Pseudanisentomon parvum Nakamura, 2010

Nakamura, Osami, 2010, Taxonomic revision of the family Eosentomidae (Hexapoda: Protura) from Japan 2701, Zootaxa 2701, pp. 1-109 : 16-19

Pseudanisentomon parvum Nakamura sp. nov.

Figs. 8–9; Table 3

Type specimens. Holotype female ( NSMT –Ap 454), Tochimoto, Otaki, Chichibu –shi, Saitama Prefecture, 900 m elevation, 35º56'57"N, 138º53'47"E, 1-V-1991, Y. Kuwabara leg. Paratypes: 4 males ( NSMT –Ap 455–458) , 3 females ( NSMT –Ap 459–461), same data as for the holotype .

Description. Body length 943 (780–988) µm. Head 97 (91–100) µm long, 62 (60–66) µm wide. Setae aa, pa and m4 present, sensilla as and ps present ( Fig. 8A); seta sp 1.3 (1.2–1.3) times longer than p; sensilla pp distinct ( Fig. 8B). Labral setae present ( Fig. 8C). Seta rs inflated, equal to sr in length ( Fig. 8C). On maxillary palpus ( Fig. 8D) sensillum md slightly longer than ml. On galea ( Fig. 8E) digit O slightly longer than M and I, M and I equal length, but I slightly broadened distally. Mandible with three teeth ( Fig. 8F). Clypeal apodemes indistinct. Pseudoculus almost circular, (8–9 µm long), inner depressions very weak and often invisible ( Fig. 8G), PR = (12–13).

Foretarsus length ( Fig. 8H, I) 64 (63–69) µm; claw 12 (11–12) 12 µm, TR = 5.4 (5.9–6.2); empodium slightly shorter than claw, 10 (9–11) µm, EU = 0.8 (0.8–0.9); sensillum s slightly longer than claw, 13 (12–13) µm. Sensillum t1 closer to α 3 than to α 3', BS = 0.9 (0.8–0.9); t2 thin; t3 slightly broadened; a not reaching base of γ 2; b and c surpassing level of β 6; d slightly broadened; e absent; f1 spatulate; f2 thin and small; g rounded-spatulate and long; a' not reaching level of α 3'; b'1 nearer to δ 3' than to δ 4'; b'2 thin; c' considerably longer than t3, reaching base of α 7. Length of middle tarsus 26 (26–28) µm, length of claw 11 (9–10) µm, empodium about 1/2 of claw length ( Fig. 8J), 5 (5–6) µm long; hind tarsus 34 (33–36) µm, claw 11 (9–11) µm, empodium longer than 2/3 of claw length ( Fig. 8K), 8 (7–8) µm; on hind tarsus ( Fig. 8K) D2 seta-like; D4 spine-like, but slender than D5.

Tracheal camerae slender and long ( Fig. 9A). Central lobe trapezoidal and inner line incised ( Fig. 9B). Laterostigmata II–III distinct, without inner structure ( Fig. 9C). On female squama genitalis ( Fig. 9D) caput processus of duck's head type, corpus processus dissolved and rod-like, lateral sclerotization distinct, filum processus long. Male genitalis with long basiperiphallar setae ( Fig. 9E).

Chaetotaxy as in Table 3. On thoracic tergites II–III, P1a and P2a seta-like; P1a posterior to P1–P2; P2a 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, about a half length of P1, at hind margin ( Fig. 9F); on tergite VIII ( Fig. 9G) P1a' oblong and anterior to P2; P1a' and P2 at almost same line between M2 and M4; P2a linear.

Diagnosis. Among the congeneric species, this new species is similar to Ps. sininotialis Zhang & Yin and Ps. minystigmum (Yin) from China ( Yin, 1979, 1999; Zhang & Yin, 1984) in possessing foretarsus shorter than 80 µm, foretarsal sensillum b'1, the long empodia on hind and middle tarsus, a pair of anterior setae on abdominal sternite VIII, and six setae on sternites IX–XI. However, this species is distinguished from the above two by the inner structure of pseudoculus without striae (three distinct striae in latter two), five pairs of anterior setae on abdominal tergite IV (four pairs in latter two) and the length of foretarsal sensillum c' longer than t3 (shorter than t 3 in latter two).

Etymology. The specific name refers to the relatively small size of this species.

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