Difference between revisions of "Aptostichus"

Latest revision as of 09:53, 20 December 2012

Taxonavigation

Ordo: Araneae
Familia: Euctenizidae

Name

Aptostichus Simon, 1891 – Wikispecies link – ZooBank link – Pensoft Profile

• Aptostichus Simon, 1891: 317 (type species by monotypy Aptostichus atomarius female lectotype from CA, San Bernardino; specimen AR4263 in MNHP, examined).–E. Simon 1892^[1]: 108.–E. Simon 1903^[2]: 901.–P. Smith 1908^[3]: 220–221–Bond & Opell 2002.
• Actinoxia Simon, 1891: 318 (type species by monotypy Actinoxia versicolor Simon juvenile holotype in MNHP, examined).–E. Simon 1892^[1]: 109. P. Smith 1908^[3]: 214 (Smith considered Actinoxia to be a junior synonym of Entychides Simon).–R. Chamberlin 1937^[4]: 9.–Synonymized by Bond & Opell 2002: 518.
• Nemesoides Chamberlin, 1919: 1–2 (Nemesoides hespera Chamberlin female holotype in MCZ, examined).–Synonymized by Bond & Opell 2002: 518.

Diagnosis

Males of this genus can be recognized by the presence of three or more spines on the distal most surface of the palpal cymbium (Figs 49, 56, 68) and a number of large, very thick spines on the distal-prolateral aspect of tibia I (Figs 48, 55). Tibia I spines are more offset proximally in the Simus and Sierra group species (Fig. 55). Entychides males have similar spination, however their spines are borne on a low apophysis whereas those of Aptostichus are not (Bond and Opell 2002^[5]). Aptostichus females have cuspules on both the labium and palpal endites; labial cuspules are generally few and/or restricted to the inner margins of the endites (Figs 38, 39). This condition is similar to that for Apomastus, however Apomastus species appear to lack labial cuspules and the distinctive Aptostichus abdominal coloration, which consists of a mottled chevron pattern (Fig. 51).

