A History of Ideas in Ichnology - Trace Fossils as Indicators of Sedimentary Environments - page 6

Paleodictyon , but he also examined the subject of trace fossils when dealing
with the origin of body fossils or, with Leonardo's words, nichi petrificati
(petrified seashells). While his contemporaries supported an inorganic origin
for body fossils, Leonardo referred to bioeroded specimens to disprove this
idea. Similarly, da Vinci used bioturbational traces ( andamenti delli lombrici
or “traces of worms”) as a paleoenvironmental tool to demonstrate the marine
origin of the sedimentary layers. Da Vinci's accurate analysis shows that, from
the beginnings of ichnology, trace fossils have been an indispensable tool for
facies analysis and paleobiology. However, Leonardo did not have influence
on his contemporaries because he wrote in mirror-image Italian, at a time when
Latin was the idiom of erudition. Despite his revolutionary conclusions, Leo-
nardo remained an isolated voice, not participating in the academic discussion.
In contrast, Ulisse Aldrovandi, the first professor of natural sciences at the Uni-
versity of Bologna, left a considerable legacy, including the word geology ( Vai
and Cavazza, 2003 ). The Musaeum Metallicum , his most extensive work in
geology and paleontology, contains several trace fossils, frequently described
in detail and with magnificent illustrations. Aldrovandi described Cosmorhaphe
as a snake-like structure, possibly suggesting an inorganic origin, but he accu-
rately interpreted bioerosional structures as produced by bioeroding mollusks
( Baucon, 2009 ).
Known for his vast cabinet of curiosities, Aldrovandi exchanged specimens
and ideas with another prominent naturalist of the Renaissance, the Swiss
Conrad Gesner. De omni rerum fossilium genere , Gesner's (1565) geological
treatise, exemplifies a common trait of the Renaissance pioneers of ichnology:
a non-exclusive interest in traces. In fact, Gesner, as many other contempo-
raries, investigated any aspect of the natural world that aroused his interest,
from trace fossils to gemstones. Though younger than Gesner, Johann Bauhin
was the main pupil of the influential naturalist. He published a tourist guide in
which he described a branched trace fossil ( Phymatoderma ). The accompany-
ing illustration shows intricate angelic figures, but Bauhin commented, “The
human figures have been mistakenly added either by the painter or the wood
cutter” ( Seilacher, 2007 ).
A chondritid was also reported by Legati (1677) when describing Ferdinando
Cospi's Wunderkammer , placed next to the Aldrovandi's Museum. Legati
followed the interpretation of Aldrovandi, who previously studied the same
specimen, and indicated it as “Wooded-stone” (“Alberina”, “Dendrite”, “Pietra
Imboscata”; Legati, 1677 ; Fig. 2 A). The “Alberina stone” was commonly
excavated in the surroundings of Bologna and used as a building material after
calcination. For this reason, Ovidio Montalbani proposed Chondrites as the sym-
bol of stone masonry, accompanied by the Latin motto, Silex medio cremium sibi
viscere sculpsit , an cupit in calcem versa parare domos? (“Hard stone has carved
out its bowels into brushwood, perhaps does it want to build houses after becom-
ing lime?”; Legati, 1677 : 174). Bioerosional traces were also present in the Cospi
collection and compared to petrified ant burrows ( Legati, 1677 :175).