Medionops, Sánchez-Ruiz, Alexander & Brescovit, Antonio D., 2017

Sánchez-Ruiz, Alexander & Brescovit, Antonio D., 2017, A new genus with seven species of the Subfamily Nopinae (Araneae, Caponiidae) from the Neotropical region, Zootaxa 4291 (1), pp. 117-143: 119-122

publication ID

publication LSID

persistent identifier

treatment provided by


scientific name


new genus

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 2View FIGURE 2 E, 20C), by the crista being extremely short, almost unnoticeable ( Figs 3View FIGURE 3 G, J; 15E, F) or absent ( Figs 9View FIGURE 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 1EView FIGURE 1; 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 2View FIGURE 2 B, C). Carapace uniformly orange, elongate, oval, widest at rear of coxae II, only gradually narrowed anterior of eyes ( Figs 6View FIGURE 6 A,B); pars cephalica not elevated; pars thoracica slightly sloping posteriorly, with slight submarginal depressions opposite intercoxal spaces ( Fig. 2View FIGURE 2 A); few dorsally directed strong bristles on clypeus ( Fig. 2View FIGURE 2 B); thoracic groove absent. Eyes dark, situated on slightly elevated black ocular tubercle, separated by about half of its diameter ( Fig. 2View FIGURE 2 C), set back from anterior margin of clypeus by about twice their diameter ( Fig. 2View FIGURE 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. 2View FIGURE 2 G); pick on prolateral side of palpal femur, situated near proximal end of podomere ( Fig. 19CView FIGURE 19). Endites orange except anterior tips with white membranous projection ( Figs 10View FIGURE 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 2View FIGURE 2 E; 20C), covered with scattered long setae, and with strong distal serrula consisting of a single tooth row ( Fig. 2View FIGURE 2 F). Labium orange, broad, rounded, fused to sternum along posterior groove, rebordered in apical part ( Figs 2View FIGURE 2 D –E; 10C; 20C). Sternum orange, oval, surface with numerous long, stiff setae ( Fig. 2View FIGURE 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. 10View FIGURE 10 C). Legs orange, formula 4123, without spines; metatarsi entire, with dorsal metatarsal stopper ( Figs 3View FIGURE 3 D, F; 4E; 11F; 15C), anterior legs with crista extremely short, not reaching one fourth of metatarsus length ( Figs 3View FIGURE 3 G, J), or almost unnoticeable ( Figs 15View FIGURE 15 B – F), or completely absent as in the Brazilian species M. claudiae  n. sp. ( Figs 9View FIGURE 9 J –K) and M. murici  n. sp. ( Figs 11View FIGURE 11 C,D,F; 13B,C); gladius with the traditional shape among nopine ( Figs 3View FIGURE 3 D, G, J; 5G; 9K; 15E), but almost unnoticeable or absent in M. murici  n. sp. ( Figs 11View FIGURE 11 C, D, F; 13B, C); all tarsi bisegmented ( Figs 3View FIGURE 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 1EView FIGURE 1; 3B,E; 4D; 5J; 9E; 13D), unpaired claws elongated, dorsally reflexed on all legs, without teeth ( Figs 3View FIGURE 3 C; 4D, G, H; 11J –L) with small projections of the cuticle distributed dorsally on proximal part ( Fig. 4View FIGURE 4 H); unpaired claws associated with large, globose translucent arolium on all legs ( Figs 1EView FIGURE 1; 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 3View FIGURE 3 B, E; 4D; 5J; 9E, F, I; 11J; 13F, H), several other setae around pretarsal claws ( Figs 9View FIGURE 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 11View FIGURE 11 A, E), bases with semicircular rim bearing slight longitudinal ridges ( Figs 3View FIGURE 3 H; 4I); tarsal organ exposed, roundish, with marginal ring slightly pronounced ( Figs 3View FIGURE 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 5View FIGURE 5 I, L; 7C, F; 19I), with a tibial brush on prolateral side of palp, near distal end ( Figs 2View FIGURE 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 10View FIGURE 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 4View FIGURE 4 J –L, 7G –I, 13J –L, 16G –I). Six spinnerets in typical caponiid arrangement ( Figs 5View FIGURE 5 A, 12G), ALS with a single, major ampullate gland spigot in males ( Figs 5View FIGURE 5 C, 12H), PMS with 7–8 ampullate gland spigots ( Figs 5View FIGURE 5 E –F, 12I) and PLS with 10–12 ampullate gland spigots ( Figs 5View FIGURE 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 6View FIGURE 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 6View FIGURE 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 4View FIGURE 4 J –L, 7G –I, 13J –L, 16G –I).

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


Prirodonamen Muzej Skopje