Description

Description. Body length 949 μm. Head length 123 μm, width 90 μm; labrum short, 5 μm, LR = 27; cephalic setae l 3, l 5, sd 4, sd 5 short setiform, 5 μm; seta d 6 present; seta sd 7 1.3 times longer than d 7 (Fig. 1 A). Maxillary palpus with two sensilla on penultimate segment, dorsal and ventral sensilla similar in shape and length (Fig. 1 B). Labial palpus reduced to three setae and one sensillum (Fig. 1 C). Canal of maxillary gland simple, proximal part short, CF = 8 (Fig. 1 D). Pseudoculus slightly broader than long, 7 μm x 9 μm, PR = 16 (Fig. 1 E). Pore fp present (Fig. 1 A). Foretarsus (Figs. 2 A – C) 109 μm long; claw 30 μm, TR = 3.6; empodium 3 μm, EU = 0.1. Dorsal sensillum t 1 claviform, almost level with α 3, BS = 0.4; t 2 thin, longer than c and d; t 3 small knob-like, its apex not pointed. Exterior sensillum a surpassing base of d; b longer than c and d; c and d close to each other, subequal in length, situated at same level with t 2; e situated about halfway between γ 3 and α 5, its apex surpassing base of α 7; f at about halfway between e and g, its apex reaching base of γ 5; g at same level with t 3, its apex reaching base of claw. Interior sensillum a' broad, distal to t 1; b' absent; c' not surpassing tarsus. Single pore present between α 3 and a, and between t 3 and g. Seta β 1 sensillum-like, δ 1 – 5 short, δ 5 proximal to δ 4. Middle tarsus 46 μm, its claw 21 μm; hind tarsus 59 μm, its claw 22 μm. Body chaetotaxy as in Table 1 and Figs. 3 A – C. On thoracic tergites II – III (Fig. 3 A), P 1 a and P 2 a lanceolate microchaetae; P 1 a almost halfway between P 1 and P 2; P 2 a slightly nearer to P 3 than to P 2; P 5 a rudimentary; 1 and 2 on thoracic tergite I 33 and 13 μm; P 1, P 1 a and P 2 on thoracic tergite II 33, 3 and 39 μm. Abdominal tergites I – V with three pairs of anterior setae (A 1, A 2, A 5); VI with four pairs (A 1, A 2, A 4, A 5); VII with three pairs (A 2, A 4, A 5) (Fig. 3 B, C). P 3 on abdominal tergites II – V situated anterior to other posterior setae; P 3 on VI – VII in the same row with other posterior setae (Fig. 3 B). Accessory setae, P 1 a, P 2 a and P 4 a, present on abdominal tergites II – VII; P 3 a on VI – VII; these setae short and less than about 1 / 6 of P 1 in length; P 1 a close to P 1; P 2 a near to P 2 (Fig. 3 B, C). Sternite VIII with a single row of four setae (Fig. 3 C). Accessory setae, P 1 a, on abdominal sternites I – VII similar to dorsal accessory setae. P 1, P 1 a and P 2 on abdominal tergite VI 36, 5 and 43 μm; P 1, P 1 a and P 2 on VII 37, 5 and 39 μm. Thoracic tergite II with pores sl and al (Fig. 3 A); III with sl. Pore psm present on abdominal tergites I – VIII, those on VIII without accompanying teeth; psl on VI – VII (Fig. 3 B); al on II – VII (Figs. 3 C, D). Sternites V with two sam; IV – VI with spsm; VII with asymmetrical spsm (Fig. 3 C). Abdominal appendage II – III each with two setae, apical seta less than a half of subapical one (Fig. 1 F). On abdomen VIII, striate band developed, striae distinct (Fig. 3 B, C); comb rectangular with 8 teeth (Fig. 1 G). Female squama genitalis with stout pointed acrostylus (Fig. 1 H). Preimago (male). Body length 780 μm in extended condition. Head length 101 – 105 μm, width 76 μm, LR = 26 – 27, CF = 8 – 9, pseudoculus circular, 8 – 9 μm x 8 – 9 μm, PR = 12 – 13. Foretarsus 86 μm; claw 26 μm, TR = 3.3; empodium 3 μm, EU = 0.1; BS = 0.4. Middle tarsus 38 – 39 μm, its claw 15 – 18 μm; hind tarsus 18 – 20 μm, its claw 18 – 20 μm. Fundamental features almost same with those of imago. P 1, P 1 a and P 2 on thoracic tergite II 21 – 26, 2 – 3 and 33 – 34 μm; P 1, P 1 a and P 2 on abdominal tergite VI 32 – 37, 4 and 35 – 36 μm; P 1, P 1 a and P 2 on VII 32, 4 and 34 – 35 μm. Maturus junior. Body length 533 μm. Head length 103 μm, CF = 10, pseudoculus 7 μm x 7 μm, PR = 14. Fore- tarsus 80 μm; claw 24 μm, TR = 3.4; empodium 3 μm, EU = 0.1. Shape and position of foretarsal sensilla same as those of preceding stages, BS = 0.4. Middle tarsus 35 μm, its claw 14 μm; hind tarsus 40 μm, its claw 19 μm. Seta Mc present instead of M 1 on abdominal tergite VIII and the following setae absent: P 1 a on abdominal tergites II – VI, A 4 on tergite VI, 4 a on tergite IX, 1, 2, and 3 a on tergite X, and 2 and 3 on sternite XI Chaetotaxic variation. Asymmetric absence of A 1 on abdominal tergite VI in maturus junior.

Common Names

No common names available.

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Arthropoda

Class: Protura

Order: Protura

Family: Acerentomidae

Genus: Gracilentulus

Species: Gracilentulus macrotarsus Nakamura, 2021