Revision of the genus Reichardtiolus Kryzhanovskij, 1959 (Coleoptera, Histeridae, Saprininae)

Abstract The genus Reichardtiolus Kryzhanovskij, 1959 is revised herein. It now contains five species: R. duriculus (Reitter, 1904) from middle Asia (with a doubtful female specimen from western China that is here tentatively assigned to this species), R. pavlovskii Kryzhanovskij, 1959 from Turkmenistan, R. sphingis (Peyerimhoff, 1936), comb. n. (transferred from Saprinus Erichson, 1834) from Egypt and Jordan, R. perses sp. n. from Iran and R. aldhaferi sp. n. from Saudi Arabia. Except for R. pavlovskii, which is a rather distinct species known only from two females, the remaining species are allopatric, very similar externally and are best separated from each other by their male terminalia. R. pavlovskii is kept in Reichardtiolus only tentatively, pending the examination of more specimens, and especially its male genitalia. R. duriculus and R. pavlovskii are re-described, while R. perses sp. n., R. aldhaferi sp. n. and R. sphingis comb. n. are provided with diagnostic descriptions because of their overall similarity with R. duriculus. Morphological differences of all species are illustrated using SEM micrographs. Male genitalia of R. duriculus, R. sphingis comb. n., R. perses sp. n. and R. aldhaferi sp. n. are illustrated and a key to the species is given. R. duriculus is newly recorded from Tajikistan.


introduction
The genus Reichardtiolus was established by Kryzhanovskij (1959) based on the species Saprinus duriculus Reitter, 1904. At the time of its designation Reichardtiolus was a mere subgenus of the genus Exaesiopus Reichardt, 1926 andKryzhanovskij (1959) included in it another species, R. pavlovskii, which he described in the same work. In their fauna of the USSR, Kryzhanovskij and Reichardt (1976) elevated the rank of Reichardtiolus from a subgenus of Exaesiopus to fully-fledged genus. Lackner (2010) summarized the knowledge about the genus without having examined the obscure and very rare taxon R. pavlovskii. During the years 2006-2013 I had the opportunity to examine a large number of Saprininae taxa, among them the rare R. pavlovskii and Saprinus sphingis Peyerimhoff, 1936, the latter of which has been treated as a species incertae sedis since its description (Peyerimhoff 1936;Mazur 1984;1997;2004;2011). One undescribed species, apparently belonging to Reichardtiolus from Saudi Arabia was recently discovered in the collections of the King Saud Museum of Arthropods (KSMA), and the author's visit to the Zoological Institute of the Russian Academy of Sciences (ZIN) yielded another new species from south-western Iran. The results of these examinations are presented below. This work presents another contribution to the on-going revisionary work of the genera of the subfamily Saprininae (Lackner 2009a(Lackner -c, 2010(Lackner , 2011aTishechkin and Lackner 2012;Lackner 2012;Lackner 2013a,b;Lackner and Gomy 2013).

