M. Brian Traw.
A revision of the neotropical orb-weaving spider genus Scoloderus (Araneae: Araneidae).
Psyche 102(1-2):49-72, 1995.

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A REVISION OF THE NEOTROPICAL ORB-WEAVING SPIDER GENUS SCOLODERUS (ARANEAE: ARANEIDAE) Museum of Comparative Zoology
Harvard University
Cambridge, Massachusetts 02 138*
More than one-fourth of the spiders examined for this revision were collected since the neotropical genus Scoloderus was revised in 1976. Thirteen names have been proposed for what appear to be five valid species (Scoloderus cordatus, S. gibber, S. nigriceps, S. tuberculifer, and S. ackerlyi). These species are distinguished by the presence or absence of abdominal humps on the female, the shape of the median apophysis of the male palpus, and the shape of the scape of the female epigynum. Abdominal coloration and pat- tern are highly variable and unreliable for identification. One new species, Scoloderus ackerlyi, is described on the basis of a single, unique female from Belize.
The orb-weaving genus Scoloderus (Simon, 1887) consists of five species, one of which is new. The genus is primarily neotropi- cal in distribution, although individuals have been recorded as far north as Georgia, United States and as far south as Rio Negro, Argentina.
Scoloderus spiders, as adults, spin very tall, rectangular webs. The most detailed information about Scoloderus web structure is known from observations of S. tuberculifer in Colombia (Eberhard, 1975). At the base is an orb-web. Radii on the upper half of the orb-web extend vertically up to 1.0 m forming a long rectangle. *Correspondence: Section of Ecology and Systematics, Corson Hall, Cornell Uni- versity, Ithaca, NY 14853. Email: mbt @ cornell.edu. Manuscript received 30 March 1995.
49




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50 Psyche 1~01. 102
Spiders spin their webs in the late evening and tear them down each morning. These webs have been hypothesized to facilitate the capture of moths. When moths strike the upper part of the web, they tumble down, losing scales along the way. By the time they reach the bottom the moths have lost so many scales that they stick to the web (Eberhard, 1975; Stowe, 1978). The first Scoloderus species described were placed in Hypoph- thalma (Taczanowski, 1879), having the type species H. deplanata Taczanowski. Simon (1887) found the name Hypophthalma preoc- cupied and determined that the species placed by Taczanowski in Hypophthalma actually belonged in two genera. The species con- sidered in this paper were ones that were placed in a new genus Scoloderus (Simon, 1887), having the type species H. cordata. The other species were placed in the genus Hypognatha Gukrin- Mkneville, having the type species H. feisthameli (=H. scutata) (Simon, 1895). Early descriptions of Scoloderus species (including S. cordatus, S. tuberculifer, S. nigriceps, S. normalis, S. hybus, S. birabeni, S. intermedius, and S. nigrocellatus) were based solely upon female specimens. One species, S. eresimorpha, was described on the basis of a single immature male (Taczanowski, 1879). Only 5'. americana and S. gibber were described with information on males. Unfortunately, the male holotype of S. gib- ber has since been lost and was not available for this revision. Abdominal pattern and coloration were important criteria for these early descriptions.
Upon discovering that abdominal coloration and pattern were highly variable in Scoloderus, Levi (1976) synonymized all Scoloderus names under either S. cordatus or S. tuberculifer. Levi's classification was based on differences in the structure of the scape of the female epigynum and the median apophysis of the male palpus. The difficulty of placing the many recently collected specimens of Scoloderus has prompted this revision. Scoloderus gibber (0.P.-Cambridge) and S. nigriceps (0.P.-Cambridge) are resurrected from Levi's (1976) synonymization. Scoloderus gibber and S. nigriceps are distinguished by the genitalia, as well as by the presence or absence of abdominal humps. Additionally, this study includes information on the structure of the male palpus of Scoloderus based upon examination under a scanning electron microscope. The palpal structure of Scoloderus



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has previously eluded accurate description due to the small size and transparency of some parts.
METHODS AND MATERIALS
Specimens were examined primarily under a dissection micro- scope for this revision. Eye sizes, distances between eyes, and clypeus height were all recorded in units of anterior median eye diameter (AME). The techniques for measuring and drawing spider body parts followed a standard method for spider genus revisions (Levi, 1993). The male palpi of four species were examined through both a dissecting microscope and a scanning electron microscope. The SEM photographs were of right palpi. In this paper, SEM photographs are printed in reverse to render them comparable to illustrations of left palpi. Specimens for this revision were generously loaned from the following collections:
AD
AMNH
BMNH
CAS
FSCA
IRSNB
MACN
MCN
MCZ
MEG
MUSM
A. Dean Collection, Texas A and M University, Col- lege Station, Texas, United States
American Museum of Natural History, New York, United States; N. Platnick, L. Sorkin
British Museum (Natural History), London, Great Britain; P. Hillyard
California Academy of Sciences, San Francisco, United States; C. Griswold, W. J. Pulawski, D. Ubick Florida State Collection of Arthropods, Gainesville, Florida, United States; G. B. Edwards
Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium; L. Baert
Museo Argentine de Ciencias Naturales, Buenos Aires, Argentina; E. A. Maury, C. L. Scioscia Museu de CiEncias Naturais, Porto Alegre, Rio Grande do Sul, Brazil; E. H. Buckup
Museum of Comparative Zoology, Cambridge, Mass- achusetts, United States; H. W. Levi
M. E. Galiano; Buenos Aires, Argentina
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima, Peru; D. Silva



