Paracerella monterey Shrubovych

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 : 72-74

Paracerella monterey Shrubovych sp. nov.

Figs. 11–31 , Table 2

Material examined. Holotype female (slide no. EMEC 78698), Crest Road, Pebble Beach, 36°33'N 121°52'E, Monterey County, California, 19. IX. 1959, coll. L.M. Smith. Paratype male (slide no. EMEC 78698), same data as holotype.

Description. Head with all setae setiform, setae l3, sd4 and sd 5 short, subequal in length, about 6 μm. Additional setae d6 absent ( Fig. 11 ). Pseudoculus slightly broadened, with short posterior extension, PR = 18 ( Fig. 12 ). Maxillary gland with broad, distinctly granulated calyx, short posterior filament and simple posterior dilation, CF = 5.8–6.1 ( Fig. 13 ). Maxillary palps with lanceolate, subequal sensilla, labial palps well developed with broad basal sensillum ( Figs. 14, 15 ). Granulation on inner margin of labium distinct.

Foretarsus ( Figs. 17, 18 ) with sensillum t1 filiform, t3 small and leaf-like; d, f and c' long, nearly setiform. Other sensilla parallel-sided. Sensilla b and c almost equal in length, slightly surpassing base of seta γ 3, b thick, c slender, g short and broadened, a’ slender. Sensillum d located slightly closer to base of e than to c; base of a' on level of t2 insertion. Length formula of sensilla: t3 <(b = c) <g <t1 <e <a' <(a = t2) <d <c' <f. Setae β 1 and δ 4 setiform, longer than the other δ-setae, β 1 shorter than δ 4, 8 and 11 μm, respectively ( Fig. 18 ). 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 2 . Setae on nota differing in length ( Fig. 20 ). Pronotal seta 1 about twice length of seta 2. Setae P1a and P2a short, setiform ( Fig. 21 ); seta P1a twice the length of P2a, 8 and 4 μm, respectively. Length ratio of mesonotal setae P1: P1a: P2 as 2:1:3. Mesonotum with sl and al pores and metanotum with sl pore only. Prosternum without pores, meso- and metasterna with one central pore ( Fig. 22 ). Seta A2 on thoracic sterna and A5 on tergite I short, setiform ( Fig. 23 ).

Accessory setae on tergites I–VI short, setiform, those on tergite VII longer, 6 and 8 μm, respectively. Tergites I–VI with a transverse line and tergite VII with two lines in anterior region ( Fig. 24 ). Pores psm present on tergites I–VII anterior to P1a, al on tergites II–VII, psl absent ( Figs. 24, 29 ).

Abdominal legs with 4, 2, 2 setae. Subapical seta (22 μm length) on second and third pairs of abdominal legs slightly longer than the apical seta, 18 μm length ( Fig. 27 ). Accessory setae on sternites I–VII slightly longer (8–10 μm) than those of tergites I–VII ( Fig. 7 ). Sternites I–II without pores ( Fig. 26 ). Sternites III–VII with single medial pore; sternites IV–V with posterior granulated areas ( Figs. 27, 28 ). Sternites II–V with several short toothed lines in lateroanterior regions ( Figs. 27, 28 ), sternite VI with a transverse line and sternite VII with two transverse lines in anterior region ( Fig. 29 ).

Abdominal segment VIII with distinct striate band; tergite and sternite with two anterior, irregular, transverse rows of small teeth ( Fig. 25 ). Pore psm with several accompanying teeth. Posterior margin of sternite VIII and laterotergites smooth. Comb VIII with 8–9 regular teeth and with straight hind margin ( Fig. 16 ). Seta 1a on tergite IX the same length and shape as seta 1. Seta 2a on tergites IX and X shorter than the other setae. Tergites VIII–XII and sternites IX, XI and XII smooth. Hind margin of sternite X with distinct teeth ( Fig. 31 ). Dorsal lobe of tergite XII with a median pore on serrate line, ventral lobe with 1+1 anterolateral pores.

