Abstracts to Articles

The Journal of Arachnology

Volume 27 Number 2

FOSSIL ARANEOMORPH SPIDERS FROM THE TRIASSIC OF SOUTH AFRICA AND VIRGINIA

Paul A. Selden: Department of Earth Sciences, University of Manchester, Manchester M13 9PL, UK
John M. Anderson and Heidi M. Anderson: National Botanical Institute, Private Bag X101, Pretoria 0001, South Africa
Nicholas C. Fraser: Virginia Museum of Natural History, Martinsville, Virginia 24112 USA

ABSTRACT. New fossil spiders from Triassic rocks of South Africa and Virginia are descnbed. Though lacking synapomorphies of Araneomorphae, certain features suggest they belong in that infraorder, and possibly in the superfamily Araneoidea. Thus, they represent the oldest known fossil araneomorphs and extend the fossil record of the infraorder by approximately 40 Ma to 225 Ma.

The Joumal of Arachnology 27:401-414

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NEW SPECIES AND CLADISTIC REANALYSIS OF THE SPIDER GENUS MONAPIA (ARANEAE, ANYPHAENIDAE, AMAUROBIOIDINAE)

Martin J. Ramirez: Laboratory of Arthropods, Department of Biology, FCEyN, Universidad de Buenos Aires, Pabellon II Ciudad Universitaria (1428) Buenos Aires, Argentina, and Museo Argentino de Ciencias Naturales, Av. Angel Gallardo 470 (1405), Buenos Aires, Argentina

ABSTRACT: The known range of the South American genus Monapia, previously known only from temperate South American forests, is expanded to central and eastem Argentina and Uruguay. A monophyletic group of five species with spinose forelegs is proposed, including M. angusta, newly transferred from Arachosia, plus four new species: M. charrua, M. gueneana, M. fierro and M. carolina. One new species, M. tandil (from Buenos Aires Province), is proposed to be the sister group of Monapia vittata. A data matrix with 43 characters for the 13 species of the genus (plus 9 amaurobioidine outgroups) was cladistically analyzed. Although relationships among species are mostly resolved, the basal phylogeny of the genus remains unclear. The previous hypothesis of relationships of Monapia alupuran is unsupported in this new analysis. Additional records are given for M. Iutea and M. dilaucollis.

The Joumal of Arachnology 27:415-431

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THE FEMALES OF ANELOSIMUS DUBIOSUS AND ANELOSIMUS JABAQUARA (ARANEAE, THERIDIIDAE)

Marcelo de Oliveira Gonzaga and Adalberto Jose dos Santos: Pos-graduacao em Ecologia, Departamento de Zoologia -IB -Universidade Estadual de Campinas. C.P. 6109. CEP: 13083-970 -Campinas, Sao Paulo, Brazil

ABSTRACT. The females of Anelosimus dubiosus Keyserling 1891 and Anelosimus jabaquara Levi 1956 are described and illustrated based on specimens collected in Jundai, Sao Paulo. Brazil.

The Joumal of Arachnology 27:432-434

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REVISION OF THE GROENLANDICA SUBGROUP OF THE GENUS PARDOSA (ARANEAE, LYCOSIDAE)

Charles D. Dondale: Eastern Cereal & Oilseed Research Centre, Research Branch, Agriculture and Agri-Food Canada, Ottawa, Ontario K1A 0C6 Canada

ABSTRACT. The groenlandica subgroup, which currently stands as a component of the Pardosa modica group, is characterized by a flat conductor tip in the male palpus and comprises P. groenlandica (Thorell 1872), P. dromaea (Thorell 1878), P. bucklei Kronestedt 1975, P. tristis (Thorell 1877), and P. prosaica Chamberlin & Ivie 1947. Neotypes are designated to stabilize each of the Thorellian names iracunda, dromaea and tristis, all original material relevant to these names having been lost or destroyed.

