Aphonopelma anax (Chamberlin, 1940)

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 : 32-40

Taxon classification Animalia Araneae Theraphosidae

Aphonopelma anax (Chamberlin, 1940) Figures 9, 10, 11, 12, 13, 14, Suppl. material 4

Dugesiella anax Chamberlin, 1940: 34; male holotype and female allotype from Kingsville, Kleberg Co., Texas, 27.515869 -97.856109 5, elev. 58ft., no collecting date, coll. Prof. J.C. Cross; 3 female paratypes from Harlingen, Cameron Co., Texas, 26.190631 -97.696103 5, elev. 40ft., 1939, coll. Bryce Brown; deposited in AMNH. [examined]

Rhechostica anax Raven, 1985: 149.

Aphonopelma anax Smith, 1995: 71.

Aphonopelma breenei Smith, 1995: 78; female holotype from Harlingen, Cameron Co., Texas, 26.190631 -97.696103 5, elev. 40ft., 1939, coll. Bryce Brown; deposited in AMNH. [examined] syn. n.

Diagnosis.

Aphonopelma anax (Fig. 9) is a member of the Hentzi species group and can be identified by a combination of morphological, molecular, and geographic characteristics. Nuclear DNA identifies Aphonopelma anax as a phylogenetically distinct monophyletic lineage (Fig. 8), supported as the sister lineage to Aphonopelma hentzi , and closely related to Aphonopelma armada . Male Aphonopelma anax can be distinguished from geographically proximate species by their unique palpal bulbs - stout and wide with distinct keels on the embolus (Fig. 10). Females can be distinguished from geographically proximate species by their unique spermathecae - short, wide, slightly rounded, without capitate bulbs (Figs 12-13). Significant measurements that distinguish male Aphonopelma anax from its closely related phylogenetic and syntopic species are Cl, M3, and F4. Male Aphonopelma anax can be distinguished by possessing a larger F4/M4 (≥0.94; 0.94-1.04) than Aphonopelma armada (≤0.92; 0.86-0.92); a larger Cl/M1 (≥1.36; 1.36-1.63) than moderatum (≤1.30; 1.13-1.30) and Aphonopelma moellendorfi sp. n. (≤1.31; 1.10-1.31); and a larger F1/M3 (≥1.28; 1.28-1.43) than Aphonopelma gabeli (≤1.24; 1.18-1.24). There are no significant measurements that separate male Aphonopelma anax from Aphonopelma hentzi . Significant measurements that distinguish female Aphonopelma anax from its closely related phylogenetic and syntopic species are P1 and T3. Female Aphonopelma anax can be distinguished by possessing a larger P1/T3 (≥13.88; 13.88-19.15) than Aphonopelma armada (≤13.84; 9.93-13.84) and Aphonopelma moderatum (≤13.12; 8.14-13.12). There are no significant measurements that separate female Aphonopelma anax from Aphonopelma gabeli or Aphonopelma hentzi . Females of Aphonopelma moellendorfi are unknown and cannot be compared.

Descriptions.

Male and female originally described by Chamberlin (1940).

Redescription of male exemplar

(APH_0924; Fig. 10). Specimen preparation and condition: Specimen collected live crossing road, preserved in 80% ethanol; deposited in AUMNH; 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 leg III removed for DNA and stored at -80°C in the AUMNH (Auburn, AL). General coloration: Generally black or faded to brown. Cephalothorax: Carapace 19.10 mm long, 18.28 mm wide; densely clothed with brown/golden iridescent pubescence appressed to surface; fringe covered in long setae not closely appressed to surface; foveal groove medium deep and straight to slightly procurved; pars cephalica region rises gradually from foveal groove, gently arching anteriorly toward ocular area; AER slightly procurved, PER recurved; normal sized chelicerae; clypeus extends forward on a very slight curve; LBl 2.96, LBw 2.94; sternum hirsute, clothed with short length black, densely packed setae. 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). Legs: Thick and hirsute; densely clothed in short black/brown pubescence. Metatarsus I slightly curved. F1 18.77; F1w 4.74; P1 8.10; T1 14.69; M1 13.41; A1 9.23; F3 15.19; F3w 4.61; P3 6.75; T3 12.07; M3 13.77; A3 9.42; F4 18.58; F4w 4.8; P4 8.16; T4 14.50; M4 19.51; A4 11.15; femur III is normal - not noticeably swollen or wider than other legs. All tarsi fully scopulate. Extent of metatarsal scopulation: leg III (SC3) = 68.9%; leg IV (SC4) = 43.4%. Two ventral spinose setae on metatarsus III; six ventral spinose setae on metatarsus IV. Coxa I: Prolateral surface a mix of fine, hair-like and medium tapered setae. The interior face of the retrolateral branch of the tibial apophyses possesses a very large megaspine that projects anteriorly. 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 three spinose setae on the prolateral tibia; PTl 9.45, PTw 2.90. When extended, embolus tapers and rapidly curves up and to the retrolateral side near apex; embolus wide and thick, with smooth dorsal and ventral keels.

