Aliatypus coylei, Hedin, Marshal & Carlson, Dave, 2011

Hedin, Marshal & Carlson, Dave, 2011, A new trapdoor spider species from the southern Coast Ranges of California (Mygalomorphae, Antrodiaetidae, Aliatypus coylei, sp. nov,), including consideration of mitochondrial phylogeographic structuring, Zootaxa 2963, pp. 55-68 : 60-63

Aliatypus coylei new species

Figs 1–5

Type material. Male holotype from Arroyo Seco Gorge, W of Arroyo Center, Monterey County, California, 36.2332°N, 121.4921°W, collected 12 October 2003, M. Hedin & J. Starrett (MY999, CASENT9039430). COI GenBank JN034076 , MorphBank images 588043-47. Female paratype from Carmel Valley Road, 1.25 km N of intersection with Tassajara Road, Monterey County, California, 36.4068°N, 121.5918°W, collected 25 November 2003, J. Starrett (MY1013, CASENT9039431). COI GenBank JN034075 , MorphBank images 588033-34.

Etymology. Patronym honoring mentor and friend Dr. Fred Coyle, in recognition of his rigorous and inspirational systematic research conducted on mygalomorph spiders, including the genus Aliatypus .

Diagnosis ( Figs 2–4 ). Males are distinguished from those of other Aliatypus species by the following combination of characters—sternum like A. thompsoni Coyle and species of the A. erebus group, with relatively large, relatively closely-spaced posterior sternal sigilla ( Coyle 1974, figs 60–64). This shape is best captured by the CL/PSL and SW/PSS ratios ( Table 2). The shape of the A. coylei palpal tibia (banana-shaped) is unlike the above species, except for A. torridus ( Coyle 1974, fig. 91). This shape is best captured by the PTX/PTL ratio ( Table 2). Leg I segments of A. coylei males are relatively longer than A. torridus males (CL/IFL ratio, Table 2).

Females are distinguished from those of other Aliatypus species by the following combination of characterssternum most like species of the A. erebus group, with relatively large posterior sternal sigilla ( Coyle 1974, figs 74–77), but not as closely spaced as those of A. thompsoni (see PSL/PSS ratio, Table 2). Aliatypus coylei also differs from A. thompsoni in having few ensiform macrosetae on metatarsus I, in possessing a thoracic pit, and in the shape of the seminal receptacles. Females of A. coylei are relatively short-legged, again like members of the A. erebus group (e.g., CL/IVTL ratio, Table 2), and possess similar-shaped seminal receptacles ( Coyle 1974, figs 174– 194). Of the species in the A. erebus group, A. erebus and A. torridus are most likely to be confused with A. coylei ( A. trophonius Coyle is diminutive, and A. plutonis Coyle is known only from far southern California). Although CL/PSL and SW/PSL ratios may be useful in distinguishing A. coylei from A. erebus and A. torridus (see Table 2), these morphological characters are unlikely to be strictly diagnostic. If genomic resources are available, the following amino acid changes in the COI reference alignment can be used to separate A. coylei from all members of the A. erebus group: position 15 (Phe in A. coylei, Ser in A. erebus group members), position 17 (Val, Glu), position 153 (Ile, Val), position 294 (Tyr, Asn), and position 310 (Cys, Asn).

Females CL/IVTL CL/PSS CL/PSL SW/PSS SW/PSL PSL/PSS A. californicus group 2.3–2.9 4.7–8.3 12.1–33.2 2.6–4.4 6.5–16.2 0.2–0.7 A. aquilonius 2.5–2.8 4.4–6.8 17.5–41 2.3–3.4 8.8–20 0.1–0.4 A. gulosus 2.9–3.3 4.8–6.3 13.5–22.2 2.6–3.4 7.1–13.7 0.2–0.4 A. thompsoni 2.6–3.1 12.7–31.6 6.5–10.9 6.6–18.4 3.3–5.7 1.3–4.1 A. erebus 3.0–3.5 7.7–14.7 6.5–9.8 4.3–8.5 3.8–5.3 0.8–2.0 A. torridus 3.1–3.4 8–10 8.3–10 4.4–5.4 4.6–5.4 0.8–1.1 A. coylei 3.1 9.3 10.8 4.9 5.7 0.9 Notes. Male and female data for species other than A. coylei are from Tables 1 & 2 of Coyle (1974). All measurements in millimeters.

