Danise and Higgs
Bone-eating Osedax worms lived on Mesozoic marine reptile deadfalls
Electronic supplementary material
Supplementary Material and Methods
Geological Setting. The Grey Chalk is divided into the lower West Melburly Marly Chalk
Formation and the upper Zig Zag Chalk Formation, and is Cenomanian in age (26). The lower
part comprises an alternation of limestones and marls (26), and is likely to have been deposited
in water depths of between 100 and 150 m (27). The Cambridge Greensand Member is a thin (~
0.6 m), remané deposit at the base of the West Melbury Marly Chalk Formation in eastern
England, around the city of Cambridge (28). It is a glauconitic marl made by a thin, but
distinctive condensed basement bed of pale greenish grey marl rich in phosphatic nodules at base
and dark green glauconite as sand-sized grains (29). Even if the Cambridge Greensand Member
was deposited during the early Cenomanian, it reworks the top of the Gault Formation below,
and its macrofossil assemblage is largely late Albian in age (30). The typical Gault lithology is a
pale-dark calcareous clay, with phosphatic, pyritic and calcareous nodules, deposited in a mid to
outer shelf environment. Estimates of water depth have fluctuated considerably, usually in the
range of 90-350 m (31).
Detailed Analytical Methods. Micro CT scanning was carried out at the Natural History
Museum, London, using an X-Tek HMX ST 225 CT cone beam system. A tungsten reflection
target was used for these scans at 210 kV, 190 µA, 708 ms exposure with a 1 mm copper filter. A
total of 3142 angular projections were collected at 0.11° angular intervals in a single 360°
rotation for each scanned sample. Data volumes were constructed using CT PRO version 2.1
1 (Metris X-Tek, UK) and analyzed using VG Studio Max 2.1 (Volume Graphics, Heidelberg,
Germany). Voxel dimensions for the two volumes were 36.6 µm for the plesiosaur bone and 62.5
µm for the cheloniid bones.
Additional references
26
Hopson, P. M. A stratigraphical framework for the Upper Cretaceous Chalk of England
and Scotland, with statements on the Chalk of Northern Ireland and the UK Offshore
Sector. British Geologica Survey, Research Report RR/05/01, pp. 102 (2005).
27
Smith, A. B., Monks, N. E. A. & Gale, A. S. Echinoid distribution and sequence
stratigraphy in the Cenomanian (Upper Cretaceous) of southern England. Proc. Geol.
Assoc. 117, 11 (2006).
28
Hopson, P. M., Wilkinson, I. P. & Woods, M. A. A stratigraphical framework for the
Lower Cretaceous of England. British Geologica Survey, Research Report RR/08/03, pp.
77 (2008).
29
Hawkes, L. The erratics of the Cambridge Greensand – their nature, provenance and mode
of transport. Quarterly J. Geol. Soc. London , 99, 12 (1943).
30
Martill, D. M. & Unwin, D. M. The world’s largest toothed pterosaur, NHMUK R481, an
incomplete rostrum of Coloborhynchus capito (Seeley, 1870) from the Cambridge
Greensand of England. Cretac.Res. 34, 9 (2012).
31
Rawson, P. F. in The Geology of England and Wales (eds P. J. Brenchley & P. F. Rawson)
Ch. 15, 256 (The Geological Society, 2006).
2 Figure S1. Detailed view of the studied fossil specimens. (a) Plesiosaur humerus (B56629).
Arrow indicates position of boring-1 in figure 1 and figure S2. (b) Detail of the area in B56629
from where Osedax boring-2 (arrow) has been reconstructed in figure 1 and figure S2. (c)
Chelone camperi? bones (B206000-1). (d-e) Details of the bioeroded areas in B206000-1
reconstructed in figure 1 and figure S3. Arrow in d indicates the position of boring shown in
figure S3e-f; arrow in e indicates the position of boring shown in figure1j-k and figure S3a-b.
3 Figure S2. CT scan profiles of Osedax borings in fossil plesiosaur humerus (B56629) (a-g) and
modern bones (h-i). (a) Cross section at position of boring-1. (b-c) Cross section and transverse
section of boring-1, reconstructed in figure 1g-h. (d) Detail of three additional Osedax borings.
(e) Cross section at position of boring-2. (f-g) Cross section and transverse section of boring-2,
reconstructed in figure 1e-f. (h-i) Comparative profiles of borings from modern Osedax species.
Scale bars are 10 mm in a & e; 1 mm in b-d, f-g; 5 mm in h-i.
4 Figure S3. CT scan profiles of Osedax borings in fossil cheloniid bones (B206000-1) (a-b, e-f)
and modern bones (c-d, g). (a-b) Cross section and transverse section of costal plate showing the
boring reconstructed in figure 1j-k. (c-d) Comparative profiles of borings from modern Osedax
species in whale and pig bone respectively. (e-f) Cross section and transverse section of rib
showing the largest boring in this specimen. (g) Comparative profiles of borings from modern
Osedax species in whale bone. Scale bars are 5 mm in a; 2mm in b-g.
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