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FIGURES 25–32. Chaetacis bandeirante new species. 25–30 in 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

FIGURES 25–32. Chaetacis bandeirante new species. 25–30, female paratype (IBSP 160897). 25–26, habitus: 25, dorsal view; 26, lateral view; 27–30, epigynum: 27, ventral view; 28, lateral view; 29, posterior view; 30, dorsal view, cleared. 31–32, female paratype (IBSP 29905). 31–32, epigynum: 31, posterior view; 32, dorsal view, cleared. Abbreviations: FD= fertilization ducts, LK= epigynum lateral keels, MP= posterior median plate, PB= spermathecae posterior bend, S= spermathecae. Scale bars: 24–26, 1mm; 27–32, 0.1mm.

FIGURES 20–24. Chaetacis bandeirante new species. 20–23, male holotype. 20–21 in 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

FIGURES 20–24. Chaetacis bandeirante new species. 20–23, male holotype. 20–21, habitus: 20, lateral view; 21, dorsal view. 22–23, left palp: 22, mesal view; 23, retrolateral view. 24, male holotype and female paratype (IBSP 160897) drawn to scale to show sexual dimorphism. Abbreviations: BP=basal projection of the median apophysis, C=conductor, CL=conductor lobe, CM= conductor basal membrane, Cy= cymbium, DL= dorsal lobe of the paracymbium, E= embolus, M= median apophysis, R= radix, RL= retrolateral lobe of the paracymbium, Te= tegular projection, Ti= tibia. Scale bars: 20–21, 1mm; 22–23, 0.1mm.

FIGURES 14–16. Micrathena gaujoni Simon, 1897 in 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

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, 1mm; 16, 0.1mm.

FIGURES 9–13. Micrathena yanomami new species, female holotype. 9–10 in 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

FIGURES 9–13. Micrathena yanomami new species, female holotype. 9–10, habitus: 9, lateral view; 10, dorsal view. 11–13, epigynum: 11, lateral view; 12, ventral view; 13, posterior view. Abbreviations: L=lobe, MP=posterior median plate. Scale bars: 9–10, 1mm; 11–13, 0.1mm.

FIGURE 8 in 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

FIGURE 8. First two components of a PCA of the measurements taken from Micrathena excavata individuals in different developmental stages. Males are represented by open squares and females by closed circles. The number close to each symbol indicates the instar. 1=postjuveniles, 2=subadults, 3=adults (males), subadults II (females), 4=adults (females).

FIGURES 1–7 in 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

FIGURES 1–7. Micrathena excavata (C.L. Koch, 1836), ontogenetic series. 1–3, male: 1, postjuvenile; 2, subadult; 3, adult; 4–7, female: 4, postjuvenile; 5, subadult I; 6, subadult II; 7, adult. All figures drawn to scale. Scale bar: 1mm.

FIGURES 39–40 in 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

FIGURES 39–40. Chaetacis bandeirante new species, male paratype (UFMG 4889). 39, male left palp, mesal view; 40, paracymbium, retrolateral view. Abbreviations: BP=basal projection of the median apophysis, C= conductor, CL= conductor lobe, CM= conductor basal membrane, DL= dorsal lobe of the paracymbium, E= embolus, M= median apophysis, R= radix, RL= retrolateral lobe of the paracymbium, Te= tegular projection. Scale bars: 39, 0.2mm; 40, 0.1mm.

FIGURES 17–19 in 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

FIGURES 17–19. Micrathena ruschii (Mello-Leitão, 1945), male (UFMG 4987). 17–18, habitus: 17, lateral view; 18, dorsal view. 19, mirror image of right palp, mesal view. Abbreviations: BP= basal projection of the median apophysis, C= conductor, CL= conductor lobe, Cy= cymbium, E=embolus, M=median apophysis, PM= paramedian apophysis, R= radix, TA= terminal apophysis, Ti= tibia. Scale bars: 17–18, 1mm; 19, 0.1mm.

