Aglaothorax dactyla ( Rentz & Weissman, 1981 ), 2025

Cole, Jeffrey A., Weissman, David B., Lightfoot, David C., Ueshima, Norihiro & Warchałowska-Śliwa, Elżbieta, 2025, A revision of the shield-backed katydid genus Aglaothorax (Orthoptera: Tettigoniidae: Tettigoniinae: Nedubini), Zootaxa 5667 (1), pp. 1-104 : 76-78

Aglaothorax dactyla ( Rentz & Weissman, 1981) stat. rev.

Neduba (Aglaothorax) diminutiva dactyla — Rentz & Weissman, 1981: 94.

Neduba (Aglaothorax) diminutiva malibu — Rentz & Weissman 1981: 95 New junior subjective synonym.

Fig. 28 (distribution), Fig. 31 (male and female habitus, calling song, male and female terminalia, karyotype), Plate 6 (male terminalia), Plate 9 (female subgenital plate), Plate 13 (male titllators), Plate 15 (male calling song).

Common name. Clawed Shieldback.

History of recognition. Described as a subspecies of Neduba (Aglaothorax) diminutiva from the western Santa Monica Mountains with populations to the east of Malibu Creek named N. (A.) d. malibu ( Rentz & Weissman 1981). Transferred to Aglaothorax where this species is currently classified ( Cigliano et al. 2025). The Santa Monica Mountains Diminutiva Group lineage shows strong genetic separation from other clades in the Group, especially from type A. diminutiva . Although we found phylogeographic separation west and east of Malibu Creek, expanded sample size negates prior morphological diagnosis of subspecies. Coupled with an absence of song and karyotype differences, we recognize A. dactyla at species rank and synonymize A. d. malibu under A. dactyla .

Type material. The holotype female of N. (A.) d. dactyla was collected from the junction of State Highway 23S and Mulholland Highway, Los Angeles County , California and is housed at CAS. The holotype male of N. (A.) d. malibu was collected at Big Rock Canyon Road 0.4 miles north of Pacific Coast Highway in Malibu , Los Angeles County , California, and is also housed at CAS. Images of the types are available at OSFO ( Cigliano et al. 2025) .

PARATYPES EXAMINED: (n=2) dactyla USA, CA , Los Angeles Co., Cal Hwy 23 Mulholland Hwy., 34.0873, -118.8742, 556 m, 21-VI-1971, DB Weissman, CAS, 1♀ ; Ventura Co., Point Mugu State Beach dune area, 34.083332, -119.050003, 4 m, 19-VII-1972, DB Weissman, CAS, 1♂ ; TOPOTYPES EXAMINED: (n=9); dactyla USA, CA, Los Angeles Co., Malibu , Eino’s , corner of Mulholland and Decker (23S), 34.08855, -118.87360, 2- VII-1976, DB Weissman, CAS, 1♂ ; SR23S & Mulholland Hwy. , 34.0873, -118.8742, 548 m, 14-VIII-1982, DB Weissman, CAS, 3♂ ; same data except 17-VI-2008, JA Cole, LACM, 1♂ ; same data except JAC, 1♀ ; malibu USA, CA, Los Angeles Co., Malibu , Big Rock Canyon Rd. at Rockport, 34.035842, -118.609528, 28-VI-1976, DB Weissman, CAS, 1♂ ; Malibu , intersection of Big Rock and Inland Roads, 34.035842, -118.609528, 5-VII-1982, DB Weissman, CAS, 2♂ .

Measurements. (mm, ♂ n=17, ♀ n=11) Hind femur ♂ 13.65–16.07, ♀ 15.70–19.35, pronotum total length ♂ 8.04–9.76, ♀ 7.05–9.95, prozona length ♂ 2.90–4.19, ♀ 3.24–5.05, metazona dorsal length ♂ 4.58–5.95, ♀ 3.40– 5.00, pronotum constriction width ♂ 2.25–3.05, ♀ 2.61–3.40, metazona dorsal width ♂ 5.60–6.65, ♀ 5.03–6.75, head width ♂ 3.35–3.88, ♀ 4.07–4.81, ovipositor length ♀ 11.00–14.30.

Distribution. Santa Monica Mountains, California.

Habitat. Coastal sage scrub, grassland, chaparral, oak woodland. Frequents hillsides, hilltops, and dry (south) slope chapparal. On California Sage ( Artemisia californica Less. ), Mulefat ( Baccharis sp. ), Laurel Sumac, Ceanothus spp. , Monkeyflower, Western Sycamore, Coast Live Oak, Scrub Oak, White Sage ( Salvia leucophylla Greene ), and Poison Oak.

Seasonal occurrence. Spring (3-V-1997, JA Cole, LACM) through summer (24-VIII-1976, PH Sullivan , CAS). Nymphs and adults occurred alongside one another at the early date record .

Stridulatory file. (n=6) length 3.20–3.90 mm, 81–106 teeth, tooth density 27.8±2.7 (25.3–32.8) teeth/mm.

Song. (n=46) Common small Aglaothorax song with slowly produced pulse trains that are countable by a human listener. Pulse trains 50±20 ms in length are produced at a rate of 5.05± 0.79 s- 1. Mean peak frequency is 15.84±4.43 kHz, with peak frequencies as high as 26.60 kHz detected with ultrasonic recording equipment. Echemes are highly variable in length and group 36±20 (5–92) pulse trains. The echeme repetition rate is 1–12 min-1. Males are synchronous chorusers. Followers may join leaders and overlap pulse trains precisely, making it difficult to gauge the number of males singing in an area. Across distance, choruses may be heard to spread like waves as males at increasing distances join the chorus center.