Material and methods
All dry-mounted specimens were relaxed in warm water for several hours or overnight, depending on the body size. After removal from original cards, the beetles were side-mounted on triangular points and observed under a Nikon 102 stereoscopic microscope with diffused light. Body structures were studied using methods described by Ôhara (1994): male genitalia were macerated in a hot 10% KOH solution for about 15 minutes, cleared in 80% alcohol, macerated in lactic acid with fuchsine, incubated at 60°C for two hours, and subsequently transferred into a 1:1 mixture of glacial acetic acid and methyl salicylate, heated at 60°C for 15 minutes and cleared in xylene. Specimens were then observed in α-terpineol in a small glass dish. Digital photographs of the male terminalia were taken by a Nikon 4500 Coolpix camera and edited in Adobe Photoshop CS4. Based on the photographs or direct observations, the genitalia were drawn using a light-box Hakuba klv-7000. SEM photographs of R. duriculus, R. pavlovskii and R. sphingis were taken with a JSM 6301F microscope at the laboratory of Faculty of Agriculture, Hokkaido University, Sapporo, Japan while those of R. aldhaferi and R. perses were taken at the Laboratory of the Electron Microscopy at the Faculty of Biology, Charles University, Prague, Czech Republic. All available specimens were measured with an ocular micrometer. Beetle terminology follows that of Ôhara (1994) and Lackner (2010). Separate lines of the same half their diameter to twice their diameter; occasionally with protuberances or shallow depressions; clypeus rectangular to rounded, occasionally margined, anterior margin may be elevated; dorsal surface densely to very densely and coarsely punctuate, punctures separated by their own to half their own diameter, in R. pavlovskii even forming longitudinal wrinkles on pronotum (Fig. 62); pronotal depressions absent; dorsal elytral striae in R. pavlovskii almost unrecognizable beneath coarse punctuation, in other congeners usually all four dorsal elytral striae 1-4 well discernible; prosternal foveae present (Fig. 10) or absent (R. pavlovskii; Fig. 68); prosternal process often compressed, concave or convex, especially on posterior half, punctate and setose; both sets of prosternal striae present (in case of R. pavlovskii only as vague rudiments); pronotal hypomeron, lateral disc of metaventrite and metepisternum setose. Protibia (Figs 1,64) with two or three short teeth each topped by variably large denticle, usually followed by one or two much smaller denticles entombed in outer margin of protibia; meso-and metafemora strongly thickened (Fig. 63); metatibia dilated and thickened; anterior surface of metatibia with two to several rows of short, stout denticles (Fig. 71).
Differential diagnosis. Members of Reichardtiolus are externally most similar to the species of the genus Exaesiopus Reichardt, 1926, differing from them especially by the absence of deep longitudinal rugae on the frontal disc. The elytra in Reichardtiolus are entirely coarsely and densely punctate, in R. pavlovskii even forming rugulose-lacunose wrinkles, whereas in Exaesiopus the elytra are always at least partly glabrous. Because of the thickened hind femora and lack of longitudinal furrows on frons, Reichardtiolus cannot be confused with any other Palaearctic taxon; for further details on differential diagnosis and a key to genera of the Palaearctic Histeridae the reader is referred to Lackner (2010).
Biology. Reichardtiolus is a psammophilous taxon, found in arid and desert habitats, often in sand or under decaying vegetation (Lackner 2010); several specimens of R. aldhaferi and R. duriculus were also collected at light or in rodent's burrows. According to Kryzhanovskij in Kryzhanovskij and Reichardt (1976) the second known specimen of R. pavlovskii was collected while digging in sands under Tamarix.
Elytral epipleuron with a row of deep punctures; marginal epipleural stria well impressed, complete; marginal elytral stria complete, deeply impressed, carinate, continued as complete apical elytra stria. Humeral elytral stria weakly impressed on basal third, often doubled; inner subhumeral stria inconspicuous, present as tiny median fragment; elytra with four dorsal striae 1-4, in large punctures, first, second and third dorsal striae about the same length, reaching approximately elytral half apically, fourth dorsal elytral stria weakly impressed on basal third (occasionally longer apically), connected to complete sutural elytral stria. Elytral disc with deep round punctuation, punctures separated by 2-4 times their diameter, becoming finer apically and laterally; between sutural elytral stria and elytral suture a row of regular fine punctures present.
Intercoxal disc of first abdominal sternite completely striate laterally, with sparse coarse punctuation.
Protibia (for fig. see Lackner 2010, fig. 603) flattened and somewhat dilated, apical protibial margin formed by anterior margin of large sub-triangular distal-most tooth topped with large triangular denticle, outer margin apart from this tooth with another similar tooth topped with large triangular denticle, followed by another, much lower tooth topped by much smaller triangular denticle and another microscopic denticle entombed in outer margin of protibia; setae of outer row on anterior surface of protibia sparse, regular and short; setae of intermediate row similarly sparse and regular, much shorter than those of outer row; protarsal groove moderately deep; anterior protibial stria present only on basal third; tarsal denticles absent; protibial spur tiny, bent, growing out from apical protibial margin; apical margin of protibia posteriorly without denticles; outer part of posterior surface of protibia sparsely punctate, distinctly separated from glabrous median part of posterior surface by irregular costiform stria fringed with sparse microscopic setae; posterior protibial stria complete, deeply impressed, with sparse microscopic setae; innerventral denticles absent; inner margin with single row of well sclerotized setae.
