The Bertie Waterlime - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 73

known. The Williamsville Waterlime
bears a related species: Acutiramus
cummingsi . It is a wider, more robust
form. Acutiramus gets its name because
its distinctive chelicera has acute tips to
each finger ( 76 ). The large size of the
animal and the enormous chelicerae with
sharp, serrated teeth suggest that this
animal was a fearsome predator. The
swimming paddles and rudder-like telson
tell us that the animal was a swimmer,
though its large size suggests that it might
not have swam very fast. It can be
imagined cruising the Silurian seas,
lashing its long claws out at the small,
primitive, jawless fish and other animals it
preyed upon.

York Silurian, and some authors consider
that the two species are actually the same
(Eldredge, 1974). Bunaia woodwardi is a
small, enigmatic form described by Clarke
(1919). Eldredge (1974) took another look
at it - there is only one slab with four
specimens on, preserved in the New York
State Museum. He wondered whether
these little creatures might actually be
young specimens of Pseudoniscus , but we
can only continue to wonder until more
specimens of, ideally, a whole range of
sizes, show a transition between the two
genera.

Scorpions
In the space of about 5 years towards
the end of the nineteenth century nearly
all of the few known Silurian scorpion
fossils were discovered, in New York,
Scotland, and Sweden (Kjellesvig-Waering,
1966). It was more than 50 years before
another Silurian scorpion was recognized,
and even this specimen had been
collected in the late nineteenth century
but misidentified as a eurypterid. Three
species of scorpion were described from
the Bertie Waterlimes of New York. The
first was discovered in 1882 by OA Osborn
but not reported in the literature
(Whitfield, 1885a) until after the first
description of one from Sweden. Whitfield
placed the American scorpion into the
same genus as the European one, calling it
Palaeophonus osborni but, following this
original notice Whitfield (1885b) gave
a more detailed description and erected a
new genus for the specimen Proscorpius
osborni . Many more specimens of this
species have since been collected
(described in Kjellesvig-Waering, 1986) by
Sam Ciurca. The second scorpion from
the Bertie is Archaeophonus
eurypteroides , described by Kjellesvig-
Waering (1966), and the third,
Stoermeroscorpio delicatus , was described
by Kjellesvig-Waering in 1986, again,
thanks to determined collecting by Sam
Ciurca ( 78 ). They are known only from
the Fiddlers Green Formation. All of these
scorpions are rather primitive in form;

Xiphosurans
Horseshoe crabs are familiar to those who
frequent the eastern seashores of North
America, where the remains of Limulus
polyphemus are commonly washed up on
beaches and, at certain times of the year,
hordes of these animals come ashore and
up estuaries to mate by moonlight (see the
delightful topic by Milne and Milne, 1965).
The epithet 'living fossil', given to Limulus ,
results from the remains of animals
strikingly similar in morphology that
are preserved in the Mesozoic
rocks of Solnhofen, Germany (see Selden
and Nudds, 2004, Chapter 10), and
quite similar forms going back to the
Pennsylvanian Period (see Mazon Creek,
Chapter 7). Earlier, more primitive,
relatives of horseshoe crabs are the -
socalled synziphosurines, which include
two species known from the Bertie
Waterlime: Pseudoniscus clarkei and
Bunaia woodwardi . Synziphosurines differ
from true horseshoe crabs in that
their opisthosomal segments are free, as in
eurypterids, not fused into a hard shield or
buckler, as in Limulus . Pseudoniscus
clarkei ( 77 ) was described by Ruedemann
(1916); it is the commoner of the two, and
most specimens come from the
Williamsville Formation bed A of Ontario.
A similar species, P. roosevelti (Clarke,
1902), occurs in lower beds of the New