Eosentomon ornatum Nakamura, 2010

Nakamura, Osami, 2010, Taxonomic revision of the family Eosentomidae (Hexapoda: Protura) from Japan 2701, Zootaxa 2701, pp. 1-109 : 80-84

Eosentomon ornatum Nakamura sp. nov.

Figs. 46–47; Table 19

Type specimens. Holotype female ( NSMT –Ap 512), Hamahigashima, Katsuren –cho, Okinawa Island , Okinawa Prefecture, 26º19'22"N, 127º57'25"E, 50 m elevation, 20-XII-1998, Y. Shishida leg. Paratypes: three females ( NSMT –Ap 513–515), same data as for the holotype ; 1 female ( NSMT –Ap 516), Chinasaki, Chinen –son, Okinawa Island , Okinawa Prefecture, 26º11'21"N, 127º49'16"E, 20 m elevation, 19-XII-1998, Y. Shishida leg. ; 1 female ( NSMT –Ap 517), Mikamisaki, Ishigaki Island , Okinawa Prefecture, 24º27'05"N, 124º04'42"E, 30 m elevation, 15- VI-1990, K. Kirihara leg.

Other specimens examined. Eight females, 5 maturi juniores, 2 larvae II, 2 larvae I, Oshaku–jinja, Kamitsuki, Miyakejima Island, Tokyo, 34º07'10"N, 139º31'21"E, 70 m elevation, litter of a forest of C. cuspidata subsp. cuspidata , Camellia japonica and Pinus thunbergii , 6-XII-1983, O. Nakamura leg.; 2 females, 1 larva II, foot of Mihara–yama, Hachijojima Island, Tokyo, 33º06'55"N, 139º48'36"E, 80 m elevation, litter of a forest dominated by Alnus sieboldiana , with a ground cover of Sasa sp. , 6-XI-1983, O. Nakamura & Y. Hagino leg.; 4 females, 1 maturus junior, 1 larva I, foot of Hachijo–Fuji, Nishi–yama, Hachijojima Island, Tokyo, 33º07'38"N, 139º47'03"E, 150 m elevation, litter of a forest dominated by A. sieboldiana and Ca. japonica , 7-XI-1983, O. Nakamura & Y. Hagino leg.; 1 female, 1 larva II, Okoshigahana, Hachijojima Island, Tokyo, 33º09'14"N, 139º44'51"E, 80 m elevation, litter of a forest dominated by Ca. japonica and Machilus thunbergii , 7-XI-1983, O. Nakamura & Y. Hagino leg.; 6 females, 2 maturi juniores, 8 larvae II, 5 larvae I, Jinda, Okago, Hachijojima Island, Tokyo, 33º07'07"N, 139º45'14"E, 80 m elevation, litter of a forest dominated by Ca. japonica and M. thunbergii , 7-XI-1983, O. Nakamura & Y. Hagino leg.; 1 female, Nakanogo, Hachijojima Island, Tokyo, 33º04'31"N, 139º49'40"E, 240 m elevation, litter of a forest dominated by C. cuspidata subsp. cuspidata , 7-XI-1983, O. Nakamura & Y. Hagino leg.; 11 females, 6 maturi juniores, 2 larvae II, 2 larvae I, Mihara–gawa, Nakanogo, Hachijojima Island, Tokyo, 33º04'06"N, 139º49'10"E, 160 m elevation, dwarf bamboo community, 7-XI-1983, O. Nakamura & Y. Hagino leg.; 2 females, 1 larva II, Noboryu–toge, Hachijojima Island, Tokyo, 33º06'51"N, 139º50'11"E, 220 m elevation, litter of a forest dominated by Ca. japonica , 7-XI-1983, O. Nakamura & Y. Hagino leg.; 3 females, 1 maturus junior, 1 larva I, Hachijo Airport, Hachijojima Island, Tokyo, 33º06'55"N, 139º47'34"E, 70 m elevation, litter of a forest dominated by Ca. japonica and Neolitsea sericea , 7-XI-1983, O. Nakamura & Y. Hagino leg.; 1 maturus junior, 4 larvae II, 1 larva I, same data as for the holotype; 1 maturus junior, 1 larva II, Mt. Nishime–dake, Kunigami–son, Okinawa Island, Okinawa Prefecture, 26º47'48"6N, 128º16'29"2E, 327 m elevation, 27- II- 2003, S. Karasawa leg.; 1 female, Omoto–dake, Ishigaki Island, Okinawa Prefecture, 24º25'28"N, 124º10'49"E, 450 m elevation, litter of a evergreen broad-leaved forest, 24-V-2000, H. Mizushima leg.; 3 females, Omoto–dake, Ishigaki Island, Okinawa Prefecture, 24º25'05"N, 124º11'13"E, 170 m elevation, litter of a evergreen broad-leaved forest, 7- III- 2002, S. Nagashima leg.; 13 females, 4 larvae II, Komi, Iriomote Island, Okinawa Prefecture, 24º19'28"N, 123º54'09"E, 20 m elevation, litter of a evergreen broad-leaved forest, 2- III- 2002, S. Nagashima leg.; 8 females, 2 maturi juniores, 1 larva II, same locality, 9-VI-2002, T. Ishikawa leg.; one female, same locality, 9-VI-2002, T. Tsuru leg.; 3 females, Mt. Inbi–dake, Yonaguni Island, Okinawa Prefecture, 24º26'52"N, 122º59'08"E, 150 m elevation, 18-VI-2001, K. Toyoda & S. Arai leg.; 7 females, 1 larva II, Kubura–dake, Yonaguni Island, Okinawa Prefecture, 24º27'13"N, 122º57'30"E, 150 m elevation, litter of a forest dominated by L. chinensis var. subglobosa , 19-V-2000, H. Mizushima leg.; 2 females, same locality, 6-VI-2001, S. Arai leg.; 1 female, Mandabaru, Yonaguni Island, Okinawa Prefecture, 24º27'26"N, 122º58'34"E, 100 m elevation, litter of a evergreen broad-leaved forest, 21-V-2000, H. Mizushima leg.