The Joumal of Arachnology 27:435-448

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A REVISION OF CENTRAL AFRICAN TRABEA (ARANEAE, LYCOSIDAE) WITH THE DESCRIPTION OF TWO NEW SPECIES FROM MALAWI AND A REDESCRIPTION OF T. PURCELLI

Mark Alderweireldt: Royal Museum of Central Africa, Department Invertebrates, Steenweg op Leuven, B-3080 Tervoren, Belgium

ABSTRACT. The central Afucan representatives of the genus Trabea are revised. Trabea straeleni (Roewer 1960) is revalidated as a good species and redescribed. Trabea heteroculata Strand 1913 is redescribed, and two new species from Malawi are added: Trabea nigristernis new species and Trabea setula new species. For comparison, a related southern African species, Trabea purcelli Roewer 1951, is redescribed. Some notes on the southern African Trabea ornatipalpis Russell-Smith 1982 are given together with a short zoogeographical discussion of the genus Trabea as a whole.

The Joumal of Arachnology 27:449-457

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THE IDENTITY OF PACHYLOIDES TUCUMANUS N. COMB. (EX BOSQIA), WITH A PROPOSAL OF GENERIC SYNONYMY AND THE NEW NAME PACHYLOIDES YUNGARUM (OPILIONES, GONYLEPTIDAE, PACHYLINAE)

Luis Eduardo Acosta: Catedra de Diversidad Animal I, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba, Av. Velez Sarsfield 299, 5000 Cordoba, Argentina

ABSTRACT. The nominal genus Bosqia Canals 1933 is determined to be junior subjective synonym of Pachyloides Holmberg 1878. This results in the new combination Pachyloides tucumanus (Canals 1933) for the only species hitherto assigned to Bosqia, and in a secondary homonymy with Pachyloides tucumanus Canals 1943. For the latter, the new name Pachyloides yungarum is proposed. The article provides a redescription of Pachyloides tucumanus (Canals 1933) new combination, including the male external and genital morphology (previously unknown). New records of the species are also reported.

RESUMEN. Se determina la sinonimia del genero nominal Bosqia Canals 1933 bajo Pachyloides Holmberg 1878. Este cambio resulta en la nueva combinacidn Pachyloides tucumanus (Canals 1933) para la unica especie hasta ahora incluida en Bosqia, asi como en la homonimia secundaria con Pachyloides tucumanus Canals 1943; para esta ultima especie se propone el nombre nuevo Pachyloides yungarum. El articulo presenta una redescripcidn de Pachyloides tucumanus (Canals 1933), comb. n., incluyendo la morfologia externa y genital del macho, hasta ahora desconocido. Se proporcionan nuevos registros de la especle.

The Journal of Arachnology 27:458-464

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NEW SYNONYMS IN THE GENERA DISCOCYRTUS AND PACHYLOIDES (OPILIONES, GONYLEPTIDAE, PACHYLINAE)

Luis Eduardo Acosta: Catedra de Diversidad Animal I, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba; Av. Velez Sarsfield 299, 5000 Cordoba, Argentina

ABSTRACT. To contribute to a depuration of the species-level taxomomy in the Gonyleptidae Pachylinae, the following synonymies are proposed: Discocyrtus minutus Roewer 1913 = Discocyrtus testudineus (Holmberg 1876); Discocyrtus spinosus Roewer 1916 and Discocyrtus exceptionalis Mello-Leitao 1933 = Discocyrtus prospicuns (Holmberg 1876); Pachylus spinosus Canestrini 1888 (currently in Pachyloides) = Discocyrtus dilatatus Sorensen 1884; Canalsia delicata Mello-Leitno 1930 (removed from the synonymy of Pachyloides iheringi Roewer 1913) and Pachyloides aelleni Silhavy 1979 = Pachyloides thorellii Holmberg 1878. All citations of Discocyrtus affinis Roewer 1913 from Argentina are referred to D. prospicuus (the full synonymy is suspected but not formally proposed). References of P. iheringi from Argentina are determined to be P. thorellii. Comments on the type material, the type localities and on misidentifications of previous authors are included.