Mesotibia (for fig. see Lackner 2010, fig. 601) slightly thickened, outer margin with two sparse rows of thin denticles greater in size apically; setae of outer row rather dense, strongly sclerotized and longer than denticles of outer margin; setae of intermediate row sparse, microscopic; posterior mesotibial stria inconspicuous; anterior surface of mesotibia imbricate, with scattered minuscule punctures with microscopic setae; anterior mesotibial stria shortened apically, almost complete; mesotibial spur stout, rather short; apical margin with several tiny denticles; claws of apical tarsomere longer than half its length; metatibia basically similar to mesotibia, but much more thickened and dilated, rows of denticles of outer margin widely separated, outer row of denticles (for fig. see Lackner 2010, fig. 602) observable only from ventral view.

Reichardtiolus sphingis
Differential diagnosis. R. sphingis is best separated from R. pavlovskii by the same characters as R. duriculus; for the differences among rest of the congeners the reader is referred to the key to species.
Biology. According to Mr. S. Bečvář (pers. comm.) the series of this species from Jordan (El Mudawwara) was found under the grass at the foot of a small sand dune.  Distribution. Egypt, surroundings of Cairo; south Jordan, 60 km N El Mudawwara (Fig. 72).

Reichardtiolus aldhaferi
Diagnostic description. Body size: PEL: 2.50-3.25mm; APW: 0.85-1.15 mm; PPW: 1.80-2.25 mm; EW: 2.00-2.50 mm; EL: 1.50-2.00 mm. Body darker than that of R. duriculus, otherwise similar to it. Legs and antennae darker than those of R. duriculus; mouthparts similar except mentum, which is on its anterior margin more emarginated than that of R. duriculus (compare Figs 4 and 35). Clypeus anteriorly elevated (Fig. 34), with slight median depression, rugosely punctate; frons (Fig. 34) coarsely and densely punctate, medially rugulose-lacunose, with shallow depressions; frontal and supraorbital striae and eyes as in R. duriculus. Pronotum slightly less acutely narrowing apically than that of R. duriculus; punctuation on pronotal disk sparser than that of R. duriculus. Elytra similar to those of R. duriculus, but dorsal elytral striae weaker, occasionally striae 3-4 shortened apically, only half as long as striae 1-2 or even evanescent; between 4 th dorsal elytral and sutural striae in several specimens punctures scratch-like and surface with variously deep longitudinal wrinkles; rarely with shallow depression between the bases of 4 th and sutural elytral striae. Punctuation of elytral disk sparser than that of R. duriculus, punctures separated by several times their diameter; in fourth elytral interval occasionally scratch-like. Propygidium and pygidium similar to those of R. duriculus, but punctuation denser and coarser in R. aldhaferi, although not as dense as in R. sphingis (compare Figs 12, 13 and 37). Structure of prosternal process similar to that of R. duriculus, but prosternal keel laterally more compressed and setose (compare Figs 10 and 36); carinal prosternal striae occasionally very approximate, medially almost united and difficult to discern; prosternal foveae smaller than those of R. duriculus. Mesoventrite sub-square, trapezoidal, punctuation sparse, punctures separated by several times their own diameter; marginal mesoventral stria always complete anteriorly, almost straight; meso-metaventral sutural stria absent, suture distinct. Metaventrite, metepisternum and abdominal ventrites similar to those of R. duriculus. Legs as in R. duriculus; except denticles of mesotibia that are sparser, thinner and shorter. Male genitalia: 8 th sternite (Figs 38-39) strongly sclerotized laterally, apically with pseudopores and a row of short setae and small velum covered with minute setae; 8 th tergite (Fig. 39)  with prominent pores; 8 th sternite and tergite fused laterally (Fig. 40). 9 th tergite (Fig.  41) well sclerotized along margins, laterally without projection (Fig. 42), apically with two bisinuate strongly sclerotized lines visible from dorsal view, apical half covered with pseudopores, sclerotization of tergite medially divided, two parts held together by weakly sclerotized part; 10 th tergite basally faintly inwardly arcuate (Fig. 41). Tips of apical end of spiculum gastrale (Fig. 43) without strongly sclerotized parts, apical end strongly inwardly arcuate, basal end outwardly arcuate. Aedeagus (Figs 45-46) similar to that of R. duriculus, but laterally more curved and medially thickened (compare Figs 23 and 46). Differential diagnosis. As with preceding species. Biology. Unknown, presumably similar to the congeners, the examined specimens were collected at light in winter months.

