Yanomamius n. gen., a new genus of tarantula from Brazilian and Venezuelan Amazon (Araneae, Theraphosidae), with description of three new species Author Bertani, Rogério 0000-0002-8186-8316 Instituto Butantan, Laboratório de Ecologia e Evolução, Av. Vital Brazil, 1500 CEP 05503 - 900, São Paulo, SP, Brazil. bertani. rogerio @ gmail. com; https: // orcid. org / 0000 - 0002 - 8186 - 8316 bertani.rogerio@gmail.com Author Almeida, Marlus Queiroz Instituto Nacional de Pesquisas da Amazônia, Laboratório de Sistemática e Ecologia de Invertebrados do Solo, CEP 69060 - 001, Av. André Araújo, Manaus, AM, Brazil. text Zootaxa 2021 2021-02-22 4933 3 324 340 journal article 7981 10.11646/zootaxa.4933.3.2 92979f75-7e46-49c9-ad01-d17939694c30 1175-5326 4554920 2DAB754B-1029-4D55-A4F5-DA3205DF679F Yanomamius n. gen. ( Figs 1 – 50 ) Holothele Karsch, 1879: 544 (in part, H. waikoshiemi Bertani & Araújo, 2006 , holotype female deposited at UCV, examined). Guyruita Guadanucci, Lucas, Indicatti & Yamamoto, 2007: 992 (in part, G. waikoshiemi ( Bertani & Araújo, 2006 )) ; World Spider Catalog, 2020. Type species. Yanomamius franciscoi n. sp. Diagnosis. Males of Yanomamius n. gen. resemble those of Schismatothele and Euthycaelus by having several short spines closely positioned at the distal retrolateral palp tibia ( Figs 13 , 33 , 48 ). They differ by the embolus tapering to its tip ( Figs 7–9 , 27–29 , 42–44 ) and by the spines in the distal retrolateral palp tibia disposed in a group, instead of in one ( Schismatothele ) or two ( Euthycaelus ) rows. Females differ from all other schismatotheline genera by the incrassate tibia I in adults ( Fig. 17 ). Etymology . The generic name is a homage to the Yanomami Indians. The distribution of the species of the genus on the Guiana Shield largely overlaps the territory of the Yanomamis. Furthermore, the first known species was found in a study on the food resources used by Yanomamis and Yekuanas. The genus is masculine in gender. Description. Carapace longer than wide, caput raised, cephalic and thoracic striae conspicuous. Fovea procurved (females) or slightly procurved (males). Clypeus short (females) or absent (males). Eight eyes arranged on tubercle, anterior eye row straight, posterior slightly recurved. Intercheliceral intumescence absent. Rastellum absent. Labium: rectangular with 141–401 cuspules (females), 423–728 cuspules (male). Labiosternal groove shallow, flat, with pair of sigilla. Maxillae: 153–198 cuspules (females), 167–272 cuspules (males) on upper mound in inner angle. Heel distinct. Anterior lobe distinct, short. Lyra absent. Short, black, spiniform setae on parts of palp and legs trochanters, maxillae and coxae of females. Sternum: Three pairs of sigilla, ovals, all ca. one diameter from margin. Book lung combs absent. Urticating setae absent. Legs: formula IV-I-II-III (males), I=IV-II-III or I-IV-II-III (females). Preening combs absent. Clavate trichobothria in two rows. Claws: ITC absent. STC bare on all legs (females), or with two very small teeth on all or only on the III-IV legs (males); 1 bare claw on female palp. Tarsi II–IV, III–IV with medial ventral weakness (cracked) (males) or integral (females). Scopulae of tarsi III–IV of males and females and palp of females divided by broad band of setae. Spinnerets: Apical segment of PLS digitiform. Male tibial apophysis with two processes, a small protuberance or a series of ridges behind the retrolateral process. Male palp tibia with distal 16–28 spines on retrolateral aspect, in a compact group. Metatarsus I narrow, pallid, weakly sclerotized, when folded it touches the retrolateral process tip ( Y. neblina n. sp. ), or passes without touching it (other species). Tibia I of adult females incrassate. FIGURES 1–6. Y. franciscoi n. sp. from Ducke Reserve, Manaus, state of Amazonas, Brazil. 1–3 paratype female (INPA 9085). 1. carapace and chelicerae. 2. eye tubercle. 3. sternum, labium, maxillae and coxae. 4–6 holotype male (INPA 9084). 4. carapace and chelicerae. 5. eye tubercle. 6. sternum, labium, maxillae and coxae. Scale bars = 1 mm. FIGURES 7–14. Y. franciscoi n. sp. from Ducke Reserve, Manaus, state of Amazonas, Brazil. 7–13 holotype male (INPA 9084). 7–9 left bulb. 7. retrolateral. 8. prolateral. 9. dorsal 10–12 left tibial apophysis. 10. ventral. 11. prolateral. 12. retrolateral. 13. left palp, retrolateral. 14. paratype female (INPA 9085), spermathecae. The arrows indicate the ridges behind the retrolateral process of tibial apophysis. Scale bars = 1 mm. Male palp: bulb pyriform, embolus thick, short or slightly elongate with two parallel prolateral keels in all species and an additional ventral keel in Y. neblina n. sp. Cymbium triangular in retrolateral view, with short incision. Spermathecae: two, each weakly sclerotized, with distal constriction, apical well sclerotized cluster of lobules and a well sclerotized subdistal or median lobule or cluster of lobules. Distribution. Brazil and Venezuela ( Fig. 50 ). Key for species of Yanomamius n. gen. (Male of Y. waikoshiemi is unknown)