Hypogastrura, Bourlet, 1839

Cipola, Nikolas Gioia, 2020, New species from the nivicola group of Hypogastrura Bourlet, 1839 (Collembola, Poduromorpha, Hypogastruridae) from Canada, Zootaxa 4786 (2), pp. 199-220 : 214-215

Key to Hypogastrura species of nivicola group from the Nearctic

1 Abd VI with some long clavate or truncate chaetae........................................................... 2

- Abd VI with only short acuminate chaetae ( Fig. 8A ).......................................................... 3

2 Ant IV with 8–13 dorsal sens; head with 1+1 vertical chaetae; both proximal and distal whorls on tibiotarsi with clavate chaetae (B2 and A1, respectively); dens in winter form with 14–25 dorsal spines..................... H. harveyi ( Folsom, 1902)

- Ant IV with 9 or less dorsal sens; head with 2+2 vertical chaetae ( Fig. 5A ); tibiotarsi with only one clavate chaeta located in distal whorl ( Figs 10A , 11A ); dens in winter form with 4–6 dorsal spines.................. H. packardi ( Folsom, 1902)

3 Body with reticular structures or granulation rather coarse..................................................... 4

- Body with uniform and fine granulation, no modifications ( Figs 5–8 )............................................ 5

4 Body with granulation rather coarse, notably in median part of posterior tergites; PAO with both anterior lobes elongated; head with 1+1 or 2+2 vertical chaetae............................................ H. macrotuberculata ( Hammer, 1953)

- Body with reticular structures; PAO with all lobes normal; head ever with 1+1 vertical chaetae................................................................................... H. reticulata (sensu Hammer 1953 not Börner 1909)

5 Abd VI with anal spine smaller than basal tubercle; anal sacs eventually everted................................... 6

- Abd VI with anal spine larger or subequal than basal tubercle ( Fig. 8 ); anal sacs not everted or never seen in specimens ( Figs 1 , 8C )................................................................................................ 7

6 Head with 1+1 vertical chaetae; Abd IV with 6 ‘a’ series chaetae, m1 chaetae absent; collophore with 6–11 chaetae per side.................................................................................. H. nivicola ( Fitch, 1847)

- Head with 2+2 vertical chaetae ( Fig. 5A ); Abd IV with 4–5 ‘a’ series chaetae, m1 chaetae present ( Fig. 7A ); collophore with 4–6 chaetae per side............................................................... H. tooliki Fjellberg, 1985

7 Ant IV with at least 10 small ventral chaetae ( Fig. 3B ); PAO with anterior outer lobe elongated ( Figs 5 A–B); Abd VI with anal spine larger than basal tubercle ( Fig. 8 ); collophore with 5 chaetae ( Fig. 13A ); dens dorsally with 8–9 spines ( Figs 13 C–D)..................................................................................... H. ottawana sp. nov.

- Ant IV devoid of ventral file; PAO with both anterior lobes larger; Abd VI with anal spine subequal to basal tubercle; collophore with 4 chaetae; dens dorsally with 3–4 spines and extending beyond distal end of mucro as a distal projection.......................................................................................... H. simsi Hart & Waltz, 1995

Figures

FIGURE 1A–B. Hypogastrura ottawana sp. nov.: habitus of specimens preserved in alcohol; A, dorsal view; B, lateral view. Scale bars: 0.2 mm.

FIGURE 3A–C. Hypogastrura ottawana sp. nov.: antennae; A, Ant I–IV left (dorsal view), a–d are ordinary chaetae; B,Ant IV left (ventral view), arrow indicate chaeta present or absent; C, different structures of the antennal segments.

FIGURE 5A–B. Hypogastrura ottawana sp. nov.: dorsal head; A, cephalic chaetotaxy, dashed line indicates chaetal series, black solid line tubercle region next to sd1 chaeta, white solid line microgranular areas, arrow indicates round granular ornamentation between the head and Th I; B, anterior eyes and PAO (right side). Scale bars: A (0.05 mm), B (0.01 mm).

FIGURE 7A–B. Hypogastrura ottawana sp. nov.: abdomen dorsal chaetotaxy; A, Abd I–IV, dashed lines is AMP chaetal series, solid lines microgranular areas and am extra chaetae between the ‘a’ and ‘m’ series; B, sensorial region of the Abd I (right side), solid lines show microgranular areas and p5s sens. Scale bar: A (0.1 mm), B (0.01 mm).

FIGURE 8A–C. Hypogastrura ottawana sp. nov.; chaetotaxy of the Abd V–VI; A, Abd V–VI dorsally; dashed lines is AMP chaetal series, solid lines microgranular areas, p3s sens and m3 on right side show chaeta present or absent; B, median region part of Abd VI (dorsal view), dashed lines is p chaetal series; C, superior and lateral lobes of Abd VI (lateral view), dashed lines indicates possible interpretation of a, m, p series on superior lobe. Scale bar: A (0.05 mm), B (0.01 mm), C (0.02 mm).

FIGURE 10A–C. Hypogastrura ottawana sp. nov.; A, leg III (anterior and outer side) and collophore (lateral view), dashed lines indicates tibiotarsal whorls, white arrow indicate subapical outer teeth and red arrow posterior chaetae of collophore; B, tenaculum (lateral view); C, male genital plate (lateral view). Scale bar: A (0.02 mm), B–C (0.01 mm).

FIGURE 11A–B. Hypogastrura ottawana sp. nov.: legs; A, chaetotaxy complete of right leg III (anterior view), M is inner chaeta, arrow indicate subapical outer teeth; B, representation of chaetae whorls (A, B, T) on right tibiotarsus III (anterior view).

FIGURE 13A–D. Hypogastrura ottawana sp. nov.: collophore and furcula; A, collophore chaetotaxy (lateral view), arrows indicate posterior chaetae; B, manubrium ventral chaetotaxy, empty circle is larger chaetae and black circle normal chaetae; C–D, dens and mucro: C, dorsal side; D, external side.