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Picture
of Aphantomartus pustulatus, a 300-million-year-old fossil trigonotarbid
from the 7-11 Mine in Ohio that was immersed in water to contrast
the body outline with the surrounding rock matrix. The fossil
was collected by Gregory McComas, an avid fossil collector and
geology graduate of Youngstown State University in Ohio, and
studied by Cary R. Easterday, a master's degree student in the
Department of Geological Sciences at Ohio State University. Easterday
found evidence that these long-extinct arachnids may have been
able to spin silk like modern spiders. Photo by Cary R. Easterday,
courtesy of Ohio State University. |
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Interpretive
drawing of Aphantomartus pustulatus, a 300-million-year-old fossil
trigonotarbid from the 7-11 Mine in Ohio, showing surface details
and outline of the body. An arrangement of tiny bumps called
a 'microtubercle row' are found along the hind legs that are
similar in shape and location to a calamistrum, a structure found
in some modern spiders that is used to spin silk. Drawing by
Cary R. Easterday, courtesy of Ohio State University. |
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Picture
of Aphantomartus pustulatus, a 300-million-year-old fossil trigonotarbid
from the 7-11 Mine in Ohio that was whitened with ammonium chloride
to show surface details on the body. The fossil was collected
by Gregory McComas, an avid fossil collector and geology graduate
of Youngstown State University in Ohio, and studied by Cary R.
Easterday, a master's degree student in the Department of Geological
Sciences at Ohio State University. Easterday found evidence that
these long-extinct arachnids may have been able to spin silk
like modern spiders. Photo by Cary R. Easterday, courtesy of
Ohio State University. |
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SEM
micrograph of Aphantomartus pustulatus, a 300-million-year-old
trigonotarbid from the 7-11 Mine in Ohio, showing the 'microtubercle
row' on the patella of the fourth walking leg (left side). A
row of tiny bumps is clearly visible. Cary R. Easterday, a master's
degree student in the Department of Geological Sciences at Ohio
State University, said this configuration of microtubercles is
highly unusual, suggesting a highly specialized function. This
microtubercle row is similar in shape and location to the calamistrum
of some modern spiders and may be evidence of silk-spinning in
this long-extinct creature. SEM micrograph by Sreenivas Bhattiprolu,
electron microscopist and microprobe analyst at Ohio State, courtesy
of Ohio State University. |
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SEM
micrograph and interpretive sketches of Aphantomartus pustulatus,
a 300-million-year-old fossil trigonotarbid from the 7-11 Mine
in Ohio, showing the distribution of microtubercles (tiny bumps)
on the abdomen. Cary R. Easterday, a master's degree student
in the Department of Geological Sciences at Ohio State University,
said that microtubercles located on the trigonotarbid abdomen
probably were not used for silk-spinning, but served other functions.
Most likely, they were attached to tactile hairs used to sense
the surrounding environment, as seen in "hairy" spiders
today. SEM micrograph by Sreenivas Bhattiprolu, electron microscopist
and microprobe analyst at Ohio State. Interpretive sketches by
Cary R. Easterday, courtesy of Ohio State University. |
