Aphonopelma xwalxwal Hamilton

Hamilton, Chris A., Hendrixson, Brent E. & Bond, Jason E., 2016, Taxonomic revision of the tarantula genus Aphonopelma Pocock, 1901 (Araneae, Mygalomorphae, Theraphosidae) within the United States, ZooKeys 560, pp. 1-340 : 254-257

Taxon classification Animalia Araneae Theraphosidae

Aphonopelma xwalxwal Hamilton sp. n. Figures 147, 148, 149

Types.

Male holotype (APH_3134) collected on Hwy S22 (Montezuma Valley Rd), 3.3 miles S junction with Palm Canyon Dr. (Borrego Springs), Anza-Borrego State Park, San Diego Co., California, 33.225633 -116.414633 1, elev. 1710ft., 4.x.2013, coll. Wendell Icenogle; deposited in AUMNH. Paratype male (APH_3133) from Hwy S22 (Montezuma Valley Rd), 4 miles S junction with Palm Canyon Dr. (Borrego Springs), Anza-Borrego State Park, San Diego Co., California, 33.224618 -116.424232 1, elev. 1935ft., 5.x.2013, coll. Wendell Icenogle; deposited in AMNH.

Etymology.

The specific epithet is a noun in apposition, referencing the word for "a type of small spider" in the language of the Cahuilla Native Americans, whose traditional territory includes the distribution of this species (from the Coachella Valley to Borrego Springs). Pronounced “hwalhwal”; xw - sounds like a light raspy sound when blowing out a candle; a - sounds like “a” in father; l - sounds like “l” in light.

Diagnosis.

Aphonopelma xwalxwal (Fig. 147) is a member of the paloma species group and can be distinguished by a combination of morphological, molecular, and geographic characteristics. Nuclear and mitochondrial DNA identifies Aphonopelma xwalxwal as a phylogenetically distinct monophyletic lineage, supported as the sister lineage to the remaining members of the paloma species group (Figs 7-8). Aphonopelma xwalxwal is the largest of the miniature Aphonopelma , and while they are very similar looking to Aphonopelma joshua , Aphonopelma xwalxwal are slightly larger and has a different mating period (fall versus summer). Aphonopelma xwalxwal can be distinguished from Aphonopelma eutylenum by its smaller size, general phenotypic appearance, and the extent of scopulation on metatarsus IV, and from all other members of the paloma species group by locality. Like Aphonopelma joshua , Aphonopelma xwalxwal possess unique stout setae on the sternum. The significant measurement that distinguishes male Aphonopelma xwalxwal from its closely related phylogenetic and syntopic species is F4. Male Aphonopelma xwalxwal can be distinguished by possessing a smaller F4/T4 (≤1.05; 1.00-1.05) than Aphonopelma eutylenum (≥1.14; 1.14-1.22), Aphonopelma icenoglei sp. n. (≥1.14; 1.14-1.18), Aphonopelma joshua (≥1.07; 1.07-1.15), and Aphonopelma paloma (≥1.14; 1.14-1.24). Females of Aphonopelma xwalxwal are unknown at this time, though juvenile males look very similar to Aphonopelma joshua .

Description of male holotype

(APH_3134; Fig. 148). Specimen preparation and condition: Specimen collected live crossing road, preserved in 80% ethanol; original coloration faded due to preservation. Left legs I, III, IV, and left pedipalp removed for measurements and photographs; stored in vial with specimen. Right legs II & III removed for DNA and stored at -80°C in the AUMNH (Auburn, AL); missing leg IV right side. General coloration: Black. Cephalothorax: Carapace 10.49 mm long, 9.92 mm wide; densely clothed with black/faded black pubescence, slight iridescence, appressed to surface; fringe covered in long setae not closely appressed to surface; foveal groove medium deep and straight; pars cephalica region rises gradually from foveal groove on a straight plane towards the ocular area; AER procurved, PER slightly recurved; normal sized chelicerae; clypeus slightly extends forward on a curve; LBl 1.45, LBw 1.50; sternum hirsute, clothed with black, unique setae; setae are stout like joshua . Abdomen: Densely clothed in short black pubescence with numerous longer, lighter setae interspersed (generally red or orange in situ); dense dorsal patch of black Type I urticating bristles ( Cooke et al. 1972) - smaller and distinct from large species; ventral setae same as dorsal. Legs: Hirsute; densely clothed with mostly short black setae, and numerous long, stout spines throughout. Metatarsus I straight. F1 11.85; F1w 2.67; P1 4.80; T1 11.72; M1 10.68; A1 6.36; F3 10.49; F3w 3.30; P3 3.74; T3 9.92; M3 11.21; A3 6.05; F4 12.65; F4w 2.81; P4 4.19; T4 12.01; M4 14.37; A4 6.80; femur III is swollen. All tarsi fully scopulate. Extent of metatarsal scopulation: leg III (SC3) = 94.7%; leg IV (SC4) = 34.8%. No distinct ventral spinose setae on metatarsus III, though numerous medium stout setae throughout; five ventral, one prolateral, and two retrolateral spinose setae - one near the margin with the tibia, on metatarsus IV; three prolateral spinose setae and one ventral on tibia I; two megaspines present on the retrolateral tibia, at the apex of the mating clasper; two megaspines on either side of the apex on the retrolateral branch of the tibial apophyses. Coxa I: Prolateral surface covered by fine, hair-like setae. Pedipalps: Hirsute; densely clothed in the same setal color as the other legs, with numerous longer ventral setae; one spinose seta at the apical, prolateral femur; one spinose seta on the prolateral patella; six prolateral spinose setae and two ventral on the palpal tibia, along with numerous medium stout setae throughout; PTl 6.382, PTw 1.744. When extended, embolus tapers with a curve to the retrolateral side; embolus slender, no keels; distinct dorsal and ventral transition from bulb to embolus.