General description

Small to medium sized trapdoor spiders. Cephalothorax longer than wide, sloping posteriorly, moderate pubescence in most species (Figs 31, 54). Carapace sclerotization equal across its length. Thoracic groove intermediate to wide, procurved or straight (Fig. 33) and deep. In some males the thoracic groove is transverse or recurved (Fig. 51). Carapace of males fringed in stout black setae (Fig. 53). Eyes on a low tubercle (Fig. 35). AME and PME subequal diameter, except in a few species, particularly in some Simus group species where the PME diameter is noticeably less than that of AME. PME row slightly procurved or straight, AME row slightly recurved (Fig. 34). Caput moderately high (Fig. 31). Carapace of ethanol preserved specimens appears orangish-yellow. The coloration of living spiders tends to be a darker brown, however there is considerable variation in the intensity of coloration. Male coloration in most specimens is dark reddish-brown. Female and male abdominal coloration very distinctive consisting of light brown or gray background with a dark mottled chevron like pattern (Fig. 51). This pattern is less distinctive in Aptostichus simus, closely related species and is reduced in most desert-adapted species.
Sternum wider posteriorly, sometimes wider than in other euctenizids, tapering anteriorly (Figs 32, 52). Posterior sigilla large and positioned mid-posteriorly in most species (Fig. 32), in some species contiguous (e.g., Aptostichus hesperus). Anterior margin of sigilla has a rounded margin. Palpal endites longer than wide often with only a few cuspules, which are restricted to the posterior margin, except in Aptostichus simus that has many cuspules arranged in a characteristic pattern (Figs 38–39). Labium wider than long, with a few, to a moderate number of cuspules (Fig. 32). Chelicerae dark brown. Rastellum consists of numerous spines not borne on a distinctive mound (Fig. 57). Fangs long and slender. Cheliceral furrow promargin with row of very large teeth. Retromarginal row consists of a patch of denticles.
Apical PLS article short, digitiform (Fig. 64). Spinnerets mostly with pumpkiniform spigots with several articulated spigots interspersed on apical and median articles of PLS and the PMS (Fig. 65). Two to three large, articulated spigots on apical most aspect of the PLS. PMS article robust. See Bond and Opell (2002)^[5] for more detailed descriptions of these spigot types.
Anterior leg articles slender relative to posterior. Tarsi short and robust (Fig. 36). Female scopulae long, dense, asymmetrical, extending full length of tarsus, no further than the metatarsus (Figs 36, 44, 60). Scopulae extend no further than the tarsus of the pedipalp. Posterior legs lack distinct scopulae. Pedipalp claw with a few (Fig. 40) to many teeth (Fig. 58). Male tarsi I and II with short sparse scopulae that are restricted to the ventral surface. In some species male tarsi are slightly bent, elongate and pseudosegmented (e.g., Aptostichus simus). Basal palpal tooth and STC I–IV basal tooth elongate and positioned on the median keel but not bifid (Figs 41, 59, 61). STC IV with 5 or more teeth (Fig. 61). Female anterior legs with very few ventral spines (Fig. 36). Prolateral surface of female patella III covered in numerous thick spines. Distal ventral aspect of tarsus IV with short, sparse spine patch. Preening combs on distal most retrolateral surface of metatarsus IV (Figs 37, 45, 62). Tarsal trichobothria arranged in a zigzag pattern with typical base (Fig. 43); low tarsal organ with central pit (Figs 42, 63). Spermathecae with an elongate base that forms a secondary spermathecal bulb in some species (Figs 46, 47, 66, 67).
Male mating clasper morphology is distinctive. Articles of leg I bear a number of large, thickened spines positioned retrolaterally on the distal aspect of the tibia (Fig. 55), except members of the Sierra and Simus species groups whose tibial spines are more concentrated proximally (Fig. 55). In most species, metatarsus I with proximal ventral to prolateral excavation bordered distally by a low mound (Fig. 55). Tibia I with 3-5 elongate spines distributed retrolaterally except in some species which have denser spine patches. Palpal cymbium with four or more dorsal spines (Figs 49, 56, 68). Palpal bulb normal (Fig. 68), embolus of some Simus group species with serrations (Fig. 50). Palpal femur short with a dorsal row of thin spines, tibia short and robust in some species (e.g., Aptostichus simus) there is a distinctive prolateral spine patch on the palpal tibia.

Distribution

Distributed primarily throughout the California Floristic Province with the greatest number of species known from Southern California; a few species are recorded from Nevada and Arizona (Table 1, Map 1).

Key to species groups and to males

Note. Like many mygalomorph taxa, species identification is a non-trivial task. These spiders generally lack distinctive somatic differences that render development of a key to females virtually impossible and a key to males difficult at best. Although, I have attempted to provide a key to male specimens, I would caution that it is far from perfect and thus suggest that the key be used in conjunction with careful examination of specimens, the species description, knowledge of from where the specimen was collected (many species are narrowly endemic), and molecular characters (if available). Generally speaking no single characteristic should be taken as definitive evidence of a species’ determination. Because species placed in the Atomarius Sibling Species Complex have been delineated on the basis of a combination of biogeographic, general somatic, ecological, and molecular characteristics, the provided key to these taxa relies heavily on data taken from the geographic location and habitat from which the specimen was collected.

The Atomarius species group

Included species.
Aptostichus atomarius Simon, 1891
Aptostichus stephencolberti Bond, 2008
Aptostichus angelinajolieae Bond, 2008
Aptostichus stanfordianus Smith, 1908
Aptostichus miwok Bond, 2008
Aptostichus dantrippi Bond sp. n.
Aptostichus pennjillettei Bond sp. n.
Aptostichus asmodaeus Bond sp. n.
Aptostichus nateevansi Bond sp. n.
Aptostichus chiricahua Bond sp. n.
Aptostichus icenoglei Bond sp. n.
Aptostichus cabrillo Bond sp. n.
Aptostichus isabella Bond sp. n.
Aptostichus muiri Bond sp. n.
Aptostichus barackobamai Bond sp. n.
The Atomarius Sibling Species Complex
The Atomarius Sibling Species Complex (Bond and Stockman 2008^[6]) comprises six closely related sibling species: Aptostichus atomarius, Aptostichus stephencolberti, Aptostichus angelinajolieae, Aptostichus stanfordianus, Aptostichus miwok Bond, and Aptostichus dantrippi sp. n. With the exception of a number of coastal dune and desert-adapted lineages these species are relatively morphologically homogenous (see analysis of morphological variation in Bond and Stockman 2008^[6]) and are difficult to distinguish; modifications to the male leg I tibia and metatarsus are indistinguishable among species. However, all species in this complex have non-overlapping ranges and thus can be ascribed to species on the basis of collecting locality and habitat; examination of diagnostic molecular markers should be employed to definitively confirm any determinations made solely on the basis of geography. Molecular studies to date further indicate Aptostichus atomarius, as defined below, may actually comprise 2–3 species; sampling at the time was insufficient to formulate these additional hypotheses with rigor.

