Yichunentulus alpatovi, Bu, Yun, Potapov, Mikhail B. & Yin, Wen Ying, 2014

Bu, Yun, Potapov, Mikhail B. & Yin, Wen Ying, 2014, Systematic and biogeographical study of Protura (Hexapoda) in Russian Far East: new data on high endemism of the group, ZooKeys 424, pp. 19-57: 26-28

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scientific name

Yichunentulus alpatovi

sp. n.

Taxon classification Animalia Protura Acerentomidae

Yichunentulus alpatovi  sp. n. Fig. 6; Table 3

Material examined.

Holotype, female (No. FE-2011035-1) (SEM), Russia, Far East, Primorsky Krai, Lazovsky area, nearby Preobrazheniye, from the mixed samples of soil and humus from mountains, 42°54. 48'N, 133°53. 96'E, 21-IX-2011, coll. Y. Bu, C. W. Huang, M. Potapov & V. Alpatov. Paratypes, 1 female (No. FE-2011035-6), 3 males (Nos. FE-2011035-4, FE-2011037-1, FE-2011045-3) (SEM; MSPU), 2 male preimagos (Nos. FE-2011038-1, FE-2011038-2) (SEM), same data as holotype.


Adult body length 1200-1350 µm (n=5).

Head (Fig. 6A). Ovate, length 120-130 µm, width 70-80 µm. Setae d6 present, sd4 and sd5 short sensilliform. Setae d6 11 µm, d7 10 µm and sd7 18 µm in length. Clypeal pore cp and frontal pore fp present. Pseudoculus round, length 7-8 µm, with short posterior extension, PR=16 (Fig. 6B). Calyx of maxillary gland smooth, without any appendix, blind end split into two leaves, posterior filament 16-17 µm, CF=7-8 (Fig. 6C). Maxillary palpus with two tapering sensilla, dorsal snsillum is evidently longer than lateral one (Fig. 6D). Labial palpus completed, with one-branched terminal tuft of setae, with three setae and one lanceolate basal sensillum (Fig. 6E).

Foretarsus (Fig. 6G, H). Length 86-93 µm, claw length 20-23 µm, without inner flap, TR=4; empodium length 4 µm, EU=0.18. Dorsal sensilla t-1 baculiform, t-2 slender and long (23 µm), BS=0.5, t-3 lanceolate. Exterior sensilla a surpassing base of b and c, b slender and short (16 µm), not reaching base of γ 3, c reaching base of f and in subequal level to b, d located higher than b and c, e long and reaching base of claw (30 µm), f slender, g broad and short (18 µm). Interior sensilla a’ broad, b’ slender and reaching base of α 6, c’ nearly reaching base of claw. Relative length of sensilla: t3 < t1 < b < (a = a’) < g < ( b’ = c’) < d < t2 < c < e < f. Setae β 1 setiform and δ 4 sensilliform. Pores close to sensilla a and t3 present. Length of middle tarsus 40 µm, claw length 17 µm. Length of hind tarsus 45 µm, claw length 20 µm.

Thorax. Thoracic chaetotaxy given in Table 3. Setae 1 and 2 on pronotum 20 µm and 12-14 µm length respectively. Mesonotum and metanotum with eight pairs of P-setae, accessory setae short sensilliform, 2 µm in length; setae P1, P1a and P2 on mesonotum 17-20 µm, 3 µm and 20-24 µm respectively. Prosternum with two pairs of anterior seta, and setae A2 and M2 sensilliform. Mesosternum and metasternum each with 7 A-setae, and setae A2 sensilliform. Pronotum and prosternum without pores. Mesonotum with pores sl and al, metanotum with pores sl only. Mesosternum and metasternum each with single median pore, situated anterioral to level of setae M.

Abdomen. Abdominal chaetotaxy given in Table 3. Tergite I with three pairs of anterior setae (A1, A2, A5). Tergites II–VI with eight pairs of posterior setae. Tergites VI and VII with four pairs of anterior setae (A1, A2, A4, A5). Tergite VII with nine pairs of posterior setae, P3a present. All accessory setae on tergites I–VII short sensilliform, 3 µm on tergites I–V, 4 µm on tergite VI, and 5 µm on VII. Tergite VIII with paired setae M1. Sternite IV–VII each with eight posterior setae, Pc absent. Sternite VIII with two rows of setae (4/2).

Tergites I and VIII with pores psm only, II–V with pores psm and al, VI–VII with pores psm, al and psl, IX–XI without pores, XII with single medial pore. Sternites I–IV without pores, V and VI each with 1+1 posterior pores anterior to seta P1 and 1+1 anteromembranal pores, VII with single posterior pore asymmetrical located left or right and 1+1 anteromembranal pores, VIII–XI without pores, XII with 1+1 pores al.

Abdominal appendages I, II, III with 2, 1, 1 segments and 4, 2, 2 setae respectively. On appendages II and III, subapical setae 16-17 µm, apical setae 13-14 µm in length. Striate band on abdominal segment VIII reduced, anterior margin regular wave shaped. Comb on abdomen VIII rectangular, with 12-13 teeth (Fig. 6I). Female squama genitalis robust, with moderate basal apodeme and pointed acrostyli (Fig. 6F). Male squama genitalis with 5+5 setae on dorsal side and 3+3 setae on ventral side (Fig. 6J).


The species is named after Dr. V. Alpatov who accompanied us during our scientific trips.


Known only from type locality.


Yichunentulus alpatovi  sp. n. is characterized by the presence of sensillum b’ on foretarus and short sensilum b on foretarsus, 6 anterior seate on tergites IV–V, swelled sensillum a’, presence of pores psl only on tergites VI and VII, and female squama genitalis with moderate basal apodeme and pointed acrostyli.


The present species is located in the genus Yichunentulus  because the labial palpus with one-branched terminal tuft of setae, with three setae and one lanceolate basal sensillum, the baculiform sensillum t1 on foretarus, reduced striate band, two pairs of anterior setae on mesonotum and metanotum, 4/2 setae on sternite VIII, and abdominal appendages II and III each with two setae of different length. Yichunentulus alpatovi  sp. n. is close to the type species Yichunentulus yichunensis  Yin, 1980 in having short sensillum b and identical body chaetotaxy. However, it can be easily distinguished from Yichunentulus yichunensis  and Yichunentulus borealis  (Nakamura, 2004), comb. n. by the presence of sensillum b’ on foretarsus. It also differs from Yichunentulus yichunensis  in the length of sensillum e (extremely long in Yichunentulus alpatovi  sp. n. vs. short in Yichunentulus yichunensis  ) and sensilla c’ (long and surpassing base of δ 6 in Yichunentulus alpatovi  sp. n. vs. short and only reaching base of β 7 in Yichunentulus yichunensis  ). It differs from Yichunentulus borealis  in the chaetotaxy of tergites IV–V (each with 6 A-setae in Yichunentulus alpatovi  sp. n. vs. 8 in Yichunentulus borealis  ), shape of sensillum a’ (slightly broad and as long as sensillum a in Yichunentulus alpatovi  sp. n. vs. distinctly swell and shorter than sensillum a in Yichunentulus borealis  ), and the body porotaxy (pore psl present on tergites VI and VII only and sternites I–IV without pores in Yichunentulus alpatovi  sp. n. vs. psl present on tergites III–VII and sternites II and IV each with 1+1 anteromembranal pores in Yichunentulus borealis  ).