Variation (5).Cl 8.389-10.491 (9.24 ± 0.36), Cw 7.387-9.92 (8.664 ± 0.45), LBl 1.142-1.454 (1.24 ± 0.06), LBw 1.211-1.503 (1.361 ± 0.06), F1 9.357-11.849 (10.398 ± 0.43), F1w 2.233-2.672 (2.407 ± 0.09), P1 3.656-4.797 (4.099 ± 0.21), T1 8.907-11.723 (10.242 ± 0.49), M1 7.681-10.68 (9.069 ± 0.51), A1 4.786-6.363 (5.39 ± 0.27), L1 length 34.436-45.412 (39.197 ± 1.9), F3 7.71-10.492 (9.045 ± 0.47), F3w 2.537-3.297 (2.854 ± 0.13), P3 3.217-3.743 (3.398 ± 0.1), T3 7.011-9.921 (8.28 ± 0.49), M3 8.272-11.209 (9.72 ± 0.5), A3 4.884-6.055 (5.419 ± 0.22), L3 length 31.169-41.42 (35.861 ± 1.74), F4 9.182-12.649 (10.644 ± 0.59), F4w 2.179-2.81 (2.357 ± 0.11), P4 3.471-4.192 (3.708 ± 0.14), T4 9.03-12.006 (10.39 ± 0.51), M4 11.074-14.367 (12.661 ± 0.57), A4 5.047-6.798 (5.724 ± 0.31), L4 length 38.048-50.012 (43.127 ± 2.02), PTl 4.878-6.382 (5.53 ± 0.25), PTw 1.309-1.744 (1.532 ± 0.07), SC3 ratio 0.651-0.947 (0.773 ± 0.07), SC4 ratio 0.348-0.485 (0.405 ± 0.02), Coxa I setae = very thin tapered, F3 condition = swollen.

Material examined.

