Mysmenopsis nadineae new species

Figs 4, 5, 12A

Type material. 1♁ holotype. BRAZIL: Amazonas, Careiro, 15.VII.2007, E.H. Wienskoski leg. (INPA) . Paratype. BRAZIL: Same data, 1♀ (INPA) .

Etymology. The specific epithet is a patronym in honor of Nadine Dupérré, arachnologist who made a major contribution to the taxonomy of Mysmenopsis, describing 25 species, almost half of the known diversity of the genus.

Diagnosis. Males of Mysmenopsis nadineae n. sp. resemble those of M. snethlageae n. sp. (Figs 7A–D) M. huascar Baert, 1990 (Figs 18–21 in Baert, 1990) and M. palpalis (Kraus, 1955) (Figs 83–84 in Kraus, 1955) by the very bulky palpal tibia, at least one and a half times wider than the tegulum, but differ by the presence of nine cusps on the retroapical margin of the tibia and by the embolus as long as broad, subquadrate in ventral view (Fig. 5C). While M. snethlageae n. sp. lack cusps and has embolus with slender and curved apex, M. huascar has two cusps and has embolus longer than wide and M. palpalis has six cusps and embolus slender with a slender embolic apophysis. Females resemble those of M. pachacutec Baert, 1990 (Figs 7–8 in Baert, 1990), M. fernandoi Dupérré & Tapia, 2015 (Figs 16–17 in Dupérré & Tapia, 2015), and M. tepuy Dupérré & Tapia, 2020 (Figs 142–143 in Dupérré & Tapia, 2020) by the presence of an invagination at the posterior margin of the epigynum, creating two acuminate posterior ends (Fig. 5E); they differ by the narrower and deeper epigynal invagination (Fig. 5E), which is broader in M. pachacutec and M. tepuy and shallower in M. fernandoi, and by the junction of the spermathecae with the copulation duct forming an elongated structure, about three times longer than wide, with a fold at the retrolateral end (Fig. 5G), while M. fernandoi and M. pachacutec has spherical spermatechae and M. tepuy has spermathecae directed anteriorly and laterally.

Description. Male holotype: Total length: 1.48; carapace length: 0.61; carapace width: 0.65; abdomen length: 0.83; abdomen width: 0.81. Cephalothorax: carapace dark brown, pear-shaped, with a central black spot (Fig. 4). Sternum dark brown. Clypeus brown, high (3x AME). Chelicerae brown. Eyes: eight, rounded, AME approximately 1.5x larger than the others, which are approximately equal size; ocular region on protuberance; AME separated by their diameter; AME–ALE touching; ALE–PLE contiguous; PLE–PME separated by their diameter; PME separated by their diameter. Abdomen: suboval, grey covered with long setae dorsally, dorsal region with white rounded spots distributed in a circle (Figs 4A, C) followed by two transversal rows of white patches (Fig. 4C). Legs: orange, patella, tibiae and metatarsi I–IV with ventral darker bands apically, femora III–IV with a median ventral darker band. Leg spination: tibia I with one apical prolateral clasping spur; metatarsus I with one subapical prolateral curved clasping spur, row of six macrosetae prolaterally (Fig. 5D). Total length leg I: 2.42 (0.63/0.20/0.67/0.44/0.48); leg II: 2.26 (0.66/0.17/0.50/0.50/0.43); leg III: 1.86 (0.59/0.13/0.38/0.38/0.38); leg IV: 2.03 (0.51/0.18/0.51/0.46/0.37). Genitalia (Figs 5A–C): tibia very bulky, about one and a half times wider than the tegulum, with nine retroapical cusps, ventral pedicel; cymbium with truncated apical region and with large sclerotized basal plate with and small basal projection, paracymbium cylindrical; embolus as long as wide, subquadrate in ventral view.

Female paratype (INPA): Total length: 1.74; carapace length: 0.77; carapace width: 0.68; abdomen length: 1.10; abdomen width: 1.00. Cephalothorax (Fig. 4B), sternum, chelicerae, clypeus, eyes, abdomen (Figs 4B, D) and legs: shape and coloration as in male. Total length leg I: 2.69 (0.78/0.24/0.68/0.51/0.48); leg II: 2.48 (0.70/0.2 3/0.58/0.49/0.48); leg III: 2.12 (0.60/0.22/0.44/0.42/0.44); leg IV: 1.82 (0.58/0.20/0.39/0.30/0.35). Genitalia (Figs 5E–G): epigynum protuding, ventral plate sclerotized, posterior margin with median invagination; posterior plate sclerotized; internal genitalia with copulation ducts anteriorly positioned with poorly defined proximal region; spermathecae elliptical, wider than long.

Distribution. Only known from the type locality.

Natural History. No data available.