20th International Congress of Arachnology

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DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Crassitarsae, males have the ventral tarsi covered with
scopula (adhesive setae) and mixed with male sensory
setae, whereas females have only adhesive setae (except
for Cyrtaucheniidae, that the males have only the male
sensory setae). The distinction between a scopula com-
posed of adhesive or sensory setae is only possible when
examined under SEM. In other families, Actinopodidae,
Antrodiaetidae, Atypidae, Ctenizidae, Hexathelidae,
Migidae, Paratropididae and representatives of Euagrinae
(Dipluridae) male representatives have sensory scopula
only, whereas females have just a few long setae. Moreover,
in these families, plus Idiopidae and Euctenizidae, we
observed differences in density of sensory setae of male
scopula. The plesiomorphic state, as it is in Liphistius ,
where males have sensory scopula three times denser in
hind legs, was observed in Actinopodidae, Hexathelidae and
Paratropididae (p<0.005), as well as in Antrodiaetidae,
Atypidae and Dipluridae (Euagrinae). The apomorphic
state, where sensory setae are denser in front legs, was
observed in Bipectina: Cyrtaucheniidae, Idiopidae and
Nemesiidae (p<0.001). These results provides new data for
phylogenetic and functional morphology approaches.
Keywords: Mygalomorphae, morphology, tarsus, seta
Student - poster presentation
Island hideouts of thieves and assassins;
biogeography of Indian Ocean Argyrodinae
spiders
*Muhammad Kala, Ingi Agnarsson
Department of Biology, University of Vermont, Room
120A Marsh Life Sciences Building, 109 Carrigan
Drive, Burlington, VT 05405, USA
The diversity of arthropods inhabiting Indian Ocean
islands is estimated to be high but remains poorly known.
Argyrodinae spiders (Araneae: Theridiidae) are found on
all of the major islands and are notorious for their unusual
foraging strategies such as occupying webs of host spiders
to steal resources (kleptoparasitism), and preying on other
spiders (araneophagy). Despite their ubiquity, however,
the historical biogeography and dispersal patterns of
Indian Ocean argyrodines as well as the evolution of these
foraging strategies (in the subfamily in general) are not
well studied. The aims of our study are to 1) test bio-
geographical hypotheses of Indian Ocean argyrodines
and 2) to understand the evolutionary history of their
foraging strategies. Here, we construct a preliminary
molecular phylogeny of western Indian Ocean argyrodines
using mitochondrial (CO1) and nuclear (ITS2) genes to
infer the biogeographical history of argyrodines and the
phylogenetic relationship between kleptoparasites and
araneophages. Our phylogeny complements a previous
study done by Su & Smith (2014), and we use it to test the
hypothesis that kleptoparasitism evolved from araneophagy
(which itself evolved from a free-living ancestor). Our study
furthermore sets the stage for future co-phylogenetic analy-
ses of argyrodines and hosts to determine their interplay.
Keywords: biogeography, Argyrodinae, phylogeny,
kleptoparasitism, araneophagy
Student - oral presentation
Systematics of the Australasian araneid
Phonognatha and evolution of orb-web
leaf retreats
*Robert J. Kallal, Gustavo Hormiga
The George Washington University, Department of
Biological Sciences, 302 Bell Hall 2029 G St NW
Washington, DC 20052, USA
The phylogenetic relationships at the base of Araneidae
are either contentious or poorly known. Two early diverg-
ing lineages within Araneidae are the Australasian genera
Phonognatha Simon, 1894 and Deliochus Simon, 1894.
Members of these genera have been placed in Araneidae,
Tetragnathidae, and Nephilidae over the course of the past
150 years. Neither genus has been revised, and 11 species
and subspecies are described between them. Some of
these taxa are biologically interesting for reasons includ-
ing curling a leaf in the orb-web to use as a retreat, male
and female cohabitation prior to mating, and reversible
color change. Recent analyses place them in the araneid
subfamily Zygiellinae, which is either sister to Nephilinae
at the base of Araneidae, or sister to all other araneids.
Morphological examination of more than 2,000 specimens
20th International Congress of Arachnology