Male squama genitalis with 7+7 setae (see Fig. 10 ). Female squama genitalis short, with stumpy bilobed acrostyli ( Fig. 19 ).

Measurements (2 adults) (in μm): body length 880–960, head 110, pseudoculus 6, posterior part of maxillary gland 18–19, posterior cephalic setae: seta d7 11, seta sd 7 13–14, seta l5 6–7, pronotal seta 1 20–21, seta 2 10–11, mesonotal seta P 1 15–17, seta P1a 8, seta P2 23, foretarsus 68–70, claw 27–28, empodial appendage 4.

Chaetal variability not observed.

Etymology. The specific name is derived from Monterey County, where the holotype was collected. Remarks. In chaetotaxy P. monterey sp. nov. is very similar to P. americana . Both these species are characterized by the absence of additional cephalic setae, by setiform shape and short length of head setae l3, sd4 and sd 5. The new species differs from P. americana in the absence of seta P1a on tergites I–VI, presence of 2 posterior setae on sternite I (4 P -setae present in P. americana ) and in shape of the comb. Foretarsal setae β 1 and δ 4 are longer than other δ-setae in P. monterey sp. nov. and seta δ 4 is longer than β 1 (11 and 8 μm, respectively), whereas β 1 and δ 4 are shorter than the other δ-setae and foretarsal setae β 1 and δ 4 are of similar length in P. americana . The lengths of notal setae are similar in both species with the exception of seta P1a, which in P. m o n t e re y sp. nov. is twice as long as P2a. Paracerella monterey sp. nov. is also characterized by peculiar lineation in anterior parts and presence of granulated areas posteriorly on sternites IV–V. These characters seem to be stable on species level. Porotaxy, maxillary sensillum shape and appearance of male and female squama genitalis are identical in both species.

Discussion. All species of Paracerella are characterized by a maxillary gland with a racemose appendage on the distal part close to the calyx, similar foretarsal length and similar pattern of foretarsal sensilla. Sensillum a reaches to the base of sensillum t2, b is equal in length with c, b is broad, sensilla d, f and c' are very long and narrowed distally; the base of sensillum d is slightly closer to e than to c, and the base of a' is level with t2. The three Paracerella species clearly differ in chaetotaxic characters (see the key) and in some other morphological characters.

Figures

FIGURES 11 – 19. Paracerella monterey sp. nov. 11) Head. 12) Pseudoculus. 13) Canal of maxillary gland. 14) Maxillary palp. 15) Labial palp. 16) Comb on Abd. VIII. 17) Foretarsus, exterior view. 18) Foretarsus, interior view. 19) Female squama genitalis. Arrows show pores. Figs. 12 – 15, paratype no. EMEC 78698; others, holotype. Scale bars: 20 µm.

FIGURES 20 – 31. Paracerella monterey sp. nov. 20) Pro- and mesonota. 21) Mesonotal setae P 1 a and P 2 a. 22) Mesosternum. 23) Setae A 2 on mesosternum and A 5 on tergite I. 24) Tergites VI – VII. 25) Tergite VIII. 26) Sternite I. 27) Sternite III with abdominal leg. 28) Sternite IV. 29) Sternite VII. 30) Sternite VIII. 31) Sternite X. Arrows show pores. Figs. 20, 24, 25, paratype; others, holotype. Scale bars: 20 µm.

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 2. Body chaetotaxy of Paracerella monterey sp. nov.

		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 10	A1, 2, 5 P1, 2, 2a, 3, 4	3 2	Ac, 2 P1
Abd. II–III	10 14	A1, 2, 3, 4, 5 P1, 2, 2a, 3, 4, 4a, 5	3 5	Ac, 2 Pc, 1a, 2
Abd. IV–VI	10 14	A1, 2, 3, 4, 5 P1, 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