Micrathena gaujoni Simon, 1897

Magalhães, Ivan L. F. & Santos, Adalberto J., 2011, Two new species and taxonomic notes on the Neotropical spiny orb-weaving spiders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata, Zootaxa 2983, pp. 39-56 : 45-46

Micrathena gaujoni Simon, 1897

Figures 14–16 , 41

Micrathena gaujoni Simon, 1897: 466 . Five female syntypes from Loja, Ecuador, deposited in MNHN 7832, not examined. Levi 1985: 478.

Diagnosis. Males of M. gaujoni differ from all other Micrathena with a coxal hook by having an extremely long embolus projecting above the terminal apophysis and lying in a very large conductor, which occupies most of the tegulum in mesal view ( Fig. 16 ). This species is most similar to M. pilaton Levi (Levi 1985 : fig. 24), from which it differs by having a much larger terminal apophysis. For the female diagnosis see Levi (1985: 478).

Description. Male from Estación Biológica Yanayacu, Ecuador, (UFMG 3355). Carapace light brown, with a dark brown band on each side ( Fig. 14 ). Chelicerae, endites, labium and sternum brown. Legs yellow proximally, brown distally. Dorsum of abdomen white with a median pattern of dark brown markings ( Fig. 14 ); venter dark brown. Carapace with oval thoracic region, narrowest behind, a circular fovea and no dimples ( Fig. 14 ). First coxa with hook and second femur with corresponding prolateral groove. Tibiae and femora I and II markedly ornamented with macrosetae on the dorsal surface; tibia II with two ventral rows of robust macrosetae, femur II with a single, median, ventral row of macrosetae ( Fig. 15 ). Abdomen rectangular, elongated, with slightly convex sides and six tiny posterior lobes ( Fig. 14 ). Total length, 5.07. Carapace 2.02 long, 1.37 wide at widest point. Abdomen 3.11 long. Length of first femur, 1.75; patella, 0.61; tibia, 1.29; metatarsus, 1.13; tarsus, 0.59. Second femur, 1.61; patella, 0.55; tibia, 1.09. Third femur, 1.02; patella, 0.35; tibia, 0.57. Fourth femur, 1.88; patella, 0.5; tibia, 1.11; metatarsus, 1.13; tarsus, 0.55. Palp with a large, undulated, twisted terminal apophysis, from which a drop-shaped membranous projection hangs. Embolus extremely long and filiform, projecting over the tegulum. Conductor very large, serving as a bed to the embolus, and attached to a pointed, sclerotized paramedian apophysis. Median apophysis comprised of three parts: a large, inverted U-shaped, basal projection, a lobe and a bended rim ( Fig. 16 ). Paracymbium large and bilobed, otherwise unmodified.

Female. Described by Levi (1985: 478).

Notes. The described male has both palps with fully expanded basal hematodochae. The described male and three other sub-adult, apparently co-specific males were collected in the same expedition and in the same area as many adult and juvenile females of M. gaujoni were. No other Micrathena of the kirbyi or guerini groups were collected in the same expedition. This represents a new record for this species ( Fig. 41 ).

Natural history. The specimens were collected in an area of tropical rainforest, in the understory vegetation. Material examined. ECUADOR. Napo: Cosanga, Estación Biológica Yanayacu (0º35’57S 77º53’26”W, 2128m ASL), A. J. Santos coll., 24–30/XI/2009, 13, 8Ƥ, 5 juveniles ( UFMG 3355).

Figures

FIGURE 41. Geographic distribution records for Micrathena yanomami new species and Chaetacis bandeirante new species, and new records for M. gaujoni, M. ruschii and C. necopinata.

FIGURES 14 – 16. Micrathena gaujoni Simon, 1897, male (UFMG 3355). 14 – 15, habitus: 14, lateral view; 15, dorsal view. 16, left palp, mesal view. Abbreviations: BH = basal hematodocha, BP = basal projection of the median apophysis, C = conductor, Cy = cymbium, E = embolus, M = median apophysis, PM = paramedian apophysis, R = radix, TA = terminal apophysis, TP = terminal apophysis projection. Scale bars: 14 – 15, 1 mm; 16, 0.1 mm.