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52 Psyche [VOI. 102
MZSP
Museu de Zoologia da Universidade de SZio Paulo, S5o Paulo, Brazil; P. Vanzolini, L. Neme, J. L. M. Leme
PAN
Polska Akademia Nauk, Warszawa, Poland; A. Slo- jewska, E. Kierych
I thank H. W. Levi for suggesting this project, providing helpful comments, and offering encouragement throughout. L. Leibensperger's logistical support and advice were greatly appreci- ated. L. Leibensperger, H. W. Levi, W. Piel, N. E. Gift, and two anonymous reviewers offered suggestions that improved the manu- script. This revision benefited greatly from illustrations drawn by H. W. Levi (Figs. 1-7, 11-14, 19, 20, 22, 23, 29-33) and his descriptions of previously examined types. Scanning electron microscopy was conducted at Harvard's Museum of Comparative Zoology with the help of R. L. Pinto.
Scoloderus Simon
Scoloderus Simon, 1887: 187. Type species by original designa- tion Hypophthalma cordata Taczanowski. The generic name is masculine.
Diagnosis. Scoloderus is close to Wixia (Levi, 1993) but has a bulging, helmet-shaped carapace (Fig. 2). The genus Carepalxis (Levi, 1992a) is also closely allied and has a bulging carapace, but one that is distinguished by two prominent knobs. Scoloderus species lack these knobs, although S. cordatus has two slight, angular projections on top of the bulge (Fig. 1). The pedicel of Scoloderus is generally attached to the posterior third of the abdomen (Fig. lo), unlike Carepalxis and Parawixia (Levi, 1993). However, pedicle attachment can be located more closely to the middle of the abdomen, as in S. cordatus (Fig. 2). The lip of the median apophysis of the male palpus (L in Fig. 7) is not exagger- ated in size as in Wixia (Levi, 1976) and Ocrepeira (Levi, 1993). Palpus of Scoloderus lacks the paramedian apophysis and general complexity of palpi in related genera Parawixia (Levi, 1992b) and Wixia (Levi, 1993). Scoloderus spiders are small (maximum total length, 4.5 mm) in comparison to species in the genus Carepalxis (maximum total length, 15.5 mm). The height of the Scoloderus



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carapace is an apomorphy. Other apomorphies include the attach- ment of the pedicel at the posterior third of the abdominal ventral region (Fig. lo), and a clypeus height of approximately two diame- ters of the anterior median eyes (Fig. 9). Description. Ocular quadrangle wider behind than in front (Fig. 1). Width of carapace behind posterior lateral eyes about 74 to 87% of width of thorax in females, 68 to 78% in males. Anterior and posterior margin of chelicerae with four and three teeth respec- tively. Epigynum of Scoloderus a lightly sclerotized, smooth plate with a lobe (Fig. 4). Lobe of epigynum shorter than half the width of basal plate. Coxa I of males with a hook protruding from its dis- tal margin. Tibia I1 of males thicker than tibia 1 with 5 to 10 macrosetae. Webs much longer than wide with orb at the base. Radii on the upper half of the orb-web extend vertically to form a rectangular ladder (Eberhard, 1975).
Note. The following parts of the median apophysis are used in identification: inner margin (IM in Fig. 7), lip (L in Fig. 7), spine (S in Fig. 16), and distal rim (DR in Fig. 7). The lip of the median apophysis is the area between the inner margin and the distal rim. Species differences. The species of Scoloderus are quite vari- able and often difficult to separate. Females are distinguished by the presence (Figs. 19, 28) or absence (Figs. 2, 10) of abdominal humps. The posterior scape of the epigynum can be reduced to a crescent (Figs. 4, 12), semicircular (Fig. 21), or narrow and pro- truding (Figs. 30, 39). Females have either a notched (Fig. 1) or flat (Fig. 9) surface at the top of the carapace hump. Males are sep- arated based on the shape of the lip of the median apophysis (L in Fig. 7). The lip of the median apophysis can either be broadly semicircular (Fig. 7), narrow (Fig. 25), or broadly rectangular (Fig. 33). The median apophysis can have a pointed distal tip (S in Fig. 16) or one that is rounded (Figs. 7, 25, 33). Distribution. All species come from tropical and subtropical America.
Key to females of Scoloderus species
1.
Scape of epigynum narrow with parallel
sides (Figs. 30, 39) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Scape of epigynum semicircular (Figs. 12, 21) or reduced to a crescent (Fig. 4) . . . . . . . . . . . . . . . . . . .3



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Psyche [Vol. 102
Width of epigynal scape at base roughly
one-third of width of basal plate at
attachment (Fig. 30); Mexico, Central and South America. (Map. 2) ............... .tuberculifer Width of epigynal scape less than
one-fifth of width of basal plate at
attachment (Fig. 39); Belize (Map. 2) ......... .ackerlyi Abdomen with paired humps (Figs. 19, 20) and shaped like a shield; United States, Mexico, Caribbean Islands (Map. 2) ........ .nigriceps Abdomen never with dorsal humps (Fig. 2); abdomen round and dark; legs often ringed; Mexico, Central and South America (Map. 1) ........ .4 Scape of epigynum broadly rounded (Fig. 4); carapace bulge often notched (Fig. 1) ........ .cordatus Scape of epigynum semicircular and
protruding (Fig. 12); carapace bulge
without notch (Fig. 9)
..................... .gibber
Key to males of Scoloderus species
The male of S. ackerlyi is not known
Palpus with median apophysis lip wide,
semicircular in shape (L in Figs. 7, 16); abdomen dark gray to green; clypeus
height greater than two diameters of anterior ....
median eyes; Mexico, Central and South America .2
Palpus with median apophysis lip narrow, rectangular in shape (Figs. 25, 33); abdomen white; clypeus height less than two diameters of anterior median eyes ......................... .3 Distal rim of median apophysis of palpus with a spine (S in Fig. 16) ................... gibber Distal rim of median apophysis of palpus without spine (DR in Fig. 7) ............... .cordatus Lip of median apophysis of palpus at
least two times longer than wide (Fig. 25); abdomen often with dorsal black stripe;
United States, Mexico, and Caribbean
islands (Map. 2) ........................ .nisriceus



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19951 Tra w
Lip of median apophysis of palpus less
than two times as long as wide (Fig. 33); abdomen with dark pigmented region on
dorsum; Mexico, Central and South
America (Map. 2) . . . . . . . . . . . . . . . . . . . . .tuberculifer Map 1. The distribution of Scoloderus cordatus and Scoloderus gibber.



