Paracerella sinensis, Bu, Yun, Ma, Yao & Luan, Yun-Xia, 2016

Bu, Yun, Ma, Yao & Luan, Yun-Xia, 2016, Paracerella Imadate in China: the description of a new species and the analysis of genetic differences between populations (Protura, Acerentomata, Nipponentomidae), ZooKeys 604, pp. 1-11 : 2-5

Taxon classification Animalia Protura Nipponentomidae

Paracerella sinensis sp. n. Figs 1, 2, 3, Tables 1, 2

Material examined.

Holotype, female (No. LM6-12D) (SEM), China, Inner Mongolia Province, Balin town, Lama Hill, extracted from the soil samples under some small pine trees, 48°19.969'N, 122°19.160'E, elev. 562 m, 12-VIII-2014, coll. W.J. Chen, C.W. Huang, Y. Ma, Y.X. Luan, and M. Potapov. Paratypes, 4 females (nos. LM6-10, LM6-11, LM6-13D, LM6-14D) (SEM), same data as holotype; 3 females (nos. HH1-1D, HH1-3D, HH1-4D) (SEM), CHINA, Heilongjiang Province, Heihe City, from the soil samples under some black birches of Tree Farm 727, 50°15.491'N, 126°48.434'E, elev. 410 m, 15-VIII-2014; 11 females (nos. WHS4-2D, WHS5-2D, WHS6-2D, WHS4-6-1, WHS4-6-2, WHS5-3-2, WHS5-4-1, WHS5-4-3 in SEM, nos. WHS4-5-1, WHS4-5-2, WHS4-5-3 in SNHM), China, Heilongjiang Province, Wudalianchi City, from three soil samples of Wohu Hill, 48°39.252'N, 126°02.281'E, elev. 480 m, 17-VIII-2014; 5 females (nos. DZH2-1D, DZH2-2D, DZH2-3, DZH2-12D, DZH2-16) (SEM), China, Heilongjiang Province, Wudalianchi City, from the soil sample under some larches in Dazhanhe National Forest Park, 48°41.726'N, 127°40.556'E, elev. 327 m, 18-VIII-2014. Other materials,1 maturus junior (no. HH7-1) (SEM), China, Heilongjiang Province, Heihe City, from the soil samples under some black oaks of Tree Farm 733, 50°13.909'N, 126°51.887'E, elev. 517 m, 15-VIII-2014; 1 maturus junior (no. WHS6-3-2) (SEM), China, Heilongjiang Province, Wudalianchi City, from three soil samples of Wohu Hill, 48°39.252'N, 126°02.281'E, elev. 480 m, 17-VIII-2014; 3 maturi juniores (nos. DZH2-18, DZH 2-19, DZH2- 20) (SEM), 2 larvae II (nos. DZH2-4, DZH2-17) (SEM), China, Heilongjiang Province, Wudalianchi City, from the soil sample under some larches in Dazhanhe National Forest Park, 48°41.726'N, 127°40.556'E, elev. 327 m, 18-VIII-2014. All specimens are collected by W. J. Chen, C.W. Huang, Y. Ma, Y.X. Luan, and M. Potapov. Twelve specimens (nos. LM6-12D, LM6-13D, LM6-14D, HH1-1D, HH1-3D, HH1-4D, WHS4-2D, WHS5-2D, WHS6-2D, DZH2-1D, DZH2-2D and DZH2-12D) are voucher specimens retrieved after DNA extraction.

Diagnosis.

Paracerella sinensis sp. n. is characterized by four pairs of A-setae on tergite I, the presence of seta Pc and P3a on tergite VII, 8 A-setae on tergite VIII, the presence of seta Pc on sternites VI and VII, 4/2 setae on sternite VIII, which are different to any other members of the genus, foretarsal sensillum a extremely long, surpassing base of sensillum e, sensilla d and a’ located in subequal level with t2, acrostyli of female squama genitalis each with two fine flaps.

Description.

Adult body length 1150-1450 μm (n = 24), body yellow-brown color (Fig. 2A).

Head (Fig. 1A). Ovate, length 140-150 μm, width 85-90 μm. Setae d6 present, sd4 and sd5 short, sensilliform. Setae d6 14-15 μm, d7 17-18 μm. Clypeal pore cp and frontal pore fp present. Pseudoculus round, length 8-10 μm, with short posterior extension, PR = 15-19 (Fig. 1B). Maxillary gland large, calyx with lateral racemose appendices and one helmet-like dorsal appendix, and bilobed posterior dilation, posterior filament length 15-17 μm, CF = 8-10 (Fig. 1C). Labial palpus well-developed, with tuft and one leaf-shaped basal sensillum (7-8 μm) (Figs 1D, 2B). Maxillary palpus with two tapering sensilla, subequal in length (8-9 μm) (Fig. 1E).

