20th International Congress of Arachnology

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convergences; however, in contrast to linyphiids, gus-
tatorial courtship does not seem to be involved in
pholcids except for one single case (Modisimus culici-
nus). This leaves a wide range of possible functions,
including intersexual as well as intrasexual scenarios
that may explain the evolution of these structures.
Obviously, this is a rich field for future observational
and experimental studies.
Keywords: Sexual dimorphism, convergent evolution,
Pholcidae, ‘head’ structures
Oral presentation
Species discovery in the Pilbara: the
curious case of Conothele
Joel Huey, Mia Hillyer, Mark Harvey
Western Australian Museum, Locked Bag 49, Welsh-
pool DC, WA 6986, Australia
Many Mygalomorph genera harbor undescribed species
diversity. In Western Australia, this was made evident in
a recently published barcoding study, which found ~140
putative new species across seven families, defined by a
9.5% divergence threshold at CO1. For the genus Cono-
thele (Ctenizidae), 13 putative species were revealed
in that study. In a more comprehensive molecular
dataset discussed here, we have revealed upwards of 30
lineages, based on that same criterion. These lineages
suggest a complex evolutionary history for this genus in
Australia, especially in the resource-rich Pilbara region
of the north-west of the continent. Reconciling these
genetic data with morphology faces some constraints.
Adult males are required for adequate morphological
species level description and diagnoses, but available
collections have few adult male specimens that can
be sequenced and linked to the phylogeny. Here we
discuss avenues to reconcile these data, and explore the
complex and incomplete biogeographic history of this
genus in Australia.
Keywords: species discovery, systematics, phylogenetics,
Mygalomorphae
Poster presentation
Species diversity of Cybaeus kuramotoi-
group (Cybaeidae) in Japan and evolution
of mating plugs associated with antagonis-
tic coevolution between males and females
Yoh Ihara
Hiroshima Environment and Health Association, 9-1
Hirosekita-machi, Naka-ku, Hiroshima 730-8631, Japan
The genus Cybaeus (Cybaeidae) comprises numerous
species endemic to Japan. The number of described species
of Japanese Cybaeus has reached 80 and there still remains
undescribed species as many as described ones. They vary in
body length with a wide range from ca. 3 to 15 mm, and a
local species assemblage usually consists of representatives
of different size classes. Each species of the assemblage often
constitutes a closely related species group together with
other similar-sized species. A series of the medium-sized
species groups (approximately 5–7 mm in body length),
such as the kuramotoi-group and the ashikitaensis-group,
is most diverse in western Japan. The kuramotoi-group con-
sists of more than 30 (including 7 described) species. The
group can be also characterized by presence of the mating
plugs, whose morphology are species-specific. The mating
plugs are broken pieces of male’s own palp derived from an
apical element of conductor. After the copulation, it is inlaid
to a crevice of epigynal plate of female to block a copulatory
pore. Female internal genitalia of the kuramotoi-group are
more developed than those of C. ashikitaensis in which the
mating plug is absent. In particular, the kuramotoi-group
has conspicuously elongated spermathecal bases in contrast
to rounded spermathecal bases of C. ashikitaensis. As the
late mate priority may be enhanced by elongated sperma-
thecal base, it is considered that males producing mating
plugs are adaptive if female’s multiple mating and resulting
sperm competition are the norm. Furthermore, when males
have larger apical elements of conductor (= mating plug),
females tend to have more elongated spermathecal bases.
The sexually antagonistic coevolution hypotheses predict
that female and male morphology will often coevolve.
Keywords: Cybaeus, kuramotoi-group, geographic
differentiation, mating plug
112 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing