A new genus of Micromygalinae (Araneae, Microstigmatidae) from Brazil, with transfer of Masteriaemboaba Pedroso, Baptista & Bertani, 2015 and description of six new species Author Passanha, Victor Author Cizauskas, Igor Author Brescovit, Antonio D. text ZooKeys 2019 814 1 32 http://dx.doi.org/10.3897/zookeys.814.29906 journal article http://dx.doi.org/10.3897/zookeys.814.29906 1313-2970-814-1 387658E351B748FB843EBA532D350F43 387658E351B748FB843EBA532D350F43 Tonton gen. n. Type species. Tonton itabirito sp. n. Etymology. The generic name is derived from the Indian Krenak word "ton-ton" , and means small. The Krenak Indians, also known as Botocudos or Aimores and inhabited mainly southeastern Brazil, with great occupation in areas of the state of Minas Gerais. The generic name is neuter. Diagnosis. Species of the genus Tonton differ from those of Micromygale , the only representative of Micromygalinae (see Platnick and Forster 1982 : figs 12-15, 23-26), by having four spinnerets (Fig. 2B, D), while Micromygale have six (see Platnick and Forster 1982 : fig. 24), lack a paraembolic apophysis on male palpal bulb (Fig. 1F), present in Micromygale (see Platnick and Forster 1982 : figs 12-15), having bilobed spermathecae (Fig. 4 E-F ), in Micromygale unilobed (see Platnick and Forster 1982 : figs 27-28), hav ing a pulmonar opening (Fig. 2C), absent in Micromygale , and the lack of an abdominal shield (Fig. 2B), present in Micromygale (see Platnick and Forster 1982 : fig. 23). Figure 1. Tonton spp. morphological characters. A serrula, lateral view B tarsal claw, retrolateral view C tricobothrium, dorsal view D detail of serrula and projected palpal coxae, ventral view E tarsal organ, dorsal view F detail of slender tricobothria, leg I. Scale bars: 20 μm (A); 30 μm (B); 5 μm (C); 20 μm (D); 5 μm (E); 300 μm (F). Figure 2. Tonton spp. morphological characters. A body coloration in dorsal view ( T. ipiau sp. n.) B body coloration in ventral view ( T. ipiau sp. n.) C booklung opening, ventral view ( T. ipiau sp. n.) D spinnerets, ventral view ( T. ipiau sp. n.) E, F detail of cuticle in T. emboaba (cephalothorax, dorsal view and Leg I, prolateral view). Scale bars: 1mm (A); 1mm (B); 50µm (C); 200µm (D); 100µm (E); 200µm (F). Description. Small-sized mygalomorph spiders, total length 1.80-3.04. Coloration: carapace in dorsal view, chelicerae, legs varying from whitish to light yellow. Palpal coxae, labium, sternum whitish to light yellow. Abdomen whitish or light yellow (Fig. 2A, B). Clypeus narrow (0.02-0.06), absent in T. itabirito sp. n. Chelicerae without rastellum. Basal segment of chelicerae with prolateral row of 6-14 teeth, 4-10 mesobasal teeth aligned (Fig. 7H). Absence of ocular tubercle, with six eyes (lateral eyes vestigial) (Fig. 6A) or absence of eyes, having only a vestigial ocular spot ( T. itabirito sp. n.) (Fig. 4A); anterior/posterior row slightly recurved, AME absent. Labium wider than long, without cuspules. Palpal coxae with short anterior lobe, bearing serrula with teeth clumped in series of several rows on distal border (Fig. 1A, D). Sternum oval, longer than wide, without visible sigilla. Legs with one row of tricobothria on tarsi/metatarsi (dorsal); two on dorsal tibia. Tarsus without scopulae, with sensorial setae thin, slightly interspaced or thick, abundant. Superior tarsal claws with one row of teeth (6-14), inferior tarsal claw present on all legs, with 1-5 teeth (Fig. 1B). Tricobothria filiform, with corrugated base, with keels until half of extension (Fig. 1C, F). Abdomen with ovate pulmonar opening (Fig. 2C). Posterior median spinneret short with spigots on apex. Posterior lateral spinneret three-segmented, long, apical segment with triangular apex, spigots present on ventral face (major ampulate, aciniform, and pumpkiniform spigots) (Fig. 2D). Female palp varying from 2-7 ventral spines tarsal basis, tarsal claw with one central row of 11-15 teeth (Fig. 6C). Male palp: cymbium with 4-6 apical spines (Fig. 7D), prolateral lobe (Figs 3E, 7D) and one row of trichobothria on tarsi and two on tibia; palpal tibia with one discreet row of retrolateral setae, on medial region (Fig. 5E), excavated in distal median area (Fig. 5E); piriform bulb (oval in T. queca sp. n.); elongated embolus almost length of the bulb (Fig. 10C). Female genitalia: two spermathecae, with two lobes each side, internal lobe long, external lobe short (Fig. 6D), except T. ipiau sp. n., almost as long as external lobe (Fig. 10 F-G ). Distribution. Cave and mountainous region of the state of Minas Gerais and states of Bahia (Atlantic forest) and Maranhao (Brazilian cerrado).