Description. Body length 969 (930–1027) µm. Head 111 (118–129) µm long, 92 (89–90) µm wide. Setae aa, pa and m4 present, sensilla as and ps present ( Fig. 46A); seta sp 1.6 (1.7) times longer than p; sensilla pp distinct ( Fig. 46B), 1 µm long. Labral setae present ( Fig. 46C). Seta rs inflated, slightly shorter than sr ( Fig. 46C). On maxillary palpus ( Fig. 46D) sensillum md, 8 (8–9) µm long, longer than ml, 7 (6-7) µm. On galea ( Fig. 46E) digit O longer than M and I. Mandible with three teeth ( Fig. 46F). Clypeal apodemes distinct ( Fig. 46C). Pseudoculus with three spots and some lines ( Fig. 46G), 12 (12–13) µm long, (10) µm wide, PR = 9 (9–11).

Foretarsus length ( Figs. 46H, I) 88 (84–90) µm; claw 17 (16–18) µm, TR = 5.3 (4.7–5.8); empodium 17 (17– 19) µm, EU = 1.0 (1.0–1.1); sensillum s almost same length as claw. Sensillum t1 at halfway between α 3 and α 3', BS = 1.2 (1.1–1.3); t2 thinly spatulate, longer than b'2; t3 very broadened, reaching praetarsus; a not reaching base of γ 2; b thinly spatulate; c not surpassing base of γ 3; d broadened, surpassing base of t3; e and g spatulate and long; f1 thinly spatulate; f2 shorter than f1; a' thinly spatulate; b'1 nearer to δ 4' than to δ 3', not reaching base of δ 4'; b'2 thinly spatulate; c' anterior to base of α 6, not surpassing tarsus. δ 3' posterior to a', at almost same level with δ 2. Length of middle tarsus 43 (41–43) µm, length of claw 13 (12–13) µm; hind tarsus 53 (53–54) µm, claw 15 (15) µm; empodia of both tarsi less than 1/7 of claw length ( Fig. 46J), 1 (1–2) µm long; on hind tarsus ( Fig. 46J) D2 and D4 spine-like.

Tracheal camerae contracted distally ( Fig. 46K). Central lobe trapezoidal, inner line incised ( Fig. 46L). Laterostigmata II–III large, with a central pore ( Fig. 46M); those on IV–VI small ( Figs. 46L, M). On female squama genitalis ( Fig. 46N) caput processus thin and bent toward median edge of stylus, corpus processus slender, filum processus long, median sclerotization present. Male unknown.