Taxon Treatment

• Bond, J; 2012: Phylogenetic treatment and taxonomic revision of the trapdoor spider genus Aptostichus Simon (Araneae, Mygalomorphae, Euctenizidae) ZooKeys, 252: 1-209. doi

Other References

1. ↑ ^{1.0 1.1} Simon E (1892) Histoire Naturelle des Araignées 1: Paris, 1–256.
2. ↑ Simon E (1903) Histoire Naturelle des Araignées 2: Paris, 669–1080.
3. ↑ ^{3.0 3.1} Smith C (1908) A preliminary study of the Araneae Theraphosidae of California. Annals of the Entomological Society of America 1: 207-236.
4. ↑ Chamberlin R (1937) On two genera of trapdoor spiders from California. Bulletin of the University of Utah Biology 28: 1-11.
5. ↑ ^{5.0 5.1} Bond J, Opell B (2002) Phylogeny and taxonomy of the genera of south-western North American Euctenizinae trapdoor spiders and their relatives (Araneae : Mygalomorphae, Cyrtaucheniidae). Zoological Journal of the Linnaean Society 136: 487-534. doi: 10.1046/j.1096-3642.2002.00035.x
6. ↑ ^{6.0 6.1} Bond J, Stockman A (2008) An Integrative Method for Delimiting Cohesion Species: Finding the Population-Species Interface in a Group of Californian Trapdoor Spiders with Extreme Genetic Divergence and Geographic Structuring. Systematic Biology 57: 628-646. doi: 10.1080/10635150802302443

