Aphonopelma chiricahua Hamilton, Hendrixson & Bond

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 : 71-77

Taxon classification Animalia Araneae Theraphosidae

Aphonopelma chiricahua Hamilton, Hendrixson & Bond sp. n. Figures 36, 37, 38, 39

Types.

Male holotype (APH_3191) collected 1 mile up the road (42 Forest Rd.) from the lookout trail, Cochise Co., Arizona, 31.886417 -109.173356 1, elev. 5083ft., 14.xi.2013, coll. Helen Snyder; deposited in AUMNH. Paratype female (APH_2097) from SWRS (Southwest Research Station, 5 miles W of Portal), Cochise Co., Arizona, 31.884056 -109.208261 5, elev. 5436ft., 30.xi.1965, coll. Jon Jenson; deposited in AMNH. Paratype male (APH_2105) from SWRS, Cochise Co., Arizona, 31.883356 -109.207107 5, elev. 5404ft., 31.x.1956, coll. E. Ordway; deposited in AMNH.

Etymology.

The specific epithet is a noun in apposition taken from type locality, the Chiricahua Mountains outside of Portal, Arizona, where this new species appears to be endemic.

Diagnosis.

Aphonopelma chiricahua (Fig. 36) is a member of the Marxi species group and can be distinguished by a combination of morphological, molecular, and geographic characteristics. Nuclear and mitochondrial DNA identifies Aphonopelma chiricahua as a phylogenetically distinct lineage (Figs 7-8), supported as a sister lineage to Aphonopelma catalina sp. n. (a species endemic to the Santa Catalina Mountains). The significant measurement that distinguishes male Aphonopelma chiricahua from its closely related phylogenetic and syntopic species is A3. Male Aphonopelma chiricahua can be distinguished by possessing a larger A3/M4 (≥0.65; 0.65-0.72) than Aphonopelma catalina (≤0.52; 0.47-0.52), Aphonopelma madera sp. n. (≤0.60; 0.54-0.60), Aphonopelma parvum sp. n. (≤0.64; 0.53-0.64), Aphonopelma peloncillo sp. n. (≤0.58; 0.45-0.58), and Aphonopelma vorhiesi (≤0.57; 0.46-0.57). The significant measurement that distinguishes female Aphonopelma chiricahua from its closely related phylogenetic and syntopic species is P1. Female Aphonopelma chiricahua can be distinguished by possessing a smaller Cl/P1 (2.21 ± (only 1 specimen)) than Aphonopelma catalina (≥2.75; 2.75-2.94), Aphonopelma madera (≥2.71; 2.71-3.01), Aphonopelma parvum (≥2.69; 2.69-3.04), Aphonopelma peloncillo (≥2.71; 2.71-3.02), and Aphonopelma vorhiesi (≥2.59; 2.59-2.88).

Description of male holotype

(APH_3191; Fig. 37). 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 III & IV removed for DNA and stored at -80°C in the AUMNH (Auburn, AL). General coloration: Generally black or faded black. Cephalothorax: Carapace 11.42 mm long, 11.22 mm wide; densely clothed with black/faded black pubescence, slightly appressed to surface and longer than lower elevation species, slight iridescence; fringe covered in long setae not closely appressed to surface; foveal groove medium deep and straight; pars cephalica region rises gradually from foveal groove, gently arching anteriorly toward ocular area; AER slightly procurved, PER very slightly recurved; normal sized chelicerae; clypeus slightly extends forward on a curve; LBl 1.37, LBw 1.61; sternum hirsute, clothed with medium black, densely packed setae. Abdomen: Densely clothed in short black/brown pubescence with numerous longer, lighter setae interspersed (generally red or orange in situ), longer with a more hirsute appearance than lower elevation species; dense dorsal patch of black Type I urticating bristles ( Cooke et al. 1972); ventral setae same as dorsal. Legs: Hirsute; densely clothed with medium length black/brown setae, and longer setae ventrally. Metatarsus I slightly curved. F1 12.72; F1w 3.28; P1 4.95; T1 11.37; M1 7.61; A1 6.16; F3 9.53; F3w 2.98; P3 4.11; T3 7.60; M3 7.79; A3 6.84; F4 11.41; F4w 3.20; P4 4.41; T4 9.67; M4 10.28; A4 7.78; femur III is normal - not noticeably swollen or wider than other legs. All tarsi fully scopulate. Extent of metatarsal scopulation: leg III (SC3) = 65.5%; leg IV (SC4) = 37.9%. Three ventral spinose setae and one retrolateral spinose seta on metatarsus III; nine ventral spinose setae, one prolateral spinose seta on metatarsus IV; two ventral spinose setae on tibia I. Coxa I: Prolateral surface a mix of fine, hair-like and thin/very thin tapered 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 and four spinose setae on the prolateral tibia; PTl 7.34, PTw 2.82. When extended, embolus tapers with a gentle curve to the retrolateral side near apex; embolus slender, no keels.