Chaetotaxy as in Table 19. On thoracic tergites II–III, P1a seta-like and longer than P1, posterior to P1–P2 and halfway between P1 and P2; P2a at same level with P2–P3, nearer to P2 than to P3. P1a on abdominal tergite I, P1a and P2a on II–V and P2a on V–VII filiform and longer than P1, at posterior margin; P1a on VI slightly shorter than P1 ( Fig. 47A); P1a short on VII and somewhat capitulate, at same level with P1–P2 ( Figs. 47A, B); on tergite VIII ( Fig. 47C) P1a' with basal dilatation and anterior to P2, P2a' linear.

Maturus junior. Body length 905 µm. Head 105µm long, 72 µm wide; pseudoculus 10 µm long, PR = 11. Foretarsus length 80 µm, claw 16 µm, TR = 5.1; empodium 15 µm, EU = 1.0; sensillum s 15 µm. Middle tarsus not measured, length of claw 8 µm; hind tarsus 49 µm, claw 12 µm. Shape and position of foretarsal sensilla same as those of imago; BS = 1.2.

Larva II. Body length 592–696 µm. Head 102–107 µm long, 72–83 µm wide; pseudoculus 8–9 µm long, 7–8 µm wide, PR = 11–14. Foretarsus length 68–72 µm; claw 15 µm, TR = 4.6–5.1; empodium 15 µm, EU = 1.0; sensillum s 14–15 µm. Length of middle tarsus 32–35 µm, length of claw 10–11 µm; hind tarsus 41–43 µm, claw 11– 13 µm. Shape and position of foretarsal sensilla same as those of preceding stages; BS = 1.1–1.2. P5 on abdominal tergites II and III displaced anteriorly and at same level with A4 on III ( Fig. 47D).

Larva I. Body length 637 µm. Head 84 µm long, 84 µm wide; pseudoculus 8 µm long, 7 µm wide, PR = 11. Foretarsus length 63 µm; claw 14 µm, TR = 4.6; empodium 13 µm, EU = 1.0; sensillum s 11 µm. Length of middle tarsus 32 µm, length of claw 10 µm; hind tarsus 36 µm, claw 11 µm. Shape and position of foretarsal sensilla same as those of preceding stages.

Diagnosis. This new species is similar to E. magnum Yin & Zhang , E. margarops Yin & Zhang , E. chunchengense Yin, Xie & Imadaté and E. huatingense Yin, Xie & Imadaté , all from China ( Yin, 1999; Yin & Zhang, 1982; Yin et al. 1995) and E. tamurai Nakamura from Taiwan ( Nakamura, 1997), in pseudoculus with inner structure of spots and lines, the presence of foretarsal sensillum b'1, the position of P1a at same level with P1–P2 on abdominal tergite VII, no anterior row of setae on the abdominal sternite VIII, and four setae on abdominal sternites IX–X.

Among these species, E. ornatum sp. nov. especially resembles E. margarops and E. tamurai in the chaetotaxy of abdominal tergites IV–VII (4, 4, 2, 2 pairs of anterior setae, respectively). It differs from these two in the structure of pseudoculus with the line not starting from spot (some lines starting from spots in E. margarops and E. tamurai ) and the thin female caput processus bent toward the median edge of the stylus (caput processus shaped like a duck’s head in E. margarops and E. tamurai ). It further differs from E. margarops in having foretarsal sensillum d long and surpassing the base of α 5 (short, not reaching the base of α 5 in E. margarops ), and from E. tamurai in having spatulate foretarsal sensilla t2, b, a' and b'2 (linear in E. tamurai ), capitulate P1a on abdominal tergite VII (setiform in E. tamurai ) and basal dilatation of P1a' on abdominal tergite VIII (base not dilated in E. tamurai ).

Chaetotaxic variations observed consisted of the asymmetric presence of A5 on abdominal tergite VI and P1 on abdominal sternite VI of one larva II from Hamahigashima and the asymmetric absence of A5 on abdominal tergite VI of another larva II from same locality.

Etymology. The specific name is derived from the “ornate” pseudoculus with three spots and four lines.

Distribution. Japan (Izu Islands of Tokyo and Okinawa).