Seven new species of Cephennium Müller & Kunze ( Coleoptera , Staphylinidae , Scydmaeninae , Cephenniini ) from California with a key to native North American species

Seven new species of Cephennium from California are described and illustrated C. celsifrons, sp. n., C. mariposae, sp. n., C. grandarboreum, sp. n., C. canestroi, sp. n., C. gilberti, sp. n., C. urbanum, sp. n. and C. aridum, sp. n. Th e single known native Nearctic species, C. anophthalmicum Brendel, was known only from moist coastal forests around the San Francisco Bay area. Th e new species greatly expand the distribution of the genus, through central and southern California, occurring in the central Sierra Nevada, south through the coast ranges and Sierra Nevada to the Santa Monica Mountains and desert foothills of the San Bernardino and San Jacinto Mountains. A key to all eight species (the entire native Nearctic fauna) of Cephennium occurring in California is provided.


Introduction
Members of the tribe Cephenniini (Coleoptera: Staphylinidae: Scydmaeninae) are primarily known to occur in the western Palearctic region, and most of the known spe-cies belong to the genus Cephennium.Newton and Franz (1998) report 124 species of Cephennium, only one of which is known to occur in the Nearctic (O'Keefe 2001).Th is species, Cephennium anophthalmicum, was described by Brendel in 1889 from Alameda County in coastal, central California, and until this time remains the only species of this genus described from the Nearctic region (O'Keefe 2001).A second species of Cephennium, C. gallicum Ganglbauer, has been reported from maritime northeastern North America, but this represents a recent introduction from Europe (Majka and Klimaszewski 2004).
Th e California Floristic Province is a biodiversity hotspot, recognized for its unique, diverse, and threatened biota (Myers et al. 2000).Th e California Beetle Project, begun in 2005, was launched to compile a complete inventory of the region's Coleoptera.Th is eff ort has documented over 8000 species, and uncovered numerous new ones, both undetected and undescribed (Caterino 2006;Caterino and Chatzimanolis 2007;Caterino et al. 2008).Th rough these eff orts the inadequacy of current documentation of the region's leaf litter fauna has become ever clearer.Intensive collecting in this microhabitat by members of the CBP has yielded several new species of Cephennium since 2004, three of which were discovered in the past two years.Along with the newly collected material, four species were discovered in the collections of the California State Collection of Arthropods (CSCA) and the Field Museum of Natural History (FMNH), whose collectors, Fred Andrews and Art Gilbert (by association, CSCA), and Al Newton and Margaret Th ayer (FMNH) are avid litter sifters.Only one of the species from our newly collected material and the material we borrowed from other collections overlap, leaving us with seven new species.Th ese seven new species represent a considerable increase in the known Nearctic fauna of this tribe and genus, and signifi cantly expand its known geographic range.

Materials and methods
Specimens examined for this study are deposited in the following institutions and collections (all collection codens follow Evenhuis (2008) and the curators responsible for borrowed specimens are listed in parentheses): CASC California Academy of Sciences, San Francisco, CA (David Kavanaugh, Jere Schweikert).CSCA California State Collection of Arthropods, Sacramento, CA (Chuck Bellamy).FMNH Field Museum of Natural History, Chicago, IL (Margaret Th ayer, Alfred Newton).LACM Los Angeles County Museum of Natural History, Los Angeles, CA (Brian Brown).MCZC Museum of Comparative Zoology, Harvard University, Cambridge, MA (Philip Perkins).SBMN Santa Barbara Museum of Natural History, Santa Barbara, CA.
Label data from the material examined are verbatim and transcribed following Ivie (1985): the end of each line on a label is indicated by a ";" (semicolon); the individual labels are separated by a "/" (backslash).
Specimens were studied with a Leica® MZ9.5 stereomicroscope equipped with a 150w Nikon MKII fi ber optic light.SEMs were taken with a Zeiss® EVO 40 XVP Scanning Electron Microscope.Specimen measurements were taken using an eyepiece micrometer in a Leica® MZ9.5 stereomicroscope at 3.2× magnifi cation.Length was measured medially from the base of the pronotum to the apex of the elytra; pronotal and eytral widths were measured at their widest points.
Male genitalia were extracted by fi rst relaxing the specimen in hot water and then the entire specimen was placed in a warm solution of 10% KOH.Once the specimen was cleared, it was removed from the KOH solution and rinsed with distilled water, and then placed in 100% EtOH for dissection.Th e specimen was placed on its dorsal surface and then the abdomen was "pumped" by compressing the abdomen repeatedly just basad of the medial lobe.Th is gentle pumping pushed the genitalia out through the apical abdominal opening.After examination, the genitalia were then placed in a vial of glycerin that was placed on the pin under the specimen labels.Males can sometimes be recognized when the outline of the genital capsule can be observed through the translucent cuticle.Otherwise, except in the case of C. celsifrons, where there is a distinct sexual dimorphism, the sexes are not usually distinguishable.

