Nasutonops, Brescovit, Antonio D. & Sanchez-Ruiz, Alexander, 2016

Brescovit, Antonio D. & Sanchez-Ruiz, Alexander, 2016, Descriptions of two new genera of the spider family Caponiidae (Arachnida, Araneae) and an update of Tisentnops and Taintnops from Brazil and Chile, ZooKeys 622, pp. 47-84 : 58-59

Taxon classification Animalia Araneae Caponiidae

Nasutonops gen. n.

Type species.

Nasutonops xaxado sp. n.

Etymology.

The generic name comes from the Latin words nasutus (with a large nose) combined with nops (less eyes), and is masculine in gender.

Diagnosis.

Males and females can be easily distinguished from all other known caponiids by the presence of a clypeal horn, projected distally (Fig. 8A, C, J). The genus resembles species of Caponina by having the palp with a globose bulb and an elongate and curved embolus in males (see Platnick 1994, figs 26-28) and by having a similar pair of boomerang-shaped sclerotized bars in the female genitalia (see Platnick 1994, figs 22-25); however, it differs by the flattened base of the embolus originating from the distal area of the male bulb (Fig. 11 D–E), rather than the median area as in Caponina . The female differs by the strongly sclerotized transverse internal fold of the female genitalia, which is observed by transparecy on the posterior border of the anterior plate (Figs 8K, 11 A–B, F–I; 12 H–J), which is not apparent in any Caponina species. These three structures support the monophyly of Nasutonops .

Description.

Moderate-sized caponiids with six eyes (Fig. 8A, G–H, J). Carapace oval, anteriorly narrowed to half its maximum width, pars cephalica depressed behind cephalic area, depressed between coxa of endite and coxa I, pars thoracica medially higher than laterally or posteriorly, gradually sloping laterally and posteriorly (Fig. 8B); cuticle smooth; few dorsally directed strong bristles on the clypeal area; carapace smooth; thoracic groove almost absent (Fig. 8A, G). Clypeal horn, distally conic, striated anteriorly and posteriorly, shorter in females (Figs 8C, J; 9 A–F; 10 E–F, H–J). Six eyes, medians largest and more elevated than laterals (Figs 8C, 9 A–B), dark, separated by almost their radius, surrounded by black pigment; laterals white and oval, posteriors half the size of anteriors (Figs 8J, 10I). Cheliceral paturon with long and strong bristles medially (Figs 9E, 10F); base of fang unmodified; median lamina short, with irregular anteromedian tip; most of the space between the lamina and base of fang occupied by white membranous lobe; lateral surface with large stridulatory ridges in males and females (Figs 9G; 10G), pick on prolateral side of palpal femur, triangular, situated at approximately one-fifth of femur length (Figs 10K, 11 C–D). Endites convergent, acuminate, not touching, covered with many long basal setae that shorten distally (Fig. 8I), with strong and long distal serrula consisting of a single tooth row with more than 20 teeth (Fig. 9H). Labium triangular, fused to sternum, covered with many scattered setae (Fig. 8 H–I); labrum short, narrow, slightly elevated. Sternum longer than wide, smooth, without radial furrows between coxae, covered with scattered long setae, not fused to carapace (Fig. 8I); cephalothoracic membranes without epimeric sclerites, but long triangular sclerites extend from sternum between coxae I and II, II and III, and III and IV, shorter triangles extend to each coxae. Leg formula 4123; legs without spines; metatarsi and tarsi entire, without subsegmentation or membranous processes; tarsi with three claws; paired claws with approximately ten teeth (more on leg I-II), distal teeth largest; unpaired claw shorter than paired ones, with five minuscule teeth (Fig. 10 A–B). Tibiae with trichobothria in a double row, metatarsi and tarsi with trichobothria in single row, bases almost smooth, with strong external border (Fig. 10C); tarsal organ exposed, oval, not elevated, consisting of two oval, sclerotized laminae (Fig. 10D); female palpal tarsus elongate, prolateral surface densely covered with setae, without claw (Figs 10L; 12C). Abdomen immaculate and pilose; epigastric plate sclerotized (Figs 8 G–H; 12 A–B), two pairs of small respiratory spiracles. Six spinnerets (Figs 8L, 12G) in typical caponiid arrangement, anterior laterals shorter than posterior laterals, with one major ampullate gland spigot and at least three smaller piriform gland spigots; posterior medians with single, very thick, medially situated spigot presumed to serve minor ampullate gland, and 5-6 smaller, more peripheral spigots arranged in a ring, presumed to serve aciniform glands; posterior laterals with 8-10 central and peripheral aciniform gland spigots. Male palpal femur twice the length of the tibia, patella shorter than the tibia, unmodified; cymbium ovoid, prolateral surface densely covered with strong setae; bulb globose; embolus long, curved at base, flattened, with small teeth in the distal third, narrowed distally, with sinuous tip (Figs 8 B–F; 9 I–L). External female genitalia with large, rectangular, sclerotized anterior plate, and postepigastric scutum represented by a pair of narrowed sclerites, represented by a transparent area on an internal strongly sclerotized trasverse fold on the posterior border of the anterior plate (Figs 8K; 12 F). Internal female genitalia consist of a pair of boomerang-shaped sclerotized bars, that may or may not converge anteriorly, associated with the uterus externus short but with a wide base occupying almost the entire width of the sclerotized bars; strongly sclerotized transverse fold runs along nearly all of the epigastric area, reaching the posterior ends of the sclerotized bars (Figs 11 A–B, F–I; 12 H–J).

Distribution.

Known only from Brazilian Caatinga in the states of Bahia and Pernambuco, Brazil.