Bulboctenus gen. nov.

Type species. Bulboctenus kayapo sp. nov.

Etymology. The generic name is a contraction of the words “bulbo” (Portuguese word for “bulb”) and “ctenus”, from the type genus Ctenus . It refers to the presence of bulbous setae on the male legs III and IV. The gender is masculine.

Diagnosis. Bulboctenus males are distinguished from those of other Cteninae by the following characters: median apophysis oriented retrolaterally, perpendicular to the tegulum longitudinal axis (Figs 1A, 10 A–C); RTA strongly excavated anteriorly (Figs 1B, 10B); the presence of bulbous setae in metatarsus III and IV ventrally (Figs 2, 18A); and thick setae on the sternum and coxae, slightly thinner in females (Fig. 3). Bulboctenus females are distinguished from those of other Cteninae by the following characters: median sector of the epigyne hexagonal (Fig. 1D); the presence of two posterior conical projections (PLP) in the median sector ventrally (Fig. 1D); and elevated lateral margins of the median sector, forming a concavity next to the copulatory openings (Fig. 1D).

Description. Medium sized ecribellate spiders. Total body length (males and females): 7.78–9.22. Carapace piriform, more accentuated in females, reddish brown, varying in specimens between lighter or darker (Figs 9, 11, 13). Thoracic groove longitudinal, in the posterior third of the carapace (Figs 4F, 9, 11, 13). Eyes: 2-4-2 ctenoid pattern (Fig. 4A), with the anterior and posterior row recurved in dorsal view (Figs 9, 11, 13). Eyes round, except the oval ALE (Fig. 4A). Clypeus with long, erect black bristles. Chelicerae: coloration like the carapace. Chelicerae promargin with three teeth, median twice as large as laterals, retromargin with four teeth of similar size, and intermarginal denticles (Fig. 4D). Cheliceral basal boss prominent. Endites three times longer than labium (Fig. 5), with external lateral margins slightly excavated, and dense apical scopula (Fig. 4B). Serrula subapical (Fig. 4C). Maxillary glands clustered, labral tongue present (Fig. 4B). Labium short, as long as wide, with rounded tip and dense apical scopula (Figs 4B, 5). Sternum oval, not extending between legs IV (Fig. 5). Trochanters deeply notched (Fig. 5). Tibiae I and II with five pairs of ventral spines, and metatarsi I and II with three pairs of ventral spines. Metatarsi III and IV with bulbous setae, conical, grooved longitudinally, with a flatted tip that might extend into a small projection distally (Figs 2, 18A). Trichobothrial bases transversely ridged (Fig. 6D). Capsulated tarsal organ with dropshaped opening (Fig. 6C). Tarsi with two pectinated claws with tufts of adhesive tenent setae inserted on moving plates (CT) in males and females (Fig. 6A, B). Female palp with pectinated claw, apical teeth elongated (Fig. 4E). Opisthosoma oval, light brown ventrally, dark brown dorsally, with a lighter central longitudinal band and numerous erect black bristles (Figs 9, 11, 13). Six spinnerets, no colulus (Fig. 7). ALS (Figs 7, 8A, D) and PLS (Figs 7, 8C, F) with two segments, PMS with one segment (Figs 7, 8B, E). ALS field with PI spigots interspersed with tartipores (Fig. 8A, D). ALS with a pair of large MAP spigots on the inner side, one reduced to a nubbin (Fig. 8A, D). PMS with small AC spigots (Fig. 8B, E), two large apical mAP spigots in females (Fig. 8E), without paracribellar spigots, and one large apical mAP spigot with a nubbin in males (Fig. 8B). Female PMS have additional large CY spigots, with conical bases and long, conical shafts (Fig. 8E). PLS conical apical segment with numerous AC spigots (Fig. 8C, F), and CY spigots (Fig. 8F) in females. Male palp (Figs 1 A–C, 10A–C, 12A–C, 17A–C): tibia straight, short (more than two thirds the size of the cymbium) (Fig. 10 A–C); RTA strongly sclerotized, with wide base and rounded tip, excavated anteriorly (Figs 1B, 10 A–B); ventral tibial process (VTP) short and round (Figs 1B, 10A); cymbium drop-shaped ventrally, with ventrobasal depression to accommodate the VTP, retrolateral cymbial process (RCP), and posterior dorsal projection (Figs 10 A–C, 15A–C); subtegulum enlarged prolaterally, visible next to the embolus (Fig. 15A); tegulum suboval, with spermatic duct visible medially (Fig. 15 A–C); embolus and median apophysis in a median hyaline area of the bulb (Fig. 15 A–C); embolus wide with rectangular base and rounded tip, slightly curved retrolaterally (Fig. 15 A–C); median apophysis cup-shaped, excavated laterally (Fig. 15 A–C); conductor hyaline, wider than long, fixed by the center, guiding the tip of the embolus (Fig. 15 A–C). Epigyne (Figs 1D, 10D, 12D, 17D): divided into median (MS) and lateral sectors (Fig. 1D); copulatory opening located anteriorly, on the elevated lateral margins of the median sector (Fig. 1D); lateral sectors with elongated and robust lateral projections (LP) medially, extending until the posterior margin of the epigyne (Fig. 1D). Vulva (Figs 1E, F, 10E, 12E, 14E, 17E): straight copulatory ducts (Fig. 16E); short fertilization ducts, originating at the base of the spermathecae (Fig. 16E); spermathecae small and round (Fig. 16E).

Composition. Bulboctenus kayapo sp. nov.; Bulboctenus itunaitata sp. nov., and Bulboctenus munduruku sp. nov.

Distribution. State of Pará, Brazil, in the cities of Santarém, Vitória do Xingú, Altamira and Novo Progresso (Fig. 19).