Karyotype. (n=3) 2n ♂ =24 (22t +XtYt), topotype T82-123 (S82-56).

Recognition. Morphology, geography. The male supra-anal plate is heart-shaped, sometimes only slightly, but the caudal margin of the plate is always indented, the paraproct processes have an internal apical tooth, and the titillator arms are long and bowed, characters that separate A. dactyla from Morsei Group species. Sympatric and nearby allopatric Morsei Group species have rounded supra-anal plates, a subapical tooth on the paraproct process, and short, barely curved titillator arms. The long, bowed titillators also separate A. constrictans from consideration, which has short titillator arms and A. oreibates , which has long titillators that show less lateral curvature. The female subgenital plate has the longest and most slender digitiform lateral processes of any Aglaothorax ; the processes of A. acrolophitus and A. poecilonotum are shorter, thicker at the base, and more strongly tapered.

Notes. Complete syntopy of A. dactyla and A. costalis in a garden were noted in their original description, where their specific distinction was evident from obvious song differences ( Rentz & Weissman 1981). We have since observed syntopy throughout the Santa Monica Mountains: both species may be found on the same plants and choruses of their divergent songs may be heard alongside one another. The history of mitochondrial capture by A. costalis and A. longipennis ( Fig. 3 ) illustrates incomplete reproductive isolation. The contact zone between A. dactyla and A. costalis is an example of reinforcement of premating isolation. Females of both species avoid songs of heterospecifics (Cole 2016), which is made possible by evolution of a rapid pulse train rate in A. costalis . In addition to song, the two species show partial ecological and temporal isolation. A. dactyla prefers the dry upland or south facing slopes while A. costalis is more common in lowland, mesic, and riparian areas. Adult activity commences and ceases earlier in the season in A. dactyla than in A. costalis . East of Malibu Creek, A. dactyla is broadly sympatric with A. longipennis but that pair are more strongly separated by habitat and have not been observed in syntopy.

Material examined. (n=51) All USA, CA, Los Angeles Co., Backbone Trailhead , at junction Stunt , Schueren , and Saddle Peak Rds., 34.0812, -118.6454, 721 m, 9-24-VI-2012, JA Cole, JAC, 2♂, 2♀ ; Calamigos Ranch , 34.09278, -118.81694, 550 m, 1-VII-1961, DL Gibo, CSUN, 1♀ ; Charmlee County Park, 34.0608, -118.8771, 427 m, 23-24-VIII-1976, PH Sullivan, CAS, 1♀ ; Charmlee Wilderness Park , 3.8 miles north of SR1 on Encinal Canyon Road, 34.0608, -118.8771, 427 m, 29-30-VI-2006, JA Cole, JF Eguizabal, LACM, 1♂ ; same data except 2-VI-2005, JA Cole, JF Eguizabal, LACM, 1♀ ; same data except JAC, 1♂ ; same data except 3-4-V-1997, JA Cole, LACM, 1♂, 1♀ ; Griffith Park , Mount Hollywood Trail, 34.1240, -118.3009, 370 m, 7-V-2002, JA Cole, JF Eguizabal, 1♂ sound record; junction Big Rock Drive and SR1, 34.0377, -118.6088, 5 m, 17-VI-2008, JA Cole, 1♂ sound record; junction Las Flores Canyon Rd. and Schueren Rd., 34.0625, -118.6486, 469 m, 24-25-VI-2012, JA Cole, JAC, 1♂ ; junction Las Flores Rd. and Gorge Rd., 34.0507, -118.6391, 66 m, 25-VI-2012, JA Cole, LACM, 1♂ ; Leo Carrillo State Park , Nicholas Flat, at end of Decker School Rd., 34.0638, -118.9128, 457 m, 3-VI-2008, JA Cole, LACM, 1♂, 1♂ sound record; same data except 5-VI-2007, JA Cole, LACM, 1♂ ; same data except 8-VI-2008, JA Cole, LACM, 1♂ ; Topanga State Park , Dead Horse Trail, 34.0915, -118.5939, 274 m, 27-28-V-2008, JA Cole, 1♂ sound record; UCLA Stunt Ranch Santa Monica Mountains Reserve , 34.0951, -118.6486, 374 m, 12-13-VI-2014, JA Cole, DA Gray, LACM, 1♂ ; Ventura Co., Point Mugu State Park , Sycamore Canyon, 34.0728, -119.0145, 4 m, JA Cole, LACM, 7♂, 1♀ ; same data except 11-VI-2007, JA Cole, LACM, 1♀ ; same data except 14-15-VI-2007, JA Cole, 1♂ sound record; same data except JA Cole, JF Eguizabal, LACM, 1♂ ; same data except 16-17-VI-2008, JA Cole, LACM, 1♀ ; same data except JAC, 1♀ ; same data except 18-VI-2007, JA Cole, 1♂ sound record; same data except 2-3-VI-2008, JA Cole, LACM, 4♂ ; same data except JAC, 1♂ ; same data except 28-29-V-2007, JA Cole, 1♂ sound record; same data except 4-VI-2007, JA Cole, AMNH, 1♂, 1♀ ; LACM, 2♂ ; same data except 5-6-VI-2006, JA Cole, LACM, 3♂, 1♀ ; JAC, 1♂; same data except 9-VI-2005, JA Cole, LACM, 1♀ .

Figures

FIGURE 3. Bayesian consensus tree of mtDNA matrix. Nodes with less than 85% posterior probability are collapsed.Terminals in red are Diminutiva Group exemplars that experienced mitochondrial capture into the Morsei Group.

FIGURE 28. Distribution of Diminutiva Group species.

FIGURE 31. A. dactyla male and female habitus, calling song, male and female terminalia, and karyotype. Idiogram shows karyotype 2n♂=24.