Key to Nearctic genera of Scydmaeninae
Th e most recent key to Nearctic genera of Scydmaenidae (=Scydmaeninae, Grebennikov and Newton 2009) (O'Keefe 2001) must be modifi ed in order to accommodate the new species of Cephennium described herein.We also revise this to refl ect Jałoszyński's (2007)

Morphological characters of significance
Th ere are a few diagnostic characters among the California Cephennium species that may aid in identifying species collected in the future, and in determining their status as described or new.Among the species we examined, characters that were useful in delimiting species included the presence of eyes and number of ommatidia, the shape of the humeral angle of the elytron, the number of scutellar setae, the vestiture and apical shape of the mesosternal keel, and the male genitalia.Within the aedeagus, structures that were morphologically useful to delimit species were the shape of the median dorsal projection and the arrangement of setae arising from the apical collar.Diagnosis.This species can be distinguished from its California congeners by the character combination of the absence of eyes, humeral angle of elytron bluntly angulate (Fig. 1A), and the absence of a basal elytral sutural ridge.Cephennium anophthalmicum most closely resembles C. urbanum, but can be separated from it by the presence of a basal elytral sutural ridge (Fig. 1G), and the apex of the mesosternal keel divergent and crescent-shaped in C. urbanum (Fig. 2G).It can be easily distinguished from C. aridum, C. celsifrons, and C. mariposae by the presence of eyes in these species (Fig. 4A, C-D), and can be separated from C. grandarboreum, C. canestroi and C. gilberti by the humeral angle of the elytron, which is raised, dorsally flattened and apically rounded in these three species (Fig. 3D-F).Redescription.Male.Length: 0.874 mm; pronotal width: 0.418 mm; elytral width: 0.475 mm.Body elongate, slender, weakly convex; testaceous; evenly and moderately pubescent; pubescence golden, slender, moderately long, weakly decumbent (Fig. 1A).Dorsal surface of head smooth, weakly pubescent, narrowing anteriorly from antennal insertions.Eyes absent.Antenna setose, antennomere I and II longer than broad, antennomeres III-VI quadrate and smaller than antennomeres II and VII, an- tennomere VIII smaller than antennomeres VII and IX, antennomeres IX-XI gradually clavate forming a loose club.Pronotum moderately pubescent, broadest between middle and anterior third, very convex in disc and moderately fl attened near each posterior angle; anterior margin not visible from above; anterior and posterior margin lacking marginal bead; lateral marginal bead complete, gradually widening towards base; lateral edge broadly rounded to posterior third, then weakly sinuate to base (Fig. 1A).Hypomeron smooth, sparsely setose towards anterior quarter and along outside (lateral) edge.Prosternum lacking protuberant nodules anterolaterad procoxal cavities (Fig. 2A).Elytra smooth, as pubescent as pronotum, covering all abdominal segments; elytral suture fl at; basomedial fovea present on each elytron; fovea moderate in size, moderately pubescent (Figs.1A, 3A).Humeral angle of elytron projecting laterally to blunt point, dorsally raised and fl attened (Fig. 3A).Scutellum weakly triangular, lacking setae (Fig. 3A).Mesosternal keel sparsely setose, lacking scale-like microsculp-
Female.Identical to male.Biology.Th is species was fi rst described from a single specimen that was sifted from vegetable debris.An additional specimen was sifted from forest duff .Beyond this, there is little known about the biology of this species.
Etymology.Th is species name is derived from the latin celsus (elevated or lofty) in combination with frons, in reference to the unique, prominent sexual dimorphism exhibited by the male.
Diagnosis.Th is species can be distinguished from all California congeners by the character combination of the presence of two ommatidia on each side of the head (Fig. 4A), the mesosternal process truncate at the apex (Fig. 2B), and the frons of the male with a median longitudinal ridge (Fig. 4B).Th e male frons structure is unique to this species.Cephennium celsifrons and C. mariposae are otherwise very similar but can be distinguished by the number of ommatidia present (2 vs. 4, respectively, Figs.4A, C).Cephennium aridum has a single ommatidium on each side of the head (Fig. 4D), and no other species exhibit any traces of eyes.
Female.Identical to male except frons fl at.Biology.Th is species has been collected from berlesed litters of oak, rotten wood, mixed oak/conifer, and mixed hardwood.Th is species apparently favors moist habitats.
Distribution.Th is species has been collected in the mid-elevations of the central Sierra Nevada, from localities in Amador and Calaveras Counties (Fig. 6).Etymology.Th is species is named for the county and town from which it was collected, Mariposa.

