Baculentulus chiangmaiensis Nakamura & Likhitrakarn

Nakamura, Osami & Likhitrakarn, Natdainai, 2009, Protura (Hexapoda) from Doi Suthep-Pui National Park, Chiang Mai, Thailand, Zootaxa 2121, pp. 1-16 : 3-6

Baculentulus chiangmaiensis Nakamura & Likhitrakarn sp. nov.

Figures 1–2 , Table 1.

Type material examined. Holotype 3, 3 paratype 3, and 5 paratype Ƥ, mixed forest. The holotype (CMUZ- 1377) and 3 paratypes (1 3, 2 Ƥ: CMUZ- 1378–1380) are deposited in the collection of the Chulalongkorn University Museum of Zoology, Bangkok, and 5 paratypes (2 3 and 3 Ƥ ( NSMT –Ap 437–441) are in the collection of the National Science Museum, Tokyo.

Other specimens examined. 4 maturi juniores and 2 larvae II, same data as for holotype; 1 maturus junior, evergreen forest.

Description. Body length 1150 (1095–1260) μm. Head 179 (164–188) μm long, 123 (104–134) μm wide. Rostrum not protruded; additional setae (a) absent; postpseudocular setae (pp) and anteropseudocular setae (ap) present ( Fig. 1 A). On maxillary palpus, dorsal sensillum d longer than ventral sensillum v ( Fig. 1 B). Labial palpus with three setae and one sensillum ( Fig. 1 C). Pseudoculus broader than long ( Fig. 1 D), (7–) 9 μm long, (9–) 11 μm wide, PR = 21 (–23). Canal of maxillary gland simple ( Fig. 1 E).

Foretarsus length ( Figs. 1 F, G) 93 (90–94) μm; claw without inner flap, 26 (25–29) μm, TR = 3.6 (3.3–3.7); empodium 3.9–4.6 μm, EU = (0.14–) 0.17; seta s longer than claw, 32 (30–33) μm. Sensillum t1 baculiform, BS = (0.52–) 0.56; t2 thin; t3 short; a just surpassing base of c; b slightly thicker than c, almost reaching base of γ4; c and d close to each other, the apices of both surpassing base of f; e and f close to each other; apices of e, f, and g reaching base of claw; a' thick, at same level as t1, apex surpassing base of b'; b' almost same level with t2, its apex surpassing base of c'; c' reaching base of claw. Seta β1 short (about 8 μm) and sensillum-like, setae δ1 to 5 short, but longer than β1. Pores between a and α3 and between g and t3. Length of middle tarsus 39 (–42) μm, claw 19 (–22) μm; hind tarsus 46 (45–48) μm, claw 20 (–23) μm

Chaetotaxy as in Table 1 and Fig. 2 . P5a on thoracic tergite II minute, about 3 μm; that on III rudimentary. A2 on thoracic sternites I–III short and sensillum-like, less than 7 μm. Abdominal tergites I–VI with three pairs of anterior setae; VII with two pairs. P3 on abdominal tergites II–VI anterior to other principal setae; those on VII slightly anterior to other principal setae. On tergites I–VII, extra accessory setae P3a present, and on I–VI, double accessory setae P1a and P1a' present. Sternite VIII without posterior setae; IX–XI with 4 setae. A5 on abdominal tergite I, P2 on abdominal sternites II–III, and accessory setae on abdominal segments I–VII all short and sensillum-like, less than 7 μm.

Integumental pores distinct. Thoracic tergites II–III with pores al and sl ( Fig. 2 A). Abdominal tergites I- VIII with psm pores, II-VI with al, VII with psl pores; IV–VII with anteromarginal pore (ag) at anterior part of pleura, a pair on IV and VII, V–VI with two pairs ( Figs. 2 A, B). Abdominal sternites V–VI with a pair of pores between A2 and P1; VII with one pore anterior to one of P1a ( Fig. 2 C). Telson with a dorsal central pore on serrate line and a pair of ventral pores at both sides.

Abdominal appendages II–III each with two setae, median apical setae (7–8 μm) subequal to 1/3 of subapical setae (20–21 μm) ( Fig. 1 H). On abdomen VIII, striate band reduced, striae not distinct ( Fig. 1 I); comb oblique and consisting of about 9 distinct teeth ( Fig. 1 J). Female squama genitalis with pointed acrostyli ( Fig. 2 D).