Variation (11).Cl 14.371-21.97 (17.885 ± 0.7), Cw 13.32-19.84 (16.557 ± 0.62), LBl 1.96-2.96 (2.341 ± 0.09), LBw 2.16-3.02 (2.711 ± 0.08), F1 14.1-19.3 (16.839 ± 0.55), F1w 3.52-5.1 (4.392 ± 0.15), P1 6.12-8.1 (7.105 ± 0.22), T1 11.32-15.71 (13.314 ± 0.39), M1 9.69-13.43 (11.878 ± 0.4), A1 6.9-9.6 (8.499 ± 0.28), L1 length 48.47-65.97 (57.635 ± 1.73), F3 11.39-16.14 (13.868 ± 0.48), F3w 3.41-5.03 (4.132 ± 0.16), P3 4.86-7.65 (6.035 ± 0.27), T3 7.91-12.16 (10.428 ± 0.43), M3 9.89-14.89 (12.572 ± 0.49), A3 6.93-9.45 (8.291 ± 0.27), L3 length 41.32-59.2 (51.194 ± 1.82), F4 13.52-19.31 (16.56 ± 0.58), F4w 3.22-4.83 (4.094 ± 0.17), P4 5.5-8.16 (6.647 ± 0.26), T4 11.15-15.56 (13.676 ± 0.41), M4 13.66-19.69 (17.13 ± 0.58), A4 8.1-11.15 (9.504 ± 0.3), L4 length 52.79-72.08 (64.171 ± 1.92), PTl 7.187-10.136 (8.709 ± 0.27), PTw 2.246-3.32 (2.882 ± 0.09), SC3 ratio 0.607-0.805 (0.713 ± 0.02), SC4 ratio 0.351-0.524 (0.44 ± 0.02), Coxa 1 setae = thick tapered, F3 condition = normal/slightly swollen.

Redescription of female exemplar

(APH_0857; Figs 11-13). Specimen preparation and condition: Specimen collected live from burrow, preserved in 80% ethanol; deposited in AUMNH; original coloration faded due to preservation. Left legs I, III, IV, and pedipalp removed for photographs and measurements; stored in vial with specimen. Right leg III removed for DNA and stored at -80°C in the AUMNH (Auburn, AL). Genital plate with spermathecae removed and cleared, stored in vial with specimen. General coloration: Faded black and light brown, medium length, dense setae cover body. Cephalothorax: Carapace 21.37 mm long, 18.26 mm wide; densely clothed with light brown pubescence closely appressed to surface; fringe densely covered in long setae; foveal groove medium deep and straight; pars cephalica region rises from thoracic furrow more steeply than male, gently arching anteriorly toward ocular area; AER procurved, PER strongly recurved; clypeus extends forward on a slight curve; LBl 2.67, LBw 3.35; sternum hirsute, clothed with light black/dark brown, me dium length dense setae. Abdomen: Densely clothed dorsally in short black 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 side with short, dense black setae. Spermathecae: Paired and separate, possessing dual bulges with the smaller near the interior, with wide bases that are not fused. Legs: Thick and hirsute; densely clothed in a mix of short black/brown pubescence setae. Coxa I: Prolateral surface a mix of fine, hair-like and thick tapered setae. F1 16.02; F1w 4.88; P1 7.53; T1 12.06; M1 9.18; A1 7.54; F3 12.72; F3w 4.56; P3 6.76; T3 9.29; M3 10.09; A3 7.54; F4 16.53; F4w 4.73; P4 7.08; T4 13.31; M4 13.26; A4 8.79. All tarsi fully scopulate. Extent of metatarsal scopulation: leg III (SC3) = 64.4%; leg IV (SC4) = 47.3%. Two ventral spinose setae on metatarsus III; seven ventral spinose setae on metatarsus IV. Pedipalps: Densely clothed in the same setal color as the other legs; one spinose seta on the apical, prolateral femur and five spinose setae on the prolateral tibia.

