The Bertie Waterlime - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 71

developed from E. remipes (which is found
in the lower Fiddlers Green Formation) by
peramorphosis: phylogenetic change in
which individuals of a species mature past
adulthood and develop new traits, i.e.,
the opposite of pedomorphosis. However,
in the study by Cuggy (1994), lacustris
and remipes plotted on the same
ontogenetic trend. He concluded that
the two belonged to the same species
and synonymized them (as E. remipes ).
A recent cladistic study of the Eurypterus
genus by Tetlie (2006) placed E. remipes
and E. lacustris as sister groups,
and E. tetragonophthalmus as sister to
E. hennigsmoeni from Norway (Tetlie,
2002). The important conclusion from
Tetlie's (2006) study was that the genus
Baltoeurypterus was invalid because its
members nested within the Eurypterus
clade.
The most recent study of the subject
by Tetlie et. al (2007), showed that the
problem with older studies was that
the provenance of the specimens could
not always be assured. These authors
obtained large samples of both forms
from known horizons and were able
to show consistent morphological
differences (primarily carapace shape
and telson serrations) between E.
lacustris and E. remipes at all sizes. They
concluded that the species are genuine,
and that E. lacustris evolved from E.
remipes through heterochrony, as
originally suggested by Tollerton (1992).
There are other eurypterids known
from the Bertie Waterlime, though not in
such abundance as those already
mentioned. Another Eurypterus , E.
dekayi , can be distinguished from the
other species of this genus by its more
numerous (4-6) spines on each segment
of its spiny prosomal appendages. This
species is very similar to Eurypterus
laculatus , first recognized by Kjellesvig-
Waering (1958) (as E. remipes laculatus ).
Both species have a rather broad
carapace but E. laculatus has a
characteristic depression surrounding
the eyes and lacks the ornament of scales

which occurs at the rear of the carapace
and first segment of the mesosoma on
other Eurypterus species. Eurypterus
dekayi occurs in the E. lacustris Fauna of
the Williamsville Formation at localities
from Ontario to Rochester. E. laculatus
occurs widely in the Fiddlers Green
Formation from Ontario to eastern New
York. It is possible that E. dekayi evolved
from E. laculatus .
Related to Eurypterus is the genus
Erieopterus , which was erected by Kjellesvig-
Waering (1958) to distinguish forms with a
smooth ornament, a definite constriction of
the body between the mesosoma and
metasoma, and lack of spines on the
anterior appendages. Erieopterus occurs in
the Devonian strata immediately overlying
the Bertie, but not in the Bertie Waterlime
itself. One species from the Williamsville
Formation, with a pustulose ornament and
a bizarre, globular telson, was originally
included in Erieopterus but then placed in
a new genus Buffalopterus by Kjellesvig-
Waering and Heubusch (1962). Though the
whole animal is unknown, fragments of
carapace indicate that this species,
Buffalopterus pustulosus , reached 1 m (3.3
ft) in length! Another group of eurypterids
not too distantly related to the family
Eurypteridae is the family Dolichopteridae.
Dolichopterus has larger eyes and more
spiny anterior appendages than Eurypterus .
The most posterior prosomal appendage is
a swimming paddle, as usual, but the
penultimate appendage is also somewhat
flattened and would also have helped
in swimming. Dolichopterus occurs

through-out the Bertie Waterlime.
Carcinosomatids are unusual
eurypterids, with a trapazoidal carapace
with eyes situated near the front corners,
very spiny anterior appendages, large
swimming paddles, and a scorpion-like
curved telson. These eurypterids were
large and their spiny appendages and
probably poisonous stinger indicate that
carcinosomatids were fearsome predators.
Paracarcinosoma scorpionis ( 74 ) occurs in
the Williamsville Waterlime from the
Syracuse area westwards to Ontario.