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5 6 Psyche [vo~. 102
Map 2. The distribution of Scoloderus nigriceps, Scoloderus tuberculifer, and Scoloderus ackerlyi.
Scoloderus cordatus (Taczanowski)
Figures 1-8; Map 1
Hypophthalma ? cordata Taczanowski, 1879: 129, pi. 2, fig. 41, 9. Female holotype from Amable Maria [Tarma Prov., Depto. Junin], Peru, in PAN, examined and illustrated by H. W. Levi (unpublished).
Hypophthalma ? eresimorpha Taczanowski, 1879: 130, pi. 4, fig. 8, d'. Juvenile male holotype from Amable Maria [Tarma Prov., Depto. Juni'n], Peru, in PAN, examined and illustrated by H. W. Levi (unpublished).




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19951 Traw 57
Scoloderus cordatus: -Simon, 1887: 187. First placement of cor- datus in Scoloderus.
Carepalxis normalis Keyserling, 1892: 53, pi. 2, fig. 42, 9. Female holotype from Taquara, Rio Grande do Sul, Brazil, in BMNH, examined and illustrated by H. W. Levi (unpublished). Note: The question marks before the specific names are those of Taczanowski and probably refer to the doubtful placement in Hypophthalma.
Description. Female from Cuyabeno, Ecuador. Carapace dark brown. Chelicerae dark brown, darker distally. S ternum dark brown. Legs light brown. Abdomen round with white spot inside a blue-gray pigmented region on dorsum, giving the spider the appearance of a bird dropping. Sides of abdomen green-brown. Venter of abdomen, blue-gray. Posterior median eyes 1.3 anterior median eye diameters (AME), laterals 0.6. Anterior median eyes 1.0 AME apart, posterior median eyes 2.0 AME apart. Anterior and posterior median eyes 5.0 AME from laterals. Clypeus height 2.5 AME. Carapace hump notched (Fig. 1). Carapace very hairy (Fig. 2). Dorsum of abdomen without humps (Figs. 2, 3). Total length 3.6 mm. Carapace 1.6 mm long, 1.4 wide, 1.2 high. Ster- num length 0.7, width 0.8. First femur 1.3 mm, patella and tibia 1.3, metatarsus 0.8, tarsus 0.4. Second patella and tibia 1.2, third 0.8, fourth 1.2.
Male from Cuyabeno, Ecuador. Coloration as in female. Poste- rior median eyes 1.3 diameters of anterior medians, laterals 0.7. Anterior median eyes 1.0 AME apart, posterior medians 2.0 AME apart. Anterior and posterior median eyes 6.5 diameters from later- als. Clypeus height 4.0 AME. Abdomen round. Carapace with dense hair, without notch. Total length 2.3 mm. Carapace 1.3 mm long, 1.0 mm wide, and 0.9 mm in height. Sternum length, 0.5; width, 0.5. Median apophysis 0.1 mm long. First femur 1.0 mm, patella and tibia 1.2 mm, metatarsus 0.7, tarsus 0.4. Second patella and tibia 0.9 mm, third 0.5, fourth 0.8. Variation. Adult female total length 2.9 to 3.6 mm; width of carapace 1.2 to 1.7. Male total length 1.5 to 2.9 mm; width of cara- pace 1.0 to 1.4 mm. Legs sometimes ringed darker brown. Dorsum and sides of abdomen with variable patterns and coloration in both sexes.




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58 Psyche [VOI. 102
Diagnosis. Lip of median apophysis of male semicircular (L in Fig. 7), distal rim lacks spine of S. gibber (Fig. 16). Female is very difficult to distinguish from S. gibber female. The scape of S. cor- datus is shorter in length and more broadly rounded (Fig. 4) than that of S. gibber (Fig. 12). See diagnosis section of S. gibber description for a further comparison. Reliable identification of female S. gibber specimens requires the presence of males. Natural History. Specimens collected in night sweeps of vegeta- tion (B. Malkin, AMNH). Found in grass and scrub (G. B. Edwards, FSCA). A silken pouch containing 18 eggs was found in Loreto Province, Peru (G. B. Edwards, FSCA). Specimens Examined. MEXICO Jalisco: 6.7 km N Autlan, Mine Rd, 7 July, 1984, 9 (J. B. Woolley, AD); 24 km SW of Aut- lan, 15 July, 1983, 9 (P. K. Kovarik, T. L. Harrison and J. C. Schaffner, AD). Veracruz: Jalapa, 6 July, 1963, 9 (D. Bixler, MCZ). PANAMA Panama: Pipeline Road, 8 km NW Gamboa, 7 August, 1983, Q (H. W. Levi, MCZ). COLOMBIA Putumayo: Buena Vista, 23-29 July, 1972, 0, 9 (W. Eberhard, MCZ). SURINAM Marowijne: Anapaike Village at Lawa River, 8-29 November, 1963, 9; Benzdorp at Lawa River, 6 November, 1963, 0, $ (both B. Malkin, AMNH). ECUADOR Napo: Rio Puyo 900 m, 1 April, 1941, C? (W. Clarke, AMNH); 18 April, 1958, 9 (R. W. Hodges, MCZ). Sucumbi'os: Tarapoa, 23 June - 1 July, 1988, 9; Cuyabeno, Napo bridge between Tarapoa and Tipishca, 30 July, 1988, 0, $ (both W. Maddison, MCZ). Pichincha: 4 km NE of Pedro Vicente Maldonado, 9-12 July, 1988, 9 (W. Maddison, MCZ); W Cayambe 2300 m, 7 June, 1965, Q (L. E. Pefia, MCZ). Los Rios: Rio Palenque, 15 February, 1979, 9 (L. Burnham, MCZ); 14 March, 1982, C? (Y. Lubin, MCZ). PERU Loreto: Rio Manatee, 18 July, 1989, 8; Explorama Lodge 80 km NE Iquitos, 16-20 July, 1989, C? (both G. B. Edwards, FSCA). Hudnuco: Tingo Maria, 2 1, 29 October, 1946, 9; 26 December, 1946, C? (all J. C. Pallister, AMNH); 23 September, 1954, C?, 9; 26 October, 1954, $ (both E. S. Ross, CAS); 10, 29 November, 1954, 9 (both E. S. Ross, E. I. Schlinger, CAS); 43 mi E of Tingo Maria, 5 Octo- ber, 1954, $ (E. S. Ross, E. I. Schlinger, CAS). Ucayali: Ivita, Rio Neshuya, 2 July, 1986, 0, Q; 14 July, 1986, 9; 26 July, 1986, C? (all D. Silva, MUSM); Madre de Di'os, Zona Reservada Tam- bopata, trocha, 30 July, 1987, $ (D. Silva, MUSM), Puerto Mal- donado, 16-23 April, 1947. Q (J. C. Pallister, AMNH). BRAZIL