Reichardtiolus pavlovskii
Antennal scape not particularly thickened, punctate dorsally, punctures with numerous long setae; club ( Fig. 65) oval, slightly depressed dorso-ventrally; without visible articulation, entire surface with thick short yellow sensilla intermingled with sparse longer erect sensilla, ventrally with two large round sensory areas (Figs 65, 66); sensory structures of antennal club not examined. Mouthparts: mandibles stout, densely punctate, dorso-lateral area with sparse short setae, acutely pointed; labrum convex with two labral setae growing out from each labral pit; square-shaped, anterior angles produced, anterior margin with deep median excavation, surface around it with four longer setae; lateral margins with double row of shorter ramose setae; disc of mentum imbricate; other parts of the mouth not examined.
Propygidium largely covered by elytra; its punctuation similar to that of elytral disc; pygidium also densely and coarsely punctate; punctures with minuscule setae.
Intercoxal disc of first abdominal ventrite completely striate laterally; completely covered with punctuation; punctures similar to those of disc of metaventrite.
Protibia (Figs 64, 67) dilated, outer margin with three large widely-spaced distal teeth topped by large triangular denticle, diminishing in size in proximal direction, followed by two smaller proximal denticles; setae of outer row thin, sparse and short; setae of median row similar to those of outer row; protarsal groove shallow; anterior protibial stria carinate, almost complete; protibial spur small, straight, growing out near tarsal insertion; outer part of posterior surface of protibia (Fig. 67) Kryzhanovskij, 1959. only with scattered microscopic denticles, demarcation line between outer and median of posterior surface non-existent; posterior protibial stria absent, near inner protibial margin a dense row of strongly sclerotized long setae present; inner margin with sparser row of thinner setae.
Mesotibia slightly thickened, outer margin with row of approximately ten long denticles increased in size apically; setae of outer row dense and long, strongly sclerotized, longer than denticles on outer margin; setae of median row absent; posterior mesotibial stria absent; anterior surface of mesotibia with additional two-three dense rows of short denticles; anterior mesotibial stria complete, terminating in several minute denticles; mesotibial spur short; apical margin of mesotibia with a row of about five short denticles; first and second tarsomere ventrally with four long, strongly sclerotized setae; third and fourth tarsomeres with only two such setae; fifth tarsomere devoid of setae ventrally; claws of apical tarsomere slightly bent, longer than tarsomere itself; metatibia (Fig. 70) much more thickened and dilated than mesotibia, outer margin and posterior surface similar to that of mesotibia; anterior surface of metatibia completely covered with six-seven rows of short, stout denticles (Fig. 71).
