Bacteria or melanosomes? A geochemical analysis of micro-bodies on a 25 million year old tadpole – Palaeobiodiversity and Palaeoenvironments

Holly E. Barden1*, Uwe Bergmann2, Nicholas P. Edwards1, Victoria M. Egerton1, Phillip L. Manning1, Sarah Perry1, Arjen van Veelen1, Roy A. Wogelius1, Bart E. van Dongen1

1 - Williamson Research Centre for Molecular Environmental Science, School of Earth Atmospheric and Environmental Sciences, University of Manchester, Williamson building, Oxford Rd, Manchester, M13 9PL

2 - SLAC , National Accelerator Laboratory, Linac Coherent Light Source, Menlo Park, CA 94025, USA

* - E-mail:

Table 1. Elemental composition (weight %) revealed by EDS of chained spherical bodies and filamentous material found on the surface of the tadpole fossil in FS003b

Element / Chained structures / Filamentous material
C / 9 / 13
O / 26 / 38
Mg / 0 / 0
Al / 1 / 1
Si / 43 / 33
S / 5 / 3
Cl / 0 / 1
K / 1 / 4
Ca / 7 / 4
Ti / 0 / 0
Fe / 7 / 3

Table 2. Table of organic absorption band assignments for tadpole and matrix (fs003b). X indicates the presence of a group, - its absence, and ? that it may be present but cannot be verified. All Bio rad source data is from the Bio-Rad KnowItAll Informatics System 8.2 Multi-Technique database. AS - asymmetric, S - symmetric, Def – deformation, Comb - combination, Over – overtone

Source / Functional group / Bond / Wavenumber
range (cm−1) / Intensity / Vibration / Tadpole / Matrix / Eumelanin
standard
Bio rad / Alkanes
(R-CH2-R) / CH / 2936-2916 / Strong / AS
stretch / X / ? / -
CH / 2863-2843 / Strong / S
stretch / X / ? / -
CH / 1485-1445 / Medium / Def / X / ? / -
Bio rad / Alcohols
(Ph-OH) / OH / 3350-3200 / Variable / Stretch / X / X / -
OH / 1390-1330 / Medium / Def / ? / - / -
CO / 1260-1180 / Strong / Stretch / X / X / -
Bio rad / Alcohol
(R-OH) / OH / 3300-3280 / Strong / Stretch / X / X / X
OH / 1450-1330 / Medium / Def / ? / - / X
CO / 1100-1000 / Strong / Stretch / ? / - / X
Bio rad / Amides (R-
CO-NH-C) / NH / 3320-3270 / Medium / Stretch / ? / ? / -
C=O / 1680-1630 / Strong / Stretch / ? / ? / -
NH / 1570-1515 / Strong / Comb / X / X / -
NH / 1305-1200 / Medium-
weak / Comb / ? / ? / -
Bio rad / Amides (R-
CO-NH2) / NH / 3375-3325 / Medium / AS
stretch / ? / ? / -
NH / 3205-3155 / Medium / S
stretch / ? / ? / -
C=O / 1680-1642 / Strong / Stretch / ? / ? / -
NH2 / 1638-1618 / Strong / Def / ? / ? / -
CN / 1420-1400 / Medium / Stretch / X / X / -
Bio rad / Nitriles
(R-CN-O) / CN / 2304-2288 / Strong / Stretch / X / X / -
NO / 1393-1365 / Strong / Stretch / ? / ? / -
Bio rad / Alkenes
((R)2C=CH2) / CH / 3095-3075 / Medium / Stretch / ? / ? / -
CH / 3040-3010 / Medium / S
stretch / ? / ? / -
CH / 1800-1750 / Medium / Over / X / ? / -
C=C / 1661-1639 / Medium / Stretch / ? / ? / -
CH / 895-885 / Strong / Def / ? / ? / -
Bio rad / Unidentified
(possibly ketone or
ester) / C=O / 1750 / Strong / Stretch / X / X / -
Bio rad / Ketone
(C-(C=O)-C-OH) / C=O / 1640-1540 / Strong / Stretch / X / ? / X
Bio rad / Carboxylic acid
(COOH) / C=O / 1600-1560 / Strong / AS
stretch / X / ? / X
C=O / 1420-1400 / Strong / S
stretch / X / - / X
Liu
et al
. 2005 / Amino acids / OH / 1050-1100 / X / X / -