Isohypsibius saltursus Schuster, Toftner & Grigarick, 1978

Kaczmarek, Łukasz, Bertolani, Roberto & Nędzyńska-Stygar, Monika, 2010, Thulinius saltursus comb. nov.: a new systematic position for Isohypsibius saltursus Schuster, Toftner & Grigarick, 1978 (Eutardigrada: Hypsibiidae) and a key for the genus Thulinius, Zootaxa 2483, pp. 58-64: 59-62

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10.5281/zenodo.195469

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http://treatment.plazi.org/id/C3073422-8E7F-FFD3-92B9-E2CCFEC7FB03

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scientific name

Isohypsibius saltursus Schuster, Toftner & Grigarick, 1978
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Isohypsibius saltursus Schuster, Toftner & Grigarick, 1978 

( Figs 1View FIGURE 1 –7)

Material examined: 28 specimens: holotype (Pope Beach, Lake Tahoe, CA, X- 10-75, sublittoral, RO Schuster, EC Toftner) and 27 paratypes (1–3. Pope Beach, Lake Tahoe, CA, X- 10-75, sublittoral, RO Schuster, EC Toftner; 4–9. Pope Beach, L. Tahoe, CA, X- 10-75, sublittoral, RO Schuster, EC Toftner; 10–11. Pope Beach, Lake Tahoe, Calif., VIII- 15-75, sublittoral, RO Schuster, EC Toftner; 12. Pope Beach, Lake Tahoe, Calif., VIII- 23-69, sand in stream, RO Schuster; 13. Pope Beach, Lake Tahoe, Calif., VIII- 28-75, sublittoral, RO Schuster, EC Toftner; 14–15. Lake Tahoe, Pope Beach, Cal., IX- 1-1974, RO Schuster, EC Toftner, Colrs.; 16. Pope Beach, Lake Tahoe, Calif., VIII- 29-69, in sand, RO Schuster; 17–19. Pope Beach, Lake Tahoe, VIII- 3-75, RO Schuster, sublittoral; 20. L. Tahoe, Pope Beach, Cal., IX- 1-74, RO Schuster, EC Toftner; 21. Pope Beach, Lake Tahoe, III- 17-1974, sublittoral, RO Schuster, EC Toftner, Colrs; 22. Pope Beach, Lake Tahoe, VIII- 28-75, sublittoral Roschwater, RO Schuster, EC Toftner; 23. Pope Beach, Lake Tahoe, X- 10-1975, sublittoral, RO Schuster, EC Toftner Colrs; 24. X- 10-1975, sublittoral Roschwater, EC Toftner; 25. Pope Beach, Lake Tahoe, XI- 7-1975, sublittoral, RO Schuster, EC Toftner; 26. Pope Beach, Lake Tahoe, XI- 7-1975, sublittoral Roschwater, RO Schuster, EC Toftner; 27. Pope Beach, Lake Tahoe, XI- 7-75, sublittoral Roshwater, EC Toftner.

Type locality: longitude 120 °01’ 30 ” and latitude 38 ° 56 ’ 20 ”, 1899 m. asl, Pope Beach, Lake Tahoe, California ( USA)

Distribution: Known only from two localities in USA (Lake Tahoe, California; Lake Erie, Ohio).

CHARACTER N RANGE MEAN SD Holotype Redescription: Adult (for measurements see Table 1): Body white/transparent, eyes absent. Cuticle smooth or slightly wrinkled, without gibbosities, spines or defined sculpture ( Fig. 2View FIGURE 2).

Buccal-pharyngeal apparatus with twelve peribuccal lamellae. Peribuccal papulae absent. Mouth anteroventral. Oral cavity armature composed of second and third band of teeth (first band of teeth absent). Second band composed of a number of irregular rows of small teeth and the third band composed of one row of larger teeth situated just under the second band of teeth ( Figs 3–4View FIGURES 3 – 4, see also Fig. 25 (SEM microphotographs) in Schuster et al. 1978).

At the posterior end of the buccal tube, rod-shaped pharyngeal apophyses present. Pharyngeal bulb spherical with three rod-shaped macroplacoids ( Fig. 4View FIGURES 3 – 4). The first macroplacoid longest, second shortest (i.e. macroplacoid length configuration is 1-3 - 2). Microplacoid and septulum absent.

Claws of the Isohypsibius  type (configuration 2 - 1-2 - 1), similar in size and shape. Basal portions on all claws normally developed and slender ( Figs 5View FIGURES 5 – 6 –7). Primary branches of claws with distinct knob and accessory points ( Figs 5View FIGURES 5 – 6 –7, black arrows). Additionally, a clearly visible septum is present between the primary branch and the rest of the claw ( Figs 5View FIGURES 5 – 6 –7). Lunules present only on external claws I–III and posterior IV ( Figs 6View FIGURES 5 – 6 –7). Two long and straight bars present only under claws on legs I–III, no other cuticular bars are present on legs ( Fig. 6View FIGURES 5 – 6). Claws I–III and anterior IV similar in length, but posterior IV clearly larger.

Eggs: oval deposited in exuvium (for more details see Schuster et al., 1978)

Remarks. Only ten specimens (including holotype) of all examined paratypes were measured (the remaining individuals are either in the simplex stage or the orientation of their structures was unsuitable for measurements).

