Paracerella americana Imadaté, 1980

Shrubovych, Julia & Smykla, Jerzy, 2012, Review of Paracerella Imadaté (Protura: Acerentomidae, Nipponentominae) with identification key and description of a new species, Zootaxa 3509, pp. 69-76 : 70-72

Paracerella americana Imadaté, 1980 .

Figs. 1–10 , Table 1

Material examined. Holotype male (slide no. EMEC 78678), redwood forest, Memorial Park, 37°15'N 122°17'E, San Mateo County, California, 12. VII. 1958, coll. D. W. Price. One male from type series (slide no. EMEC 78680), same data as holotype; 7 females and 2 males (9 slides nos EMEC 78681 to EMEC 78689), 5 miles. N. La Honda, 37°22'N 122°16'E, San Mateo County, California, 1. XII. 1957, coll. D. W. Price; one female (slide no. EMEC 78690), oak litter, San Andreas Lake, 37°35'N 122°25'E, San Mateo County, California, 13. I. 1957, coll. D. W. Price; 3 females, 1 male, 1 maturus junior (5 slides nos. EMEC 78691–78695), same data as previous female, 9. III. 1958, coll. D. W. Price, 2 females (2 slides nos. EMEC 78696, EMEC 78697), 3miles N. Sharp Park, 37°40'N 122°29'E, chaparral, San Mateo County, California, 16. XII. 1957, coll. D. W. Price.

Redescription. Head with short setae, setae l3, sd4 and sd 5 setiform, subequal in length (about 4 μm), additional setae d6 absent ( Fig. 1 ). Pseudoculus round, with short posterior extension; PR = 16–18. Canal of maxillary gland with large racemose calyx; posterior filament short, with granulated appendix close to calyx and simple posterior dilation; CF = 4.8–5.2. Maxillary palp setae lanceolate, sensilla similar in length and shape ( Fig. 2 ). Labial palps with broad sensillum ( Fig. 2 ). Granulation on inner margin of labium distinct.

On foretarsus, sensillum t1 filiform, t3 small and leaf-like; d, f and c' very long, nearly setiform. Other sensilla parallel-sided. Sensilla b and c almost equal in length, passing base of seta γ 3, b thick, c slender, g short and slender, a’ slightly thicker than other sensilla. Sensillum d situated slightly closer to base of e than to c; base of a' on level of t2 insertion. Length formula of sensilla: t3 <g <e <t1 <(b = c) <a' <t2 <a <c' <f <d. Setae β 1 and δ 4 setiform, subequal in length (6 μm), shorter than other δ-setae ( Fig. 3 ). Claw short, without inner tooth, empodial appendage short. BS = 0.6–0.8, TR = 2.4–2.6, EU = 0.14–0.15. Single pores near bases of sensilla c and t3.

Chaetotaxy formula given in Table 1 . Setae on nota differing in length ( Fig. 4 ). Pronotal seta 1 twice the length of seta 2. Setae P1a and P2a on meso- and metanota short, setiform, subequal in length ( Fig. 5 ); P2a situated close to P3. Length ratio of mesonotal setae P1: P1a: P2 as 5:1:7. Mesonotum with sl and al pores and metanotum with sl pore only. Prosternum without pores, meso- and metasterna with one central pore. Seta A2 on thoracic sterna and A5 on tergite I short, setiform.

All accessory setae on tergites I–VI short, setiform, those on tergite VII longer, 7 and 10 μm, respectively. Tergites II–VI with transverse line and tergite VII with two lines in anterior region ( Fig. 6 ). Pores psm present on tergites I–VII anterior to P1a, al on tergites II–VII, psl absent.

Abdominal legs with 4, 2, 2 setae. Subapical seta on second and third pairs of abdominal legs longer than apical seta, 16 and 11 μm, respectively. Accessory setae on sternites I–VII slightly longer than those on tergites ( Fig. 7 ). Sternites I–II without pores. Sternites III–VII with single medial pore, anterior to P1 setae ( Fig. 6 ). Sternites II and III with several short, toothed lines on lateroanterior parts, sternites IV–VII with two transverse lines in anterior region.