Images

Figures 7–10. Aptostichus icenoglei sp. n. burrow; specimen MY2465, adult female, excavated from roadside bank north of Fallbrook on DeLuz Road (San Diego County). 7 burrow with trapdoor closed 8, 9 trapdoor propped open frontal and side views 10 burrow excavated.  Figures 31–38. Standard light microscopy views of female an Aptostichus simus specimen (MY3432). 31 side view 32 ventral view, sternum 33 dorsal view, carapace 34–35 eye group, dorsal and lateral views 36 leg I prolateral view 37 leg IV retrolateral view 38 palpal endite.  Figures 39–50. Scanning electron micrographs of Aptostichus simus specimens (female AP097, 39–47; male AP819, 48–50). 39 palpal endite, arrow indicates cuspule pattern 40 left pedipalp claw, retrolateral aspect 41 leg I, tarsal claws, retrolateral aspect 42 leg I, tarsus, dorsal aspect, tarsal organ (arrow) 43 leg I, tarsus, dorsal aspect, trichobothrial base (arrow) 44 leg I, tarsal scopulae 45 leg IV, ventral junction of tarsus and metatarsus, preening comb 46, 47 cleared spermathecae and close up of left spermathecal lobe 48 leg I, retrolateral distal aspect of tibia 49 pedipalp, ventral aspect 50 serrated edge of palpal embolus.  Figures 51–56. Standard light microscopy views of Aptostichus atomarius male specimens (51–54 MY2979; 55, 56 AP357). 51 dorsal habitus view 52 ventral habitus view 53 carapace 54 lateral habitus view 55 leg I, retrolateral aspect 56 pedipalp, retrolateral aspect.  Figures 57–68. Scanning electron micrographs of Aptostichus atomarius specimens (female MY3432, 57–67; male MY2979 68). 57 left chelicerae, anterior ventral aspect 58 left pedipalp claw, retrolateral aspect 59 leg I, tarsal claw, retrolateral aspect 60 tarsal scopulae, leg I 61 leg IV tarsal claws, retrolateral aspect 62 leg IV preening comb, tarsus/metatarsus junction 63 leg I, tarsus, dorsal aspect, tarsal organ 64 spinnerets 65 spinning field, distal aspect of PLS 66, 67 cleared spermathecae and close-up of left lobe 68 pedipalp, retrolateral aspect, arrow indicates position of spines on cymbium.  Map 1. Distribution of type localities for all known species of Aptostichus. Three letter identifiers are defined in Table 1; inset shows approximate scope of study area.  Figures 69–75. Aptostichus atomarius Simon, 1891. 69–72 Specimen AP357 from San Bernardino Co., San Bernardino; scale bar = 1.0mm 69 retrolateral aspect leg I [805733] 70 prolateral aspect leg I [805737] 71 retrolateral aspect pedipalp [805743] 72 ventral aspect palpal bulb [805745] 73–75 line drawings of spination patterns on metatarsus and tibia, leg I, retrolateral aspect 73 Los Angeles Co., Baldwin Hills (AP181) 74 San Luis Obispo Co., San Luis Obispo (AP172) 75 Los Angeles Co., Eaton Canyon Park (AP157).  Figures 79–81. Aptostichus atomarius specimens, live photographs. 79 MY3794 80 AUMS74 81 AUMS71.  Figures 82–87. Aptostichus stephencolberti Bond, 2008. 82 male habitus from San Francisco Co. (AP156) [805762] 83–85 male holotype from San Mateo Co., Pescadero State Beach (MY3515); scale bar = 1.0mm 83 retrolateral aspect leg I [805751] 84 prolateral aspect leg I [805747] 85 retrolateral aspect pedipalp [805753] 86 female habitus from Santa Cruz Co., Waddell Creek Beach (MY3508) [805758] 87 cleared spermathecae, from San Luis Obispo Co., Wilder Ranch State Beach (MY3500) [805754]; scale bar = 0.25mm.  Figures 106–112. Aptostichus stanfordianus Smith, 1908.106–109 male specimen from Contra Costa Co., Orinda Village (AP162); scale bars = 1.0mm 106 male habitus [805794] 107 retrolateral aspect, right leg I [805784] 108 prolateral aspect, right leg I [805780] 109 retrolateral aspect, right pedipalp [805786] 110, 111 female habitus and cleared spermathecae from Santa Cruz Co. (MY3100) [805790, 805795] 112 cleared spermathecae from Alameda Co., Alameda (AP296) [805776]; scale bars = 0.1mm.  Figures 120–126. Aptostichus pennjillettei sp. n. from Nevada, Clark Co., Mercury, Nuclear Test Site; scale bars = 1.0mm. 120 habitus, male holotype (AP413) [805830] 121–122 male paratype (AP412), leg I 121 retrolateral aspect [805838] 122 prolateral aspect [805834] 123–125 line drawings of spination patterns on leg I, retrolateral aspect, tibia and metatarsus 126 retrolateral aspect, holotype pedipalp [805832].  