser longer erect sensilla; sensory structures of antennal club in form of four ovoid sensory areas on ventral side; vesicle(s) not examined.
Mouthparts: mandibles with rounded outer margin, densely punctate, mandibular apex pointed; sub-apical tooth of left mandible not examined; labrum convex, densely punctate; labral pits deep, each with two well-sclerotized long setae; terminal labial palpomere elongated, about twice as long as pen-ultimate, its width about one-third its length; mentum sub-trapezoid, anterior margin medially with deep notch surrounded with sparse rather long setae, lateral margins with single row of sparse shorter ramose setae; cardo of maxilla with few short setae; stipes triangular, with three short setae; terminal maxillary palpomere elongated, pointed apically, about three times as long as pen-ultimate; its width about one-third its length.  (Dahlgren, 1981) paratype, prosternum + mesoventrite. Clypeus (Fig. 27) flat, gradually sloping down laterally, coarsely and densely punctate, punctures almost confluent; frontal stria largely interrupted medially, for short distance prolonged onto clypeus, supraorbital stria well impressed, carinate; frontal disc ( Fig. 27) with coarse and dense punctures similar to those of clypeus, punctures in bottom with microsculpture; eyes convex, well visible from above.
Pronotal sides (Fig. 26) on basal half moderately narrowing anteriorly, strongly narrowing on apical half; apical angles obtuse; median emargination for head shallow; pronotal depressions absent; marginal pronotal stria complete, somewhat weakened behind head; pronotal disc matt due to very dense microsculpture, laterally with very coarse and dense punctures, separated by less than their own diameter, punctures become finer and sparser medially where they are separated by several times their diameter; several rows of ovoid punctures present along pronotal base; pronotum with ante-scutellar depression; pronotal hypomeron asetose, with fine scattered punctures; scutellum well visible.
Propygidium and pygidium densely and coarsely punctate, punctures separated by about half to their own diameter; interspaces with microsculpture.
Intercoxal disc of the first abdominal ventrite incompletely striate laterally; on basal third with irregular larger punctures separated by about their own to twice their diameter; rest of first visible abdominal ventrite with scattered microscopic punctuation.
Protibia slightly dilated, outer margin with four moderately large triangular teeth topped by short rounded denticle, diminishing in size in proximal direction, followed by three tiny denticles growing out directly from outer margin of protibia; setae of outer row regular, rather short; protarsal groove deep; anterior protibial stria shortened on basal half; setae of intermedian row not examined; two tarsal denticles present near tarsal insertion; protibial spur short, bent, growing out from apical margin of protibia; apical margin of protibia posteriorly with four tiny denticles almost abutting each other; outer part of posterior surface obscurely variolate, punctate, separated from glabrous median part of posterior surface by vague boundary and row of short sclerotized setae; posterior protibial stria complete, terminating in several tiny inner denticles; inner row of setae double, setae dense and short.
Mesotibia slender, outer margin with a single row of short denticles situated on low teeth; setae of outer row regular, sparse, longer than denticles; setae of intermedian row shorter and finer than those of outer row, regular; posterior mesotibial stria not examined; anterior surface of mesotibia glabrous, with another much sparser row of shorter denticles than those of outer row; anterior mesotibial stria complete, terminating in single tiny inner anterior denticle; mesotibial spur short; apical margin of mesotibia anteriorly with three short denticles; claws of apical tarsomere slightly bent, shorter than half its length; metatibia slenderer and longer than mesotibia, in all aspects similar to it, but denticles on outer margin much sparser, situated on even lower teeth than those of mesotibia; apical-most tooth bearing two denticles.
Male unavailable. Remarks. Dahlgren (1981) does not mention the absence of the second dorsal elytral stria, which is perhaps the best separating character from the similar species, esp. H. lutshniki.