Male unknown. Differential diagnosis. Externally somewhat similar to its congeners, it is, however, the most readily distinguishable species of the five. Body (Figs 62-63) larger than in all other congeners (up to 4.25 mm in R. pavlovskii, whereas other Reichardtiolus species attain maximal body length of 3.75 mm), cuticle dark brown to black, en-tire dorsal surface rugulose-lacunose, whereas the dorsal surface of the other species is mostly chestnut brown and punctate, never rugulose-lacunose. Dorsal elytral striae (Fig. 62) of R. pavlovskii are vaguely impressed, almost obliterated under coarse rugulose-lacunose punctuation, only first and second dorsal striae distinguishable, while with the rest of congeners they are usually distinct. This species differs likewise from the rest of its congeners by the structure of the prosternal keel (compare Figs 10-11, 36, 50 and 68), which is projected medially, strongly compressed, almost knife-like, lacking foveae, and with only vestigial striae. R. pavlovskii also differs from the other species by the lateral disc of the metaventrite and fused metepisternum (Fig. 69) that are covered with almost confluent setiferous punctures, whereas the punctures are not confluent in R. duriculus, R. perses, R. aldhaferi or R. sphingis. The protibia (Figs 64 and  67) is similar to the other three species, but adorned with three short teeth topped by acute large triangular denticle (instead of two) followed by one shorter denticle entombed in protibial margin and one more microscopic denticle. The mesotibia on its anterior surface has an additional two-three dense rows of short denticles instead of the single row present in R. duriculus, R. sphingis, R. perses and R. aldhaferi; the metatibia (Figs 70-71) is much more thickened and dilated than those of the other four species; the anterior surface of metatibia has six-seven rows of short stout denticles as opposed to only two rows in R. duriculus, R. sphingis, R. perses and R. aldhaferi. Unfortunately, the only examined specimen is a female so the male genitalia could not be compared to those of other species.
Biology. Found in the sand under Tamarix (Kryzhanovskij & Reichardt, 1976). Distribution. So far known only from two places in Turkmenistan: about 40 km north of Mary, eastern Turkmenistan and Badkhyz Nature Reserve, southeastern Turkmenistan (Fig. 72).
Remarks. Kryzhanovskij (1959), in his original description, omitted the character of the prosternal striae, and in the Fauna USSR (Kryzhanovskij and Reichardt 1976) he provided a brief re-description of this species but omitted the prosternum altogether, pointing only to the greater size and surface of the dorsal side of body as distinguishing characters for separating Reichardtiolus duriculus from R. pavlovskii. R. pavlovskii is, according to Kryzhanovskij in Kryzhanovskij and Reichardt (1976) known only from two females and I have only examined one of them, the holotype. The repository of the second specimen of this rare species is unknown. Although R. pavlovskii is morphologically rather different from the other species of the genus, I am hesitant to erect a new genus for it, especially since no male is available and the male terminalia could not be examined.

1(2)
Metatibia on anterior surface (Fig. 71) with more than 5 dense rows of tiny denticles; protibia on outer margin with three short teeth topped by denticle (Fig. 64), followed by one more small tooth embedded in the outer margin be well adapted to the psammophilous way of life with thickened femora and tibiae, enlarged protibiae with large triangular teeth each topped by a denticle, as well as having the underside of the body covered with vestiture. Phylogenetically speaking, the type species of the genus has been recovered in the recently performed cladistic analysis of the author (Lackner, unpublished) as a member of a large unresolved clade of taxa that all share a single unique synapomorphy of a single, stipe-shaped vesicle inside the internal-distal part of the antennal club, as well as several other, weaker synapomorphies. However, the species R. pavlovskii, which was also included in the analysis, has been recovered rather distant from the type species of the genus, R. duriculus. Because of the low resolution of the morphology-based cladogram, and absence of a male specimen of R. pavlovskii I decided not to alter the generic rank of the latter species. The members of the genus Reichardtiolus cover a rather vast area (Fig. 72) from the Chinese Xinjiang province in the east to the Egyptian locality in the west, from the Kazakh localities in the north to the Saudi Arabian localities in the south. Such a vast area likely houses further undescribed species of Reichardtiolus and it is hoped that this study shall encourage their discovery by fellow entomologists.