Variation (7).Cl 6.837-11.42 (8.18 ± 0.62), Cw 6.254-11.22 (8.269 ± 0.86), LBl 0.684-1.368 (0.959 ± 0.11), LBw 0.985-1.765 (1.292 ± 0.11), F1 6.145-12.718 (8.731 ± 0.77), F1w 1.898-3.281 (2.309 ± 0.19), P1 2.859-4.947 (3.517 ± 0.27), T1 5.851-11.372 (7.397 ± 0.7), M1 4.09-7.61 (5.06 ± 0.46), A1 3.572-6.165 (4.542 ± 0.31), L1 length 22.568-42.812 (29.248 ± 2.48), F3 5.591-9.531 (6.823 ± 0.5), F3w 1.688-2.982 (2.147 ± 0.18), P3 2.304-4.112 (2.896 ± 0.23), T3 4.162-7.603 (5.286 ± 0.43), M3 4.379-7.794 (5.317 ± 0.45), A3 3.955-6.838 (5.003 ± 0.35), L3 length 20.391-35.878 (25.325 ± 1.95), F4 6.648-11.414 (8.181 ± 0.62), F4w 1.74-3.205 (2.174 ± 0.2), P4 2.524-4.414 (3.141 ± 0.25), T4 5.784-9.674 (7.104 ± 0.48), M4 5.772-10.277 (7.342 ± 0.56), A4 4.944-7.78 (5.781 ± 0.38), L4 length 25.672-43.559 (31.549 ± 2.26), PTl 4.42-7.341 (5.424 ± 0.36), PTw 1.888-2.82 (2.241 ± 0.12), SC3 ratio 0.48-0.656 (0.556 ± 0.02), SC4 ratio 0.33-0.404 (0.376 ± 0.01), Coxa I setae = thin/very thin tapered, F3 condition = normal.

Description of female paratype

(APH_2097; Fig. 38). Specimen preparation and condition: Specimen collected live, preserved in unknown percentage of ethanol; original coloration faded due to preservation. Left legs I, III, IV, and pedipalp removed for photographs and measurements; stored in vial with specimen. No tissue for DNA. Genital plate with spermathecae removed and cleared, stored in vial with specimen. General coloration: Brown and faded black. Cephalothorax: Carapace 7.651 mm long, 7.479 mm wide; Hirsute, densely clothed with brown pubescence closely appressed to surface; fringe densely covered in longer setae; foveal groove medium deep and slightly procurved; pars cephalica region gently rises from thoracic furrow, arching anteriorly toward ocular area; AER slightly procurved, PER slightly recurved; robust chelicerae, clypeus extends forward on a slight curve; LBl 1.194, LBw 1.218; sternum hirsute, clothed with medium short brown setae. Abdomen: Densely clothed dorsally in brown setae 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); ventral setae shorter than dorsal. Spermathecae: Paired and separate, tapering and curving medially towards capitate bulbs, with wide bases that are not fused. Legs: Hirsute; densely clothed in short and medium brown pubescence; F1 6.261; F1w 2.223; P1 3.453; T1 4.952; M1 3.398; A1 3.011; L1 length 21.075; F3 4.989; F3w 1.645; P3 2.332; T3 3.341; M3 3.231; A3 3.681; L3 length 17.574; F4 6.292; F4w 1.897; P4 3.17; T4 5.134; M4 5.114; A4 3.995; L4 length 23.705. All tarsi fully scopulate. Extent of metatarsal scopulation: leg III (SC3) = 56.2%; leg IV (SC4) = 27.7%. Two ventral spinose setae and one prolateral spinose seta on metatarsus III; six ventral spinose setae and one prolateral spinose seta on metatarsus IV. Coxa I: Prolateral surface a mix of fine, hair-like and tapered/thin tapered setae. Pedipalps: Densely clothed in the same setal color as the other legs; one spinose seta at the apical, prolateral femur, two prolateral spinose setae on the tibia.