Cephennium mariposae
Diagnosis.Th is species can be distinguished from its California congeners by the character combination of the presence of four ommatidia on each side of the head (Fig. 4C), the mesosternal process truncate at the apex (Fig. 2C), and the humeral angle of the elytron weakly raised and dorsally fl attened (Fig. 3C).Cephennium mariposae is most similar to C. celsifrons but can be distinguished from it by the latter having only two ommatidia on each side of the head (Fig. 2A) and a more elongate and slender body form (Fig. 1B).Th is species can be easily separated from C. urbanum, C. anopthalmicum, C. canestroi, C. grandarboreum and C. gilberti by the absence of ommatidia and the apex of the mesosternal keel being divergent in these species.It can be further distinguished from C. anophthalmicum, C. urbanum and C. aridum by the humeral angle of the elytron projecting laterally to a point in these three species (Fig. 3A, G-H).
Female.Identical to male.
Biology.Th e lone specimen of this species was collected from a rotten log.Distribution.Th is species is only known from Mariposa in Mariposa County, CA (Fig. 6).Etymology.Th is species name is the combination of the Latin words grandis and arboreus, meaning very large tree, as this species is associated with coast redwoods (Sequoia sempervirens).

Cephennium grandarboreum
Diagnosis.Th is species is most similar to Cephennium gilberti but can be distinguished from it by its body size and shape.Cephennium grandarboreum is represented by the largest specimens (0.988-1.121 mm long) of this genus currently known to occur in California, and is very robust.C. gilberti is known from the smallest specimen (0.646 mm long) of this genus known to occur in California and is much more slender and elongate.Th ese two species can also be separated by the mesosternal keel, which is strongly divergent in C. grandarboreum, which has the apex ~2.4× as wide as the widest anterior point (Fig. 2D).Th e mesosternal keel of C. gilberti is weakly divergent and ~2× as wide as the widest anterior point (Fig. 2F).Cephennium grandarboreum can be separated from all other species by having two scutellar setae (Fig. 3D) instead of four (Fig. 3E) or zero (Figs 3A-C, G-H).Apart from the scutellar setae, C. grandarboreum and C. canestroi are quite similar, with rounded elytral humeral angles, but the elytral foveae are large and densely setose in C. grandarboreum (Figs.1D, 2D), whereas they are smaller and moderately setose in C. canestroi (Fig. 1E, 2E).Th e humeral angle of the elytron is also more slender and posterorly curved in C. grandarboreum (Fig. 3D) than in C. canestroi (Fig. 3E), and has a more strongly divergent mesosternal keel (Fig. 2D) than C. canestroi (Fig. 2E).
Female.Identical to male.Biology.Specimens were extracted from redwood litter and a combination of maple and redwood litter with the use of Berlese funnels.
Distribution.Th is species is known from a few localities near Big Sur, Monterey County, CA (Fig. 6).Etymology.We are pleased to name this species for Don Canestro, director of the Rancho Marino Reserve, in appreciation of his generous assistance with our fi eldwork.

Cephennium canestroi
Diagnosis.Th is species can be separated from its California congeners by the character combination of the absence of eyes, humeral plateau of the elytra raised, dorsally fl attened and apically rounded, and scutellum with four setae (Fig. 3E).Cephennium canestroi most closely resembles C. grandarboreum and C. gilberti, all having a generally rounded humeral angle (Figs.3D-F), but C. canestroi can be distinguished from them by having four scutellar setae (Fig. 3E) instead of two (Fig. 3D, F).Cephennium canestroi can be separated from C. anophthalmicum and C. urbanum by the shape of the elytral humeral angle, which projects laterally to a point in the latter two species (Fig. 3G-H).
Female.Identical to male.Biology.Th is species has been collected from Heteromeles (Toyon) and Salix (Willow) litter.Th e collecting sites occur near a native stand of Monterey Pine (Pinus radiata), and is along the coast near the town of Cambria.Collecting sites were in a rocky drainage, with sparse shrubby willow cover, facing and only a few hundred meters from the ocean, and on a shaded northeast facing slope under a very large toyon tree, with a dense understory of Rubus and Toxicodendron.
Distribution.Th is species has been only collected from San Luis Obispo County, CA, in the University of California Rancho Marino Reserve (Fig. 6).Oak; Litter" (CSCA).We did not risk dissecting the type to determine sex due to its uniqueness and minute size.