Variation (13).Cl 16.06-23.8 (20.27 ± 0.79), Cw 14.9-21.73 (17.951 ± 0.62), LBl 2.45-3.79 (2.878 ± 0.1), LBw 2.71-4.3 (3.478 ± 0.15), F1 13.12-18.14 (15.181 ± 0.45), F1w 3.87-5.8 (4.945 ± 0.18), P1 5.61-8.59 (7.196 ± 0.26), T1 9.76-13.56 (11.616 ± 0.35), M1 7.0-10.98 (8.911 ± 0.31), A1 5.73-8.34 (7.138 ± 0.19), L1 length 42.75-59.3 (50.042 ± 1.47), F3 10.94-14.63 (12.375 ± 0.37), F3w 3.36-5.13 (4.268 ± 0.17), P3 5.1 -7.72 (6.179 ± 0.23), T3 7.45-10.56 (8.816 ± 0.28), M3 8.27-12.05 (9.918 ± 0.34), A3 6.52-8.84 (7.398 ± 0.18), L3 length 38.67-53.7 (44.687 ± 1.26), F4 13.27-18.66 (15.654 ± 0.49), F4w 3.61-5.31 (4.514 ± 0.17), P4 5.34-8.4 (6.55 ± 0.28), T4 9.72-13.98 (12.038 ± 0.35), M4 10.37-16.15 (13.621 ± 0.46), A4 7.01-9.83 (8.373 ± 0.25), L4 length 45.86-66.63 (55.723 ± 1.74), SC3 ratio 0.644-0.763 (0.706 ± 0.01), SC4 ratio 0.368-0.474 (0.433 ± 0.01), Coxa 1 setae = thick tapered. Spermathecae variation can be seen in Figures 12-13.

Material examined.