Material examined.

United States: Arizona: Cochise: SWRS (5 miles W of Portal), 31.884056 -109.208261 5, 5436ft., [APH_2097, 30/11/1965, 1♀, Jon Jenson, AMNH]; Cave Creek Canyon, 31.885338 -109.175462 5, 5105ft., [APH_2101, 30/11/1963, 1♂, V. Roth, AMNH]; Upper Cave Creek Canyon, 31.900796 -109.229328 5, 5997ft., [APH_2102, 1966, 1♂, Marlene Posedly, AMNH]; South West Research Station, 31.883356 -109.207107 5, 5404ft., [APH_2105, 31/10/1956, 1♂, E. Ordway, AMNH]; Sunny Flat, 31.884963 -109.175964 4, 5108ft., [APH_2480-A, 30/10/1971, 1♂, V. Roth, AMNH]; South West Research Station-Portal, 31.883372 -109.205727 5, 5384ft., [APH_2480-B, 20/11/1971, 1♂, V. Roth, AMNH]; Chiricahua Mtns, 31.903946 -109.279016 6, 8432ft., [APH_2548, 4/11/1970, 1♂, Rustler and Long Park, Joan Harper, AMNH]; Cave Creek Canyon, on Portal Rd/42A (road to SWRS), 1 mile up the road from the lookout trail, 31.886417 -109.173356 1, 5083ft., [APH_3191, 14/11/2013, 1♂, Helen Snyder, AUMNH].

Distribution and natural history.

Aphonopelma chiricahua is a sky island endemic restricted to the Chiricahua Mountains in Cochise County, Arizona at elevations ranging from 1550 to 2700 meters in oak woodland, pine-oak woodland, and mixed conifer communities (Fig. 39). Aphonopelma chiricahua can be found inhabiting the Madrean Archipelago Level III Ecoregion. Very little is known about the natural history of this elusive species. No burrows or shelters have been observed but these spiders probably seek refuge under rocks and rarely place silk around their burrow entrances. Most specimens in natural history collections have been collected near the AMNH’s Southwest Research Station. Aphonopelma chiricahua is probably the only tarantula found at higher elevations in the Chiricahua Mountains but four other species are known from the area (including Aphonopelma chalcodes , Aphonopelma gabeli , Aphonopelma parvum , and Aphonopelma vorhiesi ) and might be syntopic with Aphonopelma chiricahua at lower elevations near various canyon mouths. An unconfirmed adult female (no voucher specimen available, identification tentatively assigned based on a photograph and locality data) was found walking across a road in Cave Creek Canyon in August during the summer monsoon season (A. Abela 2006, pers. comm.). Vouchered adult males were collected between late October and late November; an adult male and female (no voucher specimens available, identification tentatively assigned based on video images and locality data) were found mating during daylight hours in early December along Echo Canyon Trail in Chiricahua National Monument (Chiricahua National Monument 2015, pers. comm.; https://www.facebook.com/video.php?v=785835144804065). The holotype male was collected wandering across 42 Forest Road in November, one year before this video was taken. These data indicate that the breeding season for this species is restricted to late autumn and early winter, similar to that of other high-elevation species in the region ( Aphonopelma catalina and Aphonopelma madera ).

