Gracilentulus aokii Imadaté, 1982

Nakamura, Osami, 2021, The Japanese species of the genus Gracilentulus (Protura: Acerentomidae), Zootaxa 4991 (2), pp. 271-294 : 282-284

publication ID	https://doi.org/ 10.11646/zootaxa.4991.2.3
publication LSID	lsid:zoobank.org:pub:943B6E49-37EB-40BE-B0EE-39D87CEEF7BA
DOI	https://doi.org/10.5281/zenodo.5030267
persistent identifier	https://treatment.plazi.org/id/252BDE55-1662-FFC2-D285-FBD4FD37D9B3
treatment provided by	Plazi
scientific name	Gracilentulus aokii Imadaté, 1982
status

Treatment

Figs. 8–9 View FIGURE 8 View FIGURE 9

Gracilentulus aokii: Imadaté, 1982, pp.180–183 , Figs 1–8 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 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 View FIGURE 8 ); 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 View FIGURE 8 ). Pore fp present ( Fig. 8A View FIGURE 8 ).

On thoracic tergite II–III ( Fig. 9A View FIGURE 9 ), 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 View FIGURE 9 ). 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 View FIGURE 9 ); III with sl; sternite II with sc posterior to Ac. Pore psm present on abdominal tergites I–VIII ( Fig. 9B View FIGURE 9 ), those on VIII with accompanying two teeth ( Fig. 9D View FIGURE 9 ); al with II–VI; psl and lt on VI–VII ( Figs. 9B, C View FIGURE 9 ). Abdominal sternite IV and VII with asymmetric spsm; V–VI with spsm ( Fig. 9C View FIGURE 9 ). Telson with dorsal medial pore with serrate line ( Fig. 9E View FIGURE 9 ) 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).