Retrorsia richarti Shear & Marek, 2021

Shear, William A. & Marek, Paul E., 2021, Three new genera and eighteen new species of miniature polydesmid millipedes from the northwestern United States (Diplopoda, Polydesmida, Polydesmidae), Zootaxa 4975 (1), pp. 81-126 : 99-100

Retrorsia richarti Shear & Marek , n. sp.

Figs 40–46 , 124

Types. Male holotype and male and female paratypes from Thurston Co., Washington, Hospital Creek above confluence with Skookumchuck River , 46.7733°, -122.5855°, collected 12 December 2003, by W. Leonard, K. McAllister. All types deposited in CAS .

Diagnosis. The pulvillus (p, Fig. 45 ) is midlength in the acropodite of the gonopod, with the pulvillar notch (rn, Fig. 45 ) immediately distal; the terminal zone processes are short, the anterior only slightly retrorse. The anterior marginal row on the collum consists of 20 setae ( Fig. 42 ).

Etymology. The species name honors Dr. Casey Richart, Santa Barbara Botanical Garden, master naturalist and prolific collector of millipedes for this and other studies.

Description. Paratype male. Length, about 4.0 mm, greatest width 0.48 mm. Anterior marginal setal row on collum Fig. 42 ) of 20 setae. Anterior metazonites ( Figs 42, 43 ) with four rows of setae, posterior rows somewhat irregular; transitioning to five rows about ring nine. Epiproct ( Fig. 44 ) short, not decurved or swollen, with typical four spinnerets. Anterior legs crassate ( Fig. 44 ), tarsi with sphaerotrichomes. Gonopod ( Fig. 46 ) with large, inflated prefemorite. Acropodite long, slender, pulvillus (p, Fig. 46 ) about midway in their length, with pulvillar notch immediately above. Retrorse process of terminal zone (rp, Fig. 46 ) nearly straight, slightly inclined anteriorly. Subterminal process (st, Fig. 46 short, pointing directly posterior. Females similar to males in nonsexual characters.

Notes. The type locality collection included a mating pair ( Fig. 40 )

Distribution. Much of coastal northwestern Washington in the Puget Sound region, including the countes of Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Thurston, and Wahakiakum.

Records: WASHINGTON: Cowlitz Co.: Germany Creek, at end of county road, 5.5 mi north of Stella, 450 ft asl, 46.2564°, -123.1345°, 22 November 2003, W. Leonard, C. Richart, mm; Germany Creek, 5.3 mi north of SR14, 46.2590°, -123.1350°, 11 November 2004, W. Leonard, mm; Germany Creek, 5.5 mi north of SR14, 46.2608°, - 123.1343°, 8 December 2003, W. Leonard, mm. Grays Harbor Co.: Garrard Road at Weyerhauser D-line, 15 ft asl, 46.8040°, -123.3165°, 7 February 2005, m. Jefferson Co.: Falls View Campground, 7.8 mi west of Brinnon, 47.7896°, -122.9255°, 22 February 2003, W. Leonard, mm. Lewis Co.: Shaefer Park, 244 ft asl, 46.7530°, -122.9385°, 29 February 2003, W. Leonard, mm ff; end of Lepisto Road, north fork of Lincoln Creek, 46.7324°, -123.2303° 14 January 2004, C. Richart, m f. Mason Co.: 1.5 mi south, 0.5 mi west of Grapeview, 47.3354°, -122.8292°, 21 January 1968, E. Benedict, m; 2.5 mi north of Grant, 47.2761°, -122.9606°, 21 January 1968, E. Benedict, m; Beerbower Road at Schafer State Park Road, beside park, 47.1007°, -123.3873°, 11 December 2004, W. Leonard, m; Kennedy Creek, 47.0954°, -123.0820°, 30 March 2003, W. Leonard, m; Kennedy Creek, 0.6 mi upstream from Old Olympic Highway, 47.0901°, -123.1008°, 8 February 2003, W. Leonard, mm. Thurston Co.: Evergreen State College, Olympia, 47.0729°, -122.9779°, 16 March 2003, 26 January 2004, W. Leonard, mm ff; Intersection of Prather Road SW and Bicknell Road, 46.7767° -123.0505, 14 January 2004, C. Richart, mm f; McAllister Springs, 47.0491°, -122.7280°, 22 January 2000, 7 February 2004, W. Leonard, mm ff; Priest Point Park, Olympia, 47.06682°, -122.3952°, 5 January 2003, 1 February 2003, 16 February 2003, 11 January 2004, W. Leonard, mm ff; Tolmie State Park, 47.1204°, -122.7758°, 3 February 2003, W. Leonard, mm ff; Woodward Bay Natural Resource Conservation Area, 47.1271°, -122.8547°, 2 March 2003, W. Leonard, mm ff. Wahakiakum Co.: Swede Park, residence at 309 Loop Road, Grays River, 50 ft asl, 46.3075°, -123.6688°, 17 January 2004, W. Leonard, C. Richart, mm ff. Whatcom Co.: White Cap Road, 48.6623°, -122.4922°, 20 February 2004, C. Richart.

Figures

FIGURES 40–44. Retrorsia richarti, new species. 40. Mating pair, lateral view. 41. Head and anterior rings, dorsal view. 43. Midbody ring, dorsal view. 44. Pygidium, lateral view. SEM stub WS33-1.

FIGURES 45–49. Species of Retrorsia. 45, 46. Retrorsia richarti, new species. 45, Male, lateral view. 46. Gonopods in situ, lateral view. SEM stub 33-1. 47–49. Retrorsia gracilis, n. sp. 47. Gonopods in situ, anterior view. 47. The same, lateral view, anterior to the left. 49. Gonopod tip. SEM stub WS33-2. Abbreviations: p, pulvillus; rn, rounded notch distal to pulvillus; rp, retrorse process; st, subterminal process; tz, terminal zone.

FIGURES 121–126. Drawings of gonopods of polydesmid species. 121. Left gonopod of Retrorisia leonardi, mesal view. 122. Left gonopod of Retrorsia benedictae, mesal view. 123. Left gonopod of Retrorsia richarti,n. sp., mesal view. 124. Right gonopod of Retrorsia gracilis, n. sp., lateral view. 125, Gonopod tip of Retrorsia gracilis, mesal view. 126. Right gonopod of Retrorsia simplicissima, n. sp., lateral view.