Medionops new genus

Type species. Medionops blades new species.

Other species included. Medionops cesari (Dupérré) n. comb., Medionops claudiae n. sp., Medionops murici n. sp., Medionops ramirezi n. sp., Medionops simla (Chickering) n. comb. and Medionops tabay n. sp.

Etymology. The generic name is a combination of the words Medio (= meaning half in Spanish) and Nops, and is masculine in gender.

Diagnosis. Members of the genus can be distinguished from all currently known nopine genera Cubanops Sánchez-Ruiz, Platnick, Dupérré, Nops MacLeay, Nopsides Chamberlin, Nyetnops Platnick & Lise, Orthonops Chamberlin and Tarsonops Chamberlin by the shape of the endites with acute lateral projections extending dorsally on the outer sides (Figs 2 E, 20C), by the crista being extremely short, almost unnoticeable (Figs 3 G, J; 15E, F) or absent (Figs 9 K; 11D; 13B, C), and by having all pretarsi with elongated and dorsally reflexed unpaired claws, associated with a large and globose arolium (Figs 1E; 3B, C, D; 4A, B, D; 5H, J, K; 9E, F; 11B, G, J–L; 13D, E).

Description. Medium–sized caponiids with two eyes (Figs 2 B, C). Carapace uniformly orange, elongate, oval, widest at rear of coxae II, only gradually narrowed anterior of eyes (Figs 6 A,B); pars cephalica not elevated; pars thoracica slightly sloping posteriorly, with slight submarginal depressions opposite intercoxal spaces (Fig. 2 A); few dorsally directed strong bristles on clypeus (Fig. 2 B); thoracic groove absent. Eyes dark, situated on slightly elevated black ocular tubercle, separated by about half of its diameter (Fig. 2 C), set back from anterior margin of clypeus by about twice their diameter (Fig. 2 B). Chelicerae orange, with median lamina; most of distance between lamina and fang base occupied by white membranous lobe; cheliceral paturon with scattered, long, weak bristles; ectal side with stridulatory ridges (Fig. 2 G); pick on prolateral side of palpal femur, situated near proximal end of podomere (Fig. 19C). Endites orange except anterior tips with white membranous projection (Figs 10 C; 20C), wide, convergent along midline but not touching, with middle part slightly wider than distal and proximal, with acute projections extending dorsally on the outer sides (arrows in Figs 2 E; 20C), covered with scattered long setae, and with strong distal serrula consisting of a single tooth row (Fig. 2 F). Labium orange, broad, rounded, fused to sternum along posterior groove, rebordered in apical part (Figs 2 D–E; 10C; 20C). Sternum orange, oval, surface with numerous long, stiff setae (Fig. 2 D); pleural membrane with three sclerotized intercoxal extensions between coxae I and II, II and III, and III and IV, long precoxal triangles on coxae II–IV (Fig. 10 C). Legs orange, formula 4123, without spines; metatarsi entire, with dorsal metatarsal stopper (Figs 3 D, F; 4E; 11F; 15C), anterior legs with crista extremely short, not reaching one fourth of metatarsus length (Figs 3 G, J), or almost unnoticeable (Figs 15 B– F), or completely absent as in the Brazilian species M. claudiae n. sp. (Figs 9 J–K) and M. murici n. sp. (Figs 11 C,D,F; 13B,C); gladius with the traditional shape among nopine (Figs 3 D, G, J; 5G; 9K; 15E), but almost unnoticeable or absent in M. murici n. sp. (Figs 11 C, D, F; 13B, C); all tarsi bisegmented (Figs 3 B, D; 4A, E; 5G; 9E; 11A, B); pretarsus with three claws, paired claws usually with 5–8 teeth, most distal of which are largest (Figs 1E; 3B,E; 4D; 5J; 9E; 13D), unpaired claws elongated, dorsally reflexed on all legs, without teeth (Figs 3 C; 4D, G, H; 11J–L) with small projections of the cuticle distributed dorsally on proximal part (Fig. 4 H); unpaired claws associated with large, globose translucent arolium on all legs (Figs 1E; 3B, C, D; 4A, B, D; 5H, J, K; 9E, F; 11B, G, J–L; 13D, E); with numerous ventral frictional setae on tarsi (Figs 3 B, E; 4D; 5J; 9E, F, I; 11J; 13F, H), several other setae around pretarsal claws (Figs 9 F–H; 13E, F, G, I). Sense organs scanned only in M. blades n. sp. and M. murici n. sp. Tibiae, metatarsi, and tarsi with trichobothria in single row (Figs 11 A, E), bases with semicircular rim bearing slight longitudinal ridges (Figs 3 H; 4I); tarsal organ exposed, roundish, with marginal ring slightly pronounced (Figs 3 I, L; 4C, F; 11H–I); slit sensillae on tibiae, metatarsi and tarsi. Male and female palpal tarsus elongated, without claw, retrolateral and ventral surfaces densely covered with strong setae; with oval pad of fine chemoreceptor setae on dorsal, distal part (Figs 5 I, L; 7C, F; 19I), with a tibial brush on prolateral side of palp, near distal end (Figs 2 I; 5I; 7B; 9A; 12B; 19B, L). Abdomen dorsally with pattern of lines, spots, chevrons or bands; almost unnoticeable in M. tabay n. sp. and M. ramirezi n. sp.; ventrally immaculate (Figs 10 B; 20B), lighter, with only slightly sclerotized epigastric and postepigastric scutum, with two pairs of respiratory spiracles clustered around epigastric groove; anterior spiracles leading to wide, short tracheal trunk ending in numerous long tracheoles; posterior spiracles leading to two large tracheal trunks extending anteriorly into cephalothorax (inner trunks connected), plus single, much narrower trunk extending posteriorly for most of abdominal length and few short, small tracheoles extending posteriorly (Figs 4 J–L, 7G–I, 13J–L, 16G–I). Six spinnerets in typical caponiid arrangement (Figs 5 A, 12G), ALS with a single, major ampullate gland spigot in males (Figs 5 C, 12H), PMS with 7–8 ampullate gland spigots (Figs 5 E–F, 12I) and PLS with 10–12 ampullate gland spigots (Figs 5 A–B, 12G). Male palpal morphologywith short patella; tibia excavated ventrally; cymbium elongated, not swollen, distal surface acuminate; bulb globose, oval, originating near proximal ventral surface of cymbium, with very long embolus ventrally directed, protruding dorsally from proximal–posterior prolateral surface of bulb making strong curvature near its base toward ventral part of animal (Figs 6 D; 8D; 10D; 14D; 17D; 18D; 20D), with elaborate tip. External female genitalia with a weakly sclerotized anterior plate, strong sclerotization around spiracles and on outer ends of posterior receptaculum (noticeable by transparency) (Figs 6 C; 8C; 14C; 17C; 18C). Internal female genitalia consisting of transverse, wide, anteriorly directed, weakly sclerotized receptaculum (r); most of species with sinuous distal margin of receptaculum (dmr) with median concavity (mc); proximal margin associated with a dorsally projected internal fold (if), sometimes along with posterior plate (pp); uterus externus (ue) anterior to receptaculum, membranous and anteriorly directed (Figs 4 J–L, 7G–I, 13J–L, 16G–I).

Distribution. South America and Panamá (Fig. 21).