United States: Texas: Bexar: Hollywood Park, 220 Mecca, 29.59413 -98.47946 2, 934ft., [APH_0033, 2/6/2006, 1♂, Connor Shannon, Ryan Tubbesing, AUMNH]; Cameron: 2100 W. San Marcelo Blvd #158, Brownsville, 25.95835 -97.500489 2, 21ft., [APH_0523, 20/5/2009, 1♂, Lilia Perez, AUMNH]; Brownsville, 25.901747 -97.497484 5, 26ft., [APH_2045, 4/1963, 1♀, 1♂, Ted Beimler, AMNH]; Brownsville, field NE Coffeeport Rd, 25.948055 -97.480915 1, 19ft., [APH_0459-0462, 9/4/09, 1♀, 3 juv, Brent E. Hendrixson, AUMNH]; Harlingen, 26.190631 -97.696103 5, 39ft., [APH_2043, 15/11/1939, 1♀, B. Brown, AMNH]; [APH_2044, 1939, 1♀, Bryce Brown, AMNH]; Harlingen, Dixieland Park, 26.16825 -97.72063 1, 43ft., [APH_1273-1275, 12/5/11, 3 juv, Brent E. Hendrixson, Kate Hall, Austin Deskewies, Alexis Guice, AUMNH]; Harlingen, McKelvey Park, 26.180254 -97.679291 1, 35ft., [APH_0463, 9/4/09, 1 juv, Brent E. Hendrixson, AUMNH]; [APH_1271-1272, 11/5/11, 2 juv, Brent E. Hendrixson, Kate Hall, Austin Deskewies, Alexis Guice, AUMNH]; Harlingen, S of town, 26.145617 -97.661717 5, 41ft., [APH_0924, 2006, 1♂, Dave Moellendorf, AUMNH]; Laguna Vista, 26.100864 -97.290234 5, 12ft., [AUMS_2355, 4/1998, 1♂, R.G. Breene, AUMNH]; [AUMS_2583, 4/1998, 1♂, R.G. Breene, AUMNH]; [AUMS_2609, 1998, 1♂, R.G. Breene, AUMNH]; [AUMS_2613, unknown, 1♀, R.G. Breene, AUMNH]; [AUMS_2690, 4/1998, 2♂, R.G. Breene, AUMNH]; [AUMS_2695, 4/1998, 1♀, R.G. Breene, AUMNH]; [AUMS_3268-3269, 3/1998, 2♂, R.G. Breene, AUMNH]; [AUMS_3271, 4/1998, 1♂, R.G. Breene, AUMNH]; [AUMS_3274, 4/1998, 1♂, R.G. Breene, AUMNH]; [AUMS_3315, 4/1998, 1♂, R.G. Breene, AUMNH]; Laguna Vista, Roloff Park, 26.10243 -97.291 1, 3ft., [APH_0455-0458, 9/4/09, 2♀, 2 juv, Brent E. Hendrixson, AUMNH]; Los Fresnos, 26.071744 -97.476373 5, 23ft., [AUMS_2688, 1999, 1♀, R.G. Breene, AUMNH]; South Padre Island, 26.076567 -97.16315 5, 4ft., [APH_0858, 2006, 1♀, Dave Moellendorf, AUMNH]; DeWitt: between Cuero and Westhoff on Hwy 87, 29.1221 -97.410817 1, 303ft., [APH_0859-0861, 9/2008, 3♀, Chris A. Hamilton, AUMNH]; [APH_0947, 9/2008, 1♂, Chris A. Hamilton, AUMNH]; Dimmit: 6.7 miles E Maverick County Line on US-277, 28.625443 -100.004038 1, 659ft., [APH_0473, 11/4/2009, 1 juv, Brent E. Hendrixson, AUMNH]; Chaparral Wildlife Management Area, Blocker Pond, 28.3125 -99.40694 1, 570ft., [APH_0025, 12/3/2002, 1♂, Brent E. Hendrixson, WTAMU Herp Class, AUMNH]; 3 miles NW Catarina on US-83, 28.37472 -99.64806 1, 560ft., [APH_0042, 12/3/2000, 1 juv, Brent E. Hendrixson, AUMNH]; Duval: 4.4 miles E Hwy-339 on FM-2295, 27.58835 -98.33743 1, 340ft., [APH_1270, 11/5/11, 1 juv, Brent E. Hendrixson, Kate Hall, Austin Deskewies, Alexis Guice, AUMNH]; 5.3 miles SE Webb County Line on Hwy-44, 27.907752 -98.723635 1, 497ft., [APH_0529, 3/6/09, 1♀, Brent E. Hendrixson, Courtney Dugas, Sloan Click, AUMNH]; S of San Diego, TX on Hwy-359, 27.733177 -98.262366 1, 339ft., [APH_0584, 14/6/2009, 1 juv, Brent E. Hendrixson, Courtney Dugas, Sloan Click, AUMNH]; Fayette: La Grange, 29.914417 -96.866267 1, 330ft., [APH_0804-0806, 5/2008, 3♀, Chris A. Hamilton, AUMNH]; [APH_0808, 5/2008, 1♀, Chris A. Hamilton, AUMNH]; [APH_0809, 5/2008, 1♀, Chris A. Hamilton, AUMNH]; [APH_0898, 5/2008, 1♂, Chris A. Hamilton, AUMNH]; La Grange, S side of river, 29.874417 -96.850383 1, 345ft., [APH_0811, 7/2008, 1♀, Chris A. Hamilton, AUMNH]; [APH_0810, 5/2008, 1♀, Chris A. Hamilton, AUMNH]; [APH_0899, 5/2008, 1♂, Chris A. Hamilton, AUMNH]; [APH_0901, 5/2008, 1♂, Chris A. Hamilton, AUMNH]; La Grange, on FM155, 29.859333 -96.848033 1, 348ft., [APH_0900, 5/2008, 1♂, Chris A. Hamilton, AUMNH]; La Grange, rest stop on Hwy 77, 29.843383 -96.9091 1, 377ft., [APH_0902-0903, 5/2008, 1♀, 1♂, Chris A. Hamilton, AUMNH]; Gonzales: 6.1 miles SE of Gonzales, 29.497194 -97.380048 5, 328ft., [APH_2658, 18/6/1956, 1♂, W. McAlister, AMNH]; Harris: Houston, 29.760193 -95.36939 6, 43ft., [APH_2650, 6/1959, 1♂, Mrs. Emilie Steude, AMNH]; Jim Hogg: 0.9 miles E Zapata County Line on FM-2687, 26.939665 -98.941918 1, 