FIGURES 33–38. Chaetacis bandeirante new species. 33–37 in 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

FIGURES 33–38. Chaetacis bandeirante new species. 33–37, female paratype (UFMG 4889). 33, female carapace, dorsolateral view; 34, cephalic tubercle, dorsolateral view; 35, abdominal setal bases, ventral view; 36–37, epigynum: 36, ventral view; 37, posterior view; 38, female (IBSP 48980), spermathecae, dorsal view. Abbreviations: B=epigynal bulge, CT=cephalic tubercle, Di= dimple, FD= fertilization ducts, Fo= thoracic fovea, LK= epigynum lateral keels, MP= posterior median plate, PB= spermathecae posterior bend, S=spermathecae, SF= stridulating files of the booklung cover. Scale bars: 33, 1mm; 34, 35, 38, 0.1mm; 36, 37, 0.2mm.

FIGURE 41 in 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

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 33–41 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figures 33–41. Species included in this study. Fig. 33. Micrathena spinosa, female internal genitalia, dorsal, cleared. Fig. 34. Micrathena horrida, female internal genitalia, dorsal, cleared. Fig. 35. Micrathena fissispina, female internal genitalia, dorsal, cleared. Fig. 36. Micrathena schreibersi, female internal genitalia, dorsal, cleared. Fig. 37. Chaetacis aureola, male first tibia, lateral. Fig. 38. Micrathena schreibersi, male palpus, retrolateral. Fig. 39. Micrathena bifida, male palpus, mesal. Fig. 40. Micrathena swainsoni, male palpus, apical. Fig. 41. Micrathena bifida, male palpus, retrolateral. Abbreviations: BP, basal projection of the median apophysis; C, conductor; CL, conductor lobe; CM, conductor basal membrane; Cy, cymbium; DP, digitiform projection of the median apophysis; E, embolus; MA, median apophysis rim; MAL, median apophysis lobe; Me, metatarsus; P, paracymbium; Pa, patella; PH, paracymbium hump; PM, paramedian apophysis; R, radix; S, spermathecae; SP, spermathecae projections; ST, subtegulum; Ta, tarsus; TA, terminal apophysis; TAP, terminal apophysis projection; Ti, tibia; TM, tibial macrosetae; TP, tegular projection. Scale bars = 0.1 mm except 40 = 0.5 mm.

Figures 26–32 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figures 26–32. Species included in this study. Fig. 26. Micrathena furcata, female carapace, dorsal. Fig. 27. Micrathena digitata, female sternum, ventral. Fig. 28. Micrathena spitzi, female sternum, ventral. Fig. 29. Micrathena spinosa, female sternum, ventral. Fig. 30. Micrathena digitata, abdomen end, lateral. Fig. 31. Micrathena lepidoptera, female abdomen, ventral. Fig. 32. Micrathena spinosa, epigynum and booklungs, ventral. Abbreviations: EP, epigynum sclerotized plate; LMA, large median apodeme; LPB, lateral pigmented bands; MPS, median pigmented stripe; PSL, posterior spine lobe; SA, small apodeme; SpA, spinnerets apodeme; SR, spinnerets sclerotized ring; ST, spinnerets tubercle; VS, ventral spines. Scale bars: 26, 29, 30, 31, 32 = 1 mm; 27, 28 = 0.5 mm.

Figures 22–25 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figures 22–25. Scanning electron microscopy images of species included in the current study. Fig. 22. Wagneriana dimastophora, male copulatory bulb, mesal. Fig. 23. Micrathena nigrichelis, female eye region, dorsolateral. Arrow indicates the post-ocular macroseta. Fig. 24. Gasteracantha. cancriformis, female carapace, dorsolateral. Fig. 25. Micrathena plana, female carapace, dorsolateral. Abbreviations: ALE, anterior lateral eye; AME, anterior median eye; BL, bulb length; BW, bulb width; C, conductor; CH, cephalic hump; E, embolus; LSR, lateral setae rows; MA, median apophysis rim; P, pleura; PLE, posterior lateral eye; PM, paramedian apophysis; PME, posterior median eye; R, radix; TA, terminal apophysis; TF, thoracic fovea; TP, tegular projection.