In the original description, Schuster et al. (1978) drew lunules on the posterior claws IV and divided cuticular bars although these characters were not mentioned in the text. We also observed the lunules only under external claws I–III and posterior IV. The bases of the internal claws were slightly expanded. In most of the specimens two separate cuticular bars were visible (one bar under each claw), but in some specimens it was difficult to see this separation.

Differential diagnosis. Thulinius saltursus  comb. nov. differs from:

T. augusti  by: presence of lunules under the external and posterior claws, cuticular bars on legs divided, shorter and slightly broader basal claws, absence of subdivided lobes around the mouth.

T. itoi  by: absence of lunules under the internal and anterior claws, cuticular bars on legs more robust and divided, lower pt of stylet insertion point (71.3–74.7 in T. saltursus  and more than 80.0 in T. itoi  ).

T ruffoi  by: absence of lunules under the internal and anterior claws, cuticular bars on legs divided.

T. stephaniae  by: presence of lunules under the external and posterior claws, cuticular bars on legs less strong and divided.

TABLE 1. Measurements and pt values of selected morphological structures of nine paratypes and holotype of Thulinius saltursus comb. nov. (N = number of specimens or structures measured; RANGE = the smallest and the largest structure found among all specimens measured; SD = standard deviation, bc = basal claw, pb = primary branch, sc = secondary branch).

Body 10 Buccal tube 10 µm 369.6–621.0 34.1–51.5 pt – – µm 493.3 43.1 pt – µm 86.9 5.7 pt – – µm 541.2 45.4 pt – –
Stylet support insertion point 10 25.3–37.3 71.3–74.7 31.7 73.5 3.9 1.1 33.9 74.7
Buccal tube external width 10 Buccal tube internal width 10 4.9–10.0 3.2–8.0 12.6–19.5 8.7–15.6 7.1 5.1 16.4 11.7 1.7 1.5 2.2 2.1 8.0 5.0 17.6 11.0
Macroplacoid 1 10 4.9–9.7 14.4–18.9 7.2 16.5 1.5 1.5 8.0 17.6
Macroplacoid 2 10 Macroplacoid 3 10 3.2–6.4 4.3–8.6 8.4–12.6 12.6–16.9 4.7 6.5 10.8 14.9 1.2 1.4 1.5 1.5 4.5 6.5 9.9 14.3
Macroplacoid row 10 14.6–28.0 42.6–54.4 20.7 47.5 4.3 3.8 22.6 49.8
Claw I - external – bc 7 Claw I - external – pb 6 7.0–11.4 10.2–15.5 18.3–24.4 0.0–35.1 9.2 13.1 21.9 27.1 1.7 2.3 2.3 12.1 - - - -
Claw I - external – sb 7 8.2–13.9 23.1–27.2 10.7 25.5 1.9 1.7 - -
Claw I - internal – bc 7 Claw I - internal – pb 7 6.1–9.4 8.9–13.7 15.8–20.5 24.2–29.7 7.9 11.4 18.4 26.7 1.4 2.0 1.5 2.1 9.3 13.5 20.5 29.7
Claw I - internal – sb 7 7.8–12.3 20.5–25.8 9.9 23.1 1.6 1.7 11.7 25.8
Claw II - external – bc 5 Claw II - external – pb 5 7.9–11.7 8.6–16.2 20.5–23.2 25.2–35.7 9.6 14.1 22.0 31.8 1.4 3.1 1.3 4.7 9.3 16.2 20.5 35.7
Claw II - external – sb 5 10.5–14.1 25.0–31.1 12.2 28.0 1.4 2.8 14.1 31.1
Claw II - internal – bc 6 Claw II - internal – pb 6 6.0–9.2 10.0–13.8 17.1–19.6 25.8–30.4 8.0 12.0 18.4 27.8 1.2 1.6 1.0 1.7 8.8 13.8 19.4 30.4
Claw II - internal – sb 6 8.4–10.9 19.6–24.6 9.6 22.3 0.9 1.8 10.9 24.0
Claw III - external – bc 8 Claw III - external – pb 8 7.3–11.5 10.9–17.1 20.3–24.4 28.7–37.8 9.8 14.4 22.5 33.4 1.7 2.0 1.3 2.9 11.0 16.1 24.2 35.5
Claw III - external – sb 8 8.7–15.5 23.7–30.2 11.7 26.8 2.2 2.5 12.9 28.4
Claw III - internal – bc 8 Claw III - internal – pb 8 6.0–9.9 9.2–14.2 15.6–19.6 23.6–31.1 7.7 11.7 18.2 27.7 1.3 2.0 1.4 2.1 8.9 14.1 19.6 31.1
Claw III - internal – sb 8 8.2–11.8 20.9–26.0 9.9 23.6 1.5 1.7 11.8 26.0
Claw IV - anterior – bc 7 Claw IV - anterior – pb 7 7.2–10.4 10.9–15.3 19.3–22.9 27.2–33.7 8.8 13.0 20.5 30.5 1.1 1.6 1.2 2.3 10.4 15.3 22.9 33.7
Claw IV - anterior – sb 7 8.2–13.2 21.9–29.1 10.9 25.3 1.9 2.3 13.2 29.1
Claw IV - posterior – bc 6 Claw IV - posterior – pb 6 8.0–12.1 12.3–19.2 21.8–24.7 32.4–42.3 9.9 15.9 23.4 37.4 1.4 2.6 1.0 3.8 10.4 19.2 22.9 42.3
Claw IV - posterior – sb 6 10.2–14.2 27.6–30.0 12.3 28.9 1.5 1.1 13.6 30.0