Retrorsioides linnensis 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 : 105

Retrorsioides linnensis Shear & Marek , n. sp.

Figs 59–68 , 128

Types. Male holotype and male and female paratypes from Wells Creek Road , 0.7 mi from SR34, 44.4696°. - 123.4899°, Linn Co., Oregon, collected 9 December 2005 by W. Leonard and C. Richart. All types deposited in CAS .

Diagnosis. The seventh segment of the antenna has a small distal knob set with 6–8 sensilla ( Fig. 60 ). The gonopod ( Figs 66 , 128 ) is short and stout with all processes and the pulvillus clustered near the tip. The prefemorite (pf, Fig. 66 ) is flattened. The anteriorly directed process has a small basal tooth.

Etymology. The species epithet is an adjective referring to the type locality in Linn Co., Oregon.

Description. Length about 4 mm, greatest width 0.42 mm. Head densely setose, cuticle alveolate. Collum with anterior marginal row of 18 setae. Anterior metazonites with three rows of setae, transitioning to four rows ( Fig. 62 ) at about ring 5; setal tubercles becoming low on posterior segments. Epiproct ( Fig. 63 ) not swollen, short. Anterior legs ( Fig. 65 ) crassate, tarsi with sphaerotrichomes ( Fig. 64 ). Gonopod ( Figs 66–68 , 128 ) with flattened prefemorite (pf, Fig. 66 ). Acropodites (ac, Fig. 66 ) short stout, processes and pulvillus crowded toward tip. Pulvillus (p, Fig. 68 ) in distal third of acropodite; pulvillar process (pp, Fig. 68 ) a short, triangular tooth. Anteriorly directed process (adp, Fig. 68 ) long, flattened, with marginal teeth. Terminal zone (tz, Fig. 68 ) bifurcate, bent laterally. Female similar in nonsexual characters.

Distribution. Linn and Tillamook Cos., Oregon.

Records: OREGON: Tillamook Co.: 1 mi west, 0.5 mi south of Lee’s Camp, 700 ft asl, 45.5883°, -123.5349°, 4 November 1972, E. M. Benedict, mm, ff; FR14, 4.2 mi northeast of SR22, Suislaw National Forest, 900 ft asl, 45.2248°, -123.8337°, 10 December 2005, W. Leonard, C. Richart, m. f.

Figures

FIGURES 56–60. Species of Retrorsioides, n. gen.. 56–58. Retrorsioides castellum, n. sp. 56. Gonopods, lateral view, anterior to the right. 57. Pulvillus with probable spermatic mass.58. Female genitalia, ventral view. SEM stub WS32-17. 59, 60. Retrorsioides linnensis, n. sp. 59. Midbody ring, dorsal view. 60. Tip of antenna, apical view. SEM stub WS33-15. Abbreviations: adp, anteriorly directed process; p, pulvillus; pp, pulvillar process.

FIGURES 61–66. Retrorsioides linnensis, n. sp. 61. Accessory sensory area on seventh antennal segment. 62. Midbody ring, dorsal view. 63. Pygidium, lateral view. 64. Sphaerotrichomes on tarsus of third leg. 65. Left third leg, posterior view. 66. Gonopods in situ, posteriolateral view. SEM stub WS33-15. Abbreviations: ac, acropodite; pf, prefemorite; st, sphaerotrichome.

FIGURES 67–72. Species of Retrorsioides n. gen. 67, 68. Retrorsioides linnensis, n. sp. 67. Gonopod tip, posterior view. 68. Same, mesal view. 69–72. SEM stub WS33-15. Retrorsioides kittitas, n. sp. 69. Head and anterior rings, dorsal view. 70. Midbody ring, dorsal view. 71. Pygidium, lateral view. 72. Female genitalia, ventral view. SEM stub WS32-17Abbreviations: adp, anteriorly. directed process; p, pulvillus; pp, pulvillar process; tz, terminal zone.

FIGURES 127–132. Drawings of gonopods of polydesmid species. 127. Tip of gonopod of Retrorsioides castellum, n. sp., mesal view. 128. Right gonopod of Retrorsioides linnensis, n. sp., lateral view. 129. Left gonopod of Retrorsioides kittitas, n. sp., lateral view. 130. Right gonopod of Retrorsioides bannerti, n. sp., lateral view. 131. Right gonopod of Rowlandesmus millicoma, n. sp., mesal view. 132. Right gonopod of Rowlandesmus dentogonopus, n. sp., lateral view. Abbreviations: adp, anteriorly directed process; p, pulvillus; pf, prefemorite; pp, pulvillar process; tz, terminal zone.