RESUMEN. A fin de contribuir a una depuracidn taxondmica en Gonyleptidae Pachylinae, se proponen las siguientes sinonimias: Discocyrtus minutus Roewer 1913 = Discocyrtus testudineus (Holmberg 1876); Discocyrtus spinosus Roewer 1916 y Discocyrtus exceptionalis Mello-Leitao 1933 = Discocyrtus prospicuus (Holmberg 1876); Pachylus spinosus Canestrini 1888 (hasta ahora en Pachyloides) = Discocyrtus dilatatus Sorensen 1884; Canalsia delicata Mello-Leitao 1930 (excluida de la sinonimia de Pachyloides iheringi Roewer 1913) y Pachyloides aelleni Silhavy 1979 = Pachyloides thorellii Holmberg 1878. Todas las referencias de Discocyrtus affinis Roewer 1913 para Argentina son referidas a D. prospicuns (se sospecha la sinonimia plena de ambas especies, pero no se la propone formalmente). Se determina que las citas de P. iheringi para Argentina corresponden a P. thorellii. Se incluyen comentarios sobre el material tipico, las localidades tipo y sobre los errores de identificacidn de autores Drevios.

The Journal of Arachnology 27:465-469

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THERMAL TOLERANCES AND PREFERENCES OF THE CRAB SPIDERS MISUMENOPS ASPERATUS AND MISUMENOIDES FORMOSIPES (ARANEAE, THOMISIDAE)

Victoria R. Schmalhofer: Graduate Program in Ecology and Evolution; Department of Ecology, Evolution, and Natural Resources; Rutgers University, Cook College; 14 College Farm Road, New Brunswick, New Jersey 08901-8551 USA

ABSTRACT. Misumenops asperatus (Hentz 1847) and Misumenoides formosipes (Walckenaer 1837) are diurnally-active, flower-dwelling crab spiders (Thomisidae) commonly inhabiting open fields. In laboratory experiments, both species remained active over a temperature range of approximately 46 °C. The spung-maturing M. asperatus tolerated significantly lower temperatures than the summer-maturing M. formosipes (CTmin = - 1.4 °C and 2.2 °C, respectively), while M. formosipes tolerated significantly higher temperatures than M. asperatus (CTmax, = 48.2 °C and 45.1 °C, respectively). Misumenops asperatus displayed thermal discomfort over a broader range of temperatures (36-44 °C) than did M. formosipes (41-46 °C). In a laboratory thermal gradient apparatus M. asperatus tended to prefer cooler temperatures than M. formosipes (14.4 °C and 18.4 °C, respectively). Regression analysis of literature data for 21 species of spiders showed a significant positive relationship between the thermal preference of a species and its CTmax. For their CTmax's, which were high compared to most other spider species, M. asperatus and M. formosipes preferred low temperatures. The coupling of low thermal preferences and high thermal tolerances displayed by M. asperatus and M. formosipes is unusual for ectothermic organisms.

The Journal of Arachnology 27:470-480

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PARAPHYLY OF THE ENOPLOGNATHA OVATA GROUP (ARANEAE, THERIDIIDAE) BASED ON DNA SEQUENCES

A.-M. Tan (1), R.G. Gillespie (1) and G.S. Oxford (2)
(1) Center for Conservation Research and Training, University of Hawaii, 3050 Maile Way, Gilmore 409, Honolulu, Hawaii 96822, USA
(2) Department of Biology, University of York, RO. Box 373, York YO1 SYW, UK

ABSTRACT: Five species of Enoplognatha Pavesi 1880 were recently recognized as a monophyletic Enoplognatha ovata group based on morphological data. We analyzed the E. ovata clade for monophyly using four species in the E ovata group (E. ovata (Clerck 1757), E. Iatimana Hippa & Oksala 1982, E. margarita Yaginuma 1964 and E. afrodite Hippa & Oksala 1983) and three other closely related taxa (E. japonica Bosenberg & Strand 1906, E. thoracica (Hahn 1833), and E intrepida Sorensen 1898). Two species of the presumed sister genus (Steatoda Sundevall 1833) were employed as outgroups. The results indicate that the "E ovata clade" is not monophyletic.