526ft., [APH_1131, 15/3/2010, 1 juv, Brent E. Hendrixson, Gerri Wilson, Thomas Martin, AUMNH]; 2.0 miles N Starr County Line on FM-649, 26.81392 -98.855998 1, 625ft., [APH_1130, 15/3/2010, 1 juv, Brent E. Hendrixson, Gerri Wilson, Thomas Martin, AUMNH]; Karnes: Karnes City, 28.885483 -97.902683 1, 411ft., [APH_0864-0866, 9/2008, 2♀, 1 juv, Chris A. Hamilton, AUMNH]; [APH_0952, 9/2008, 1♂, Chris A. Hamilton, AUMNH]; Kleberg: Kingsville, S Brahma Blvd, 27.4806 -97.855767 1, 77ft., [APH_0856-0857, 9/2008, 2♀, Chris A. Hamilton, AUMNH]; Kingsville, 27.515869 -97.856109 5, 56ft., [APH_2046, 27/6/1970, 1♂, Gillaspy, AMNH]; Kingsville, field at high school, along Caesar Ave across street from cemetery, 27.506531 -97.879785 1, 65ft., [APH_0579-0583, 13/6/2009, 4 juv, Brent E. Hendrixson, Courtney Dugas, Sloan Click, AUMNH]; La Salle: Cotulla, 28.436934 -99.235032 1, 437ft., [APH_3129, 2013, 1♂, Roger Birkhead, AUMNH]; Los Angeles, 28.460017 -98.9999 1, 391ft., [APH_0871, 2008, 1♀, Sky Stevens, AUMNH]; Maverick: 4.2 miles SW Zavala County Line on Hwy-57, 28.88947 -100.16539 2, 711ft., [APH_1458, 24/1/2012, 1 juv, Stanley A. Schultz, AUMNH]; 4.6 miles E/SE Eagle Pass (jct US-57) on US-277, 28.69567 -100.39303 1, 833ft., [APH_0055, 17/7/2006, 1♂, Brent E. Hendrixson, AUMNH]; [APH_0058, 17/7/2006, 1♀, Brent E. Hendrixson, AUMNH]; [APH_0084, 17/7/2006, 1♀, Brent E. Hendrixson, AUMNH]; 9.0 miles NE US-57 on FM-481, 28.928198 -100.262798 1, 787ft., [APH_1149-1150, 17/3/2010, 2 juv, Brent E. Hendrixson, Gerri Wilson, Thomas Martin, AUMNH]; McMullen: 1.25 miles N FM-3445 on TX-16, 28.520536 -98.547662 1, 300ft., [APH_1117, 14/3/2010, 1 juv, Brent E. Hendrixson, Gerri Wilson, Thomas Martin, AUMNH]; Nueces: Corpus Christi, Meldo Park, approx. 2 blocks SW Santa Fe St on Brawner Parkway, 27.747437 -97.379802 1, 41ft., [APH_0577-0578, 13/6/2009, 2 juv, Brent E. Hendrixson, Courtney Dugas, Sloan Click, AUMNH]; Starr: San Carlos, Hwy 649 ~ 2 miles N of 2686 junction, 26.720783 -98.8468 1, 411ft., [APH_0889, 18/4/2008, 1♀, Christian Cox, Corey Roelke, AUMNH]; Washington: 2301 Running Valley Lane, Washington, 30.225692 -96.160138 1, 224ft., [APH_3123, 13/6/2013, 1♂, Chuck Matula, AUMNH]; 5 miles west of Carmine, 30.140828 -96.759342 5, 433ft., [APH_2660, 27/6/1960, 2♀, W. McAlister, AMNH]; Brenham, 30.145467 -96.43435 5, 323ft., [APH_0968, 6/2006, 1♂, Dave Moellendorf, AUMNH]; Chappell Hill, 1/4 mile S of intersection of Old Chappell Hill Rd and Pulaski School Rd, 30.1577 -96.288344 1, 282ft., [APH_3121, 20/5/2013, 1♂, Todd Burch, AUMNH]; [APH_3122, 30/5/2013, 1♂, Todd Burch, AUMNH]; Webb: 0.8 miles NW Hwy-44 on US-83, 28.03711 -99.54681 1, 820ft., [APH_1285, 13/5/2011, 1♂, Brent E. Hendrixson, Kate Hall, Austin Deskewies, Alexis Guice, AUMNH]; 1.1 miles SW Duval County Line on US-59, 27.786023 -98.818769 1, 451ft., [APH_0524-0528, 3/6/09, 3♀, 2 juv, Brent E. Hendrixson, Courtney Dugas, Sloan Click, AUMNH]; 3.2 miles W FM-2895 on TX-359, 27.454855 -99.136257 1, 511ft., [APH_1125, 15/3/2010, 1 juv, Brent E. Hendrixson, Gerri Wilson, Thomas Martin, AUMNH]; 3.6 miles NW I-35 on US-83, 27.80051 -99.46291 1, 760ft., [APH_1281-1282, 13/5/2011, 2 juv, Brent E. Hendrixson, Kate Hall, Austin Deskewies, Alexis Guice, AUMNH]; 4.3 miles E Loop-20 on US-59 at Los Tios Creek, 27.56159 -99.39045 1, 470ft., [APH_1280, 13/5/2011, 1 juv, Brent E. Hendrixson, Kate Hall, Austin Deskewies, Alexis Guice, AUMNH]; 5.1 miles SE La Salle County Line on Hwy-44, 28.012456 -99.195109 1, 454ft., [APH_0530-0531, 3/6/2009, 2 juv, Brent E. Hendrixson, Courtney Dugas, Sloan Click, AUMNH]; Wharton: El Campo, 29.19405 -96.2617 1, 90ft., [APH_0800-0803, 7/2008, 4♀, Chris A. Hamilton, AUMNH]; Zapata: 2.0 miles NW FM-2687 on US-83, 26.80362 -99.142 1, 410ft., [APH_1277-1279, 13/5/2011, 1♂, 2 juv, Brent E. Hendrixson, Kate Hall, Austin Deskewies, Alexis Guice, AUMNH]; Mexico: Nuevo Leon: Cañon de la Huasteca, 25.61484 -100.47585 1, 2600ft., [APH_0056, 24/7/2006, 1♀, Brent E. Hendrixson, AUMNH].

