Cephennium aridum Hopp & Caterino, 2009

Hopp, Katie & Caterino, Michael, 2009, Seven new species of Cephennium Müller & Kunze (Coleoptera, Staphylinidae, Scydmaeninae, Cephenniini) from California with a key to native North American species, ZooKeys 24 (24), pp. 31-54 : 48-50

Cephennium aridum Hopp & Caterino , sp. n.

urn:lsid:zoobank.org:act:859E5725-2579-406B-8E7A-7AB07AE6739B

Figs 1H, 2H, 3H, 4D, 5F, 6

Type Material. Holotype. Male. “CA: San Bernardino Co.; 34.1405°N, 116.4541°W; UC Burns Reserve ; Railroad Cyn, IV.1.2008; sifted from grass & flood debris; M. Ca-

debris; M. Caterino & R. Leschen”/ “CA BEETLE PROJ; CBP 0072926” ( SBMN [gold coated for SEM]).

Paratypes (9): “CALIF: Riverside Co ; 4mi SE Valle Vista; II-1978 K.Cooper; Oak litter 78-57”/ “ CEPHENNIUM ; spp.; S. O’KEEFE DET ‘90” (1 SBMN) ; “CALIF: Riverside Co ; Palm Canyon Aqua [sic]; Caliente Reservation; IV-27-1978 78-67; K.W.Cooper ”/ “berlese litter; at base of Washingtonia filifera ” (1 CSCA) ; “CALIF: Riverside Co.; Whitewater cyn. Palm Oasis; V-4-1987 to XI-27-1988; Rolf L. Aalbu coll.”/ “Ethylene-glycol pitfall; trap at base of Washingtonia filifera ” (2 CSCA) ; “CAL- IF: Riverside Co.; 2 mi. E Gilman Hot; Springs , Lamb Canyon; V-18-1978 / XI-13- 1979; Fred G. Andrews; Antifreeze pit trap ” (5 CSCA) .

Etymology. This species name refers to its occurrence in the arid regions of the western Mojave/ Colorado desert transition zone.

Diagnosis. This 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 ).

Description. Male. Length: 0.817 –0.912 mm; pronotal width: 0.304 –0.342 mm; elytral width: 0.352 –0.418 mm. Body elongate, slender, weakly convex; amber-yellow, translucent; evenly and moderately pubescent; pubescence golden, slender, moderately long, weakly decumbent (Fig. 1H). Dorsal surface of head smooth, sparsely pubescent, narrowing anteriorly from antennal insertions. Single ommatidium present on each side of head ( Fig. 4D ). Antenna setose, antennomeres I and II longer than broad, antennomeres III-VI quadrate and smaller than antennomeres II and VII, antennomere 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 part and moderately flattened near each posterior angle; anterior margin not visible from above; anterior and posterior margin lacking marginal bead; marginal bead complete laterally, gradually widening towards base; lateral edge broadly rounded to posterior third, then weakly sinuate to base (Fig. 1H). Hypomeron smooth, sparsely setose towards anterior quarter and along outside (lateral) edge. Prosternum with small, weakly protruding, oblique narrowly ovate nodules anterolaterad procoxal cavities ( Fig. 2H ). Elytra smooth, lacking striae, as pubescent as pronotum, covering all abdominal segments; elytral suture absent; basomedial fovea present on each elytron; fovea small, moderately pubescent (Figs. 1H, 3H). Humeral angle of elytron projecting laterally to sharp point ( Fig. 3H ). Scutellum weakly triangular, lacking setae ( Fig. 3H ). Mesosternal keel sparsely setose, with scale-like microsculpture over most of its length, abruptly smooth in posterior extreme, apex moderately bifid, divergent projections short, diverging at ̴90° an- gle ( Fig. 2H ). Metathoracic wings vestigial. Femora strongly clavate in distal half; tibiae expanded and becoming more densely setose towards distal half. Five visible abdominal sternites, ventrites V and VI largely fused. Aedeagus with median lobe bulbous, heavily sclerotized, truncate at apex, with very short median dorsal process, weakly emarginate for reception of apex of apical digiform process; apical collar not apparent; dorsal parameres slender, extending well beyond end of median lobe, each with two subapical setae (Fig. 1H).

Female. Unknown.

Biology. The type of this species was sifted from grass and flood debris in a small, spring-fed, but frequently dry drainage. Other specimens were sifted from litter of the native California Fan Palm ( Washingtonia filifera ), which also occur in scattered springfed drainages in the Colorado (and broader Sonoran) desert.

Distribution. This species is known from several localities in the far northeastern Colorado desert, in San Bernardino and Riverside Counties, CA (Fig. 6).

Figures

Figure 2. A–H Mesosternal keel SEMs A Cephennium anophthalmicum Brendel B Cephennium celsifrons Hopp & Caterino C Cephennium mariposae Hopp & Caterino D Cephennium grandarboreum Hopp & Caterino E Cephennium canestroi Hopp & Caterino F Cephennium gilberti Hopp & Caterino G Cephennium urbanum Hopp & Caterino H Cephennium aridum Hopp & Caterino.

Figure 3. A–H Base of left elytron A Cephennium anophthalmicum Brendel B Cephennium celsifrons Hopp & Caterino C Cephennium mariposae Hopp & Caterino D Cephennium grandarboreum Hopp & Caterino E Cephennium canestroi Hopp & Caterino F Cephennium gilberti Hopp & Caterino G Cephennium urbanum Hopp & Caterino H Cephennium aridum Hopp & Caterino.

Figure 4. A–D Characters on the head, including number of ommatidia and male frons A–B Cephennium celsifrons Hopp & Caterino C Cephennium mariposae Hopp & Caterino D Cephennium aridum Hopp & Caterino.