Stachia oregonensis, Smolis, Adrian, 2010

Smolis, Adrian, 2010, Two new species of Collembola: Friesea kariae sp. nov. (Neanuridae) and Stachia oregonensis sp. nov. (Odontellidae) from North America, Zootaxa 2515, pp. 36-44 : 40-43

Stachia oregonensis sp. nov.

Figs 18–31

Diagnosis. This species can be recognized by the following characters: postantennal organ with three lobes, lobes in PAO apically rounded, Ant. IV with 5 flame-shaped and 3 globuliform sensilla, trochanters with 3 setae each, femora I, II, III with 7, 6, 6 setae respectively, claw with unguiculus, abdominal segments I–IV with setae a1, even anal lobes with 2+2 microsetae.

Type material. Holotype: male on slide, USA: Oregon, Lane Co., 6.5 km East of Blue River town, 520 m above sea level, “Cougar 1” site ( Fig. 32 ), old-growth forest of Tsuga heterophylla zone, 22.IX.2006, A.

Smolis coll., in USNM. Paratypes: 5 females, 2 males and 7 juveniles, same locality as holotype, 22.IX.2006, A. Smolis, 10 and 4 paratypes in ZIWU and OSAC respectively.

Other material. 1 female and 1 juvenile, USA: Oregon, Lane Co., 6.5 km North–East of Blue River town, 450 m above sea level, “Mona Creek” site, valley of Mona Creek, mixed forest of Tsuga heterophylla zone, 3.X.2006, A. Smolis coll., in ZIWU; 8 specimens, Canada: British Columbia, Vancouver Island, Pacific Rim National Park, Green Point, litter in forest of Picea sitchensis , near beach, 9.VI.1983, A. Fjellberg, Fjellberg’s collection.

Etymology. The new species is named after the state Oregon.

Description. Body length (without antennae) 0.36–0.56 mm (holotype: 0.47 mm). Colour of the body in alive and alcohol white. Habitus typical of the genus ( Fig. 18 )

Area ocularis without eyes. Postantennal organ triangular consisting of three lobes, partially covered by cuticular folds ( Figs 21 and 22 ). Granulation fine and heterogeneous. Dorsal side of head and thorax with characteristic longitudinal and transverse ridges ( Fig. 18 ). Granules coarser and larger towards end of abdomen. Buccal cone short, labium as in Fig. 19 . Mandible invisible, chaetotaxy of labrum difficult to observe and precise. Maxilla as in Fig. 20 .

Dorsal chaetotaxy of head as in Fig. 18 . Seta c3 and 3 setae d present. Head with 2+2 setae along ventral line. Antennae distinctly shorter than head, conical in shape. Chaetotaxy of antennae III–IV as in Figs 23 and 24 . Ant. I with 7 setae, Ant. II and III with 10 setae. Ant. III and IV fused dorsally. Eversible sac between III and IV Ant. absent. AOIII with two very small internal sensilla and two small slightly curved guard sensilla ( Fig. 23 ). Ventral microsensillum on Ant. III present. Ant. IV without apical vesicle, with very small subapical organite, 2 microsensilla, 5 short and relatively thick flame-shaped sensilla, and 3 small globuliform sensilla ( Figs 23 and 24 ).

Dorsal chaetotaxy of thorax as in Fig. 18 . Sensillar formula of thorax 0 22. Sensilla relatively thin, as long as nearest ordinary setae or slightly longer. Seta a2 present on Th. II–III. Thoracic sterna without setae.

Legs chaetotaxy from I to III: tibiotarsi with 7 setae each; femora with 7, 6, 6; trochanters with 3 each; coxae with 3, 4, 4; subcoxae with 0, 2, 2. Claws without inner tooth, empodial appendage needle-like and very short ( Figs 27–29 ).

Dorsal chaetotaxy of abdomen as in Fig. 18 . Sensillar formula of Abd. 11111, sensilla similar in morphology and length to ordinary setae. Seta a1 present on Abd. I–IV. Ventral chaetotaxy of Abd. as in Figs 30 and 31 . Ventral tube with 3+3 setae. Retinaculum absent. Furcula reduced, mucro paddle-like, not separated from dens. Dens with 2+2 microsetae ( Figs 25 and 26 ). Anal lobes with 2 microsetae hr each ( Fig. 31 ).

Notes. The new species seems to be a resident of mixed conifer/broadleaf and conifer forests of both Tsuga heterophylla and Picea sitchensis zones ( Franklin & Dyreness 1988). It was found in deep soil and litter layers of lower elevation and coastal forests, on Oregonian localities predominantly near streams. Bisexual species.

Discussion. The differences between all known species of the genus Stachia are provided in the key. Among members of Stachia , only the new species has 7, 6, 6 setae on femora I, II, III, respectively. The presence of unguiculus on legs and setae a1 on abdominal segments I–IV locates S. oregonensis sp. nov. very near S. minuta Folsom, 1932 , described from Hawaii (deep soil of pineapple field). However, both mentioned taxa can be distinguished additionally by trochanteral chaetotaxy (three setae in S. oregonensis , two setae in S. minuta ), the shape of postanteannal lobes (rounded in S. oregonensis , pointed in S. minuta ) and the different arrangement of labial setae.

Figures

FIGURE 32. Old-growth forest of Tsuga heterophylla zone, “ Cougar 1 ” site. Type locality of Friesea kariae sp. nov. and Stachia oregonensis sp. nov.

FIGURES 18 – 31. Stachia oregonensis sp. nov.: 18, habitus and dorsal chaetotaxy; 19, labium and adjacent setae; 20, maxilla, ventral view; 21, postantennal organ, dorsal view; 22, postantennal organ, lateral view; 23, antennal segments III – IV, dorsal view; 24, antennal segments III – IV, ventral view; 25, furcula, lateral view; 26, furcula, ventral view; 27, claw III, lateral view; 28, leg III, ventrolateral view; 29, leg III, dorsolateral view; 30, abdominal segments II – VI, ventral view; 31, microsetae on anal lobes.