Distribution and natural history.

In the United States, Aphonopelma anax is widely distributed throughout South Texas (Fig. 14). We only sampled a single individual from western Nuevo Leon but the species distribution model predicts suitable habitat for this species throughout northeastern Mexico in Coahuila, Nuevo Leon, and Tamaulipas. The vast majority of specimens were collected at elevations between sea level and 300 meters along the Western Gulf Coastal Plain (Fig. 1I) or Southern Texas Plains Level III Ecoregions, but other samples were obtained from the Texas Blackland Prairies, East Central Texas Plains, South Central Plains, and the very southern edge of the Edwards Plateau. The specimen from Nuevo Leon (at Huasteca Canyon near Monterrey) was collected at an elevation of approximately 850 meters. This species has been observed in syntopy with Aphonopelma moderatum (burrows located fewer than 50 centimeters from each other) at several different locations near the Rio Grande from Eagle Pass (Maverick County) to Rio Grande City (Starr County). Aphonopelma anax may also be found alongside Aphonopelma armada and Aphonopelma hentzi . Burrows are typical of that for North American tarantulas (i.e., circular and generally covered by a thin veil of silk) and specimens can be readily collected by pouring a small amount of water into their burrows. In extreme South Texas, Aphonopelma anax is probably active year-round; however, in more northern populations, spiders likely plug their burrows for short periods of time during the winter. The breeding period appears to be restricted to spring and early summer (April-July); adult males have been observed in large numbers at night along roads following heavy bouts of rain (United States Border Patrol 2009, pers. comm.).

Conservation status.