Discussion
Although Mazur (2011) did not provide any background information or justification for separating Hemisaprinus from Saprinus and erecting it as an independent genus he was motivated by the presence of the prosternal foveae in Hemisaprinus for his nomenclatural act (Mazur, pers. comm. 2014). Indeed, the presence of prosternal foveae is completely alien to Saprinus species and can justify the separation of Hemisaprinus from Saprinus. In the recently performed phylogenetic analysis aimed at disentangling the relationships of the genera and subgenera of the Saprininae (Lackner, unpublished) the type species of Hemisaprinus, H. subvirescens was recovered deeply nested in the clade containing most of the type species of the Palaearctic and Nearctic taxa traditionally allied with Saprinus (sensu Mazur 2011). Its position is, however, not near the type species of Saprinus, S. semistriatus and its placement in the clade was unambiguously supported by one synapomorphy: sensory structures of the antenna, which form regular patches on ventral side of the club and are usually four in number (Fig. 3). Saprinus, with 154 currently valid species is the most species-rich and widely distributed genus of the entire subfamily occurring on all continents except Antarctica (Mazur 2011). The genus Saprinus is most likely non-monophyletic and its phylogeny-based revision is highly necessary (see also Lackner 2010). Hemisaprinus, although presumably related to Saprinus based on external as well as genitalic characters (Lackner, unpublished), is presumed to be monophyletic sharing the synapomorphy of present prosternal foveae. It contains three species that, on one hand, share the synapomorphy of the presence of prosternal foveae, on the other hand, however, the species differ in the arrangements of the two sets of prosternal striae. Carinal prosternal striae of H. subvirescens do not enter the prosternal foveae; while the lateral prosternal striae do. In the case of the two other species (H. lutshniki and H. cyprius) the carinal prosternal striae do terminate in the prosternal foveae, while the lateral prosternal striae terminate near the apices of carinal prosternal striae. According to my recent studies on the morphology of the Saprininae, the configuration of the two sets of prosternal striae was found to be a rather variable character, even within one genus (and even within one species!) and I was unable to score this character unambiguously or parse it into discrete character states. Hence, I refrained from using this character in my phylogenetic studies (Lackner, unpublished) and do not use the different arrangements of the two sets of striae to further split Hemisaprinus.
On the other hand, a very similarly structured prosternal process, including the prosternal foveae is found among some members of the Nearctic and Neotropical subgenus Hesperosaprinus Wenzel, 1962 of the genus Euspilotus Lewis, 1907. The author is not familiar with most members of this species-rich subgenus (45 currently valid species, Mazur 2011), but based on the morphology studied and dissections of the antennal club of the type species of the subgenus, E. (H.) assimilis (Paykull, 1811) at least two fundamental differences among this species on one hand, and members of Hemisaprinus on the other hand, were observed. The prosternal foveae of E. (H.) assimilis are connected by marginal prosternal stria, whereas such stria is lacking in members of Hemisaprinus; and, furthermore, the sensory structures of the antenna of E. (H.) assimilis consist of two (ventral and dorsal) circular sensory areas and a single, ball-shaped vesicle. The antennal character perhaps best separates the members of the two respective genera Hemisaprinus and Euspilotus. However, further studies of this enigmatic structure are required, especially among Nearctic and Neotropical Saprininae. Dahlgren (1981) had some doubts about the placement of Saprinus cyprius into the subgenus Hemisaprinus, and remarked that: "Because the prosternal foveae are normally present in [S. (Hemisaprinus)] subvirescens and [S. (H.)] lutshniki this species [S. cyprius] should be assigned to the subgenus Hemisaprinus. However, the appearance of cyprius is very different from these [two] species, and thereby the subgenus would be very heterogeneous. It seems that the genus Saprinus shows a tendency to produce species with prosternal pits and this tendency becomes manifested in different branches of the genealogical tree". Although Dahlgren (1981) did not explicitly place S. cyprius into Hemisaprinus, Mazur included it in this subgenus already in the first edition of his catalogue (1984) without providing any reason. Presumably it was likewise the presence of the prosternal foveae that inspired this placement.