20th International Congress of Arachnology

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DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Pseudoscorpiones is a mesodiverse order into the Class
Arachnida. Species delimitation into several genus has
been done in this group by means of taking diagnostic
characters as linear measurements or proportions
without any statistical criteria. Because of this, one
specimen could be considered as a new species taking
into account only its size or either how stouter or
slender a structure can be if compared with itself in
other species. Furthermore, it ignores the variability of
this kind of characters, due to the fact that measure-
ments may differ depending on the instruments or who
conducts the research. On the other hand, the neo-
tropical genus Apolpium Chamberlin, 1930 (Olpiidae)
has seven species described from Costa Rica to Ecuador
with diagnostic characters such as length/width pro-
portions of chela and length/width of pedipalpal tibia
and patella and total length of the body. Therefore,
the aim of this study was to explore and assess the
potential and role of these morphometric characters
in species delimitation for Apolpium . In order to
achieve this, 170 specimens were studied from six col-
lections, as well as the five types of the seven species.
From the examined material, 36 measures were taken
from 17 structures in all the body on 57 selected indi-
viduals. Then, a pool of statistics analyses including a
Kolmogorov-Smirnoff test, cluster analyses, multiple
correlations, principal components, discriminant func-
tion and multidimensional scaling were carried on.
Those morphometric characters together showed first,
that there was no significant difference of most of the
proportions between males and females; second, a high
correlation between structures of same appendages
was evidenced; and finally the proportions lacked of
explicative power to differentiate species. Given this,
proportions themselves do not support enough the
Apolpium species proposed currently and other kind of
characters have to be explored in order to find trust-
able diagnostic ones.
Keywords: Pseudoscorpiones, morphometric characters,
multivariate analyses, species delimitation
Student - oral presentation
Understanding how changes in the
ground spider community can enhance
restoration practices
*Sarah J. Rose, P. Charles Goebel
Forest Ecosystem Restoration and Ecology Laboratory,
The Ohio State University School of Environment and
Natural Resources, 1680 Madison Ave., Wooster, OH
44691, USA
Fire-dependent jack pine forests of Michigan are the focus
of conservation and restoration efforts as they are the
breeding ground for the endangered Kirtland’s Warbler
(KW). Current forest management practices, focused on
increasing KW habitat, however, simplify landscape struc-
ture. Without an understanding of how these ecosystems
naturally respond to wildfire there are insufficient metrics
to measure the success of restoration that emulates fire
and post-fire succession. One such metric, or indicator of
ecosystem function, is spider community structure and
diversity. Specifically, the ground hunting spider guild
(GHSG) is a good choice as they respond to environmental
changes and are easily sampled. To quantify the GHSG
community we established pitfall traps in 12 former
wildfire sites in northern Lower Michigan. Sites were cat-
egorized as either young (2–7 years post-fire) or mature
(23–41 years post-fire) and all were relatively unaltered
by human activity. We observed significant differences in
the GHSG community composition between the age classes
(MRPP=0.001), and higher diversity (Shannon Diversity
Index) in mature (H’=2.11versus young (H’=1.49) stands
(p<0.01). Non-metric multidimensional scaling revealed
that stand age, canopy cover, ground cover, and under-
story plant community composition and density (below
1 m) are important drivers of GHSG abundance. These
data provide valuable insights into the role that natural
disturbances, and their legacies, play in shaping jack pine
forest ecosystems. Differences in the GHSG suggest that the
heterogeneous stand structure associated with naturally
regenerating stands may provide a variety of microcli-
mates, habitat structures, and prey availability; making
them suitable for maintaining a high diversity of spiders
20th International Congress of Arachnology