Hypogastrura ottawana, Cipola, 2020

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 : 200-214

Hypogastrura ottawana sp. nov.

Figs 1–13 , Table 1

Type material. Holotype female in slide (058/ INPA): Canada, Quebec, Ottawa municipalities, Val-des-Monts to

40 km north of Ottawa , 63 Chemin des Épinettes, next of Lac Bastien, 45.75°N, 75.74°W, forest, 233 m, 27.i.2017, manual sampling on snow, GF Miranda coll. 11 paratypes: 1 male, 3 females and 2 females juveniles on slides and 3 specimens in alcohol (058/ INPA), plus 2 females on slides ( CC / UFRN and CNC), same data as holotype .

Diagnosis. Species of the nivicola -group; body black blue ( Fig. 1 ); Ant IV dorsally with 6 sens (S1–2, S4, S7–9) and 5 ssc, 3 of which in “a”-set (a1–3), chaeta i absent; ventrally with 3 sa and 11 ssc (2 larger, 2 median and 7 short) ( Figs 3 A–B); four labral papillae ( Fig. 2C ); cephalic chaetotaxy with all chaetae subequal, except sd5, sd4, g1, g3, g5, g4`–5`gently largest; PAO with outer anterior lobe elongated, dorsal interocular tubercles not prominent ( Fig. 5 ); labial palp with appendages d2 and e2 smaller, a1, b1 and b2 reduced and apically rounded, papilla E with small lp spine-like ( Fig 4A ); head to Abd V with 1, 1, 2, 1, 2, 2, 2, 2, 1 microgranular areas; Th II to Abd IV with additional chaetae (m2’, m3’, p3a, am) not frequent for the genus; Abd IV with p1–3 chaetae subequal in length; Abd V with p1 chaeta larger than p2 ( Figs 6A , 7 , 8A ); Abd V–VI devoid of clavate chaetae, anal spine larger than basal tubercle ( Fig. 8 ); tibiotarsus only with acuminate chaetae on proximal row (B1–6), M chaeta subequal to others ( Fig. 11 ); collophore with 5 chaetae ( Fig. 13A ); manubrium dorsally with 12 chaetae ( Fig. 13B ); dens dorsally with 8–9 (4 larger) striated spines apically conical (commonly) and bi-, or tridentate in winter form ( Figs 13 C–D), summer form unknown; mucro boat-shaped with 1 dorsal subapical tooth ( Fig. 13D ).

Description. Total length (head+trunk) of specimens 1.63–1.71 mm (n=3), holotype 1.63 mm. Body dark navy blue with small intersegmental areas depigmented in Th I to Abd I dorsally, Th I–III laterally including part of epicoxa III, and basal part of manubrium ventrally ( Fig. 1 ). Body with uniform secondary granulation formed by sets of small, projecting and apically rounded granules ( Fig. 7B ); Head to Abd V with small microgranular areas of different form, 1+1 on head, Th I, Th III and Abd V and 2+2 on Th II, Abd I to IV ( Figs 5–8 ). Body chaetae smooth or unilaterally serrated by one or more denticles in 2/3 distal ( Fig. 3C , 6C ) and generally subequal in length; tergal s-sens smooth and apically rounded ( Figs 3C , 7B ).