Aphonopelma anax is very common throughout its distribution. Extensive fieldwork near Edinburg and McAllen (Hidalgo County) suggests that some local populations of Aphonopelma anax have probably been extirpated due to extensive agriculture in the Lower Rio Grande Valley, but overall the species is fairly abundant throughout South Texas. These spiders appear to thrive in a variety of anthropogenic settings including golf courses, residential lawns, city parks, roadside picnic areas, and mowed highway shoulders. The status of Aphonopelma anax is likely secure.

Remarks.

Aphonopelma anax is one of the largest and most robust Aphonopelma within the United States. This species exhibits size variation within males and females across their distribution, with northern populations generally smaller and the southern populations representing the largest tarantulas in the United States. Other important ratios that distinguish males: Aphonopelma anax possess a smaller M1/F4 (≤0.75; 0.69-0.75) than Aphonopelma moderatum (≥0.80; 0.80-0.88) and Aphonopelma moellendorfi (≥0.81; 0.81-0.88). No other ratios distinguish female Aphonopelma anax from their syntopic or closely related phylogenetic species. 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 none are claimed to be significant at this time (see Suppl. material 2). During evaluation of traditional PCA morphospace, males of Aphonopelma anax separate from Aphonopelma moderatum , Aphonopelma moellendorfi , and Aphonopelma gabeli along PC1~2, but do not separate from Aphonopelma armada or Aphonopelma hentzi . Females separate from moderatum along PC1~2, but do not separate from Aphonopelma armada , Aphonopelma gabeli , Aphonopelma hentzi . Females of Aphonopelma moellendorfi are unknown at this time and cannot be compared. Interestingly, Aphonopelma anax males separate from Aphonopelma gabeli , Aphonopelma moderatum , and Aphonopelma moellendorfi in three-dimensional PCA morphospace (PC1~PC2~PC3), but do not separate from Aphonopelma armada and Aphonopelma hentzi . Aphonopelma anax females separate from Aphonopelma armada and Aphonopelma moderatum , but do not separate from Aphonopelma gabeli and Aphonopelma hentzi . PC1, PC2, and PC3 explain ≥87% of the variation in male analyses and ≥96% of the variation in female analyses.

It is important to note the tremendous amount of variation that can be observed in the shape of the spermathecae from numerous populations of Aphonopelma anax (Figs 12-13). Previous taxonomic work considered this amount of variation to represent differences between species (e.g., Smith 1995 differentiated his new species Aphonopelma breenei from Aphonopelma anax on the basis of its spermathecae) ( Smith 1995) but our samples demonstrate that the shape of spermathecae is quite variable and is not useful for differentiating these two species. The spermathecae are however useful for distinguishing Aphonopelma anax from other members of the Hentzi species complex ( Aphonopelma armada and Aphonopelma hentzi ). This information was used to place Aphonopelma harlingenum (whose type locality is surrounded by Aphonopelma anax ) into synonymy with Aphonopelma hentzi and not Aphonopelma anax . It is also important to note that the paratype of Aphonopelma harlingenum that is found in the same jar as the Aphonopelma harlingenum holotype is a female of Aphonopelma anax (see spermathecae in Fig. 12C). Additionally, as seen in the spermathecae, we find that palpal bulb variation is extreme both across and within Aphonopelma species - an unfortunate finding that further enforces our idea that these traditionally used morphological characters are ineffective species delimiters. Unless these characters are extreme autapomorphies (i.e. Aphonopelma anax spermathcae and palpal bulbs, Aphonopelma gabeli spermathecae) that can be used in conjunction with other evidence to determine species boundaries in this group of spider, they should not be regarded as taxonomically informative.

Mitochondrial DNA (CO1) identifies Aphonopelma anax as a polyphyletic group with respect to Aphonopelma armada and Aphonopelma hentzi (Fig. 7). A second lineage of Aphonopelma anax is sister to a lineage of Aphonopelma hentzi ; both of these lineages were previously identified as putative cryptic species ( Hamilton et al. 2014). The AE data demonstrate that CO1 is not effective at accurately delimiting species boundaries within this group. Finally, we examined the holotype and freshly collected topotypic material of Aphonopelma breenei . Our morphological and molecular analyses fail to recognize this species as a separate, independently evolving lineage. As a consequence, we consider Aphonopelma breenei a junior synonym of Aphonopelma anax .