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19951 Traw 59
Amapd: Serra do Navio, June, 1966, Q (M. E. Galiano, MEG). Pard: Belh, Fazenda Velha, July, 1970, 8, 9; Belem, August 1971, (7 (M. E. Galiano, MEG); 8 August, 1962, 9 (K, Lenko, MZSP); Rio Gurupi, Uma, 2-30 May,
1963, $ (3. Malkin,
AMNH). Ronddnia: Fazenda Rancho Grande NE Cacaulandia, Figures 1-8. Scoloderus coniaius (Taczanowski). 1-6, female. 1, eye region and chelicerae. 2, lateral. 3. dorsal. 4-6, epigynum. 4, ventral, 5, posterior. 6, lateral. 7, 8, left male palpus,
Scale lines, 1 mm; genitalia 0.1 mm.
Abbreviations, DR, distal rim. E, embolus. IM, inner margin. L, lip.



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60 Psyche 1~01. 102
2-15 December, 1990, 0, Q (G. B. Edwards, FSCA). Bahia: Fazenda Matiapa Camacan, 16 October, 1978, Q (J. Santos, MCN). Goias: Pirapitinga Piren6polis Goias, 23 June, 1942, Q (F. Lane, MZSP). Rio de Janeiro: Nova Igua~u, 7 September, 1961, 9; Represa Rio Grande, February, 1976, 0, Q; Mangaratiba, Febru- ary, 1976, d', Q; Silva Jardin, August, 1975, d' (all M. Alvarenga, AMNH). S6o Paulo: Caraguatatuba, 16 November, 1942, Q (B. Scares, MZSP); Juquia, Poco Grande, 23 March, 1951, 0; 21-26 July, 1949, d' (both F. Lane, MZSP); Marsilae, 12 March, 1967, 9 (P. Biasi and F. Lane, MZSP); Osasco, 26 October, 1941, 9; 28 November, 1943, 9; Municipio de Itu, Fazenda Paud Alho, 2 February, 1959, Q (both F. Lane, MZSP); Boraceia, 9-15 February, 1949, Q (D. Silva, MZSP). Rio Grande do Sui: Aqua Belas Viamiio, 13 September, 1984, 9; Cauela, 3 1 December, 1973, d'; Garruchos Siio Borja, 7 December, 1975, 0; Irai, 20 November, 1975, d', Q; Montenegro, 20 December, 1977, Q; Passo do Bugio Butia, 13 May, 1982, Q; Passo Fundo, 12 October, 1985, 9; Salto do Yucuma, 16 January, 1985, 0, Q (all A. A. Lise, MCN); Fazenda Recanto de Figueira Arroio dos ratos, 1 August, 1986, d'; Montenegro, 7 July, 1977, <?; Vila Oliva, 5 January, 1976, Q (all E. Buckup, MCN); Vila Oliva, 15 January, 1974, Q (F. Meyer, MCN); Guaiba, 25 December, 1988, C? (A. Bonaldo, MCN); Tgrejinka, Jaquera, 19 October, 1967, C?, 9 (P. Biasi, MZSP). PARAGUAY Alto Parand: SE of Nararyal, 18 August, 1988, Q (L. E. Pefia, AMNH); Tatiyupi Reserve, 1984, 9; Itabo Reserve, 5 June, 1984,
C?, Q (both L. Baert, IRSNB).
ARGENTINA Misiones: Monte Carlo, l3Om, 5 December, 1965, (Giaschi, AMNH); January, 1966, 0, Q (M. E. Galiano, MEG); Eldorado, 11 September-15 November, 1964, Q (A. Kovacs, AMNH); November, 1970, Q (M. E. Galiano, MEG); Parque Nacional Iguazu, Arroyo Yacui, January, 1966, Q; Decem- ber, 1972, 0, Q (both M. E. Galiano, MEG); N Wanda, 12 July, 1988, Q (L. E. Pefia, AMNH). Rio Negro: El Bolson area, 1965-1966, C?, Q (A. Kovacs, AMNH).




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19951 Tra w 61
Scoloderus gibber 0. P.-Cambridge
Figures 9-17; Map 1
Scoloderus gibber 0. P.-Cambridge, 1898: 282, pi. 36, fig. 4, 0,Q. Female syntype from Bugaba, Panama, in BMNH, examined and illustrated by H. W. Levi (unpublished). F. P.-Cambridge, 1904: 521, pi. 5 1, fig. 8, 9. Petrunkevitch, 19 11: 386. Roewer, 1942: 872. Bonnet, 1958: 3955.
Scoloderus birabeni Mello-Leitilo, 1945: 242. Female holotype from Puerto Victoria, Misiones Province, Argentina, in Museum of La Plata, examined and illustrated by H. W. Levi (unpub- lished). NEW SYNONYMY.
Scoloderus intermedius Gerschman de Pikelin and Schiapelli, 1948: 13, figs. 14-17, Q. Female holotype from Santa Maria, Misiones Province, Argentina, in MACN, examined by M. B. Traw. NEW SYNONYMY.
Synonymy. Scoloderus birabeni and S. intermedius are both included in S. gibber because both lack tubercules on the abdomen (Fig. 11) and have an epigynum with a protruding scape (Fig. 12). Description. Female from Depto. Madre de Dios, Peru. Cara- pace, chelicerae dark brown. Sternum, coxae light brown. Legs light brown, ringed dark brown. Dorsum of abdomen mottled gray- green; sides white. Venter of abdomen blue-gray. Posterior median eyes 1.0 diameters of anterior median eyes (AME), laterals 0.7. Anterior median eyes 1.0 AME apart, posterior median eyes 1.6 AME apart. Anterior and posterior median eyes 4.5 AME from lat- eral eyes. Clypeus height 2.3 AME. Carapace very hairy, hump without notch (Fig. 9). Dorsum of abdomen without humps (Fig. lo), Total length 3.3 mm. Carapace 1.6 mm long, 1.4 wide, and 1.1 high. Sternum length 0.9 mm, width 1.3. First femur 1.6 mm, patella and tibia 1.7, metatarsus 0.8, tarsus 0.5. Second patella and tibia 1.4 mm, third 0.8, fourth 1.1.
Male from Depto. Madre de Dios, Peru. Coloration as in female. Posterior median eyes 1.0 AME, laterals 0.6. Anterior median eyes 1 .I AME apart, posterior median eyes 1.7 AME apart. Anterior and posterior median eyes 4.0 AME from laterals. Clypeus height 2.5 AME. Carapace very hairy, without notch. Median apophysis of palpus with sharply pointed distal tip (S in Fig. 16). Total length 2.5 mm. Carapace 1.4 mm long, 1.2 wide, 0.8 high. Sternum