Cephennium gilberti
Etymology.We name this species in honor of Dr. Art Gilbert, collector of the unique specimens of two of the species described herein, including this one.
Diagnosis.Th is species can be distinguished from its California congeners by the character combination of the eyes absent, humeral angle of the elytron raised, dorsally fl attened and apically rounded (Fig. 3F), scutellum with two setae (Fig. 3F), and the mesosternal keel weakly divergent at the apex (Fig. 2F).Th is species most closely resembles C. grandarboreum, but can be distinguished from it by its smaller size (0.646 mm long), more elongate and slender body (Fig. 1F), the posterior angles of the pronotum being sharper in C. gilberti (Fig. 1F), and the mesosternal keel more weakly divergent at the apex with the apex approximately only 2× as wide as the widest point anterior to the apex (Fig. 2F), as opposed to the apex strongly divergent and nearly 2.4× as wide as the widest point anterior to the apex as in C. grandarboreum (Fig. 2D).C. gilberti can be separated from C. anophthalmicum, C. urbanum and C. aridum by the humeral angle of the elytron, which projects laterally to a point in these species (Fig. 3A, G-H).Finally, it can be distinguished from C. celsifrons, C. mariposae and C. aridum by the presence of ommatidia in these species (Fig. 4A, C-D).
Biology.Th is species has been collected only from berlesed oak litter.Distribution.Th is species is known from a single locality fi ve miles east of Glennville, at about 1800m in the southern Sierra Nevada of Kern County, CA (Fig. 6).Etymology.Th e species name urbanum signifi es the proximity of the Santa Monica Mountains to the urban development of greater Los Angeles.Th ese mountains represent an extremely important island of native biodiversity surrounded by development.

Cephennium urbanum
Diagnosis.Th is species can be distinguished from its California congeners by the character combination of the absence of eyes, humeral angles of elytral project laterally to a sharp point (Fig. 3G), presence of a basal elytral sutural ridge (Fig. 1G), and the apex of the mesosternal keel crescent-shaped (Fig. 2G).Th is species most closely resembles C. anophthalmicum but they can be separated by the basal sutural ridge, absent from C. anopthalmicum, and the apex of the mesosternal keel, which is divergent and crescent-shaped in C. urbanum (Fig. 2G) and very weakly divergent and angulate in C. anophthalmicum (Fig. 2A).It can be easily distinguished from C. celsifrons, C. mariposae and C. aridum by the presence of eyes in these species (Fig. 4A, C-D).Finally, it can be distinguished from C. grandarboreum, C. canestroi and C. gilberti by the humeral angle of the elytron, which is raised and rounded in these three species (Fig. 3D-F).
Female.Identical to male.Biology.Th is species has been sifted and extracted by Berlese funnels from Quercus (oak) and Heteromeles (Toyon) litter as well as mixed litters of Quercus and Rhus (sumac), Quercus and Salix (willow), Quercus and Platanus (sycamore), Quercus, Ceanothus (California lilac), and Heteromeles, and from a Neotoma (woodrat) nest pile under Quercus.
Distribution.Th is species has mainly been collected in the Santa Monica Mountains in Los Angeles County, CA, with a single record from 'Pasadena' in the western foothills of the San Gabriel Mountains (Fig. 6).Etymology.Th is species name refers to its occurrence in the arid regions of the western Mojave/Colorado desert transition zone.