The Journal of Arachnology 27:481-488

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CHEAP TRANSPORT FOR FISHING SPIDERS (ARANEAE, PISAURIDAE): THE PHYSICS OF SAILING ON THE WATER SURFACE

Robert B. Suter: Department of Biology, Vassar College, Poughkeepsie, New York 12604 USA

ABSTRACT. Many pisaund spiders inhabit the edges of bodies of fresh water and actively propel themselves across the water surface using both rowing and galloping gaits. They also sail across the water, taking advantage of the wind and their nearly frictionless interaction with the water surface. The physical interactions of Dolomedes triton (Walckenaer 1837) (Araneae, Pisauridae) with moving air, in a wind tunnel in which the floor was water, formed the core of the present investigation. Spiders in an elevated (sailing) posture were subjected to greater drag forces attnbutable to air motion than were spiders in a prone (non-sailing) posture and therefore were transported substantially faster than prone spiders. In the context of transport velocity, the benefit of adopting an elevated posture was substantially greater (relative to mass) for small spiders than for large ones, although even under the relatively steady flow conditions of the wind tunnel the velocities of the small spiders in the elevated posture were more variable than either small prone spiders or large spiders. The efficacy of adopting an elevated posture was a consequence of the steep air velocity gradient that existed above the surface of the water in the wind tunnel and that also exists above any pond over which the air is moving. Taken as a whole, the data indicate that sailing is a remarkably cheap form of transportation for Dolomedes, but that, at least at the edges of large bodies of water, it involves risks because it is directionally uncontrolled.

The Journal of Arachnology 27:489-496

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NOTES ON THE SOCIAL STRUCTURE, LIFE CYCLE, AND BEHAVIOR OF ANELOSIMUS RUPUNUNI

Leticia Aviles: Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721 USA
Patricio Salazar: Departamento de Biologia, Pontificia Universidad Catolica del Ecuador, Quito, Ecuador

ABSTRACT: Observations on the colony structure, life cycle, and behavior of Anelosimus rupununi in eastem Ecuador point to a level of social organization similar to that of Anelosimus eximus and Anelosimus domingo, confirming its status as a non-territorial, permanently-social species. Anelosimus rupununi colony members were seen to cooperate in prey capture and transport, to feed communally, and to take tums in tending the egg sacs. Sex ratios were also highly female-biased. There were, however, some interesting differences with these other species. Anelosimus rupununi egg sacs were grouped as part of maternal care efforts, with grouped sacs being more likely to be tended than ungrouped sacs. Males and females apparently matured at the same instar, males appeared shorter-lived than females, and individuals within the nests were clearly synchronized with each other in the stage of their life cycle. Also, as would be expected from its notably smaller body size, A. rupununi's life cycle appeared shorter than that of A. eximius.

The Journal of Arachnology 27:497-502

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MOVEMENT OF THE MALE BROWN TARANTULA, APHONOPELMA HENTZI (ARANEAE, THERAPHOSIDAE), USING RADIO TELEMETRY

Margaret E. Janowski-Bell and Norman V. Horner: Department of Biology, Midwestern State University, Wichita Falls, Texas 76308-2099 USA

ABSTRACT. This study was designed to gain insight into the "migratory" life history component of the male brown tarantula, Aphonopelma hentzi (Girard 1854), and to determine if radio telemetry could successfully answer questions regarding the ecology of theraphosids. Tarantulas were equipped with radio transmitters and movement monitored using an antenna and radio receiver. Overall movement of males was in all directions and randomness could not be excluded as a factor. Individual males moved relatively large distances, up to 1300 m, and significant directedness was only found in three individuals. In addition, notes on habitat, ecology and behavior are presented.

