Snoqualmia snoqualmie Shear, 2012

Shear, William A., 2012, Snoqualmia, a new polydesmid milliped genus from the northwestern United States, with a description of two new species (Diplopoda, Polydesmida, Polydesmidae), Insecta Mundi 2012 (238), pp. 1-13 : 8-10

Snoqualmia snoqualmie Shear , new species

( Figures 1-8 , 19, 20)

Types: Male holotype and male and female paratypes from Twin Falls/Iron Horse trailhead,

highway I-90 at Snoqualmie River, 47°26.651 N,

121°57.217 W, King Co., Washington, collected 25

February 2004 by W. Leonard and C. Richart, deposited in Virginia Museum of Natural History.

Etymology. The species epithet is a noun in apposition, referring to the type locality in the

Snoqualmie Valley.

Diagnosis. Individiuals of Snoqualmia snoqualmie are a little more than half as long as those of their only known congener, S. idaho , which also have far more complex gonopods.

Description. Male: Length, 4.0 mm, width 0.45 Figure 1 3 . Snoqualmia idaho , n. sp., gonopods, mm. Antennae short, clavate, sixth antennomere posterioventral view.

enlarged, with accessory sensory areas distal.

Head and collum subequal in width; collum transversely oval, with anterior marginal row of 18-20 acute setae, additional setae scattered ( Fig. 1 ). Typical midbody segment ( Fig. 2 ) with low, strongly toothed, horizontal paranota slightly extended anteriorly, with 3 rows of acute setae set on low swellings, anterior row with 14-16 setae, middle row with 16-18, posterior row with 14-16; ozopores simple, without rims, directed laterally on paranota ( Fig. 3 ). Pygidium ( Fig. 5, 6 ) rounded, with anterior row of 6 acute setae, 8-10 additional scattered setae; pygidial process prominent, lacking alveolate sculpture, proximally constricted, with 6 long, acute setae and 4 spinnerets, distinctly swollen distally, decurved in lateral view.

All legs markedly more crassate than those of female, femora swollen; pregonopodal legs more so than others ( Fig. 1 ). Gonopods ( Fig. 7, 8 , 19, 20) with hemispherical coxae filling gonostome and tightly appressed in midline, distinct flaplike portion covers articulation of telopodite. Prefemur large, transversely articulated with coxa, then elongate parallel to body axis; posterior surfaces with many long setae and small cuticular teeth. Attachment of acropodite broad, acute lateral process near origin. Acropodite shaft with broad, curved, toothed lamella, distal zone elongate, with lateral rows of coarse teeth. Pulvillus prominent, sessile, subtended by one small and two large processes; posteriorly at base of distal zone is alate, coarsely toothed process extending anteriorly and laterally.

Female. Length, 4.2 mm, width 0.44 mm, nonsexual characters as in male, but more slender, legs not crassate. Third sternum unmodified.

Distribution. Washington: King Co.: 1.5 mi. N of Hobart, Issaquah Exit on Rt. 18, N47°27.135, W121°57.217, 25 February 2004, W. Leonard, C. Richart, female presumably this species; I-90 Exit #37, N47°26.613, W121°40.061, 1300 asl, 21 January 2005, W. Leonard, C. Richart, male; I-90 Exit #38, near Olallie State Park, N47°26.651, W121°40.081 25 February 2004, W. Leonard, C. Richart, male.

Notes. The known localities for this species are tightly clustered in the Snoqualmie Valley east of Seattle, as can be seen from the coordinates given.

Near the ozopores are some minute cuticular structures that may be proprioceptors of some kind ( Fig. 4 ). They closely resemble the objects called intercalary microscutes described by Akkari and Enghoff (2011) from several polydesmidan species.

Despite the much greater complexity of the gonopods of S. idaho , it is possible to suggest potential homologies in the processes of the gonopods of the two species (see Fig. 19-22 as labeled). The distal zone is indicated by b, and is more strongly developed in S. snoqualmie , with rows of teeth. Process a is the most likely candidate for homology, being similarly alate and toothed in both species, extending anteriorly and laterally. Process c subtends the pulvillus (p); something similar occurs in nearly all polydesmids. In S. snoqualmie , processes e and f appear not to have correspondants in S. idaho , but see (f?) as labeled on Figure 15 . Process d is at least positionally similar in the two species, but far larger in S. Idaho , and divided into two distinct parts (d1, d2).

While the habitat in which the specimens were collected is dominated by coniferous trees such as western hemlock and western redcedar, the material was all taken from deciduous leaf litter derived from red alder, poplar, and deer fern (W. Leonard and C. Richart, pers. comm.).

Figures

Figures 1-6. Snoqualmia snoqualmie, n. sp. 1) Anterior end of male, dorsal view. 2) Poriferous midbody segment, dorsal view. 3) Ozopore, dorsal view. 4) Micropore and possible proprioceptors near ozopore, magnified from Fig. 3. 5) Pygidium, dorsal view. 6) Pygidium, lateral view.

Figures 7-8. Snoqualmia snoqualmie, n. sp., gonopods. 7) Oblique lateral view from right side. 8) Lateral view from left side.

Figures 14-18. Snoqualmia idaho, n. sp. 14) Nonporiferous midbody segment, dorsal view. 15) Gonopods, lateral view from left side. 16) Left gonopod, posterioventral view. 17) Gonopods, anterior view. 18) Gonopod pulvillus, lateral view.