Yamatentomon mikawa, Nakamura, 2025

Yamatentomon mikawa sp. nov.

Figs. 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5 ; Table 2

Materials examined. Holotype male (NSMT-Ap 742), shore of Lake Mikawa-ko (Habu Dum), Habu-chô , Toyotashi, Aichi Prefecture, Honshu, Japan, 35°01'55"N, 137°23'54"E, elev. 470 m, deciduous broad-leaved forest dominated by Quercus serrata , 29-IX-2013, Y. Takai leg. GoogleMaps Paratypes: four males (NSMT-Ap 743–744) ( SMNH Ap- 40893–40894) , four females (NSMT-Ap 745–746) ( SMNH Ap-40895–40896), same data as for holotype GoogleMaps .

Additional specimens examined: three males, nine females, three preimagoes, and four maturi juniores, same data as for holotype GoogleMaps .

Diagnosis. Cephalic setae d6 absent; tergite VII with anterior setae A4'; posterior accessory setae on thorax and abdomen all setiform, longer than one-quarter length of P1; P3a on tergite II absent; P3a present on tergites III–VII; sternite I without pores.

Description. Body length 1047 (936–1170) μm in unexpanded condition. Head length 174 (172–188) μm; width 125 (118–139) μm; rostrum short, 13 (10–13) μm, LR = 13 (13–15) ( Fig. 3A View FIGURE 3 ). Head setae all setiform, l3 length 10 (10–11) μm, slightly shorter than sd4, 14 (13–14) μm, and sd5, 16 (14–16) μm ( Figs. 3A, B View FIGURE 3 ); additional setae d6 absent ( Fig. 3A View FIGURE 3 ); setae d7, 26 (24–27) μm, slightly longer than or subequal to sd7, 22 (24–27) μm ( Fig. 3A View FIGURE 3 ). Maxillary palpus with two sensilla, dorsal one slender, 10 (9–12) μm, subequal to length of medially broadened ventral one, 10 (9–11) μm ( Figs. 3D, E View FIGURE 3 ). Praelabium with fringe, labial palpus with tuft of setae and broad sensillum ( Fig. 3C View FIGURE 3 ). Canal of maxillary gland simple, proximal part rather broad, CF = 13 (11–13) ( Fig. 3F View FIGURE 3 ). Pseudoculus shortened, 8 (8–9) × 11 (9–15) μm, with minute lever, PR = 22 (19–24) ( Fig. 3B View FIGURE 3 ).

Foretarsus ( Figs. 3G, H View FIGURE 3 ) 124 (112–127) μm long; claw 50 (46–51) μm, with distinct inner flap, TR = 2.5 (2.4– 2.7); empodium length 5 (5–7) μm, EU = 0.10 (0.09–0.12); S-shaped seta 54 (52–56) μm, slightly longer than claw. Dorsal sensillum t1 baculiform, BS = 0.6 (0.6–0.7); t2 thin; t3 leaf–like. Apex of exterior sensillum a surpassing base of d; b strikingly long, its apex surpassing base of β6; apex of c surpassing base of e; d slightly nearer to e than to c, its apex surpassing base of α5; apex of e surpassing base of g; f close to g, both apices surpassing base of claw. Interior sensillum a' broad, its apex surpassing base of α4; b' absent; apex of c' s urpassing base of claw. Pores present near bases of sensilla c and t3. Setae β1 and δ4 long, setiform; β1 28 (24–28) μm, slightly longer than δ1, and about half length of β2, 50 (51–54) μm; δ4 46 (40) μm, about twice the length of δ1; δ1‒δ3 and δ5 short, setiform; δ1 shortest, 21 (19–22) μm; δ2, δ3 and δ5 subequal in length, 24 (20–26) μm. Middle tarsus 62 (60–66) μm, claw 27 (26–28) μm; hind tarsus 70 (69–76) μm, claw 29 (28–30) μm.

