Acerentulus sinensis, Wu, Donghui & Yin, Wenying, 2007

Wu, Donghui & Yin, Wenying, 2007, New records of the genera Acerentulus and Brasilidia (Protura: Acerentomidae) from China, with descriptions of two new species, Zootaxa 1561, pp. 53-61 : 53-57

Acerentulus sinensis sp. nov.

( Figs. 1–18 )

Type material. Holotype: female, from the coniferious forest of Nanhu, 43º51´N, 125º18´E, Changchun city, Jilin Province, northeastern China, collected by Dr. Donghui WU in July, 2006.

Paratypes: 5 females, same data as holotype. Holotype and paratypes are deposited in the Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China.

Diagnosis. Foretarsal sensillum f slightly near to e than to g, apices of both f and g surpassing base of tarsus, f longer than g, c' long and thin, its apex surpassing base of tarsus. P1a and P2a present on urotergite VII, urotergites VI and VII with 8 anterior setae (A1, A2, A4 and A5). Connecting line on urosternites IV-VI absent.

Head: 150 µm long in dorsal view, setae pp and ls present, a absent ( Fig. 1 ). Median pore present. Rostrum protruded. Pseudoculus almost circular, broader than long, longitudinally divided ( Fig. 2 ), PR=16. Canal of maxillary gland simple ( Fig. 3 ), the proximal part 30 µm long with distinct tripartite posterior dilation, CF=5. Maxillary palpus with two sensilla, one being seta-like and the other sensillum-like ( Fig. 4 ). Labial palpus with apical tuft of setae and broad sensillum ( Figs. 5 ).

Legs: Foretarsus length 115 µm, claw 25 µm, without inner or outer flap, TR =4.6 ( Figs. 6, 7 ); Empodium length 6 µm, EU=0.24; S-shaped seta longer than claw, 30 µm. Dorsal sensillum t1 claviform, BS=0.39; t2 thin; t3 shaped like a willow leaf. Exterior sensillum a really long, between y 2 and y 3; b long, subequal to c in length, base at same level as c; apices of b and c surpassing base of y 3, b and c close to each other; d reaching the base of f; e not surpassing tarsus; f slightly near to e than to g, both apices of f and g surpassing tarsus, f longer than g. Interior sensillum a' a little broad and distal to t1, reaching base of t2; b' thin, surpassing base of c'; c' thin, its apex surpassing tarsal base. Ventral seta β 1 and interior seta δ 4 short, sensillum-like, β 1 shorter than δ 4. Interior setae δ 1, δ 2, δ 3 and δ 5 short but longer than δ 4, apically pointed. Pores present between a and a3 and between t3 and g. Middle tarsus length 45 µm, claw length 20 µm. Hind tarsus length 47 µm, claw length 22.5 µm.

Larva II Maturus Junior Imago

Formula Complementary setae Formula Complementary setae Formula Complementary setae

Dorsal

Body: Chaetotaxy as shown in Table 1 and Figs. 8–13 . Thoracic tergites II–III each with two pair of dorsal anterior setae (A2, A4), seta P2a on meso- and metanotum nearer to P3 than to P2. Urotergites I–V each with three pairs of anterior setae (A1, A2, A5), P1a and P3a absent; urotergites VI and VII with 8 anterior setae (A1, A2, A4, A5), P1a and P3a absent on urotergite VI, P1a and P3a present on urotergite VII; urotergites IX and X with 12 setae. Urosternites I–VII with 3 anterior setae; urosternite VIII with 4 anterior setae and 2 posterior setae; urosternites IX–X with 4 setae; urosternites XI–XII with 6 setae.

Seta P1a and 2a on thoracic tergites II and III, short and lanceolate, 2 µm long. Seta P5a on thoracic tergites II and III minute, 3 µm long. Seta M1a on thoracic sternite I, A1a on thoracic sternites I–III, P1a on abdominal sternites I–VI, P2a on abdominal tergites I, and P2a and P4a on abdominal tergites II–VI, short and sensillum-like, about 5 µm. Setae P1a, P2a, P3a and P4a on abdominal tergites VII and P1a on abdominal stergites VII, short hair-like, 6 µm long. Connecting line on urosternites IV-VI absents ( Fig. 11 ).

Integumental pores distinct ( Figs. 8, 10–13 ). Thoracic tergite II with two pairs of pores; one between A2 and P2, the other posterior to P4; tergite III with a pair of pores anterior to P2. Abdominal tergites I – VI with a pair of pores between P1 and P2, tergite VII with a pair of pores close to P1a; tergite VIII with a pair of pores between M2 and M3, without denticles. Abdominal sternites IV and VI each with a pair of pores anterior to P1, sternite VII with one pore between P1. Telson with a dorsal central pore and a pair of ventral pores at both sides.

Abdominal appendages II and III each with three setae ( Fig. 14 ). On abdomen VIII, striate band well developed, with distinct striae ( Fig. 12, 13 ), comb with about 8–11 teeth ( Fig. 15 ). An irregular row of minute granules visible just posterior to the strate band. Female squama genitalis is shown as Fig. 16 .

Maturus junior: Length of body 1250–1300 µm, foretarsus length 88–91µm, TR =4.5–5, BS=0.44–0.46.

