Isotomiella macedoi de Mendonça, MC, Abrantes, EA, Neves & Acr 2012

Total body length of the holotype 0,74 mm. Habitus typical of the genus. Color white. Integument without craters. Pseudopores and integument channels not observed. Antennae subequal to head diagonal. Length of Ant I to IV (30 µm, 40 µm, 40 µm, 65 µm). Ant IV with one conspicuous tulip-shaped microsensillum with three or four small spines at apex protected by a curved chaeta, six broad and subequal sensilla, eight supplementary very thin sensilla (seven dorsal external, six dorsal internal and one shorter and thicker dorsal). Ant III with about 35-40 ordinary chaetae, two small sensory rods (3 µm), three guard sensilla (7 µm) and one short sensillum below (Fig. 1). Ant II with about 40 smooth ordinary chaetae, 2 basal microsensilla, one dorsal and one ventral, and one dorso-lateral sensillum (Fig. 2). Ant I with 14 smooth ordinary chaetae, two lateral ciliated chaetae, two ventral and unequal sensilla (10 µm and 4 µm) and two basal microsensilla, one dorsal and one ventral. Labral chaetae pattern 4/5,5,4, the third row with two lateral acuminate chaetae and the last row with two anterolateral chaetae strongly thickened (Fig. 3). External lobe of maxilla with bifurcate palp and four sublobal chaetae (Fig. 4). All chaetae of head smooth. Axial chaetotaxy pattern from Th II to Abd IV as 20,14/6,6,6,6 by half tergite. Th II with 1+1 lateral ciliated macrochaetae (45 µm) and 3+3 lateral sensilla (5 µm). Th III with 1+1 lateral ciliated macrochaetae (50 µm) and 2+2 lateral sensilla (5 µm); all the other chaetae smooth (Fig. 5). Abd I with 1+1 lateral ciliated macrochaetae (40 µm) and 2+2 ciliated chaetae (30 µm) between the lateral macrochaetae; sensilla absent. Abd II with 1+1 lateral ciliated macrochaetae (40 µm) and 2+2 ciliated chaetae between lateral macrochaetae; sensilla absent and without the lateral area devoid of chaetae. Abd III with 2+2 anterior ciliated chaetae (35 µm) and 2+2 posterior ciliated chaetae (35 µm ) between the lateral ciliated macrochaetae (40 µm), 1+1 ventral sensillum (5 µm). Abd IV with many ciliated chaetae (35-50 µm) and few smooth chaetae, 3+3 posterior sensilla (11 µm). Abd V-VI with several ciliated macrochaetae of different sizes (60-75 µm) and few smooth chaetae, 1+1 long and thick dorso-lateral sensillum (spl) with apex slightly curved (20 µm), 3+3 dorso-lateral sensilla sa, spe, spi (11 µm) and 1+1 ventral sensillum sv (5 µm) (Fig. 6). Dorso-lateral sensillary pattern of the body 3,2/0,0,1,2,5 (Fig. 7) Subcoxa I of legs I, II, III with 2, 3, 2 ciliated chaetae. Femur III with tenent hair smooth and two ciliated chaetae (Fig. 8). Tibiotarsus III strongly thickened on males, with about 40 smooth chaetae and 2 thin erect stick-like chaetae (10 µm); on females the tibiotarsus III are normal without stick-like chaetae. Unguis plump (20 µm) and unguiculus (10 µm) lanceolated (Fig. 9). Ventral tube (45 µm) with 4+4 anterior, 2+2 posterior and 4+4 distal chaetae (Fig. 10). Tenaculum with 4+4 teeth and 1 chaeta. Subcoxae anterior with 15 chaetae of which one ciliated; subcoxae posterior with 9 chaetae of which 6 ciliated (Fig. 11). Manubrium (55 µm) with 5+5 ventro-distal, 4+4 lateral, and 12+12 dorsal smooth chaetae. Dens long, (125-130 µm) crenulated, with about 40 anterior and 6 posterior smooth chaetae. Mucro small (7 µm), tridentate, the 2 basal teeth symmetrical (Fig. 11-12). Male genital plate as in Fig. 13.