Gracilentulus aokii : Imadate 1982
Creators: name: Nakamura, Osami
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Entognatha
Protura
Acerentomidae
Gracilentulus
Gracilentulus aokii

description: Gracilentulus aokii Imadaté, 1982
Figs. 8–9
Gracilentulus aokii: Imadaté, 1982, pp.180–183, Figs 1–8.- Imadaté & Harada, 1983, p.20.- Imadaté, 1985, 546.- Imadaté & Ohnishi, 1993, Tables 2,3.- Szeptycki 1993, p.388.- Imadaté, 1994, p.54.-Szetycki, 2007, p. 59.
Materials examined. Holotype female (NSMT-Ap 78); two females, Shimonada, Futami-cho, Iyo-gun, Ehime Prefecture, 26-I-1978, collected by J. Aoki.
Diagnosis. Foretarsal sensillum t1 same level with α3, a’ distal to t1, e, f and g subequal in length; posterior accessory setae P1a and P2a on thoracic tergites II–III lanceolate microchaetae, P3 on abdominal tergites VI–VII same row with other posterior setae. Pores lt present on VI–VII.
Supplementary notes on description. Examination of the specimens revealed that some characters needed correction or were omitted in the original description.
Cephalic setae l3, l5, sd4, sd5 short setiform, about 5 μm; seta d6 present; seta sd7 1.3 times longer than d7 (Fig. 8A); labrum short, 3 μm, LR = 30. Maxillary palpus with two sensilla on penultimate segment, dorsal and ventral sensilla similar to each other in shape and length (Fig. 8B, C). Pore fp present (Fig. 8A).
On thoracic tergite II–III (Fig. 9A), P1a and P2a lanceolate microchaetae; P1a halfway between P1 and P2; P2a near to P3. Setae P1 and P2 on thoracic tergite I 24 and 13μm; P1, 1a and P2 on II 21–23, 2–3 and 26–27 μm. Posterior principal setae P3 on abdominal tergites II–V anterior to other posterior ones; but P3 on VI and VII at same row with other posterior ones (Fig. 9B). P1, P1a and P2 on abdominal tergite VI 23–25, 4 and 26–27 μm; P1, P1a and P2 on VII 23–25, 3–4 and 25–27 μm.
Thoracic tergite II with pores sl and al (Fig.9A); III with sl; sternite II with sc posterior to Ac. Pore psm present on abdominal tergites I–VIII (Fig. 9B), those on VIII with accompanying two teeth (Fig. 9D); al with II–VI; psl and lt on VI–VII (Figs. 9B, C). Abdominal sternite IV and VII with asymmetric spsm; V–VI with spsm (Fig. 9C). Telson with dorsal medial pore with serrate line (Fig. 9E) and a pair of ventral sal pores at both sides.
Notes. The original description states that the principal posterior setae P3 on abdominal tergite VI are situated anterior to other posterior setae. In the present observation, however, the position of P3 on VI was in the same row as the other posterior setae. Additionally, in the present study, the posterior accessory setae P1a and P2a on thoracic tergites II–III were identified as lanceolate microchaetae (though their shape was not mentioned in the original description).
The current study revealed that G. aokii shared the following common characteristics with G. macrotarsus sp. nov., G. chichibuensis, and G. shippingensis: lanceolate microchaetae P1a and P2a on thoracic tergites II–III and the posterior position of P3 on abdominal tergite VI. Gracilentulus aokii differs from G. macrotarsus sp. nov. by the position of foretarsal sensillum t2 (distal to c and d in G. aokii) and the presence of P3a on abdominal tergite VI (absent in G. aokii). Furthermore, G. aokii differs from both G. chichibuensis and G. shippingensis by the setae on the labial palpus (three setae in G. aokii; four setae in the latter two species). Additionally, it differs from G. chichibuensis by the length of foretarsal sensilla b (surpassing the base of f in G. aokii but not in G. chichibuensis) as well as e and f (neither apex reaching the base of the claw in G. aokii; almost reaching this position in G. chichibuensis), and differs from G. shippingensis in the chaetotaxy of abdominal tergite VII (six and eight anterior setae in G. aokii and G. shippingensis, respectively).
Distribution. Japan (Honshu, Shikoku).
description: Published as part of Nakamura, Osami, 2021, The Japanese species of the genus Gracilentulus (Protura: Acerentomidae), pp. 271-294 in Zootaxa 4991 (2) on pages 282-284, DOI: 10.11646/zootaxa.4991.2.3, http://zenodo.org/record/5030484