Figures 127–133. Aptostichus asmodaeus sp. n. from Contra Costa Co., Mt. Diablo. 127–132 male holotype (AP428); scale bars = 1.0mm 127 habitus [805850] 128–130 leg I 128 retrolateral aspect [805844] 129 prolateral aspect [805848] 130 line drawing of spination patterns on leg I, retrolateral aspect, tibia and metatarsus 131–132 pedipalp, retrolateral aspect of photograph [805852] and line drawing 133 cleared spermathecae (AP551) [806573]; scale bar = 0.1mm.  Figures 134–141. Aptostichus nateevansi sp. n. from Los Angeles Co., Santa Catalina Island (holotype) and San Clemente Island (paratype). 134–136, 139, 140 male holotype (AP420); scale bars = 1.0mm 134 habitus [805860] 135 retrolateral aspect, leg I [805854] 136 prolateral aspect, leg I [808858] 137, 138 male paratype (AP429) 137 retrolateral aspect, leg I 138 prolateral aspect, leg I 139 line drawings of leg I spination patterns, retrolateral aspect of patella, tibia and metatarsus and prolateral aspect of patella and tibia 140 retrolateral aspect, pedipalp [805864] 141 cleared spermathecae (AP543) [806576]; scale bar = 0.1mm.  Figures 146–150. Aptostichus icenoglei sp. n.; scale bars = 1.0mm. 146–148, 150 male holotype from Riverside Co., Winchester (AP391) 146 habitus [805874] 147 retrolateral aspect, leg I [805866] 148 prolateral aspect, leg I [805870] 149 line drawings of leg I article spination patterns of holotype and additional specimens from the type locality 150 retrolateral aspect, pedipalp [805872].  Figures 165–168. Aptostichus isabella sp. n. male holotype (MY3824) from Kern Co. 165–167 leg I 165 retrolateral aspect [805901] 166 prolateral aspect [806607] 167 line drawing, retrolateral aspect 168 retrolateral aspect, pedipalp [805903]. Scale bars = 1.0mm.  Figures 174–180. Aptostichus barackobamai sp. n. 174–176 male holotype from Mendocino Co. (AP411) 174 habitus [806630] 175 retrolateral aspect, leg I [806634] 176 prolateral aspect, leg I [806636] 177–179 male paratype from Tehama Co. (MY3805) 177 retrolateral aspect, leg I [806638] 178 prolateral aspect, leg I [806642] 179 retrolateral aspect, pedipalp [806644] 180 line drawings of leg I holotype and paratype specimens; retrolateral aspect of holotype pedipalp. Scale bars = 1.0mm.  Figures 188–191. Aptostichus hesperus (Chamberlin, 1919). 188 sternal sigilla pattern (indicated by circled area, labium at top of photograph; MY2526)) [805941] 189 line drawing of rastellar spine pattern for Aptostichus hesperus and other Hesperus group species 190 cleared spermathecae, specimen from San Bernardino Co., Yucaipa (MY2526) [805942]; scale bar = 0.1mm 191 photograph of live specimen from Riverside Co., Winchester(MY2496).  Figures 197–203. Aptostichus hedinorum sp. n. 197–200 male holotype (MY3779); scale bars = 1.0mm 197 habitus [806056] 198 retrolateral aspect, leg I [806048] 199 prolateral aspect, leg I [806052] 200 pedipalp, leg I [806054] 201 female habitus (MY3781), from type locality [806058] 202, 203 cleared spermathecae, female paratype (AP675) [806608] and additional specimen from type locality (MY3781) [806702]; scale bars = 0.1mm.  Figures 243–248. Aptostichus derhamgiulianii sp. n.; scale bars = 1.0mm. 243–246 male holotype (AP 415) Inyo County 243 habitus [806016] 244 retrolateral aspect, leg I [806010] 245 prolateral aspect, leg I [806014] 246 retrolateral aspect, pedipalp [806018] 247 male paratype (AP424) from Mono County, retrolateral aspect, leg I [806020] 248 line drawings, spination pattern, leg I tibia and metatarsus of holotype and paratype; retrolateral view, holotype pedipalp.  Figures 249–256. Aptostichus mikeradtkei sp. n. 249–252 male holotype (AP1085), from San Diego Co.; scale bars = 1.0mm. 249 habitus [806034] 250 retrolateral aspect, leg I [806032] 251 prolateral aspect, leg I [806028] 252 retrolateral aspect, pedipalp [806036] 253–255 cleared spermathecae; scale bars = 0.1mm 253 female paratype (AP1148) [806705] 254, 255 additional specimens from vicinity of type locality (AP1155, 1247) [806620, 806623] 256 sternum of paratype female (AP1148) [806038].  