The Journal of Arachnology 27:503-512

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PHENOLOGY AND LIFE HISTORY OF THE DESERT SPIDER, DIGUETIA MOJAVEA (ARANEAE, DIGUETIDAE)

April M. Boulton and Gary A. Polis: Department of Environmental Science and Policy, University of California, Davis, California 95616 USA

ABSTRACT. The desert spider, Diguetia mojavea Gertsch 1958, is a numencal dominant in many Califomia deserts. We report data collected over a three-year period (1984-86) on reproduction, life history, phenology, microhabitat, prey, and dispersion for D. majavea in the Coachella Valley, California. This is one of few studies to calculate life history table parameters for a desert arachnid. The average female laid 1065 eggs, while the net reproductive rate (Ro) was 1.41; generation time (T) was calculated as 204.85 days. These spiders appear to fit a Type III survivorship curve. Density of D. majavea was typical for a desert spider at 0.02 spiders/m2. Finally, our findings complement the only other study on D. majavea (Nuessly & Goeden 1984).

The Journal of Arachnology 27:513-521

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HOST SPECIFICITY AND DISTRIBUTION OF THE KLEPTOBIOTIC SPIDER ARGYRODES ANTIPODIANUS (ARANEAE, THERIDIIDAE) ON ORB WEBS IN QUEENSLAND, AUSTRALIA

Paul Grostal and David Evans Walter: Department of Entomology, The University of Queensland, St. Lucia, Queensland 4072, Australia

ABSTRACT. We investigated host specificity, the effects of host size, and the effects of the size, structure and occupancy of host webs on the abundance of the kleptobiotic spider Argyrodes antipodianus O.R-Cambridge 1880. The kleptobiont is not host specific, but does prefer orb webs that are surrounded by a scaffold of threads (barrier-web). Across all hosts, host size had little effect on the abundance of the kleptobiont, while host density and the presence of other species of Argyrodes on webs had no effect. Web diameter, although not strongly related to the abundance of A. antipodianus in the field, limited kleptobiont numbers in greenhouse experiments On webs of the Golden Orb Spider, Nephila plumipes (Latreille 1804), numbers of A. antipodianus were not affected by size of the scaffold or by aggregation of host webs. However, presence of host males was associated with a significantly higher abundance of A. antipodianus, suggesting that these kleptoparasites may take advantage of distracted females and impose a cost on mating in N. plumipes.

The Journal of Arachnology 27:522-530

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ABUNDANCE OF SPIDERS AND INSECT PREDATORS ON GRAPES IN CENTRAL CALIFORNIA

Michael J. Costello: University of California Cooperative Extension, 1720 South Maple Ave., Fresno, Califomia 93702 USA
Kent M. Daane: Center for Biological Control, Division of Insect Biology, Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720 USA

ABSTRACT We compared the abundance of spiders and predaceous insects in five central California vineyards. Spiders constituted 98.1% of all predators collected. More than 90% of all spiders collected were from eight species of spiders, representing six families. Two theridiids (Theridion dilutum and T melanurum) were the most abundant, followed by a miturgid (Cheiracanthium inclusum) and an agelinid (Hololena nedra), Predaceous insects comprised 1.6% of all predators collected, and were represented by six genera in five families Nabis americoferis (Heteroptera, Nabidae) was the most common predaceous insect, with its densities highest late in the growing season. Chrysoperla carnea, Chrysoperla comanche and Chrysopa oculata (Neuroptera, Chrysopidae) and Hippodamia convergens (Coleoptera, Coccinellidae) were most abundant early in the season. The dominance of spiders may be due to their more stable position in the vineyard predator community compared to predaceous insects. We also suggest that the low percentage of predaceous insects (e,g,, lacewings) may reflect the lack of preferred prey (e,g,, aphids) on grapevmes.


The Journal of Arachnology 27:531-538

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This page was posted 12 / 21 / 2000 and modified 11 / 27 / 2009