Larva II Maturus junior Imago Formula Composition of setae Formula Tertiary setae Formula Complementary setae

(Dorsal)

Thorax I 4 1, 2 4 4 II–III 6 A2, 4, M 6 6 14 P1, 1a, 2, 3, 4, 4a, 5 16 P2a 16

Abdomen I 0 6 A1, 2, 5 6 10 P1, 2, 2a, 3, 5 12 P1a 16 P1a’, 4 II–III 0 6 A1, 2, 5 6 12 P1, 2, 2a, 3, 4, 5 16 P1a, 4a 20 P1a’, 3a IV–VI 0 6 A1, 2, 5 6 12 P1, 2, 2a, 3, 4, 5 16(18) P1a,(3a), 4a 20 P1a’, 3a VII 0 4 A2, 5 4 14 P1, 2, 2a, 3, 4, 4a, 5 18 P1a, 3a 18 VIII 2–6 A3, M2, 3, 4 6–7 A1, 3, Mc 6–8 +M1,-Mc 8 P2, 3, 4, 5 8 8 IX 8 1, 3, 4, 5 12 2, 3a 14 4a X 8 1, 3, 4, 5 12 2, 3a XI 6 1, 2, 3 6 Telson 9 c, 1, 2, 3, 4 9 9

(Ventral)

Maturus junior. Body length 835–1020 μm; head 150–155 μm long, 115–134 μm wide; pseudoculus 7 μm long, 8–9 μm wide, PR = 20.9–21.5. Foretarsus length 74–79 μm; claw 22–23 μm, TR = 3.4–3.5; empodium 3–4 μm, EU = 0.14–0.15; seta s 25–26 μm; BS = 0.51–0.56; middle tarsus 38 μm, claw 18 μm; hind tarsus 44 μm, claw 20 μm.

Larva II. Body length 545 and 550μm; head 115 and 118 μm; pseudoculus 6 μm long, 7 μm wide, PR = 20.1 and 20.7. Foretarsus length 51 μm; claw 18 and 20 μm, TR = 2.8 and 2.9; empodium 2 and 3 μm, EU = 0.12 and 0.13; seta s 22 μm; BS = 0.52. Foretarsal sensillum b' absent. Middle tarsus 25 and 27 μm, claw 14 and 15 μm; hind tarsus 27 μm, claw 14 and 16 μm. Integumental pores distinct on abdominal tergites V–VIII, sternite VII and telson and ag on tergites VI–VII.

Diagnosis. The genus Baculentulus consists of 34 species worldwide and is distributed in southwestern and eastern Asia, North and South America, eastern Africa, and Australia. Among them, B. chiangmaiensis is similar to B. numatai (Imadaté) from Nepal ( Imadaté, 1965) in possessing accessory setae P1a' on abdominal tergites I-VI and sensillum b' on foretarsus. B. chiangmaiensis is different from B. numatai in having two pairs of anterior setae on abdominal tergite VII (only A 5 in B. numatai ), shape of A4 on tergites I–VI (very short and accessory seta-like in B. numatai ), and presence of P3a on tergites I–VI (absent in B. numatai ).

This new species resembles B. bisetuli Yin from Yunnan, China ( Yin, 1985) in having P1a' on abdominal tergites I-VI, but is easily distinguished from B. bisetuli in the presence of foretarsal sensillum b' (absent in B. bisetuli ), 4 anterior setae on abdominal tergite VII (only 2 in B. bisetuli ), presence of P3a on tergites II–VI (absent in B. bisetuli ) and 4 setae on sternite XI (2 setae in B. bisetuli ).

The porotaxy of B. chiangmaiensis is unique in that thoracic tergite III possesses pores al and sl, whereas only sl is usually present in Acerentomidae .

Chaetotaxic variations were observed in three maturi juniors: asymmetric absence of A1 on abdominal tergite VI and A5 on VII in one maturus junior, absence of P2a on thoracic tergite II in one maturus junior, and absence of P1a on abdominal tergites I and II on another specimen.

Etymology. The specific name is derived from the name of the province, Chiang Mai, where the type locality is located.

Figures

FIGURE 1. Baculentulus chiangmaiensis sp. nov. A, Dorsal view of head; B, maxillary palpus; C, labial palpus; D, pseudoculus; E, canal of maxillary gland; F, interior view of foretarsus; G, exterior view of foretarsus; H, abdominal appendage II; I, striate band on abdominal tergite VIII; J, comb on abdominal tergite VIII; K, female squama genitalis. Arrows indicate pores. A, C – J, Holotype, male; B, paratype, female. Scale bar: 20 μm for A, F, G; 10 μm for B – E, H – J.

FIGURE 2. Baculentulus chiangmaiensis sp. nov. A, Thoracic tergite III and abdominal tergite I, left half; I, abdominal tergites V – VIII, left half; B, abdominal tergites V – VIII, left half; C, abdominal sternites VI-VII; D, female squama genitalis. Arrows indicate pores. A, B, Holotype, male; C, D, paratype, female. Scale bar: 20 μm.