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62 Psyche [vo~. 102
length 0.6, width 0.6. Median apophysis 0.1 mm long. First femur 1.4 mm, patella and tibia 1.6, metatarsus 0.7, tarsus 0.4. Second patella and tibia 1.2 mm, third, 0.7, fourth 0.9. Variation. Adult female total length 2.9 to 3.6 mm, width of carapace 1.4 to 1.6. Male total length 1.8 to 2.9 mm, width of cara- pace 1.0 to 1.3.
Diagnosis. Males of S. gibber are easily distinguished from males of other species by the spine on the distal rim of the median apophysis of the palpus (S in Fig. 16). Females of S. gibber and S. cordatus are extremely difficult to tell apart. Both species occupy similar geographical ranges (Map 1) and have very similar abdom- inal shapes (Figs. 2, 10). However there appear to be three basic differences between S. cordatus and S. gibber females. The scape of S. gibber females (at 6 hr in Fig. 12) is a larger portion of a cir- cle than that of S. cordatus females (at 6 hr in Fig. 4). S. gibber females have a level top to the carapace bulge (Fig. 9) unlike S. cordatus females which have a notch (Fig. 1). This character is less reliable because some S. cordatus females do not have a notched carapace. Females of S. gibber also have considerably more hair on the carapace (Fig. 10) and legs (Fig. 11) than do females of S. cordatus (Figs. 2, 3). Specimens of S. cordatus were much more numerous (roughly 50 localities) in the collections examined than were those of S. gibber (roughly 10 localities). Therefore it was difficult to ascertain the variability of S. gibber morphological characteristics. However, it appears that the abdominal coloration and design of both S. gibber and S. cordatus are highly variable and should not be used for identification. The abdominal pattern shown for S. gibber (Fig. 11) was also found on many specimens that were clearly S. cordatus.
Specimens Examined. MEXICO Nayarit: Tepic, 2 August, 1947, 9 (C. J. Goodnight, AMNH). Colima: 10 mi NE Comala, 17-19 July, 1983, dl, 9 (P. K. Kovarik, T. L. Harrison, and J. C. Schaffner, AD). Oaxaca: 23 km SW Valle Nacional on HWY 175, 25 June, 1983, d1 (W. Maddison, MCZ). GUATEMALA Tikal, 7 July, 1975, d1 (W. C. Sedgewick, MCZ). PERU Loreto: Genaro Herrera, 25 August, 1988, $ (D. Silva, MUSM). Pasco: Huan- cabamba, 11 September, 1987, C?, Q (D. Silva, MUSM). Depto. Madre de Dios: Albergue Cusco Amazonico, Rio Madre de Dios, 6-10 March, 1990, 7-18 July, 1989, d1, Q (both D. Silva,



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19951 Traw 63
MUSM). BRAZIL Mato Grosso: Chapada dos Guimariies, 18 November, 1983, C? (M. Hoffman, MCN). Rio Grande do Sul: Tenente Portela, 11 September, 1976, C? (S. Scherer, MCN); Sino dal, Siio Leopoldo, 21 October, 1967, d1 (P. Biasi, MZSP). Figures 9-17. Scoloderus gibber O.P. -Cambridge. 9-14, female. 9, eye region and chelicerae. 10, lateral. 11, dorsal. 12-15, epigynum. 12, ventral. 13, posterior. 14, cleared. 15, lateral. 16, 17, left male palpus. Scale lines, 1 mm; genitalia 0.1 mm.
Abbreviation, S, spine.




