Eosentomon impar Nakamura, 2010

Nakamura, Osami, 2010, Taxonomic revision of the family Eosentomidae (Hexapoda: Protura) from Japan 2701, Zootaxa 2701, pp. 1-109 : 49-52

Eosentomon impar Nakamura sp. nov.

Fig. 27; Table 11

Type specimens. Holotype female ( NSMT –Ap 481), Kenmarubi, Mt. Fuji, Fujiyoshida–shi, Yamanashi Prefecture, 35º27'06"N, 138º45'12"E, 1060 m elevation, litter of a forest dominated by P. densiflora , 22-IX-2001, R. Itoh leg. Paratypes: 3 females ( NSMT –Ap 482–484), same data as for the holotype; 1 female ( NSMT –Ap 485), Mt. Komaga–take, Kanegasaki–cho, Iwate Prefecture, 39º11'21"N, 140º55'41"E, 920 m elevation, litter of a forest dominated by F. crenata , 18-VIII-2001, H. Tamura et al. leg.; 1 female ( NSMT –Ap 486), Otaki, Chichibu–shi, Saitama Prefecture, 35º56'58"N, 138º53'57"E, 900 m elevation, 1-V-1991, Y. Kuwabara leg.; 2 females ( NSMT – Ap 487–488), Busseki, Nakatsugawa, Chichibu–shi, Saitama Prefecture, 35º59'44"N, 138º49'30"E, 670 m elevation, litter of a forest dominated by F. crenata and Q. crispula , 26- IV- 1988, K. Machida leg.; 2 females ( NSMT –Ap 489–490), Omaru–yama, Kamikuisshiki–mura, Yamanashi Prefecture, 35º26'32"N, 138º38'26"E, 1130 m elevation, litter of a forest dominated by F. crenata and Q. crispula , 18- IV- 2001, R. Itoh leg.

Other specimens examined. One female, Mt. Iwate –san, Takizawa –mura, Iwate Prefecture, 39º50'29"N, 141º01'22"E, 1080 m elevation, litter of a forest dominated by Q. crispula , 28-VI-1985, O. Nakamura leg.; 1 female , Bato –machi, Tochigi Prefecture, 36º45'57"N, 140º08'52"E, 150 m elevation, litter of a forest dominated by Quercus serrata , 8-VII-2002, Y. Hagiwara leg.

Description. Body length 605 µm (605–852 µm). Head 104 (96–107) µm long, 80 (68–84) µm wide. Setae and sensilla on head similar to the preceding species ( Figs. 27A, C, F); seta sp 1.3 (1.2–1.7) times longer than p; seta rs inflated, as long as sr ( Fig. 27B). On galea ( Fig. 27D) digit O longer than M and I, M and I close to each other. Mandible with 3 teeth ( Fig. 27E). Clypeal apodemes distinct ( Figs. 27A, B). Pseudoculus circular ( Fig. 27F), 11 (9–11) µm long, PR = 9 (9–11).

Foretarsus length ( Figs. 27G–I) 69 (59–71) µm; claw 15 (14–16) µm, TR = 4.9 (4.4–5.1); empodium as long as claw, 15 (13–16) µm, EU = 1.0; sensillum s slightly longer than claw, 16 (16–17) µm. Sensillum t1 closer to α 3 than to α 3 ', BS = 0.9 (0.8–0.9); t2 thinly spatulate; t3 broadened, reaching base of α 7; a not reaching base of γ 2; b spatulate; c reaching nearly to base of γ 3; d broadened, surpassing base of α 6; e and g roundedly spatulate and long; f1 thinly spatulate; f2 reaching base of γ 5; a' at same level with α 3; b'1 nearer to δ 3' than to δ 4', slightly broadened and almost reaching base of δ 4'; b'2 thin; c' absent. Length of middle tarsus 36 (29–38) µm, length of claw 11 (9– 11) µm; hind tarsus 45 (36–45) µm, claw 11 (10–13) µm; both empodia short ( Figs. 27J, K), 3 (1–2) µm long; on hind tarsus ( Fig. 27K) D2 and D4 spine-like, but more slender than D5.

Tracheal camerae distally contracted ( Fig. 27L). Central lobe trapezoidal and inner line constricted in middle ( Fig. 27M). Laterostigmata II–IV large, with no inner structure; those on V–VII small. On female squama genitalis ( Fig. 27N) S-shaped sclerotization on processus sternalis, caput processus of duck’s head-type, filum processus long. Male unknown.

Chaetotaxy as in Table 11. On thoracic tergites II–III, P1a seta-like, posterior to P1–P2; P2a seta-like, nearer to P2 than to P3. P1a on abdominal tergite I, P1a and P2a on II–VI and P2a on VII filiform and longer than P1; P1a on VII sensillum-like and about one-third length of P1, posterior to P1–P2; on tergite VIII P1a' oblong and anterior to P2 ( Fig. 27O); P1a' and P2 nearly the same level with M4; P2a linear. Setae 1 and 2 on abdominal tergite XI microchaetae. A pair of ventral anterior setae on telson small and sensillum-like.

Diagnosis. The present species is similar to E. brevicorpusculum Yin and E. dissimilis Yin from China ( Yin 1965, 1979, 1999) in many respects, but this new species is different in the absence of foretarsal sensillum c' (present in the latter two). Moreover the present species is different from E. brevicorpusculum in having four pairs of anterior setae on abdominal tergites V–VI (five pairs in E. brevicorpusculum ), and from E. dissimilis in three pairs of anterior setae on the abdominal tergite VII (four pairs in E. dissimilis ) and the length of foretarsal sensillum b'1 reaching nearly to base of δ 4' (not reaching base of δ 4 in E. dissimilis ). The present species is also similar to E. udagawai , E. taiwanense Nakamura, 1997 from Taiwan ( Nakamura, 1997) and E. pusillum Ewing from Michigan, Florida and Carolina, USA ( Ewing, 1940; Bernard, 1990), but it is easily distinguished by the long empodium on the hind tarsus (short in this new species).

Chaetotaxic variations observed consisted of the asymmetric absences of P1 on the abdominal tergite III in one female and A3 on the abdominal sternite III in another female from Mt. Fuji .

Etymology. The specific name is the Latin word for “unequal” and referes to the long inclusion of this species in E. udagawai and its allies.

Distribution. Japan (Honshu).