Abdominal segment VIII with a distinct striate band; tergite with two anterior, irregular, transverse rows of small teeth. Pore psm with several accompanying teeth. Posterior margin of sternite VIII and laterotergites smooth. Comb VIII with 6–7 irregular teeth and with concave hind margin ( Fig. 8 ). Seta 1a on tergite IX same length and shape as seta 1. Seta 2a on tergites IX and X shorter than other setae. Tergites and sternites IX–XII smooth. Dorsal lobe of tergite XII with median pore on serrate line, ventral lobe with 1+1 anterolateral pores.

Female squama genitalis short, with short, blunt, trilobed acrostyli ( Fig. 9 ). Male squama genitalis with 7+7 setae, additional seta absent ( Fig. 10 ).

Measurements (17 adults) (in μm): total length 900–990, head 105–110, pseudoculus 6–7, posterior part of maxillary gland 21–22, posterior cephalic setae: seta d7 7–9, seta sd 7 11–13, seta l5 5–6, pronotal seta 1 20–23, pronotal seta 2 10–13; mesonotal seta P 1 18–23, mesonotal seta P1a 4–5, mesonotal seta P 2 28–31, foretarsus 66–72, claw 27–28, empodial appendage 4.

Remarks. In this redescription new morphological characters are added, such as chaetotaxy of head; length of seta on head, nota and foretarsus; porotaxy and lineation of tergites and sternites; shape of maxillary palp sensilla, comb and male squama genitalis. According to Imadaté (1980), in P. americana the shape of the accessory setae on the tergites is sensilliform and acrostyli are pointed. However, reexamination of the type material indicates that shape of accessory setae on the tergites is setiform, and acrostyli are not pointed, but trilobed. Paracerella americana is similar to P. s h i r a t k i in the pattern of foretarsal sensilla, but it differs from the latter species by the presence of 8 and 6 pairs of anterior setae on tergites VII and VIII, respectively (6 and 4 pairs of A -setae in P. shiratki ), absence of seta P1a on tergite VII and by the shape of the comb.

Figures

FIGURES 1 – 10. Paracerella americana Imadaté, 1980. 1) Head. 2) Maxillary and labial palpi. 3) Part of foretarsus, interior view. 4) Pro- and mesonota, left part. 5) Mesonotal seta P 1 a. 6) Sternite VII. 7) Setae P 1 a on sternite VII and P 2 a on tergite VII. 8) Comb on Abd. VIII. 9) Acrostylus of female squama genitalis. 10) Male squama genitalis. Arrows show pores (fp = frontal pore, al = anterolateral, sl = sublateral, psm = posterosubmedial). Fig. 9, paratype no. EMEC 78681; others, paratype no. EMEC 78680. Scale bars: 20 µm.

Tables

TABLE 1. Body chaetotaxy of Paracerella americana Imadaté, 1980.

		Dorsal		Ventral
Segment	Formula	Setal composition	Formula	Setal composition
Th. I	4	1, 2	4+2 6	A1, 2, M1 P1, 2, 3
Th. II	8 16	A2, 3, 4, M P1, 1a, 2, 2a, 3, 3a, 4, 5	5+2 4	Ac, 2, 3, M P1, 3
Th. III	8 16	A2, 3, 4, M P1, 1a, 2, 2a, 3, 3a, 4, 5	7+2 4	Ac, 2, 3, 4, M P1, 3
Abd. I	6 12	A1, 2, 5 P1, 1a, 2, 2a, 3, 4	3 4	Ac, 2 P1, 1a
Abd. II–III	10 16	A1, 2, 3, 4, 5 P1, 1a, 2, 2a, 3, 4, 4a, 5	3 5	Ac, 2 Pc, 1a, 2
Abd. IV–VI	10 16	A1, 2, 3, 4, 5 P1, 1a, 2, 2a, 3, 4, 4a, 5	3 8	Ac, 2 P1, 1a, 2, 3
Abd. VII	8 14	A2, 3, 4, 5 P1, 2, 2a, 3, 4, 4a, 5	3 8	Ac, 2 P1, 1a, 2, 3
Abd. VIII	6 15	A1, 4, 5 Pc, 1, 1a, 2, 2a, 3, 3a, 5	4 0	1, 2
Abd. IX	12	1, 1a, 2, 2a, 3, 4	4	1, 2
Abd. X	10	1, 2, 2a, 3, 4	4	1, 2
Abd. XI	6	1, 3, 4	6
Abd. XII	9		6