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64 Psyche [vo~. 102
Scoloderus nigriceps (0.P.-Cambridge)
Figures 18-26; Map 2
Carepalxis tuberculifera: -Keyserling, 1892: 50, pi. 2, fig. 40, Q. McCook, 1893: 207, pi. 13, fig. 6, 9. Not S. tuberculifer (0. P.- Cambridge).
Carepalxis nigriceps: 0. P.-Cambridge, 1895: 158, pi. 19, fig. 9, 9. Female holotype from Teapa, Tabasco State, Mexico, in BMNH, examined and illustrated by H. W. Levi (unpublished). F. P.- Cambridge, 1904: 521, pi. 51, fig. 7, 9. Petrunkevitch, 191 1: 386. Roewer, 1942: 872. Bonnet 1958: 3955. Scoloderus nigriceps: -F. P.-Cambridge, 1904: 521, pi. 51, fig. 7, Q. First placement of nigriceps in Scoloderus. Scoloderus tuberculifer. -Cornstock, 1912: 447, fig. 456, 9. Com- stock, 1940: 461, fig. 456, Q. Not S. tuberculifer (0. P.-Cam- bridge).
Scoloderus cordatus: -Levi 1976: 386 (in part). Synonymy. S. tuberculifer (cited by Comstock, 1912; 1940) has a scape with rounded, not parallel sides and hence is not S. tuber- culifer (0.P.-Cambridge). Since its range is in the United States and since the female has humps on the abdomen, it is S. nigriceps. Scoloderus cordatus and S. nigriceps were synonymized by Levi (1976). However, S. nigriceps differs from S. cordatus and S. gib- ber in both morphology and distribution. Scoloderus nigriceps has a shield-shaped abdomen with paired humps at the top, while the abdomens of S. cordatus and S. gibber are round and without humps. Neither S. cordatus nor S. gibber occurs in the United States, while S. nigriceps is primarily found in the United States (Map 1). The illustrations of S. cordatus in Levi (1976) are now considered to be of S. nigriceps.
Description. Female from Florida. Carapace dark orange-brown. Chelicerae orange-brown. Sternum, coxae, legs light brown. Abdomen white on dorsum, sides; venter, blue-gray. Posterior median eyes 1.1 diameters of anterior median eyes (AME), laterals 0.7. Anterior median eyes 1.5 AME apart, posterior medians 2.4 AME apart. Anterior and posterior median eyes 5.5 AME from lat- eral eyes. Clypeus height 2.0 AME. Carapace hump without notch (Fig. 18). Dorsum of abdomen with three humps, one central ante- rior and two on shoulders (Figs. 19, 20). Total length 3.5 mm. Carapace 1.6 mm long, 1.4 wide, and 1.1 high. Sternum length



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19951 Traw 65
0.8, width 0.8. First femur 1.8 mm, patella and tibia 1.8, metatar- sus 0.9, tarsus 0.5. Second patella and tibia 1.6 mm, third 1.0, fourth 1.4.
Male from Florida. Coloration as in female. Posterior median eyes 1.1 diameters of anterior medians, laterals 0.7. Anterior median eyes 1.5 AME apart, posterior median eyes 2.2 AME apart. Anterior and posterior median eyes 5.5 AME from the lateral eyes. Clypeus height 2.0 AME. Abdomen without humps. Carapace hump small, without notch. Total length 2.3 mm. Carapace 1.3 mm long, 1.1 wide, and 0.8 high. Sternum length 0.5, width 0.5. Median apophysis 0.1 mm long. First femur 1.5 mm, patella and tibia 1.5, metatarsus 0.7, tarsus 0.4. Second patella and tibia 1.2 mm, third 0.7, fourth 0.9.
Variation. Total length of adult female 2.9 to 4.3 rnm; width of carapace 1.2 to 1.7. Male total length 1.9 to 2.6 mm; width of cara- pace 0.9 to 1.2.
Diagnosis. Abdomen of female oblong, white, and often with humps (Figs. 19, 20), while females of S. gibber and S. cordatus never have humps (Figs. 2, 10). Epigynum lobe semicircular (Fig. 21). Lip of median apophysis of male palpus is rectangular, not more than one-half as wide as long, and heavily sclerotized (Fig. 25).
Natural History. The web, as observed at the Archbold Biologi- cal Station, Florida, is a rectangle 5 by 40 cm oriented vertically with the web center strongly offset basally (Levi, 1978). The extended vertical surface area of this web is likely an adaptation for the capture of moths that are able to escape from ordinary webs (Eberhard, 1975). When moths strike the upper region of the web, they lose scales as they tumble down its surface, finally sticking at the base of the web, having lost their protective cover. Specimens Examined. UNITED STATES Georgia: Thomas Co., Bar -M Ranch, S of Boston, 25 June, 1978, $ (H. W. Levi, MCZ). Florida: Indian River Co., Sebastian, March 1932, 0, $ (G. Nel- son, MCZ). Highlands Co., Archbold Biological Station, 7 March, 1976, C? (H. W. Levi, MCZ); Dade Co., Royal Palm State Park [Royal Palm Visitor Center, Everglades National Park], 6-24 March, 1924, <31, 9 (W. S. Blatchley, MCZ). Collier Co., Collier- Seminole State Park, 1 April, 1985, $ (W. Maddison, MCZ). BAHAMAS Grand Bahama Island: Freeport, Pinter's Point, 8 March, 1967, C?; Nassau, 24 November, 1959, 9 (both A. M.



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66 Psyche [vo~. 102
Nadler, AMNH). CUBA Havana, 24-30 April, 1915, O(F. Cervera, MCZ). MEXICO Yucatan: Chichen Itza, 13 July, 1952, <31, $; Motul, 11 July, 1952, 0; Dolores Otero 13 July, 1952, d' (all J. C. Pallister, AMNH). JAMAICA Saint Andrew's Par.: NE slope of Long Mountain, 26 October, 1957, 0, 9 (A. M. Chicker- ing, MCZ).
Figures 18-26. Scoloderus nigriceps (O.P. -Cambridge). 18-24, female. 18, eye region and chelicerae. 19, lateral. 20, dorsal. 21-24, epigynum. 21, ventral. 22, pos- terior. 23, cleared. 24, lateral. 25, 26, left male palpus. Scale lines, 1 mm; genitalia 0.1 mm.




