Description

Redescription. Body length 1149 ± 125 µm (range: 904 – 1366; n = 23). Head 135 ± 13 µm long (range 119 – 182; n = 24); setae sd 4 and sd 5 present, seta d 6 (Rusek et al. 2012) absent (Fig. 1). Rostral setae r 1 and r 2 nearly 10 µm long, labral seta lb 1.5 times longer than rostral setae (Fig. 2). Single frontal pore anterior to level of pseudoculi (Fig. 3). Rostrum very short. Pseudoculus slightly elliptic, 9 µm long (range: 8 ‒ 11; n = 24), longitudinally divided (Fig. 4); PR = 14.6 (range 12.2 – 18.2, n = 23). Proximal part of maxillary gland long and terminally dilated (Fig. 5), length 26 µm (range: 22 – 32; n = 23), CF = 5.2 (range: 4.3 – 6.3; n = 22). Maxillary palpus with slender setaceous sensilla (Fig. 6). Labial palpus with distinctly thickened sensillum (Fig. 7). Foretarsus length 88 ± 3 µm (range: 78 – 92; n = 22), claw 24 µm (range: 22 – 26; n = 18), without inner tooth, TR = 3.6 (range 3.4 – 4.0; n = 18); empodium length 5 µm (range: 4 – 6, n = 10), EU = 0.19 (range 0.16 – 0.24, n = 10); S-shaped seta longer than claw, 28 µm (range: 25 – 32; n = 10). Sensillum t 1 claviform, BS = 0.35 (range 0.27 – 0.42, n = 22); t 2 thin, t 3 proximally dilated. Sensillum a long, distinctly broadened basally, passing base of seta γ 3; sensilla b ‒ g slender, long; b, c and d of equal length; sensilla b and c reaching the base of e, sensillum d reaching the base of f, sensilla e and f almost of equal length, not reaching the empodium, sensillum g passing the base of claw, f nearer to e than to g (Fig. 8). Sensillum a’ broad, barely reaching the base of b’, b’ and c’ almost of equal length and thin, the apex of c’ reaching the empodium (Fig. 9). Ventral seta β 1 very short, barely reaching the base of δ 2; δ 4 situated more proximally than sensillum c’. Foretarsal pores present near the bases of sensilla c and g (Fig. 8). Middle tarsus length 37 µm (range: 34 – 39; n = 20); claw length 17 µm (range: 14 – 19; n = 20). Hind tarsus length 41 µm (range: 39 – 44; n = 20); claw length 17 µm (range: 14 – 20; n = 18). Thoracic tergite I (Fig. 10) with two pairs of setae (ratio of setae 1: 2 = 2.77: 1; range 2.18 ‒ 4.00; n = 16) (Table 1). Thoracic tergites II and III (Fig. 10) each with two pairs of anterior setae (A 2, A 4); setae P 1 a and P 2 a very short; seta P 2 a nearer to P 3 than to P 2. Seta P 5 very short. Length ratio of setae P 1: P 2 on mesonotum as 1: 1.31 (range 1.15 – 1.43, n = 18). Tergites I – V each with three pairs of anterior setae (A 1, A 2, A 5); tergites II ‒ V lacking setae P 1 a and P 3 a. Seta A 4 present on tergites VI ‒ VII. Seta P 3 on urotergites II ‒ VI anterior to line P 2 ‒ P 4 (Fig. 11). Tergite VIII (Fig. 12) with 3 pairs of anterior setae (A 2, A 4, A 5); P 1 a absent. Tergites IX and X with 12 setae; tergites XI and XII with 6 and 9 setae, respectively (Fig. 10, Table 1). Prosternum (Fig. 14) formula 4 + 4 / 6, mesosternum and metasternum (Fig. 15) formulae typically 5 + 2 / 4 and 7 + 2 / 4, respectively. Sternites I – VII with 3 anterior setae (Figs. 16 ‒ 17); sternites VIII ‒ X with 4 setae; sternites XI and XII with 6 setae (Fig. 18). Thoracic tergites II and III (Table 2) with sl pores; al pores on mesonotum. Tergites I ‒ VIII with psm pores, on tergite VIII opening between two small pointed teeth; al pores on tergites II ‒ VII; psl pores on tergites VI ‒ VII (Fig. 11). Tergite XII with ac pore (see Galli & Capurro, 2013, Fig. 12). Thoracic sternites and abdominal sternites I ‒ II without pores. Sternite III with an asymmetrical spsm pore near the base of a seta P 1 a (10 adults); in four adults such pore is nearly medial, in three adults two symmetrical spsm pores present. Sternites IV ‒ VI with symmetrical spsm pore near the base of seta P 1 (Fig. 16); spm pore far from posterior margin on sternite VII (Fig. 17); sternite XII with sal pores (see Shrubovych, 2014 — Fig. 18). Imago and Pre-imago Maturus Junior Larva II Formula Complementary Setae Formula Complementary Setae Dorsal Connecting lines on anterolateral corners of sternites IV – VI absent. Pleural pectines weakly developed (Fig. 19). Abdominal appendages II and III with long subapical seta and two setae, one lateral-apical and the other median-apical; comb VIII with 8 – 9 long teeth (Fig. 13). Penis with 6 + 6 setae (Fig. 20). Female squama genitalis with three spines on each acrostylus (Figs. 21 ‒ 22). Chaetotaxic variation infrequent; asymmetrical shift of seta P 1 towards P 2 on abdominal tergite I (one adult); symmetrical absence of seta A 4 on tergite VI (one maturus junior); symmetrical absence of seta A 1 on tergite VII (one maturus junior); presence of seta Ac rather than setae A 1 (formula 7 / 16) on tergite VII (one adult); symmetrical absence of seta A 4 on tergite VI (one maturus junior); absence of seta Pc (formula 3 / 4) on sternite III (two adults – this arrangement may be the chaetotaxy of the holotype – see Rusek & Stumpp 1988); presence of seta Ac rather than setae A 1 (formula 3 / 2) on sternite VIII (one adult); sternite XI with only two setae (one maturus junior). Pre-imago. Length of body 967 µm (range 797 ‒ 1130; n = 4), head 113 µm (range 105 ‒ 121; n = 4), foretarsus length 75 µm (range 70 ‒ 79; n = 4), TR = 3.0 – 4.1, BS = 0.34 – 0.43. Chaetotaxy (Table III) identical to that of adults. Maturus junior. Length of body 973 ± 123 µm (range: 787 – 1121; n = 12), head 114 ± 11 µm (range: 98 – 138; n = 11), foretarsus length 73 ± 6 µm (range: 63 – 88; n = 12), TR = 3.5 ‒ 4.2, BS = 0.23 ‒ 0.55. Chaetotaxy (Table III) differing from that of adults in presence of seta Pc instead of setae P 1 on tergite VIII. Larva II. Two specimens: length of body 800 µm, head 91 and 98 µm, foretarsus length 58 µm, TR = 3.4. Chaetotaxy is shown in Table III.

Common Names

No common names available.

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Arthropoda

Class: Protura

Order: Protura

Family: Acerentomidae

Genus: Acerentulus

Species: Acerentulus apuliacus Rusek & Stumpp, 1988