Cephennium aridum
Diagnosis.Th is species can be immediately distinguished from all of its California congeners by the presence of a single ommatidium on each side of the head (Fig. 4D).Besides this somewhat cryptic character, C. aridum shares a sharply angulate humeral process only with C. urbanum.Th e mesosternal keel of C. aridum, however, has scalelike microsculpture between the mesocoxae (Fig. 2H), whereas that of C. urbanum has only setose punctures between the coxae, its scale-like microsculpture being restricted to the extreme anterior end (Fig. 2G).Th e mesosternal process of C. urbanum is also distinctly crescent-shaped (Fig. 2G), where that of C. aridum is angulate (Fig. 2H).
Female.Unknown.Biology.Th e type of this species was sifted from grass and fl ood debris in a small, spring-fed, but frequently dry drainage.Other specimens were sifted from litter of the native California Fan Palm (Washingtonia fi lifera), which also occur in scattered springfed drainages in the Colorado (and broader Sonoran) desert.
Distribution.Th is species is known from several localities in the far northeastern Colorado desert, in San Bernardino and Riverside Counties, CA (Fig. 6).(Caterino, unpublished data).Th e cool and foggy coastal environments conceivably provide similar microhabitats to those inhabited by the genus further northward.Th e discovery of Cephennium in the Santa Monica Mountains, however, represents a major disjunction, not only in distance, but into much drier environments, mostly dominated by chaparral and relatively sparse oak woodland.Th e presence of C. aridum on the fringes of the Colorado desert takes this to an extreme, occurring in areas receiving less than 10 inches of rain/year.Finding additional, localized species in the Sierra Nevada also extends the range of the genus into true montane habitats.Together these new localities indicate surprising adaptability in ecological requirements, and suggest that many other populations of these beetles will be discovered through diligent searching.
Aside from the above habitat-related observations, we know very little about the natural history of these beetles, as all were collected through Berlese extraction of sifted leaf litter.Th e litters represent a variety of plants and plant communities, from fan palm oases to chaparral, redwood forest, and oak woodland.In these habitats, species of Cephennium are expected to be armored mite predators, with suction disks on their labium, and rasp-like mandibles to slowly grind a hole in the thick dorsal surface of the mite (Schmid 1988;Newton and Franz 1998;O'Keefe 2001;Jałoszyński 2009).We have observed similar labial suction disks to those described for European species.Th us, it is probably a safe speculation that the new species are also specialist oribatid mite predators.
Th e biogeographic history of the California Floristic Province is complex and poorly understood.While broad scale distributional patterns have long been evident, understanding the fi ner scale movements of lineages through time has suff ered from very fragmentary data on distribution patterns for those smaller, more sedentary taxa that would be most expected to refl ect deep history.Th e cryptic fauna of leaf litter stands to greatly increase not only our knowledge of gross biodiversity, but also the evolutionary processes responsible for generating and maintaining it.Th e insect fauna of this region in general remains woefully underdocumented.Increased survey eff ort focusing on the more cryptic elements of the regional fauna would be repaid many times over in biogeographic understanding and in management applicability.

Figure 6 .
Figure 6.Distribution map for all California species of Cephennium.

Cephennium Müller & Kunze
Type Material.Not seen.A holotype was not designated for this species.However, it was described from a single specimen from Alameda County that was sifted from vegetable debris together with a large number of Pinodytes cryptophagoides (currently Catopocerus cryptophagoides) by Marie Fuchs (Brendel 1889).We attempted to track down this specimen but were not able to locate it at either the Academy of Natural Sciences in Philadelphia, the original repository of the Brendel collection, or the Museum of Comparative Zoology at Harvard University, the current repository for the Brendel collection.However, we did see a specimen from the MCZC that was determined as C. anophthalmicum from Alameda County.Because the label data do not exactly match the information presented by Brendel (1889) we believe this is only a topotype, and not a primary type.We choose not to designate a neotype here as it is possible that the original type specimen is still in existence somewhere.Material Examined."Alameda; Co. CAL."/ "Laundry; Farm"/ "H. C. FALL; COLLECTION"/ "Cephennium; anophthalmicum; Brend."(1 MCZC); "Mill Valley;

Hopp & Caterino, sp. n.
San Luis Obispo Co. Cephennium gilberti Hopp & Caterino, sp.n.Kern Co. Cephennium urbanum Hopp & Caterino, sp.n.Los Angeles Co. Cephennium aridum Hopp & Caterino, sp.n.Riverside Co. and San Bernardino Co. Discussion Th e discovery of these new species constitutes a signifi cant expansion of the known range of Cephennium, and Cephennini in general, in the New World.Previously represented by a single species, confi ned to moist coastal forests of central California, Cephennium appeared to have a minimal, possibly relictual, presence in North America.Th e discovery of several additional species, across widely separated and ecologically varied habitats instead indicates that the group has undergone considerable diversifi cation in the region.Th e type localities of C. grandarboreum and C. canestroi, in Monterey and San Luis Obispo Counties, alone would represent only a slight extension of range down the coast, into an area otherwise known to host several southernmost records for various beetles