Aglaothorax segnis Rehn & Hebard, 1920

Aglaothorax segnis Rehn & Hebard, 1920 View in CoL comb. restored

Aglaothorax segnis View in CoL — Rehn & Hebard, 1920: 225.

Aglaothorax segnis View in CoL — Tinkham, 1944: 291 (Incorrect synonymy).

Neduba (Aglaothorax) ovata segnis — Rentz & Birchim, 1968: 85 (A change in status).

Aglaothorax segnis View in CoL comb. restored (Restored to species status as proposed by Rehn & Hebard, 1920).

Fig. 6 View FIGURE 6 (distribution), Fig. 10 View FIGURE 10 (male and female habitus, calling song, male and female terminalia, karyotype), Plate 4 View PLATE 4 (male terminalia), Plate 7 View PLATE 7 (female subgenital plate), Plate 10 (male titillators), Plate 14 (male calling song).

Common name. Sluggish Shieldback.

History of recognition. Described in Aglaothorax ( Rehn & Hebard 1920) . Name erroneously applied to eastern Sierra Nevada populations that belong to both A. giganteus and A. ovatus ( Tinkham 1944) . Transferred to Neduba (Aglaothorax) and relegated to a subspecies of ovatus ( Rentz & Birchim 1968) . Returned to Aglaothorax ( Rentz & Colless 1990) where this species remains as a subspecies of A. ovatus ( Cigliano et al. 2025) . Based on phylogenetic and cytogenetic evidence, we elevate A. segnis to species rank, reinstating the taxonomic status of this species as originally described.

Type material. The holotype male housed at ANSP is from Crestline, Lincoln County, Nevada, taken from Joshua tree at 6000 feet elevation. Images of the type are available at OSFO ( Cigliano et al. 2025) . TOPOTYPES EXAMINED: (n=10) USA, NV , Lincoln Co., 13 miles E Panaca on State Highway 319, 37.790280, -114.150913, 1950 m, 11-VIII-1988, DB Weissman, DC Lightfoot, CAS, 1♂, 1♀ GoogleMaps ; 16 miles E Panaca Summit , 37.764601, - 113.897074, 11-VIII-1988, DB Weissman, DC Lightfoot, CAS, 1♂ GoogleMaps ; 18 miles E Panaca on State Highway 319, 37.790059, -114.059173, 1720 m, 11-VIII-1988, DB Weissman, DC Lightfoot, CAS, 1♂ GoogleMaps ; 7 miles E of Panaca , 37.790450, -114.260999, 1829 m, 20-VIII-1982, DB Weissman, CAS, 2♂ GoogleMaps ; Beaver Dam State Park , 37.521362, -114.072202, 12-IX-1973, RC Bechtel, GM Nishida, NDAC, 4♂ GoogleMaps .

Measurements. (mm, ♂ n=5, ♀ n=2) Hind femur ♂ 16.65–17.35, ♀ 19.40–20.74, pronotum total length ♂ 11.15– 13.99, ♀ 13.34–14.35, prozona length ♂ 4.56–5.66, ♀ 5.62–6.15, metazona dorsal length ♂ 6.59–8.44, ♀ 7.72–8.20, pronotum constriction width ♂ 2.97–3.90, ♀ 3.69–5.00, metazona dorsal width ♂ 7.35–8.75, ♀ 8.50–9.25, head width ♂ 5.06–5.62, ♀ 6.05–6.67, ovipositor length ♀ 19.41–20.41.

Distribution. Mountain ranges of southeastern Nevada at high elevation. The type locality is in the Cedar Range. Other populations are known from the Clover Mountains and Bristol Range.

Habitat. Pinyon-juniper woodland. Taken from high branches of Utah Juniper ( Juniperus osteosperma (Torr.) Little ).

Seasonal occurrence. Limited records suggest mid- to late summer adult activity (4-VIII-2005, JA Cole, LACM) that extends into Fall (12-IX-1973, RC Bechtel & GM Nishida, CAS) .

Stridulatory file. (n=5) length 4.85–5.10 mm, 102–117 teeth, tooth density 21.7±1.1 (20.6–23.4) teeth/mm.

Song. (n=18) Brief echemes (“chirps”) similar to A. armiger . Pulse trains 50±10 ms in length are repeated at a rate of 10.1± 1.52 s- 1. Mean peak frequency is 14.13±2.77 kHz; high frequency recordings show song energy at the ultrasonic boundary at 20.25 kHz. Echemes group 3±1 pulse trains with 0.71–3.56 (mean 1.53±0.75) s of silence between echemes.

Karyotype. (n=6) 2n ♂ =24 (22t +XtYt), topotype T88-43 (S88-93).

Recognition. Morphology, geography, and karyotype. A. segnis is separated from all Ovatus Group species except A. strobilion and most A. gurneyi by the apical, mesally directed tooth on the male paraproct process; rarely, the cercus terminates in a double tooth, with one of the two teeth positioned apically. All other Ovatus Group species have a subapical ventrally directed tooth. The male paraproct in A. segnis is about three times as long as wide, as opposed to thick and about twice as long as wide in other Ovatus Group species. The A. segnis male supra-anal plate is wider than long and reflexed caudally, a condition like that of A. armiger and A. strobilion but unlike A. giganteus , A. khioneos , A. ovatu s, and A tinkhamorum , which have supra-anal plates that are as long as wide. A. segnis and A. strobilion have abundant longitudinal black streaks on the pronotal disk, unlike the disk of A. armiger which typically has reduced black marking. The A. segnis pronotum is broader than that of A. strobilion , with a concomitant increase in the ratio of the pronotal constriction width to metazona width in the former versus the latter ( A. segnis 2.24–2.47 vs. A. strobilion 1.97–2.20). Female A. segnis have the shortest subgenital plate lateral processes of any Ovatus Group species (although females of A. strobilion are unknown). Geographically, A. segnis occupies mountain ranges in the northeasternmost extent of the Mojave Desert where that desert interdigitates with the Great Basin Desert. The 2n ♂ =24 karyotype is shared only with A. gurneyi ; all other Ovatus Group species have 2n ♂ =23, including A. strobilion , which superficially resembles this species.

Notes. This species inhabits remote areas and is thus seldom encountered. Individuals perch high in large trees and are thus difficult to collect when found. The 2n ♂ =24 karyotype is shared with another sky island endemic Ovatus Group species, A. gurneyi of the California Transverse Ranges.

Material examined. (n=7) All USA, NV, Lincoln Co., 27 mi. N Pioche on Hwy. 93, 38.32116, -114.452214, 1981 m, 20-VIII-1982, DB Weissman, CAS, 2♂ GoogleMaps ; Hwy. 319, 1.9 miles west of Utah State Line , 37.72564, -114.0844, 1804 m, 19-VIII-2009, DB Weissman, DC Lightfoot, CAS, 1♂ GoogleMaps ; Oak Spring Summit Picnic Area , along US93 , 9.3 mi. E of Caliente, 37.5923, -114.6828, 1901 m, 4-VIII-2005, JA Cole, LACM, 1♂ GoogleMaps ; same data except JAC, 2♂ GoogleMaps ; Pioche , 37.929685, -114.452214, 1848 m, 20-VIII-1958, RC Bechtel, NDAC, 1♀ GoogleMaps .