Holotype male ( Fig. 2 ). Carapace 3.7 long, 3.2 wide, pars cephalica 2.2 long. Thoracic groove slightly oval, pit-like, anterior edge recurved. Cluster of postocular setae forming small backwards-pointing triangle. Leg I IFL 4.2, ITL 2.7, IML 2.6, ITarL 1.5. Dorsal setae on tibia and metatarsus mostly appressed, ventral ensiform macrosetae on tibia and metatarsus numerous, tibial dorsal macrosetae erect. Pedipalp PFL 4.7, PPL 2.8, PTL 3.9, PTX 2.0, PTT 0.7, PED 1.0, PCA 0.4. Tibia elongate, roughly banana-shaped, hirsute. Palpal bulb with loosely looped sperm reservoir, base of embolus relatively distant from base of inner conductor sclerite (ICS). Sternum SL 2.2, SW 1.9, posterior sternal sigilla moderately close (PSS 0.5), oval-shaped, faint. Abdomen tergite II large, tergite III subequal to tergite II, boundary indistinct; tergite I minute.

Paratype female ( Figs 3–4 ). Carapace 6.5 long, 4.9 wide, pars cephalica 4.2 long. Thoracic groove pit-like, anterior edge slightly recurved. Cluster of postocular setae forming small backwards-pointing triangle. Chelicerae with row of 2 retrolateral macroteeth, 6 prolateral macroteeth, 7–8 intermediate microteeth. Leg I IFL 4.0, ITL 2.4, IML 1.8, ITarL 1.0, 11 ensiform macrosetae on metatarsus. Leg IV (right) IVFL 4.1, IVTL 2.1, IVML 3.2, IVTarL 1.4. Pedipalp tarsus with 7 ensiform macrosetae on prolateral surface, 3 ensiform macrosetae on retrolateral surface. Sternum SL 4.2, SW 3.4, posterior sternal sigilla well separated (PSS = 0.7), large (PSL = 0.6), oval-shaped. Seminal receptacles with relatively large bulbs as compared to stalk diameter, stalks short, with single bend.

Other records. The species is known from 20 other geographic locations, represented by 28 adult specimens (Table 1). Two other locations are represented only by immature specimens (sites 3 and 23, Table 1); DNA analyses indicate that these immatures are A. coylei specimens.

Geographic variation. A male from site 9 (Table 1) is smaller-bodied than the holotype male, but otherwise conforms to the holotype in shape of palpal tibia, details of the bulb, and shape of sternal sigilla. Female specimens vary noticeably in shape of the seminal receptacles, although most possess relatively large bulbs, with short, narrow stalks. An exception is MY2671 from site 24 (Table 1), with seminal receptacles not unlike A. gulosus Coyle , with straight, short stalks leading to bulbs of only slightly larger diameter ( Fig. 3 L). Specimens from several sites include more stalk bends than the holotype female (e.g., Fig. 3 E, G, J, K). The general characteristics of sternal sigilla morphology (large, fairly close together, diverging oblong shape) is similar among female specimens, with minor exceptions. For example, specimen MY374 from site 12 (Table 1) has relatively widely spaced, less elongate posterior sigilla ( Fig. 4 B). Several other females have irregular-shaped sigilla (e.g., Figs 4 D, E).