Figures 257–261. Aptostichus edwardabbeyi sp. n. 257, 258 habitus and cleared spermathecae of female paratype from Santa Cruz Co., Arizona (MY2279); scale bar = 0.1mm [806086] 259–261 male holotype (AP402) [806706]; scale bar = 1.0mm 259 retrolateral aspect, leg I [806078] 260 prolateral aspect, leg I [806076] 261 retrolateral aspect, pedipalp [806072].  Figures 262–265. Aptostichus anzaborrego sp. n., male holotype from San Diego County (AP1199); scale bars = 1.0mm. 262 habitus [806106] 263 retrolateral aspect, leg I [806102] 264 prolateral aspect, leg I [806098] 265 retrolateral aspect, pedipalp [806104].  Figures 266–272. Aptostichus sinnombre sp. n., male specimens from San Diego County; scale bars = 1.0mm. 266–268 male holotype (MY3761) 266 retrolateral aspect, leg I [806546] 267 prolateral aspect, leg I [806550] 268 retrolateral aspect, pedipalp [806552] 269–271 male paratype (MY3823) 269 retrolateral aspect, leg I [806554] 270 prolateral aspect, leg I [806558] 271 retrolateral aspect, pedipalp [806560] 272 line drawing, spination pattern, leg I tibia and metatarsus of holotype.  Figures 274–280. Aptostichus simus Chamberlin, 1917 male specimens from San Diego County; scale bars = 1.0mm. 274 habitus (AP1209) [806521] 275–278 secondary sexual characteristics (AP819) 275 retrolateral aspect, leg I [806525] 276 prolateral aspect, leg I [806529] 277 ventral view, pedipalp bulb [806531] 278 retrolateral aspect, pedipalp [806533] 279, 280 line drawings, leg I articles 279 retrolateral and prolateral aspect of specimen from San Diego County, Imperial Beach 280 retrolateral aspect, tibia and patella, in descending from San Diego County, Imperial Beach and Santa Barbara County, Carpinteria State Beach.  Figures 281–283. Aptostichus simus female specimens. 281 habitus, from San Diego County (AP067) 282 cleared spermathecae (MY3447), from San Luis Obispo County [806538]; scale bar = 0.1mm 283 cephalothorax, ventral aspect, from San Diego County (AP095) [806542].  Figures 304–310. Aptostichus lucerne sp. n. from San Bernardino County. 304–307 male holotype (AP434); scale bars = 1.0mm and 0.5mm (306) 304 retrolateral aspect, of right leg, leg I [806479] 305 prolateral aspect, of right leg, leg I [806483] 306 oblique, ventral/retrolateral aspect of palpal bulb [806485] 307 retrolateral aspect, pedipalp [806487] 308, 309 male paratype 308 retrolateral aspect, leg I [806489] 309 prolateral aspect, leg I [806493] 310 line drawings of leg I spination pattern; retrolateral aspect tibia and metatarsus; prolateral aspect of tibia.  Figures 316–322. Aptostichus fisheri sp. n. from Kern County; scale bars = 1.0mm. 316 habitus of male paratype (AP954) [806438] 317–319 male holotype (AP955) 317 retrolateral aspect, leg I [806442] 318 prolateral aspect, leg I [806446] 319 retrolateral aspect, pedipalp [806448] 320, 321 male paratype (AP407) 320 retrolateral aspect, leg I [806450] 321 prolateral aspect, leg I [806454] 322 line drawings of leg I spination pattern and pedipalp; retrolateral aspect, patella, tibia, metatarsus, tarsus; prolateral aspect, tibia and patella; retrolateral aspect, pedipalp.  Figures 332–336. Aptostichus sierra sp. n. male holotype (AP400) from Fresno County; scale bars = 1.0mm. 332 habitus [806511] 333 retrolateral aspect, leg I [806515] 334 prolateral aspect, leg I [806517] 335 retrolateral aspect, pedipalp [806519] 336 line drawings of leg I tibia and patella spination patterns; retrolateral aspect; prolateral aspect.  Figures 337–341. Aptostichus huntington sp. n. male holotype (AP408) from Fresno County; scale bars = 1.0mm. 337 retrolateral aspect, leg I [806469] 338 prolateral aspect, leg I [806473] 339 retrolateral aspect, pedipalp [806475] 340 sternum [806477] 341 line drawings of leg I and pedipalp spination patterns; retrolateral aspect patella, tibia, metatarsus, and tarsus; prolateral aspect tibia and patella; retrolateral aspect, pedipalp.