Head. Antennae shorter than head, length ratio of antennae: head = 1: 1.15–1.28 (n=3), holotype 1: 1.15; antennal segments ratio as I: II: III: IV = 1: 1.02–1.21: 1.19–1.79: 1.74–2.07, holotype 1: 1.21: 1.43: 1.91. Ant IV–III with several different types of chaetae ( Figs 2 A–B, 3A–C). Ant IV with simple apical bulb; dorsally with 6 sens (S1–2 and S4 inner, S7–9 outer), 1 ms, 1 os, 5 ssc (a1–3 as ordinary chaetae plus 2 inner), and 16 smooth chaetae being 9 ordinary (b1–3, c1–3, d1–3) and 5 short distal surrounding the apical bulb, chaeta i absent; ventrally with 3 sa, 11 ssc on distal half (2 larger inner, 2 median and 7 short in sensory file), and 22 smooth chaetae (9 short in sensory file), 1 outer present or absent ( Figs 3 A–B). Ant III with 2 short club in AIIIO, 2 guard sens and 1 ms on outer side; 19 chaetae in total, 11 dorsal and 8 ventral ( Fig 3A ). Ant II–I with smooth chaetae; Ant II with 13 chaetae, 6 dorsal and 7 ventral; Ant I with 9 chaetae, 6 dorsal (1 smaller) and 3 ventral ( Fig. 3A ). Eyes of subequal size, interocular region with 3 chaetae (oc1–3), oc2 larger; tubercle not prominent and next to sd1 chaetae; dorsal cephalic chaetotaxy with 1 A (a0), 5 d (d1–5), 5 sd (sd1–5), 2 v (v1–2), 5 c (c1–5), 5 p (p1–5), 5 g (g1–5) and 4 g` (g1`–2`, g4`– 5`) chaetae, sd5, sd4, g1, g3, g5, g4`–5`chaetae largest ( Fig. 5A ). PAO with 4 separate lobes, anterior outer lobe elongated, other lobes rounded and subequal ( Figs 5 A–B). Clypeal area with 2+2 (L1–2) smooth chaetae. Labrum with 4 rounded labral papillae, inner papillae gently smaller; labrum with numerous robust granules, prelabral and labral formula as 4/5, 5, 4; all chaetae smooth ( Fig. 2C ). Labial palp with five main papillae (A–E) plus one hypostomal papilla (H) with 1, 4, 0, 3, 6, 2 guard appendages, respectively, d2 and e2 smaller, a1, b1 and b2 reduced and apically rounded, papilla E with small, spine-like lp; labium with 6 smooth proximal chaetae (a1–6) ( Figs 2C , 4A ). Maxillary palp with ta larger than bc, sublobal plate with 2 appendages (sb1, sb2), pleural lobe with 2 chaetae (pl1, pl2), all smooth ( Figs 2C , 4B ). Basomedian and basolateral labial fields with chaetae a1–5, m, e, l1–2 smooth; both fields with ungranulated regions ( Fig. 4C ). Ventral cephalic chaetotaxy with 17 smooth chaetae and 1 lateral serrated chaeta, 2 postlabial chaetae larger (antero-medial and antero-lateral), other subequal ( Fig. 4C ). Mandible with 5 apical incisive teeth on right side and 4 on left side. Maxilla with 3 subequal outer teeth and 6 inner lamellae apparently of notha type (see Fjellberg 1984: 92, fig. 12), except by 1 lamella acuminate ( Fig. 4D ).

Thorax dorsal chaetotaxy ( Figs 6 A–B). Th I with 3 ‘m’ chaetae (m1, m3–4). Th II, series ‘a’ with 6 chaetae (a1–6); series ‘m’ with 6 chaetae (m1–6) and 1 s-sens (m7s), posteriorly 2 extra chaetae (m2´–3´); series ‘p’ with 5 chaetae (p1–3, p5–6) and 1 s-sens (p4s); laterally with 1 ms smooth and apically pointed ( Fig. 6B ). Th III, series ‘a’ with 6 chaetae (a1–6) plus 1 extra chaeta (am) posteriorly; series ‘m’ with 5–6 chaetae (m1–6) and 1 s-sens (m7s), m2 present or absent, posteriorly 1 extra chaeta (m3´); series ‘p’ with 5 chaetae (p1–3, p5–6) and 1 s-sens (p4s). Th II–III with chaetae m7s and p6 larger, other subequal.

Abdomen dorsal chaetotaxy ( Figs 7–8 ). Abd I, series ‘a’ with 6 chaetae (a1–6); series ‘m’ with 5 chaetae (m2–4, m6–7); series ‘p’ with 7 chaetae (p1–4, p6–7) and 1 s-sens (p5s). Abd II, series ‘a’ with 7 chaetae (a1–7); series ‘m’ with 5 chaetae (m2–4, m6–7); series ‘p’ with 7 chaetae (p1–4, p6–7) and 1 s-sens (p5s). Abd III, series ‘a’ with 7 chaetae (a1–7); series ‘m’ with 5 chaetae (m2–4, m6–7); series ‘p’ with 7 chaetae (p1–4, p6–7) and 1 s-sens (p5s). Abd I–III with 1 extra chaetae (p3a) on ‘p’ series; chaeta p7 larger, other subequal, chaetae m1 and m5 absent. Abd IV, series ‘a’ with 7 chaetae (a2–7, a3a extra) plus 1 extra chaeta (am) posteriorly; series ‘m’ with 6 chaetae (m1, m3–7); series ‘p’ with 6 chaetae (p1–4, p6–7) and 1 s-sens (p5s); chaetae p5s and p7 larger, other subequal; a1 and m2 absent. Abd V, series ‘a’ with 4 chaetae (a1, a3–5); series ‘m’ with 2–3 chaetae (m1, m3, m5), m3 present or absent; series ‘p’ with 5 chaetae (p1–2, p4–6) and 1 s-sens (p3s); about 13–15 granules between both p1 chaetae, chaetae p1, p3s and p5 larger, other subequal. Abd VI with 2 chaetae rows anteriorly to anal spines, series ‘a’ with 3 chaetae (a1–3), and series ‘p’ with 3 chaetae (p0, p2–3) and 1 anal spine smooth and slightly curved, longer than their basal tubercle ( Figs 8 A–B); posteriorly to anal spines has one row of 3 chaetae possibly true ‘p’ series ( Fig. 8C ).