Larva II: Foretarsal sensilla b' absent ( Fig. 17–18 ). Length of body 960–1110 µm, foretarsus length 70– 75 µm, TR =5.4–5.8, BS=0.42–0.44.

Distribution. Jilin Province, northeastern China.

Etymology. The specific name sinensis refers to China, the country where the new species was found.

Remarks. The new species is similar to A. silvanus ( Szeptycki 1991) from Poland in chaetotaxy (urotergite VI and VII with 8 anterior setae, seta P1a and P3a absent on urotergite VI, P1a and P3a present on urotergite VII). It can be distinguished from A. silvanus by the characteristics of the foretarsal sensillae such as the length of f and c', the apex of c' surpassing tarsus, f longer than g, and by the shape of female squama genitalis. Compared with the other Far East species of Acerentulus , the new species differs clearly from A. kisonis , A. keikoae and A. omoi in chaetotaxy, Pc absent on urosternite VII of the new species.

Figures

FIGURES 1 – 11. Acerentulus sinensis sp. nov. 1. Head, dorsal view. 2. Pseudoculus. 3. Canal of maxillary gland. 4. Maxillary palpus. 5. Labial palus. 6. Foretarsus, exterior view. 7. Foretarsus, interior view. 8. Mesonotum. 9. Mesosternum. 10. Urotergites VI – VII. 11. Urosternites VI-VII. Arrows indicate pores.

FIGURES 12 – 18. Acerentulus sinensis sp. nov. 12. Urotergites VIII – XII. 13. Urosternites VII – XII. 14. Abdominal appendage II. 15. Comb on abdominal tergite VIII. 16. Female squama genitalis. 17. Foretarsus (Larva II), exterior view. 18. Foretarsus (Larva II), interior view. Arrows indicate pores.

Tables

TABLE 1. Chaetotaxy of Acerentulus sinensis sp. nov.

Thorax I 4	1, 2 4	1, 2 4	1, 2
II-III ------	A2, 4, M1 ---------- P1, 1a, 2, 3, 4, 5, 5a ()	A2, 4, M1 ---------- P1, 1a, 2, 2a, 3, 4, 5, 5a ()	A2, 4, M1 P1, 1a, 2, 2a, 3, 4, 5, 5a
Abdomen I ------	P1, 2, 2a, 3, 4 ------	A1, 2 -------------- P1, 2, 2a, 3, 4 ()	A1, 2, 5 P1, 2, 2a, 3, 4
II-V ---------- ()	P1, 2, 2a, 3, 4, 4a, 5 ---------- ()	A1, 2, 5 ---------- P1, 2, 2a, 3, 4, 4a, 5 ()	A1, 2, 5 P1, 2, 2a, 3, 4, 4a, 5
VI ---------- ()	P1, 2, 2a, 3, 4, 4a, 5 ---------- ()	A1, 2, 5 ---------- P1, 2, 2a, 3, 4, 4a, 5 ()	A1, 2, 4, 5 P1, 2, 2a, 3, 4, 4a, 5
VII ---------- ()	P1, 2, 2a, 3, 4, 4a, 5 ---------- ()	A1, 2, 4, 5 ---------- P1, 1a, 2, 2a, 3, 3a, 4, 4a, 5 ()	A1, 2, 4, 5 P1, 1a, 2, 2a, 3, 3a, 4, 4a, 5
VIII ---------- ()	A5, M 2, 3, 4 ---------- P2, 3, 4, 5 ()	A2, 4, 5, M1, 2, 3, 4 ---------- P2, 3, 4, 5 ()	A2, 4, 5, M1, 2, 3, 4 P2, 3, 4, 5
IX 8	1, 2, 3, 4 12	1, 2, 3, 3a, 4, 5 12	1, 2, 3, 3a, 4, 5
X	8	1, 2, 3, 4 12	1, 2, 3, 3a, 4, 5
XI	6	1, 2, 3 6	1, 2, 3
XII 9	9	9
Ventral Thorax I ---	A1, M1 -- P1, 2	A1, 1a, M1, 1a -- P1, 2, 3	A1, 1a, M1, 1a P1, 2, 3
II ---	Ac, A1a, 2, M1 -- P1	Ac, A1a, 2, M1 -- P1, 2	Ac, A1a, 2, M1 P1, 2
III ---	Ac, A1a, 2, M1 -- P1	Ac, A1a, 2, 3, M1 -- P1, 2	Ac, A1a, 2, 3, M1 P1, 2
Abdomen I ---	Ac, A2 -- P1	Ac, A2 -- P1, 1a	Ac, A2 P1, 1a
II–III ---	Ac -- Pc, P1a, 2	Ac, A2 -- Pc, P1a, 2	Ac, A2 Pc, P1a, 2
IV-VII ---	Ac -- P1, 2, 3	Ac, A2 -- P1, 1a, 2, 3	Ac, A2 P1, 1a, 2, 3
VIII 4	A1, 2 --	A1, 2 -- P1a	A1, 2 P1a
IX 4	1a, 2 4	1a, 2 4	1a, 2
X	4	1a, 2 4	1a, 2
XI	2	2 6	1, 1a, 2
XII 6	1a, 2, 3 6	1a, 2, 3 6	1a, 2, 3