46
very likely transmitted to hosts of the fossil flea. Some reports on the ancient history
of Y. pestis infecting humans have used ancient DNA obtained from teeth and bones
to characterize strains that caused Black Death during the fourteenth to seventeenth
centuries. While these reports are too young to be classified as fossils, they demonstrate the use of molecular genetic techniques for tracing the history of various
human pathogens (Bos et al. 2011). Bacteria have also been detected in fossil teeth,
as demonstrated by Fostowicz-Frelik and Frelik (2010), who reported filamentous
actinomycetes in a North American Eocene rabbit tooth. Actinomycetes were also
recognized in a Miocene Sivapithecus (Hershkovitz et al. 1997).
Discovering bacteria in coprolites (fossil feces) is to be expected but whether
these bacteria are saprophytic or parasitic is difficult to determine. An example is
the Permian actinomycete, Palaeostromatus diairetus, that was recovered inside fish
coprolites. Colonies consisted of groups of substrate mycelia with emerging spore
chairs separated by elongate connectives (Fig. 2.25). This actinomycete was probably part of the gut flora and whether it was innocuous, beneficial or pathogenic is
difficult to determine (Dentzien-Dias et al. 2016).
Actinobacteria also infect plants and one such species with coccoidal cells was
found infecting the petals of the mid-Cretaceous fossil flower, Eoëpigynia burmensis, in Myanmar amber (Poinar et al. 2007) (Fig. 2.26). It was not possible to determine if these fossils belonged to the family Micrococcacaeae or Microbacteriaceae,
both of which contain species that infect plant surfaces. Actinobacteria were also
reported from silicified wood of a Late Cretaceous Laurinoxylon and an Early
Cretaceous Protocupressinoxylon in Romania. Iamandei (2003) concluded that the
presence of filamentous and coccoid bacteria in xylem elements indicated a pathogenic condition.
Fig. 2.24 A group of
coccobacilli (arrow)
adhering to the tip of the
beak of the flea,
Atopopsyllus cionus, in
Dominican amber. Scale
bar = 35 μm
G. Poinar
very likely transmitted to hosts of the fossil flea. Some reports on the ancient history
of Y. pestis infecting humans have used ancient DNA obtained from teeth and bones
to characterize strains that caused Black Death during the fourteenth to seventeenth
centuries. While these reports are too young to be classified as fossils, they demonstrate the use of molecular genetic techniques for tracing the history of various
human pathogens (Bos et al. 2011). Bacteria have also been detected in fossil teeth,
as demonstrated by Fostowicz-Frelik and Frelik (2010), who reported filamentous
actinomycetes in a North American Eocene rabbit tooth. Actinomycetes were also
recognized in a Miocene Sivapithecus (Hershkovitz et al. 1997).
Discovering bacteria in coprolites (fossil feces) is to be expected but whether
these bacteria are saprophytic or parasitic is difficult to determine. An example is
the Permian actinomycete, Palaeostromatus diairetus, that was recovered inside fish
coprolites. Colonies consisted of groups of substrate mycelia with emerging spore
chairs separated by elongate connectives (Fig. 2.25). This actinomycete was probably part of the gut flora and whether it was innocuous, beneficial or pathogenic is
difficult to determine (Dentzien-Dias et al. 2016).
Actinobacteria also infect plants and one such species with coccoidal cells was
found infecting the petals of the mid-Cretaceous fossil flower, Eoëpigynia burmensis, in Myanmar amber (Poinar et al. 2007) (Fig. 2.26). It was not possible to determine if these fossils belonged to the family Micrococcacaeae or Microbacteriaceae,
both of which contain species that infect plant surfaces. Actinobacteria were also
reported from silicified wood of a Late Cretaceous Laurinoxylon and an Early
Cretaceous Protocupressinoxylon in Romania. Iamandei (2003) concluded that the
presence of filamentous and coccoid bacteria in xylem elements indicated a pathogenic condition.
Fig. 2.24 A group of
coccobacilli (arrow)
adhering to the tip of the
beak of the flea,
Atopopsyllus cionus, in
Dominican amber. Scale
bar = 35 μm
G. Poinar