Antrodiaetus metapacificus , Cokendolpher, James C., Peck, Robert W. & Niwa, Christine G., 2005

Cokendolpher, James C., Peck, Robert W. & Niwa, Christine G., 2005, Mygalomorph spiders from southwestern Oregon, USA, with descriptions of four new species, Zootaxa 1058, pp. 1-34: 26-29

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Antrodiaetus metapacificus

n. sp.

Antrodiaetus metapacificus  n. sp.

Figs. 1View FIGURE 1, 7View FIGURE 7, 14View FIGURES 12 – 15, 28–29View FIGURES 22 – 33, 37View FIGURES 34 – 37, 44 –45View FIGURES 42 – 45, 52View FIGURES 49 – 52

Type Material. Oregon (all collected on 9 Oct. 2002 by Niwa and Peck USFS): Josephine County, Galice Ranger District, Siskiyou National Forest, N 42 ° 32 ’ 52 ”, W 123 ° 37 ’ 59 ” (652 m elevation), 1 male holotype ( NMNHAbout NMNH), 2 male paratypes (1, JCC; 1, WFIC).

Diagnosis. This species differs from many members of the genus by having the three opisthosomal sclerotized patches fused into a single scutum ( Fig. 14View FIGURES 12 – 15). Others with this characteristic occur in Japan, eastern North America, and the Pacific Northwest of the USA (Oregon: A. coylei  n. sp. and northeastern Washington: A. cerberus Coyle  ). Antrodiaetus metapacificus  n. sp. can be distinguished from A. coylei  n. sp. by lacking a small cheliceral distodorsal projection ( Fig. 37View FIGURES 34 – 37) and differs from A. cerberus  by the overall smaller size. The prosomal dorsal shield length is 5.2–5.4 in A. cerberus  and 3.9–4.7 in the new species.

Etymology. Meta (Greek)  means, among other things, to be derivative or related. In this case it is used to show the relationship of this species to A. pacificus  . This species will key to A. pacificus  in Coyle (1971). This primarily based on the notion that A. pacificus  consists of individuals with less than 30 % of the male tibia I macrosetae being ensiform. The percentage is actually much lower (0–3 %) in the western examples of A. pacificus  (see comments below under that species).

Distribution. Known only from a single location within the Galice Ranger District, Siskiyou National Forest, Josephine County, Oregon ( Fig. 1View FIGURE 1).

Description. Female unknown. Male (n = 3): body small, total body length 8.45 (6.35, 7.9), and yellowish­brown, appendages and sclerotized patches on opisthosoma more evenly light brown with leg I patella to tarsus reddish­brown, dark brown pigment encircling anterior median eyes and between posterior median eyes and lateral eyes.

Dorsal shield of the prosoma 4.5 (3.95, 4.7) long, 3.2 (2.6, 3.35) wide, with setae scattered sparsely over pars thoracica except denser along lateral and posterior borders.

Opisthosoma 3.95 (2.4, 3.2) long, 2.4 (2.75, 3.2) wide; all three dorsal sclerotized patches fused into single scutum (in holotype the area after the first is almost divided, but this junction is undetectable in paratypes) ( Fig. 14View FIGURES 12 – 15); male genital plate with sclerotized parts undivided, straight to recurved ( Figs. 28–29View FIGURES 22 – 33).

Chelicera with large area on upper ectal surface without setae; without distodorsal projection ( Fig. 37View FIGURES 34 – 37).

Palp with tibia swollen. Tibia 2–2.4 times longer than wide; widest in proximal third; 2.6 (2.05, 2.3) long, 1.28 (0.85, 1.05) wide. Tip of outer conductor sclerite ( Fig. 52View FIGURES 49 – 52) roundly pointed; closely appressed to inner conductor sclerite. Tip of inner conductor sclerite well sclerotized and not curved.

Leg I ( Figs. 44–45View FIGURES 42 – 45) without any segment being greatly enlarged or modified with processes; femur 3.9 (3.35, 3.65) long, patella 1.7 (1.5, 1.85) long, tibia 2.55 (2.25, 2.7) long, 0.5 (0.75, 0.9) wide, metatarsus 3.35 (2.8, 3.05) long, tarsus 2.4 (1.65, 1.8) long. Tibia I with relatively dense group of prolateral macrosetae medially (not reaching distal end of segment). Tibia I with relatively dense group of prolateral macrosetae medially (not reaching distal end of segment): 31 (9 ensiform) [28 (8 ensiform), 35 (10 ensiform)] macrosetae. Tibia I with 6 (6,7) medial (not extending to distal end) macrosetae ventrolaterally, the longest seta about width of tibia (noticeably longer than any prolateral macrosetae). Tibia I without large heavy macrosetae ventrally; tibia and metatarsus I not swollen in lateral view; metatarsus I slightly sinuous to straight, without macroseta ventrally; other setae ventrally on metatarsus I = 2 times greatest width of segment.

Wandering Activity. This species was only recorded on 9 October 2001 ( Fig. 7View FIGURE 7).

Comments. Antrodiaetus metapacificus  n. sp. was found at a single site within the Douglas­fir/dry shrub plant association of the western Siskiyou Mountains. The overstory of this relatively low elevation site (652 m) was dominated by Douglas­fir (36 % cover) but also included incense­cedar (12 %) and Oregon ash ( Fraxinus latifolia Bentham  ) (5 %). Twenty­three understory plant species were recorded at the site, with pacific madrone ( Arbutus menziesii Pursh  ) (6 %), Oregon ash (5 %) and tanoak (4 %) most common. The site faced SE and had a slope of approximately 24 °.


Smithsonian Institution, National Museum of Natural History