Conservation status.

It is difficult to assess the conservation status of Aphonopelma chiricahua due to small sample sizes and the very cryptic nature of these spiders. This species does not occur outside of the Chiricahua Mountains so its narrow distribution is one factor that may threaten its future survival. These mountains have the advantage of being somewhat protected by their remoteness and management by the federal government (Coronado National Forest, Douglas Ranger District, Chiricahua National Monument); however, these habitats have also been subjected to habitat degradation from recent urban growth, human-caused forest fires, off-road driving, poorly managed livestock grazing, invasive species, recreational activities, human immigrants, and illegal drug trafficking ( Coronado Planning Partnership 2008). Climate change in the sky island region ( Brusca et al. 2013, Mitchell and Ober 2013, Moore et al. 2013, Hendrixson et al. 2015) also poses a potential threat to the future survival of Aphonopelma chiricahua .

Remarks.

Aphonopelma chiricahua is morphologically very similar to other Madrean sky island endemics in the Marxi species group, although generally smaller than Aphonopelma catalina , Aphonopelma madera , and Aphonopelma vorhiesi . Other important ratios that distinguish males: Aphonopelma chiricahua possess a larger Cl/M3 (≥1.46; 1.46-1.61) than Aphonopelma catalina (≤1.42; 1.26-1.42), Aphonopelma parvum (≤1.39; 1.20-1.39), Aphonopelma peloncillo (≤1.40; 1.20-1.40), and Aphonopelma vorhiesi (≤1.43; 1.24-1.43); by possessing a larger L3/Cl (≥2.98; 2.98-3.19) than Aphonopelma madera (≤2.95; 2.71-2.95). Other important ratios that distinguish females: Aphonopelma chiricahua possess a smaller M3/P4 (1.02 ± (only 1 specimen)) than Aphonopelma catalina (≥1.48; 1.48-1.52), Aphonopelma madera (≥1.39; 1.39-1.48), Aphonopelma parvum (≥1.32; 1.32-1.54), Aphonopelma peloncillo (≥1.39; 1.39-1.67), and Aphonopelma vorhiesi (≥1.27; 1.27-1.64). For both males and females, 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 chiricahua separate from Aphonopelma parvum and all other miniature species along PC1~2, but do not separate from Aphonopelma catalina , Aphonopelma madera , Aphonopelma peloncillo , and Aphonopelma vorhiesi . Though we only have one female of Aphonopelma chiricahua , it appears to separate from all other sky island species ( Aphonopelma catalina , Aphonopelma madera , Aphonopelma peloncillo , and Aphonopelma vorhiesi ), grouping more closely with the miniature species in morphospace along PC1~2. Interestingly, Aphonopelma chiricahua males separate from Aphonopelma parvum , Aphonopelma peloncillo , and Aphonopelma vorhiesi in three-dimensional PCA morphospace (PC1~PC2~PC3), but do not separate from Aphonopelma catalina , Aphonopelma madera , Aphonopelma marxi . There is only one Aphonopelma chiricahua female, but she separates from all other phylogenetic sister species or syntopic species - Aphonopelma catalina , Aphonopelma madera , Aphonopelma marxi , Aphonopelma parvum , Aphonopelma peloncillo , and Aphonopelma vorhiesi . PC1, PC2, and PC3 explain ≥96% of the variation in all analyses.

This species was first identified as novel by Jung (1975) but was never formally described. Of particular note is the size of the holotype male and paratype female; the two specimens probably represent opposite extremes on the size spectrum for what is possible in this species. The rather large holotype male was chosen because it was a fresh specimen and could be associated with molecular data. The female, though small, is sexually mature (based on spermathecal development).