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19951 Tra w 67
Scoloderus tuberculifer (0. P.-Cambridge) Figures 27-34; Map 2
Carepalxis tuberculifera 0. P.-Cambridge, 1889: 48, pi. 4, fig. 9, Q. Female holotype from Bugaba, Chiriqui Prov., Panama, in BMNH, examined and illustrated by H. W. Levi (unpublished). F.P.-Cambridge, 1904: 521. Petrunkevitch, 19 11: 386. Roewer, 1942: 872. Bonnet, 1958: 3955.
C. americana 0.P.-Cambridge, 1889: 49, pi. 4, figs. 7-8, d', 9. Female syntype and holotype from Bugaba, Chiriqui Prov., Panama, in BMNH, examined and illustrated by H. W. Levi (unpublished). Keyserling, 1892: 51, pi. 2, fig. 41, d', 9. F. P. - Cambridge, 1904: 521, pi. 5 1, fig 6, 9. NEW SYNONYMY. Scoloderus tuberculifer: -Simon, 1895: 828. First placement of tuberculifer in Scoloderus.
Scoloderus hybus Chamberlin, 1916: 260, pi. 19, fig. 9, 9. Female holotype from Paltaybamba, Depto. Junin; Peru, in MCZ, exam- ined and illustrated by H. W. Levi (unpublished). NEW SYN- ONYMY.
Scoloderus nigrocellatus Gerschman de Pikelin and Schiapelli, 1948: 14, pi. 1, figs. 18-21, 2. Female holotype from Santa Maria, Misiones Province, Argentina, in MACN, examined and illustrated by H. W. Levi (unpublished). NEW SYNONYMY. Synonymy. Carepalxis americana, Scoloderus hybus, and S. nigrocellatus are all synonymized under S, tuberculifer due to the characteristic elongated, parallel-sided scape of the epigynum. Description. Female from Summit, Panama. Carapace, che- licerae dark brown. Sternum brown. Legs light brown to brown. Dorsum of abdomen light gray with variable black marking. Sides of abdomen white. Venter of abdomen tan or blue-gray. Posterior median eyes 1.3 anterior median eye diameters (AME), laterals 0.8. Anterior median eyes 1.5 AME apart, posterior medians 2.0 AME apart. Anterior median eyes 5.0 AME from laterals. Posterior median eyes 6.0 AME from laterals. Clypeus height 2.5 AME. Carapace hump without notch (Fig. 27). Dorsum of abdomen with three humps, one central and two at shoulders (Figs. 28, 29). Total length 4.3 mm. Carapace 1.8 mm long, 1.7 wide, 1.3 high. Ster- num length 0.9 mm, width 0.9. First femur 2.1 mm, patella and tibia 2.1, metatarsus 1.2, tarsus 0.5. Second patella and tibia 1.7 mm, third 1.0, fourth, 1.7.




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68 Psyche [VOI. 102
Male from Summit, Panama. Coloration as in female. Posterior median eyes 1.2 AME, laterals 0.7. Anterior median eyes 1.0 AME apart, posterior medians 1.5 AME apart. Anterior and posterior median eyes 4.0 AME from laterals. Clypeus height, 1.5 AME. Abdomen without humps. Carapace without notch. Total length 2.3 mm. Carapace 1.3 mm long, 1.1 mm wide, and 0.8 mm in height. Sternum length 0.6, width 0.6. Median apophysis 0.1 mm in length. First femur 1.6 mm, patella and tibia 1.6 mm, metatarsus 0.8, tarsus 0.4. Second patella and tibia 1.2 mm, third 0.7 mrn, fourth 1.0 mm.
Variation. Adult female total length 3.6 to 4.3 mm; width of carapace 1.3 to 1.7. Male total length 2.1 to 2.6 mm; width of cara- pace 0.9 to 1.3. Dorsum and sides of abdomen with variable pat- terns and coloration in both sexes, particularly with respect to proportion of white.
Diagnosis. Abdomen of female white, shield-shaped, and with humps (Fig. 29). Scape of epigynum with parallel sides (Fig. 30). Lip of median apophysis of male rectangular, not heavily sclero- tized, twice as long as wide (Fig. 33).
Natural History. This species has been found in the secondary growth of tropical dry forest in Colombia. Webs were constructed each night and torn down by morning. The specific pattern of web construction has been described in detail (Eberhard, 1975). Web shape similar to that of S. nigriceps (Levi, 1978). Webs of juvenile S. tuberculifer are simple, lacking the extended upward "ladder" (Eberhard, 1975).
Specimens Examined. UNITED STATES Florida: Dade Co., Royal Palm State Park [Royal Palm Visitor Center, Everglades National Park], 7-14 March, 1930, $ (W. S. Blatchley, MCZ). MEXICO Jalisco: 27 km N. Autlan, Mine Rd, 7 July, 1984, 9; 17 mi N of Guadalajara, 6 July, 1984, C? (both J. B. Woolley, AD). PANAMA Panama: Madden Dam, 6 September, 1956, 9 (W. E. Lundy, AMNH); Experimental Gardens, 14 July, 1954, d', 9; Balboa, 1936, 9; Barro Colorado Island, July, 1950, d\ 9; Chili- bre, July, 1950, $; Forest Reserve, 28 July, 1954, 9; Summit, 17 August, 1954, 9; Fort Sherman, August, 1939, d', 9; Porto Bello, August, 1936, d', 9 (all A. M. Chickering, MCZ). GREATER ANTILLES, Jamaica: Negril, 24 March, 1955, d'; 2 mi SW Unity valley, 18 March, 1955, d' (both A. M. Nadler,



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tuberculifer
Figures 27-34. Scoloderus tuberculifer (O.P. -Cambridge). 27-32, female. 27, eye region and chelicerae. 28, lateral. 29, abdomen, posterior. 30-32, epigynum. 30, ventral. 31, posterior. 32, cleared. 33, 34, left male palpus. Scale lines, 1 mm; genitalia 0.1 mm.
AMNH); St. Catherine Par., Mount Diablo, 2 mi N of Ewarton, 13 August, 1958, Q (A. Archer, AMNH); Ewarton, 29 November, 1957, d' (A. M. Chickering, MCZ). Claremont, 22 July, 1960, 9 (P. Vaurie, AMNH). St. Andrew's Par., Stony Hill, 18 October, 1957, d', 9; Hermitage Reserve, 5 November, 1957, d'; Jack's Hill Road, 6 December, 1957, 0; Morces Gap, 22 July, 1958, 9; NE slope of Long Mountain, 26 October, 1957, @, 9; St. Andrew's Ferry, 0.9 mi W on Red Hills Road, 28 October, 1957, 9 (all A. M. Chickering, MCZ). LESSER ANTILLES, Dominica:



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70 Psyche [VOI. 102
Bataka, 30 January, 1968, Q (B. Malkin, AMNH). VENEZUELA Tachira: San Juan de Colon, 15 August, 1984, Q (J. Plagens, FSCA). COLOMBIA Valle: Cali, 1000m 1973, 6, Q (W. Eber- hard, MCZ). PERU Tumbes: Lechugal, Q (J. Stolzman, PAN). BRAZIL Pard: Belkm, Fazenda Velha, July 1970, Q (M. E. Galiano, MEG). Mato Grosso do Sul: 260 km N of Xavantina, Feb- ruary-April 1969, d' (Xavantina - Cachimbo Expedition, MCZ). Rio Grande do Sul: Barra do Rebeiro, 13 November, 1976, (M. Tavares, MCN); Encantado, 7 March, 1984, 9; Gravatae, 21 Octo- ber, 1983, 9; Mucum, 2 March, 1984, (?; Porto Alegre, 17 December, 1983, 9; Triunfo, 28 November, 1989, 8, 9 (all A. Brescovit, MCN); General Cgmara, 19 October, 1982, $ (E. Buckup, MCN). BOLIVIA: Yungas: La Paz, 17-25 December, 1955, 9 (L. Pefia, MCZ). ARGENTINA Chaco: Selva de Rio de Oro, 27 January, 1965, 9 (M. E. Galiano, MEG). Scoloderus ackerlyi new species
Figures 35-41 ; Map 2
Holotype. BELIZE Mountain Pine Ridge, [16*53'N, 88'55'W], February, 193 1, 9 (H. H. Bartlett, MCZ) deposited in MCZ. The species is named after David D. Ackerly, an ecologist whose insight into the natural world has greatly influenced the author. Description. Female holotype. Carapace, chelicerae, and ster- num brown. Coxae, legs light brown, darker on femur I, 11. Dor- sum, venter of abdomen white. Light gray stripes on sides of abdomen, extending away from pedicel. Posterior median eyes 1.3 anterior median eye diameters (AME), laterals 0.8. Anterior median eyes 1.5 AME apart, posterior medians 2.0 AME apart. Anterior and posterior median eyes 5.0 AME from laterals. Cara- pace hump without notch. Clypeus narrow, 2.0 AME. Total length 4.3 mm. Carapace 1.7 mm long, 0.6 wide, 1.2 high. Sternum length 0.9, width 0.8. First femur 2.0 mm, patella and tibia 1.8, metatar- sus 1 .O, tarsus 0.5. Second patella and tibia 1.6 mm, third 1.0, fourth 1.4.
Male unknown.
Diagnosis. Scape of epigynum of S. ackerlyi is substantially more elongated and narrowed distally (Fig. 39) than that of S. tuberculifer (Fig. 30).




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Traw
Figures 35-41. Scoloderus ackerlyi new species, female. 35, eye region and che- licerae. 36, lateral. 37, dorsal. 38, abdomen, dorsal. 39-41, epigynum. 39, ventral. 40, posterior. 4 1, lateral.
Scale lines, 1 mm; genitalia 0.1 mm.
Bonnet. P. 1958. Bibliographia Araneorum. Toulouse. 2(4): 3027-4230. Cambridge, F.P. 1904. Arachnida, Araneidea and Opiliones. 2: 465-545. In Biologia Centrali-Americana, Zoologia, London.
Cambridge, O.P. 1889- 1902. Arachnida-Araneidea. 1 : 1-3 17. In Biologia Centrali- Americana, Zoologia, London.
Chamberlin, R.V. 1916. Results of the Yale-Peruvian Expedition of 191 1. The Arachnida. Bull. Mus. Comp. Zool. 60(6): 175-299. Comstock, J.H. 1912. The Spider Book. Doubleday, New York. 729 pp.



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72 Psyche [VOI. 102
. 1940. The Spider Book, 2nd edition. Doubleday, New York. 802 pp. Eberhard, W.G. 1975. The 'inverted ladder' orb web of Scoloderus sp. and the intermediate orb of Eustala (?) sp. (Araneae: Araneidae). J. of Natur. Hist. 9:93-106.
Gerschman de Pikelin, B.S. and R.D. Schiapelli. 1948. Arafias Argentinas 11. Corn. Arg. Mus. Nat. Hist. 4:13.
Keyserling, E. 1892. Die Spinnen Amerikas, Epeiridae. Nurnberg. 4: 1-377. Levi, H.W. 1976. The orb-weaver genera Verrucosa, Acanthepeira, Wagneriana, Acacesia, Wixia, Scoloderus, and Alpaida north of Mexico (Araneae: Aranei- dae). Bu!l. Mus. Comp. Zool. 147:351-391. -- . 1978. Orb-weaving spiders and their webs. Amer. Scient. 66(6):734-742. . 1992a. The American species of the orb-weaver genus Carepalxis and the new genus Rubrepeira (Araneae: Araneidae). Psyche 98:25 1-264. -- - . 1992b. Spiders of the orb-weaver genus Parawixia in America (Araneae: Araneidae). Bull. Mus. Comp. Zool. 153:l-46. . 1993. The neotropical orb-weaving spiders of the genera Wixia, Pozonia, and Ocrepeira (Araneae: Araneidae). Bull. Mus. Comp. Zool. 153:47-14 1. McCook, H. C. 1893. American Spiders and their Spinningwork, Philadelphia. 3: 1-407.
Mello-Leilgo, C. 1945. Arafias de Misiones, Corrientes y Entre Rios. Rev. Mus. La Plata, (Nueva Serie), Zoologia, 4:213-302. Petrunkevitch, A. 1911. A synonymic index-catalogue of spiders of North, Central and South America with all adjacent islands. Bull. Amer. Mus. Natur. Hist. 29: 1-791.
Roewer, C.F. 1942. Katalog der Araneae von 1758 bis 1940. Bremen. 1:l-1040. Simon, E. 1887. Observations sur divers Arachnides: synonymies et descriptions. Ann. Soc. Ent. France 6(7): 158-193.
Stowe, M.K. 1978. Observations of two nocturnal orbweavers that build specialized webs: Scoloderus cordalus and Wixia ectypa (Araneae: Araneidae). J. Arechnol. 6:141-146.
-- . 1895. Histoire Naturelle des Araignkes, led. 1 :761-1084. Taczanowski, L. 1879. Les Arankides du Pkrou Central. Horae Societatis Entomo- logicae Rossicae. St. Petersburg, 15: 102-136.



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