Abdomen ventral chaetotaxy ( Fig 9 A–E). Abd I devoid of chaetae. Abd II with 4 inner and 2 outer chaetae. Abd III with 7 inner and 4–5 outer chaetae, 1 posterior gently larger. Abd IV with 5–7 inner and 4 outer chaetae, 1 median larger ( Figs 9 A–B). Abd V with 4 outer chaetae, 1 posterior larger ( Figs 9 B–E). Abd VI with 17–18 chaetae in each inferior lobe ( Fig. 9B ).

Legs ( Figs 10A , 11 A–B). Epicoxa I, II, III with 1, 3, 3 serrated chaetae respectively; subcoxa I, II, III with 0, 3–4, 3 chaetae respectively (II–III with 1 serrated mac); coxa I, II, III with 3, 8, 8 chaetae respectively. Trochanter I, II, III with 7, 7, 7 chaetae respectively. Femur I, II, III with 14, 13, 12 chaetae respectively. Tibiotarsus I, II, III with 19, 19, 18 smooth chaetae respectively in B (B1–7), A (A1–7) and T (T1–4) rows; B1 and B2 larger, B5, A4–6 and T1–4 gently smaller, other subequal, A1 as tenent hair gently capitate; M chaeta subequal to others and present between B4 and B5 chaetae; B7 absent in tibiotarsus III. Pretarsus with one small anterior and one posterior smooth chaeta. Ungues with 1 unpaired small inner tooth at little more 1/2 from base, outer side with one pair of lateral teeth subapically. Unguiculus formed by three lamellae (ai, pi, pe) with apical thin filament (formed by ai and pi lamellae) reaching to apex of ungues inner tooth, ai lamella basally broad.

Collophore distally with 5 smooth chaetae on each side, one of which thin and smaller ( Figs 10A , 13A ). Tenaculum with 4 teeth on each ramus, no chaetae on corpus ( Fig. 10B ).

Manubrium dorsally with 12 chaetae distributed in four transverse rows, 1 proximal chaeta larger, others subequal ( Fig. 13B ); ventral side without chaetae. Dens dorsally with numerous granular tubercles, 7 chaetae (1 proximal larger), and 8–9 (4 larger) striated spines apically conical (commonly) and bi-, or tridentate; internally with 2 proximal dental fold and ventro-distally with apical hyaline area, both ungranulated ( Figs 12 , 13 C–D). Mucro boat-shaped, gently pointed apically and with two (inner and outer) unequal lamellae, dorsally with 1 subapical conical tooth.

Genital plate only with smooth chaetae. Female ( Figs 9 C–E) with 1 ag chaeta (absent in subadult), 5–7 paired plus 1 unpaired cg chaetae (3–4 paired in subadult), and 1 reduced eg posterior chaetae near genital opening. Male with 1 ag chaeta, 14–15 paired plus 1 unpaired cg superior chaetae, and 2 reduced eg chaetae near genital opening; laterally to genital plate 1 chaeta present or absent ( Fig. 9B )

Etymology. Refers to the type locality of the new species, Ottawa, Canada.

Remarks. Hypogastrura ottawana sp. nov. resembles others species of the nivicola group as H. peloponnesica Dányi, 2013 from Greece, H. macrotuberculata ( Hammer, 1953) and H. simsi Hart & Waltz, 1995 from the Nearctic by dark body color, Ant IV with not more than 6 dorsal sens, head with 2+2 vertical chaetae (eventually 1+ 1 in H. macrotuberculata ), and never observed anal sacs everted on Abd VI ( Tab. 1). Beyond these characteristics, the new species is more similar to H. peloponnesica and H. macrotuberculata by ungues with outer pair of lateral teeth (apparently absent in H. simsi ) and Abd VI with anal spine larger than basal tubercle (subequal and smaller respectively in H. simsi and H. macrotuberculata ).

Hypogastrura ottawana sp. nov. differs from these species by Ant IV with 7 ventral ssc (18 in H. peloponnesica and absent in H. simsi ), head dorsal tubercle not prominent (developed on others species, but unknown in H. simsi ), PAO only with outer anterior lobe elongated (both anterior lobes larger in these species), and 4 labral papillae (5 in H. peloponnesica ). In dorsal chaetotaxy, H. ottawana sp. nov. differs from these species exclusively by 2 extra chaetae in Th II (m2’, m3’), 2 in Th III (am, m2’), and 1 in Abd I–III (p3a), all absent in H. peloponnesica and unknown in others species, although these extra chaetae are atypical in genus, seen only in H. arnei Skarżyński, 2019 from the United States, whose position in modern species groups of the genus is not clear.