United States: California: Riverside: Carrizo Creek,.25 miles S of Hwy 74 bridge, 4 miles S of Palm Desert or Hwy 111, 33.643993 -116.400317 4, 2572ft., [AUMS_3319, 27/3/1972, 1♂, W. Icenogle, AUMNH]; Deep Canyon, 33.669056 -116.367683 5, 699ft., [AUMS_2668, 23/10/1963, 1♂, E. Schlinger, AUMNH]; on Hwy 74, 2.5 miles S of Carrizo Creek bridge, 6.5 miles S of Palm Desert or Hwy 111, 33.627668 -116.40353 4, 2925ft., [AUMS_3318, 15/10/1976, 1♂, W. Icenogle, AUMNH]; P.L. Boyd Deep Canyon Reserve Center, 3.5 miles S of Palm Desert, 33.674866 -116.371261 4, 639ft., [AUMS_2670, 13/10/1969, 1♂, Saul Frommer, AUMNH]; P.L. Boyd Deep Canyon Reserve, 0.4 miles N of reserve station, 33.653477 -116.37419 4, 891ft., [AUMS_2348, 22/9/1995, 1♂, T.R. Prentice, AUMNH]; P.L. Boyd Deep Canyon Reserve, 0.5 miles below reserve gate, 33.677408 -116.370109 4, 613ft., [AUMS_2345, 27/9/1995, 1♂, T.R. Prentice, AUMNH]; P.L. Boyd Deep Canyon Reserve, 1.1 miles below reserve gate, 33.684368 -116.364817 4, 558ft., [AUMS_2352, 21/9/1995, 1♂, T.R. Prentice, AUMNH]; P.L. Boyd Deep Can yon Reserve, at reserve gate - North, 33.670726 -116.372949 4, 684ft., [AUMS_2344, 21/9/1995, 1♂, T.R. Prentice, AUMNH]; P.L. Boyd-Deep Canyon Reserve, 0.2 miles below reserve gate, 33.586027 -116.276451 4, 613ft., [AUMS_3280, 27/9/1995, 1♂, T.R. Prentice, AUMNH]; San Diego: Hwy S22 (Montezuma Valley Rd), 1.6 miles S junction with Palm Canyon Dr. (Borrego Springs), Anza-Borrego State Park, 33.2409 -116.403283 1, 1148ft., [APH_3132, 5/10/2013, 1♂, W. Icenogle, AUMNH]; Hwy S22 (Montezuma Valley Rd), 2.8 miles S junction with Palm Canyon Dr. (Borrego Springs), Anza-Borrego State Park, 33.231167 -116.411606 1, 1474ft., [APH_3130, 4/10/2013, 1♂, W. Icenogle, AUMNH]; Hwy S22 (Montezuma Valley Rd), 3.2 miles S junction with Palm Canyon Dr. (Borrego Springs), Anza-Borrego State Park, 33.225583 -116.413067 1, 1673ft., [APH_3131, 4/10/2013, 1♂, W. Icenogle, AUMNH]; Hwy S22 (Montezuma Valley Rd), 3.3 miles S junction with Palm Canyon Dr. (Borrego Springs), Anza-Borrego State Park, 33.225633 -116.414633 1, 1710ft., [APH_3134, 4/10/2013, 1♂, W. Icenogle, AUMNH]; Hwy S22 (Montezuma Valley Rd), 4 miles S junction with Palm Canyon Dr. (Borrego Springs), Anza-Borrego State Park, 33.224618 -116.424232 1, 1935ft., [APH_3133, 5/10/2013, 1♂, W. Icenogle, AMNH].

Distribution and natural history.

Aphonopelma xwalxwal is presently known from only two areas along the foothills and mountains west of Palm Springs and Borrego Springs (Fig. 149). The species can be found inhabiting the Sonoran Basin and Range Level III Ecoregion, in particular this species appears to be restricted to the Western Sonoran Mountains and Western Sonoran Mountain Woodland and Shrubland. Aphonopelma xwalxwal can be found in syntopy with Aphonopelma eutylenum . The breeding season, when mature males abandon their burrows in search of females, occurs during the fall (October).

Conservation status.

The distribution of Aphonopelma xwalxwal appears to be restricted to the mountains and foothills on the eastern side of the Peninsular Ranges and San Jacinto Mountains. In historical collections, this species appears to have been collected somewhat infrequently. Based on our own fieldwork in search of females of this species, we found burrows to be incredibly difficult to find due to the steep, rocky nature of their habitat, and the harsh, dry environments that likely keeps them inactive for most of the year. The species is likely secure, but populations should be monitored due to the continued expansion of human activity and development in Southern California.

Remarks.

Other important ratios that distinguish males: Aphonopelma xwalxwal possess a larger T3/A3 (≥1.41; 1.41-1.64) than Aphonopelma eutylenum (≤1.35; 1.30-1.35), Aphonopelma icenoglei (≤1.37; 1.24-1.37), Aphonopelma joshua (≤1.37; 1.19-1.37), and Aphonopelma paloma (≤1.31; 1.21-1.31); by possessing a larger L4 scopulation extent (34%-48%) than Aphonopelma paloma (5%-24%) and smaller than Aphonopelma eutylenum (62%-77%). Certain morphometrics have potential to be useful, though due to the amounts of variation, small number of specimens, and the small differences between species, no other are claimed to be significant at this time (see Suppl. material 2). During evaluation of PCA morphospace, males of Aphonopelma xwalxwal separate from Aphonopelma eutylenum and all other miniature species along PC1~2, except for Aphonopelma joshua . Interestingly, Aphonopelma xwalxwal males also separate from Aphonopelma eutylenum and all other miniature species, except for Aphonopelma joshua , in three-dimensional PCA morphospace (PC1~PC2~PC3). PC1, PC2, and PC3 explain ≥97% of the variation in all analyses.