Eosentomon mizushimai Nakamura, 2010

Nakamura, Osami, 2010, Taxonomic revision of the family Eosentomidae (Hexapoda: Protura) from Japan 2701, Zootaxa 2701, pp. 1-109 : 73-76

Eosentomon mizushimai Nakamura sp. nov.

Figs. 42–43; Table 17

Type specimen. Holotype female ( NSMT –Ap 509), Komi, Iriomote Island , Okinawa Prefecture, 24º19'28"N, 123º54'09"E, litter from evergreen broad-leaved forest, 20 m elevation, 2-III-2002, S. Nagashima leg.

Description. Body length 890 µm. Head length 129 µm. Setae aa, pa and m4 present, sensilla as and ps present ( Fig. 42A); seta sp 1.2 times longer than p; sensilla pp rudimentary. Labral setae present ( Fig. 42B). Seta rs inflated, shorter than sr ( Fig. 42B). On maxillary palpus ( Fig. 42C) sensillum md as long as ml. On galea ( Fig. 42D) digit O longer than M and I; I thicker than M. Mandible with three teeth ( Fig. 42E). Clypeal apodemes indistinct. Pseudoculus 16 µm long, without inner structure ( Fig. 42F), PR = 8.

Foretarsus length ( Figs. 42G, H) 86 µm; claw 17 µm, TR = 5.2; empodium 16 µm, EU = 0.9; sensillum s slightly longer than claw, 18 µm. Sensillum t1 slightly nearer to α 3 than to α 3', BS = 1.2; t2 thin; t3 thin, surpassing base of α 7; a not reaching base of γ 2; b linear; c surpassing base of γ 3; d basally broadened, surpassing base of t3; e and g roundedly spatulate and long; f1 thin; f2 slightly broadened; a' surpassing level of β 2; b'1 absent; b'2 thin; c' very broadened, reaching praetarsus. A pore close to α 3' as well as y. Length of middle tarsus 41 µm, length of claw 13 µm; hind tarsus 47 µm, claw 14 µm; empodia of both tarsi short ( Fig. 42I), 3 µm long; on hind tarsus ( Fig. 42I) D2 and D4 spine-like, but D4 slightly more slender than D2.

Tracheal camerae short and broadened ( Fig. 43A). Central lobe sinuate ( Fig. 43B). Laterostigmata II–IV distinct ( Fig. 43C), II–III with a central spot, IV without inner structure. On female squama genitalis ( Fig. 43D) caput processus of duck’s head-type, filum processus long, proximo-lateral sclerotization distinct. Male unknown.

Chaetotaxy as in Table 17. On thoracic tergites II–III, P1a and P2a seta-like, posterior to P1–P2. P1a on abdominal tergite I, P1a and P2a on II–VI and P2a on VII filiform and longer than P1 ( Fig. 43E); P1a on VII sensillum and less than one-eighth length of P1, at hind margin ( Fig. 43F); on tergite VIII ( Fig. 43G) P1a' with basal dilatation and slightly anterior to P2; P2a linear.

Diagnosis. This new species belongs to the kumei -group ( Tuxen, 1964). It is similar to E. kumei from Japan ( Imadaté, 1974b, 1995; Imadaté & Yosii, 1959) and E. dusun Imadaté from Borneo ( Imadaté, 1965b) in lacking the inner structure of pseudoculus and foretarsal sensillum b'1, and having two pairs of anterior setae (A4, A5) on abdominal tergites VI–VII, a single row of seven posterior setae on abdominal sternite VIII, and four setae on abdominal sternites IX–X. The new species differs from E. kumei and E. dusun in having five pairs of anterior setae on abdominal tergite IV (four pairs in E. kumei and E. dusun ). This species is clearly separated from E. kumei by the length of foretarsal sensillum a surpassing level of β 2 (very short, not reaching level of β 2 in E. kumei ) and the position of P1a posterior to P1–P2 on the abdominal tergite VII (at same level with P1–P 2 in E. kumei ); and from E. dusun by the long,very broadened sensillum c’ and basally broadened sensillum d on the foretarsus (short and thin c’ and thin d in E. dusun ), and P1a longer than P1 on abdominal tergites II–VI (short in E. dusun ).

Etymology. The specific name is dedicated to Dr. Hiroki Mizushima, who kindly loan and offer of materials from Ryukyu Islands, including the present new species.

Distribution. Japan (Okinawa, known only from the type locality).