Body chaetotaxy as in Table 2 and Figs. 4A–C View FIGURE 4 , 5A–F, H, I View FIGURE 5 . Length of pronotal seta 1 44 (40–45) μm, about 1.6 times longer than seta 2, 28 (26–28) μm. On mesonotum and metanotum, setae P1a and P2a setiform, P1a longer than P2a; P1a about half of P 1 in length, P2a longer than one-quarter of P1 length. P5a on mesonotum gemmate, on metanotum rudimentary ( Figs. 4A, B View FIGURE 4 ); P1, P1a, and P2a on mesonotum 64 (64–68) μm, 32 (24–31) μm and 17 (15–19) μm, respectively; those on metanotum 59 (48–56) μm, 28 (28–32) μm and 18 (16–20) μm, respectively. M2 on prosternum and A2 on mesosternum and metasternum short setiform, 11 (10–11) μm ( Fig. 5C View FIGURE 5 ). Abdominal tergite I with four pairs of anterior setae, ( A1, A2, A3 and A5); A5 short, 10 (9–13) μm; II–VI with five pairs of anterior setae, ( A1–A5) ( Figs. 5A, B, E, F View FIGURE 5 ); VII with six pairs of anterior setae, A4' present ( Fig. 5H View FIGURE 5 ); P3 on tergites II–VII situated in same row as P1, P2, and P4 ( Figs. 5A–C View FIGURE 5 ); tergite II with eight pairs of posterior setae, P3a absent ( Fig. 5A View FIGURE 5 ); III–VII with nine pairs of posterior setae, P3a present ( Figs. 5B, C, E View FIGURE 5 ); accessory setae on I–VII setiform, P1a and P2a longer than P3a and P4a; P1a and P2a, 18–22 (21–26) μm, about one-third of P 1 in length; P3a 16–19 (16–21) μm and P4a 13–16 (13–20) μm. Sternites VI–VII with Pc seta ( Fig. 5F, H View FIGURE 5 ); VIII with single row of four setae.

Mesonotum with al and sl pores; metanotum with sl pore ( Fig. 4A, B View FIGURE 4 ). Mesosternum and metasternum with a group of three or four sc pores ( Fig. 4C View FIGURE 4 ). Tergite I with pore psm; II–VI with psm and al ( Figs. 5A, B View FIGURE 5 ); VII with psm, psl, and al ( Figs. 5C, H View FIGURE 5 ); VIII with psm with accompanying teeth ( Fig. 5D View FIGURE 5 ). Sternites II–III with single pore spm ( Fig. 5A View FIGURE 5 ); IV–V with two spm ( Fig. 5E View FIGURE 5 ); VI–VII with a pair of spsm and four sam ( Figs. 5F, H View FIGURE 5 ); on VI one + a group of adjacent three (three to four) sam on connecting line ( Figs. 5F, G View FIGURE 5 ); on VII a group of adjacent four (three or four) sam on intersection of connecting lines ( Fig. 5G View FIGURE 5 ). Abdominal segment XII with a central pore on tergite and a pair of anterolateral pores on sternite ( Fig. 5I View FIGURE 5 ).

Abdominal appendages II and III each with two setae, subequal in shape and length, 16–17 (15–18) μm ( Fig. 3I View FIGURE 3 ). On abdomen VIII, striate band developed, striae distinct and nearly reaching the anterior line; small teeth scattered in a rough line anterior to setae ( Fig. 5D View FIGURE 5 ); comb consisting of 17 (16–20) teeth with rounded margin, protruded posteriorly ( Fig. 3J View FIGURE 3 ). Female squama genitalis with sharply pointed acrostylus ( Fig. 3K View FIGURE 3 ); male squama genitalis with 7+7 setae ( Fig. 3L View FIGURE 3 ).

