Hesperentomon septemsetum, Bu, Yun & Yin, Wen Ying, 2007

Bu, Yun & Yin, Wen Ying, 2007, The Protura from Xinjiang, Northwestern China, Zootaxa 1437, pp. 29-46 : 29-30

Hesperentomon septemsetum new species

( Figs. 1 – 11 )

Diagnosis. The present species is characterized by the presence of seven setae on urosternites VIII and IX, sensillum b'-2 on foretarsus and the posterior accessory seta P1a on urotergites I – VI.

Description. Adult. Body length 1570 µm.

Head— Long-elliptic, length 138 µm, width 93µm. Head setae short, rostrum not protruded. Submedial and sublateral additional setae present. Two additional pairs of pores between pseudocelli and in posterior part of head present. ( Fig. 1 ). Pseudoculus pear-like, elongate, with long lever, length 15 µm, width 7.5 µm. PR=9.2 ( Fig. 2 ). Canal of maxillary gland long, with sausage-like calyx and bulb-like posterior dilation. CF=3.4 ( Fig. 4 ). Maxillary palpus with two subequal sensilla, parallel-side. Labial palpus well developed, with four setae and apical tuft, with no basal sensillum.

Thorax— Chaetotaxy as shown in Table 1 . Mesonotum with two pairs of anterior setae (A2 and A4), with nine pairs of posterior setae, P5a and P5a' very short ( Fig. 5 ). P5a on metanotum also very short. Length ratio of P1: P1a: P2 on mesonotum as 2:1:2.7. Pronotum with no pores. Mesonotum and metanotum with pores sm and sl. Sternites of thorax with single median pore, situated on prosternum posteriorly, on mesosternum and metasternum anteriorly to level of seta M.

Foretarsal length 105 µm, claw length 20 µm, with one pair of inner flap, TR =5.3; Empodium length 3.8 µm, EU=0.19; S-shaped seta shorter than claw. Dorsal sensillum t-1 and t-2 slim and long, BS=0.82; t-3 sword-like. Exterior sensillum a, b, c, d, e, f and g all short sword-like and in different length, d relatively long. Interior sensillum a', b'-1, b'-2, c'-1 and c'-2 also short sword-like in different length. Length formula of foretarsal sensilla as: f = b'-2 <c = b'-1 = c'-1 <e = t-3 = a' <a = c'-2 <b <g <d <t-1 <t-2 ( Figs. 6 – 7 ). Middle tarsal length 50 µm, claw length 20 µm. Hind tarsal length 55 µm, claw length 23 µm.

Abdomen —Chaetotaxy as shown in Table 1 . Urotergite I with two pairs of anterior setae (A1, A2), with seven pairs of posterior setae. Urotergites II – VII with four pairs of anterior setae (A1, A2, A4, A5), with eight pairs of posterior setae. Urotergites I – III with pore psm, psl, al and pl, Urotergites IV – VII with pores psm, psl and al. Abdominal legs are typical of the genus, each with four setae. Urosternites I – III with one single medial pore, IV – VII with three (one medial and two sublateral) pores on posterior half of sternite.

Striate band on abdominal segment VIII absent. Urosternite VIII with setae 0/7, with medial seta Pc. Urosternite IX also with seven seate (M, 1, 1a, 2). Urotergite VIII with pores psm and pl, sternite with three (one posterior medial and two sublateral) pores. Comb on abdomen VIII rectangular, with seven teeth on hind margin ( Fig. 10 ). Base of some setae on segments X – XII surrounded with very small ciliae, similar to that of H. martynovae Szeptycki. Urotergites IX – XII with single median pore. Urosternites XI – X with three pores, XI with no pores, XII with 1+1 pores on its anterolateral part ( Figs 8 – 9 ).

Female squama genitalis relatively long, with acrostyli short subuliform and bifurcated ( Fig. 11 ). Male unknown.

Younger instars

Maturus junior— Body length 1345 – 1475 µm. Head length 138 – 155 µm, width 93 – 100 µm. Pseudoculus pear-like, with some little granules on the surface, length 13 – 15 µm, width 7.5 – 10 µm, PR=10 – 11( Fig. 3 ). Fortarsal length 90 – 103 µm; claw length 18 – 20 µm; TR =4.5 – 5.5; Empodium length 3.8 µm, EU=0.19 – 0.22; S-shaped seta length 15 µm; BS=0.71 – 0.8; Middle tarsal length 45 – 48 µm, claw length 18 – 20 µm. Hind tarsal length 48 µm, claw length 20 µm. Compared with imago, urotergite X lack three pairs of setae(1a, 2a, 3a), urosternites VIII and IX lack medial seta, urosternite X lack 1a, urosternite XI lack setae 1, 3, and urosternite XII with five pair of setae. Comb on abdominal VIII with seven teeth.

Other younger instars —unknown.

Holotype —female (No: W0601) (mounted), from coniferous forest of Mt. Nanshan, 43 o 25' 338 N, 87 o 09' 875 E, 2100 m alt., Urumchi, Xinjiang Province, China, 21-V-2006, collected by Dr. Yun-Xia Luan, Yan Gao and Yun Bu.

Paratype —2 maturus juniors (No: W0604, W0646) (mounted), same data as for holotype.

Etymology. The name septemsetum indicates that the new species with seven setae on urosternites VIII and IX.

Distribution. Xinjiang Province, Northwest China.

Remarks. The 12 known species of genus Hesperentomon Price, 1960 are all provided with six setae on urosternite VIII and IX, while the present species with seven which is obviously different from all known species. By comparison, the new species is similar to H. macswaini Price, 1960 from California, H. martynovae Szeptycki, 1988 from Altai Mts and H. kuratai Imadaté, 1989 from Japan, but it can be distinguished from macswaini by the presence of sensillum b'-2 on foretarsus, from martynovae by the chaetotaxy of mesonotum and the female squama genitalis, from kuratai by the position of sensillum a' on foretarsus.

Figures

FIGURES 1 – 11. Hesperentomon septemsetum sp. n. 1, head, dorsal view (arrows – pores). 2, pseudoculus of imago. 3, pseudoculus of maturus junior. 4, canal of maxillary gland. 5, mesonotum. 6, foretarsus, exterior view. 7, foretarsus, interior view. 8, urotergites VIII – XII. 9, urosternites VIII – XII. 10, comb on abdominal VIII. 11, female squama genitalis.