Distribution. Most records are from the southern Coast Ranges, including the Gabilan, Diablo, Santa Lucia, and La Panza Ranges. Two isolated records are from further south in California, with a record from the Transverse Ranges (site 23, Table 1, Fig. 1 ), and a record from the Santa Monica Mountains (site 24, Table 1, Fig. 1 ).

Natural history. Consistent with the relatively broad geographic distribution of this species, populations have been found in several habitat types including coastal redwood forest, Monterey Pine forest, mixed Pinus sabiniana / Quercus woodland, and habitats dominated by Adenostemma / Arctostaphylos chaparral scrub. Essentially all collections are from more mesic microhabitats within these larger habitat types, including north-facing ravines, shaded banks, and shaded roadcuts. Burrows have been found on essentially vertical banks (e.g., sites 1, 5, 13, 15), but also on shallower slopes (e.g., sites 10, 12, 22). Many burrows were characterized by almost a complete absence of silk. Adult females have been collected throughout the year; two adult male specimens were collected from burrows in October (Table 1).

Figures

FIGURE 2. Male holotype, MY 999 (CASENT 9039430), W of Arroyo Center (site 19): A) carapace and abdomen, viewed dorsally, B) left pedipalp, viewed retrolaterally, C) left leg I, viewed retrolaterally, D) sternum and chelicerae, viewed ventrally, E) palpal bulb, viewed ventrally. Scale bar A – D = 1 mm, E = 0.5 mm.

FIGURE 3. Female spermathecae, viewed ventrally: A) MY 1013 (CASENT 9039431) paratype female, Carmel Valley Road (site 18), B) MY 1326, Laureles Grade Road (site 13), C) MY 374, Jack’s Peak County Park (site 12), D) MY 955, W of Pinnacles NM (site 8), E) MY 3059, Palo Colorado Road (site 15), F) MY 4194, Harlan Mtn Road (site 5), G) MY 4362, Hidden Valley Road (site 1), H) MY 1645, Coalinga Road (site 10), I) MY 1642, Lonoak Road (site 11), J) MY 829, E of Santa Margarita (site 22), K) MY 1010, S of Gorda (site 20), L) MY 2671, Kanan Dume Road (site 24). Colored dots correspond to genetic groups of Fig. 5. Site numbers correspond to Table 1 and Fig. 1 C. Scale bar = 0.5 mm.

FIGURE 4. Female sternal sigilla, viewed ventrally: A) paratype female, MY 1013, Carmel Valley Road (site 18), B) MY 374, Jack’s Peak County Park (site 12), C) MY 2671, Kanan Dume Road (site 24), D) MY 4194, Harlan Mtn Road (site 5), E) MY 1642, Lonoak Road (site 11) F) MY 829, E of Santa Margarita (site 22). Colored dots correspond to genetic groups of Fig. 5. Site numbers correspond to Table 1 and Fig. 1 C. Scale bar = 1 mm.

FIGURE 1. A) Adult female Aliatypus coylei (MY 4194), Harlan Mountain Road, Gabilan Range, San Benito County; B) Aliatypus trapdoor, Harlan Mountain Road, Gabilan Range, San Benito County; C) Known distribution of Aliatypus coylei. Site numbers correspond to Table 1; some geographically adjacent sites are represented by a single white circle. Regional records of other Aliatypus species as follows: red dots = A. janus, blue dots = A. torridus (records from Coyle 1974, Coye & Icenogle 1994; Satler et al. in review; personal observations). San Luc = Santa Lucia Range, Gab = Gabilan Range, Diablo = Diablo Range.

FIGURE 5. A) Majority-rule consensus phylogram resulting from partitioned Bayesian analysis. Aliatypus coylei haplotypes are labeled with specimen number, location abbreviation, and site number (corresponding to Fig. 1). Posterior probability values are shown for both partitioned (above branches) and unpartitioned (below branches) analyses. Samples with morphological images included in Figs 3 and 4 are highlighted. B) Geographic distribution of haplotype groupings. Site numbers correspond to Fig. 1.