Figures 18–21 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figures 18–21. Scanning electron microscopy images of species included in the current study. Fig. 18. Chaetacis aureola, female fourth leg, ventral. Fig. 19. Micrathena horrida, epigynum, and book lung covers, anterolateral. Circles indicate anterior apodemes. Fig. 20. Micrathena nigrichelis, epigynum, subventral. Fig. 21. Micrathena nigrichelis, male copulatory bulb, mesal. Abbreviations: BP, basal projection of the median apophysis; C, conductor; CL, conductor lobe; CO, copulatory openings; CS, coxal spines; E, embolus; EL, epigynum lobe; FSB, femoral setal bases; LP, epigynum lateral plates; MA, median apophysis rim; PM, paramedian apophysis; R, radix; SF, booklung stridulating files; TA, terminal apophysis; TB, epigynum transverse bar; TP, tegular projection.

Figure 10 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figure 10. Optimization of the lengths of the first (left) and second (right) pairs of posterior spines under a squaredchange parsimony model. Values are expressed as a proportion of carapace length. Darker values indicate greater lengths and the scale is the same for both traits. Spines are considered to be extremely elongated if longer than the carapace. Micrathena spiders are highlighted by the grey background.

Figure 11 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figure 11. Optimization of female (left) and male (right) carapace lengths under a squared-change parsimony model. Values are expressed in millimetres. Darker values indicate greater lengths and the scale is the same for both sexes. The greater the difference of tone between males and females, the higher the sexual size dimorphism for a given species. Micrathena spiders are highlighted by the grey background.

Figure 7 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figure 7. Character optimizations of the discrete data set in the tree obtained through implied-weighted parsimony (k = 5). Character numbers are indicated above circles and character states are indicated below circles. Filled circles indicate convergence-free apomorphies, open circles represent homoplasious synapomorphies. For character descriptions, see Appendix 1. The grids near the nodes represent a sensitivity analysis using different values of k; open cells represent presence of the corresponding clade in a given weighting scheme, whereas filled cells represent its absence. Different Micrathena species groups are indicated by the alternating background colour. Scale bar = 2.0 mm. All spiders (females at left, males at right) drawn to scale and printed approximately at natural sizes. Continued in Figs 8 and 9.

Figures 5–6. Optimal trees obtained under Bayesian analyses. Fig. 5. Mkv model. Fig. 6 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figures 5–6. Optimal trees obtained under Bayesian analyses. Fig. 5. Mkv model. Fig. 6. MkvG model. Posterior probabilities values are indicated below branches.

Figures 3–4. Optimal trees obtained under parsimony analyses. Fig. 3 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figures 3–4. Optimal trees obtained under parsimony analyses. Fig. 3. Unweighted analysis [length = 575.3; consistency index (CI) = 0.305; retention index (RI) = 0.693]. Fig. 4. Implied weighted analysis (k = 5; length = 579.718; fit = 105; CI = 0.303; RI = 0.689). Bremer supports and symmetric resampling values are indicated below and above branches, respectively. Symmetric resampling values are given in frequency differences (GC; Goloboff et al., 2003).

Figures 1–2. Abdominal spine homology and measurements taken for this study. Fig. 1 in Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

Figures 1–2. Abdominal spine homology and measurements taken for this study. Fig. 1. Chaetacis bandeirante, female habitus, dorsal. Arrows indicate primary apodemes. Fig. 2. Chaetacis bandeirante, female habitus, lateral. Abbreviations: AS, anterior spine; AW, abdomen width; CL, carapace length; CW, carapace width; ES, eye interdistance; FL, femur length; FSL, first posterior spine length; LS1, first lateral spine; LS2, second lateral spine; LS3, third lateral spine; PS1, first posterior spine; PS2, second posterior spine; PS3, third posterior spine; RW, rim width; SCL, spinneret cone length. Scale bars = 1 mm.