Preimago (n = 3). Body length 891–969 μm; head length 147–164 μm; rostrum 10–12 μm, LR = 13–17; CF = 11–16; pseudoculus shortened, 7–8 × 9–10 μm, PR = 19–22. Foretarsus length 100–105 μm; claw 41–42 μm; empodium 4–5 μm; S-shaped seta 41–45 μm; TR = 2.5–2.6, EU = 0.10–0.12, BS = 0.6. Shape and position of foretarsal sensilla similar to those of adult. Middle tarsus length 49–53 μm, claw 22–23 μm; hind tarsus 53–58 μm, claw 23–24 μm. Setae P3a on tergites II–IV absent; A4' on VII asymmetrically absent. Sternite IV with five anterior setae ( Ac, A2, A3). Thoracic tergites and sternites without pores, but a group of four adjacent sc present on mesosternum in one specimen. Porotaxy on tergites II–VII same as those of adults. Sternites II–IV with one spm; V with two spm; VI–VII with one spsm and a group of adjacent three sam on transverse line; Abdominal segment XII with central dorsal pore.

Maturus junior (n = 4). Body length 754–956 μm; head length 126–161 μm; rostrum 9–11 μm, LR = 11–14; CF = 11–13; pseudoculus shortened, 7 × 8–10 μm, PR = 18–22. Foretarsus length 87–107 μm; claw 36–41 μm; empodium 4–5 μm; S-shaped setae 38–43 μm; TR = 2.5–2.7, EU = 0.11–0.13, BS = 0.5–0.6. Shape and position of foretarsal sensilla similar to those of adult. Middle tarsus 43–53 μm, claw 19–22 μm; hind tarsus 52–61 μm, claw 22–25 μm. Body chaetotaxy given in Table 2. Thorax without pores. Porotaxy on tergites I‒VIII same as those of adult; sternites IV–V with one s pm; sternites VI–VII with two sam on transverse line.

Chaetotaxic and porotaxic variation. Imago with A2 on sternite II asymmetrically absent, P2 on sternite III asymmetrically doubled in one paratype female (NSMT-Ap 745) . P1 on mesonotum and metanotum asymmetrically absent in one paratype female (NSMT-Ap 746). Pc on tergite IV present in one male. A1 instead of Ac on sternite IV, V and VI in six, nine and 10 specimens , respectively. Sternite III with one spm in two specimens and three spm in one specimen; IV with one spm in three specimens and a pair of spsm in two specimens; V with one spm in one specimen , three spm in two specimens, a pair of spsm in one specimen and a group of adjacent two sam on anterior connecting line in one specimen; VI with two pairs of spsm in one specimen .

One preimago with P1a on tergite II absent.

Maturus junior (n = 4): A4 on tergite IV, P1a on tergite I absent and P2 on sternite I asymmetrically absent in one specimen. A4 and P3a on tergite III and A3 on sternite VII asymmetrically present in one specimen . P3a on tergite IV asymmetrically absent in one specimen. P1 on sternite I asymmetrically absent in one specimen.

Remarks. This new species is similar to Y. yamato in many respects, but is distinguished by the absence of P3a on tergite II and the pore on sternite I (both present in Y. yamato ), as well as the lengths of foretarsal sensilla g and c' (not surpassing the tarsus in Y. yamato ). Additionally, the absence of additional cephalic setae d6 can often be used as a distinguishing characteristic (as they are frequently present in Y. yamato ).

The present species also resembles Y. fujisanum and Y. brevisetum in the absence of cephalic setae d6 and the presence of A4' on tergite VII and P3a on tergites IV–VII. However, it differs from Y. fujisanum in the shape of the accessory setae on tergites II–VI (sensilliform in Y. fujisanum ) and in the length of the foretarsal sensillum b (not reaching the base of γ 4 in Y. fujisanum ). Additionally, it differs from Y. brevisetum in the presence of A1 on tergite VII (absent in Y. brevisetum ) and in the absence of P3a on tergite II (present in Y. brevisetum ).

Distribution. Japan ( Aichi Prefecture, Honshu), known only from the type locality.

Etymology. The specific name, a noun in apposition, is derived from a native appellation referring to the region where this new species was collected.