The new species differs also by Abd IV with 1 extra chaeta (am) and p1–3 chaetae with similar length (p1 larger and p3 smaller in H. peloponnesica ), beside 3 specific chaetae on Abd V (m1, m5, p2), since m5 is absent in H. peloponnesica , p2 absent in H. macrotuberculata , and m1 absent in both species. Other differences of H. ottawana sp. nov. is collophore with 5 chaetae (4 in H. peloponnesica and H. simsi , and up to 6 in H. macrotuberculata ), manubrium with 12 dorsal chaetae (10 in H. peloponnesica , unknown in others species), and dens dorsally with 8–9 (4 larger) conical spines eventually bi-, or tridentate, while in others species is conical, being 3–4 in H. simsi , 4–7 in H. peloponnesica , and absent in H. macrotuberculata .

Hypogastrura ottawana sp. nov. also resembles H. tooliki in Ant IV with 6 dorsal and 7 ventral sens (scc), four labral papillae, head with 2+2 vertical chaetae, Abd IV p1–3 chaetae with subequal length, Abd IV devoid of clavate chaetae, as well as clavate extra chaeta on tibiotarsus absent ( Tab. 1). However, H. ottawana sp. nov. differs from this species by Ant I with 9 chaetae (8 in H. tooliki ), head dorsal tubercle not prominent (clearly developed in H. tooliki ), Abd IV with 1 (am) extra chaetae (absent in H. tooliki ), Abd V with m1 and m3 chaetae (both absent in H. tooliki ), anal sacs not everted (frequently everted in H. tooliki ), and dens dorsally with 7–9 spines (2–3 in H. tooliki ).

The dark blue body of H. ottawana sp. nov. is typical also for other species of the nivicola group such as H. harveyi ( Folsom, 1902) , H. nivicola ( Fitch, 1847) and H. packardi ( Folsom, 1902) . These species differ by the presence of clavate chaetae on Abd VI in H. harveyi and H. packardi , and at least 1 outer clavate chaetae in tibiotarsal proximal row in H. harveyi , all absent in new species. In addition, H. ottawana sp. nov. also differs from H. harveyi by Abd IV with all posterior chaeta subequal in length (p2 and p4 larger than others in H. harveyi ). The species H. harveyi , H. macrotuberculata , H. nivicola , H. packardi , and H. tooliki has also been recorded in the region of the new species, Quebec, Canada ( Christiansen & Bellinger 1998; Therrien et al. 1999; Babenko et al. 2019). Other differences between species of the nivicola group from the Nearctic realm is given in table 1.

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 2A–C. Hypogastrura ottawana sp. nov.: head parts; A–B, Ant IV: A, distal view (right Ant), black arrows indicates sa, white arrows ssc, S1–9 is s-sens; B, inner view (left Ant), white arrows indicates sa, S1–9 is s-sens and a1–3 ordinary chaetae (ssc); C, mouthparts (anterior view), L2 is clypeal chaeta, A–E is labial papillae, ‘a1’, ‘b1’ and ‘b2’ finger-shaped appendages, ‘d2’ and ‘e2’ reduced appendages, ‘lp’ lateral process. Scale bars: 0.02 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 4A–D. Hypogastrura ottawana sp. nov.: mouthparts and ventral head; A, labial papillae A–E and proximal chaetae (right side), ‘a–e’ is appendages of the labial papillae and ‘lp’ lateral process of papilla E; B, maxillary palp, sublobal plate and pleural lobe (right side); C, chaetotaxy of the basomedian and basolateral labial fields and postlabial region; D, left maxilla (dorsal view), 1–5 are maxillary lamellae.

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 6A–C. Hypogastrura ottawana sp. nov.: thorax dorsal chaetotaxy; A, Th I–III, dashed line indicates AMP chaetal series and solid lines microgranular areas; B, Th II laterally (left side), ms is smooth microsensillum apically pointed, a6 and p6 smooth chaetae; C, Tergal chaeta unilaterally serrated. Scale bars: A (0.05 mm), B–C (0.005 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 9A–E. Hypogastrura ottawana sp. nov.: abdomen ventral chaetotaxy; A, Abd II–IV (right side); B, Abd IV–VI of male paratypes (complete); C–E, Abd V of female (right side); C, holotype, D, adult paratype, E, subadult paratypes, arrows indicate chaetae present or absent.

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 12A–B. Hypogastrura ottawana sp. nov.: furcula (lateral view); A, dens and mucro, red arrows indicate granular tubercles, white arrow dental fold, and black arrow apical hyaline area; B, dental spine. Scale bar: A (0.02 mm), B (0.002 mm).

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.