Foretarsus (Fig. 1F, G, H). Length 100-107 μm, claw length 20-25 μm, TR = 4.2-5.2; empodium length 5 μm, EU = 0.2-0.25. Dorsal sensilla t1 filiform, BS = 0.75-0.85, t2 slender and long (25 μm), t3 lanceolate and short. Exterior sensilla a broad and long (35-55 μm), surpassing base of d, b broader and longer than c, c short and slender, d filiform, same level to t2 and a’, e short, f and g filiform and long. Interior sensilla a’ broad and long, surpassing base of δ 5, b’ absent, c’ slender and surpassing base of claw. Relative length of sensilla: t3 <e <c <d <t1<(b = g = t2)< a’ < c’ <f <a. Setae β 1 (9 μm) and δ 4 (13 μm) setiform. Pores close to sensilla c and t3 present. Length of middle tarsus 50 μm, claw length 23-25 μm. Length of hind tarsus 55 μm, claw length 25 μm.

Thorax. Thoracic chaetotaxy given in Table 1. Setae 1 and 2 on pronotum 31 μm and 21 μm length respectively (Fig. 2C). Mesonotum and metanotum with eight pairs of P-setae, accessory setae short sensilliform, 6-8 μm in length; setae P1, P1a and P2 on mesonotum 21-25 μm, 5-6 μm and 35-36 μm respectively (Fig. 2D, E). Prosternum with two pairs of anterior seta, and setae A2 and M2 sensilliform, 6-7 μm (Fig. 2F). Mesosternum and metasternum with 5 and 7 A-setae respecitvely, and setae A2 on mesosternum and metasternum sensilliform, 6-7 μm (Fig. 2G, H). Pronotum without pores. Mesonotum and metanotum with pores sl and al. Sterna without pores.

Abdomen. Abdominal chaetotaxy given in Table 1. Tergite I with four pairs of anterior setae (A1, A2, A3, A5) (Fig. 2I). Tergites II–VI with five pairs of anterior setae and eight pairs of posterior setae (Fig. 2J). Tergite VII with five pairs of anterior setae and 19 posterior setae, Pc and P3a present (Fig. 3A). Accessory setae on tergites I–VI short sensilliform, 6-7 μm on tergites I–III, 7-9 μm on tergite IV–VI, and on VII setiform (13-16 μm). Tergite VIII with seta Mc (Fig. 3B). Sternites IV–V each with eight posterior setae (Fig. 3E). Sternites VI–VII each with nine posterior setae, Pc present (Fig. 3F, G). Sternite VIII with two rows of setae (4/2) (Fig. 3J). Hind margin of tergites IX–XI and sternites IX–X with distinct denticles.

Tergites I–III and VII with pores psm and al, IV–VI with pores psm, al and psl, VIII with pores psm only, IX–XI without pores, XII with single medial pore. Pores psm on tergite VII close to seta P1 (Fig. 3A). Sternites I–V without pores (Fig. 3C, D, E), VI and VII each with single medial pore spm, on VI located close to Pc and on VII located in central position (Fig. 3F, G). Sternites VIII–XI without pores, XII with 1+1 sal pores.

Abdominal appendages I, II, III with 2, 1, 1 segments and 4, 2, 2 setae respectively (Fig. 3C, D). On appendages II and III, subapical setae 19-21 μm, apical setae 18-19 μm in length. Striate band on abdominal segment VIII well-developed (Fig. 3H, I, J). Comb on abdomen VIII rectangular, with 12-13 teeth (Fig. 1I). Female squama genitalis robust, with short basal apodeme and pointed acrostyli, each acrostylus with two fine flaps (Fig. 1J). Male unknown.

Etymology.

The species is named after the Latin name of China, the place where the species was found.

Distribution.

Inner Mongolia and Heilongjiang, China.

Remarks.

The new species is placed in the genus Paracerella because of the three pairs of A-setae on both meso- and metanota, filiform sensillum t1 on foretarsus, sensilla d and a’ located in subequal level with t2, and well-developed striate band. Paracerella sinensis sp. n. can be easily distinguished from the other three species of the genus by the chaetotaxy of tergites I, IV and VIII, sternites VI–VIII, as well as the length of foretarsal sensillum a.

Among 24 adults of Paracerella sinensis observed, the length of sensillum a is variable between individuals: in most specimens it can surpass base of e (holotype and most of paratypes) (Fig. 1F), in some specimens it is a little shorter, only surpassing base of d (nos. LM6-10, LM6-14D) (Fig. 1H), in some specimens it is extremely long as reaching or surpassing base of f (nos. LM6-13D, HH2-4D, WHS4-6-1), even reaching base of g (no. WHS4-2D). The four species of Paracerella can be distinguished by the following key.