Xestipyge skelleyi Warner, 2021

Warner, William B., 2021, A brief review of the New World Xestipyge Marseul (Coleoptera: Histeridae: Dendrophilinae: Paromalini) with description of a new species from the southwestern USA, Insecta Mundi 2021 (854), pp. 1-12 : 8-11

Xestipyge skelleyi Warner , new species

Figures 10–14 , 18

Type material. Holotype male and allotype female (both deposited at ASUT) labeled: USA:AZ:Pima Co.; Forest Rd.62, 2.8mi. W of Hwy.83, N end of Santa Rita Mtns., 31°48′43″N, 110°44′04″; xii.14.2007; Neotoma nest// P.E.Skelley & W.B.Warner, ex Neotoma nest Berlese samples. Diagnosis. Body relatively elongate-elliptical for genus; elytra without pseudostriae except in apical ninth or less, inner subhumeral stria similar coarseness to dorsal striae and complete or nearly so, 4 th dorsal stria forming complete loop with sutural stria, 5 th dorsal stria enclosed within loop and ending free at about basal third or fourth; female pygidium without incised chevron; male with tegmen very elongate, parameres with distinct triangular expansion at about apical 4⁄5 ( Fig. 18 ).

Description of male. Body elliptical; color piceous to dark reddish brown; “ground punctuation” with micropuncture groupings longitudinally separated by about their own widths, slightly denser on pronotum. Head with vertex and front finely and relatively evenly punctate, punctures mostly separated by 1–3× their own diameters; pronotum coarsely and densely punctate in about lateral thirds and in narrow band about 3 punctures deep along posterior margin in middle third, leaving roughly triangular middle portion subimpunctate (i.e. only with microsculpture). Elytron with outer subhumeral distinctly indicated at least in middle third or more, inner subhumeral stria complete or nearly so, nearly as coarse as dorsal striae, dorsal striae complete except for 5th extending anteriorly to about basal quarter beneath sutural arch, all dorsals with strial punctures separated by about 2–4× their own diameters, punctures finely crenulating strial channels, interval between 5th dorsal and suture with scattered coarse punctures in apical half or less, outer intervals impunctate or with sparse coarse punctures in apical quarter or less; all intervals with short apical pseudostriae on and near apical declivity. Propygidium with disc coarsely and moderately densely punctate, punctures similar in size to coarse punctures on elytral apices; pygidium moderately densely punctate, but punctures fine (mostly ¼ or less size of propygidial punctures) and evenly distributed. Prosternum with broadened apical section anterior to antennal club fossae roughly punctate, carinal striae distinct and subparallel in posterior two thirds, their anterior apices slightly (abruptly) converging and ending free; mesosternum with anterior marginal third nearly semicircularly emarginated to receive apex of prosternum, margins lateral to emargination more strongly beaded, bead continuous with lateral metasternal stria, meso-metasternal suture evident; metasternum slightly more than 3× as long as mesosternum, lateral stria ending near middle, lateral section continuous with middle section in posterior half; first abdominal sternite in middle 2⁄5 slightly depressed within basal suture and longitudinal lateral stria at each side forming rectangular area, lateral striae laterally with approximate weaker second stria for much of their length; medial sections of meso- and metasternum and first abdominal sternites forming area of similar sculpture throughout: punctures sparser and smaller medially, in lateral sections punctures coarser and denser. Protarsi with ventral setae flattened and broadened (elongate subfoliate). Genital capsule with 8 th tergite trilobed: medial lobe about 1/3 shorter than lateral lobes and concavely truncated, external subapex of lateral lobes with laminar hyaline lobe, lateral lobes abruptly converging, narrowing and extended medially before apices of these lamina, lateral apices of lobes with several setae extending perpendicularly (i.e. apically in line with long axis of genitalia); tegmen very elongate, parameres slightly shorter than basal piece, expanded to nearly right-triangular “arrowhead” slightly apical to apical 4⁄5, expansion width about ¼ parameral length (dorsal view of combined parameres).

Length: 1.8–2.3 mm; total length: 2.4–2.9 mm; widest width: 1.7–1.8 mm.

Female. Externally nearly identical to male except protarsi with setae simple; pygidium evenly convex without hint of incised chevron or vague depression in apical half. Length: 1.9–2.2 mm; total length: 2.3–2.8 mm; widest width: 1.5–1.9 mm.

Variation. Specimens in the type series are fairly uniform, with minor variation in sculpture and size. Four paratypes have a short (2–3 puncture widths) break at base of sutural stria, one of these also has a longer break in sutural arch at the base of the fourth dorsal on the left elytron.

The California specimens mentioned below have very similar body form and essentially identical genitalia to the holotype, and apparently belong with this species. However, all the California specimens seen consistently differ from the Arizona specimens in having the lateral metasternal stria complete to the metatrochanter, mesosternal marginal bead in anteromedial concavity more strongly incised than laterally, prosternum with strial loop in posterior 2/3 narrower, femora slightly wider, uniformly more pronounced/deeper surface sculpture, with coarse punctures along lateral stria of 1 st abdominal sternite invading deeper towards midline along its basal margin, elytron with sutural stria basally more often tending to be discontinuous in variably short lengths. Additional data (e.g., genetic sequencing) may demonstrate that the California populations represent a distinct specific or subspecific taxon, so they are not included in the paratype series.

Paratypes (5 males, 9 females): same data as holotype (14). Other specimens examined ( CASC, USNM): Cal., C.W. Leng collection (1) ; Cal. : Marin Co., Aug, A. Koebele (1) ; California: Sonoma County, 1.5 mi. W of Bloomfield , 29.IX.1970, ex cow pat (16) ; Cal. , Mendocino Co., vi-20-20, E.S.Ross collection (1) ; Cal. Los Angeles Co., Van Dyke Collection ; Cal., Alameda , i-17-1935, Van Dyke Collection (1) . Paratypes are deposited at CASC, CMNH, CSCA, FMNH, FSCA, UAIC, and the private collections of N. Degallier, P.Kovarik, T. Lackner, and the author.

Etymology. I take pride in naming this new species for Paul E. Skelley, coleopterist extraordinaire, excellent collector and field companion, who did the bulk of the field labor sifting the dusty Neotoma Say and Ord mound sample that held most of the type series while I mostly slouched limply in the truck cab coughing and sneezing with a bad cold and fever.

Remarks. Amongst the New World Xestipyge , X. skelleyi appears closest in appearance to X. conjunctum , but, the different range, elytron with stronger subhumerals and complete (or nearly so) 4 th dorsal to sutural strial loop, male tegmen shape, and lack of an incised chevron on the pygidium of females will immediately separate specimens of X. skelleyi .

Figures

Figures 10–12. Xestipyge skelleyi, paratype male. 10) Genital capsule. 11) Dorsal habitus. 12) Ventral habitus.

Figures 13–14. Xestipyge skelleyi, male. 13) Pygidia and elytral apices, apicodorsal view. 14) Lateral habitus.

Figures 15–19. Xestipyge species tegmena, dorsal view. 15) X. garbigliettii, Durango, Mexico. 16) X. multistriatum, Veracruz, Mexico. 17) X. conjunctum, SC, USA. 18) X. skelleyi, holotype. 19) X. geminatum, NC, USA.