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within detrital, terrestrial, and aquatic food chains, the
pathway for mercury biomagnification remains unknown.
We collected two widespread wolf spiders,
Pardosa milvina
and
P. saxatilis
, at sites along the Susquehanna River
near a coal-fired power plant and compared total mercury
levels to spiders from an uncontrolled coal fire burn site
(Centralia, PA) and reference sites away from the river or
point sources of mercury pollution (agricultural fields).
We collected 89
Pardosa milvina
and
P. saxatilis
across
the six sites and measured total mercury among individual
spiders. We found significant differences in mercury level
between these species despite being very similar in size,
microhabitat, phenology, and phylogenetic proximity. We
also found higher mercury levels among adult male rather
than female spiders suggesting either trophic dimorphism
or mercury depuration among females during egg pro-
duction. Total mercury levels varied significantly by site.
Spiders from Centralia had total mercury levels up to three
times higher than those in riparian zones adjacent to the
power plant and about nine times higher than spiders
collected from agricultural fields. Significant differences
in total mercury across different age classes were also
found, indicating significant bioaccumulation. Our results
suggest that these species may serve as important bioin-
dicators for mercury bioaccumulation, biomagnification
and transport across diverse habitat types. The high levels
near Centralia, PA, suggest that, counter to conventional
wisdom, aquatic environments are not necessary for sig-
nificant terrestrial mercury bioaccumulation to occur.
Keywords: total mercury bioaccumulation, biomagnifi-
cation, wolf spider, riparian
Oral presentation
Comparative analysis of euchelicerate
genomes supports a single origin of the
arachnid book lung
Prashant P. Sharma
1
, Evelyn E. Schwager
2
, Alistair P.
McGregor
2
1
Department of Zoology, University of Wisconsin-
Madison, Madison, WI, USA 53706;
2
Department of
Biological and Medical Sciences, Evolution of Animal
Development and Morphology, Oxford Brookes
University, Gipsy Lane, Oxford OX3 0BP, UK
prashant.sharma@wisc.eduThe phylogenetic position of Scorpiones and the attendant
evolutionary scenario of arachnid terrestrialization have
a long and contentious history. The datasets of morpholo-
gists and paleontologists typically recover scorpions at
or close to the base of the arachnid tree of life, whereas
recent phylogenomic analyses have recovered support
for a clade comprised of scorpions and tetrapulmonates
(Arachnopulmonata). To adjudicate between these com-
peting hypotheses with an independent data class, we
examined the structure and composition of euchelicer-
ate genomes, using mandibulate genomes as a point of
reference. Here we show that a partial or whole genome
duplication event is shared by arachnopulmonates, to
the exclusion of apulmonate arachnids. Furthermore, we
show that one or more whole genome duplication events
independently occurred in Xiphosura. The signature of the
duplication in Arachnopulmonata is retained by devel-
opmental patterning genes, with gene expression surveys
revealing several cases of putative sub-functionalization
of resulting paralogs in scorpion and spider exemplars.
Taken together, these data imply a single origin of the
arachnid book lung and transform previous scenarios of
the evolution of terrestrialization in Arachnida.
Keywords: genomics, evo-devo, phylogenomics, terrestri-
alization, Hox genes
Poster presentation
High throughput analysis of shape evolu-
tion in the armored harvestman family
Podoctidae
Prashant P. Sharma
1
, Mark A. Santiago
2
, Perry A.C.
Buenavente
3
, Arvin C. Diesmos
3
, Milan Janda
4
, Sarah L.
Boyer
5
, Ronald M. Clouse
2
, Ward C. Wheeler
2
1
Department of Zoology, University of Wisconsin-
Madison, 430 Lincoln Drive, Madison, WI 53706, USA;
2
Division of Invertebrate Zoology, American Museum of
Natural History, Central Park West at 79
th
Street, New
York, NY, USA;
3
Zoology Division, National Museum of
the Philippines, Padre Burgos Avenue, Ermita 1000,
Manila, Philippines;
4
Biology Centre, Czech Academy
of Sciences, Branisovska 31, 370 05, Ceske Budejovice,
174
DENVER MUSEUM OF NATURE & SCIENCE
REPORTS
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No. 3, July 2, 2016
Cushing