Vol.3, No.11, 914-920 (2011) Natural Science
http://dx.doi.org/10.4236/ns.2011.311117
The world’s oldest fossil seal record
Cajus Diedrich
PaleoLogic, Research Institute, Halle, Germany;
Received 12 September 2011; revised 22 October 2011; accepted 28 October 2011.
ABSTRACT
A femur fragment with an Early Lutetian (early
Middle Eocene) age is the world’s oldest fossil
record from a seal, and, is described as Pra-
ephoca bendullensis nov. gen. nov. spec. This
find pushes back the earliest evolution of seals
into the Paleocene epoch. The femur has ple-
siomorphic terrestrial mammal characteristics
but has a morphology that is already closer to
that of Miocene and present day seals. The Eo-
cene seal femur was found at Fürstenau-Dalum
in north-west Germany, in a conglomerate rich
in shark teeth that was deposited in a coastal
delta environment to the north-west of the cen-
tral European Rhenish Massif mainland, in the
southern pre-North Sea Basin. This discovery
has led to a revision of the theory that phocids
originated along the coastline of the North
American continent. Instead they can now be
interpreted to have originated in the tropical
Eocene climate of central Europe. Although the
fossil records of pinnipeds in Europe during the
Eocene, Oligocene and Miocene are extremely
sparse, they appear to have inhabited the pre-
North Sea basin, within the influence of tem-
perate and arctic upwellings. The distribution of
abundant teeth from white and megatooth sharks
of two different lineages appears to correlate
with that of the seals, which the sharks most
probably hunted; providing supporting evidence
that the phocids were already adapted as shal-
low marine coastal inhabitants by this time.
Keywords: Oldest Seal Remains; Praephoca
bendullensis Nov. Gen. Nov. Spec.; Giant Shark
Predation; Middle Eocene; Shallow Marine Coastal
Deltaic Influenced Habitats; Pre-Northsea Basin of
Central Europe
1. INTRODUCTION
The oldest seals on planet Earth were thought to have
appeared about 28 m.y. ago during the North American
Oligocene [1], but more recent reports claim to have
found an even younger (Miocene) “missing link” between
terrestrial mammals and the basal pinnipeds in the Arctic
[2]. DNA analyses on pinnipeds have, however, sug-
gested an older (Eocene) age for their ancestors [3,4],
but until now without any supporting fossil evidence.
A newly discovered seal femur from a recently exca-
vated site at Fürstenau-Dalum in north-west Germany
(Figures 1(a) and (b)) [5] and a review of other rare
European remains of Oligocene age from the pre-North
Sea basin have now combined to suggest a different
scenario from that proposed by previous authors, who
have suggested a basal pinniped evolution starting in, or
along the coastline of, the North American landmass [4].
Neither the palaebiogeography nor the suggested (but
unproven) Eocene age for the beginning of the evolution
of evolution of earless seals (phocids) [3,4,6,7] can be
supported by the evidence from this new fossil seal site
in Germany. This vertebrate-rich site has been the sub-
ject of interdisciplinary studies; it contains mainly shark
remains but also a variety of marine mammals [5]. Con-
vincing evidence has been identified from this site of a
“missing link” seal with a Middle Eocene or even older
(Lower Eocene) age [5]. North-western Germany also
provides insights into both the palaeoenvironment (Fig-
ure 1(b)) and the palaeoecology of these, the earliest
(and already fully developed) seals in the world, as well
as into their main predators, the ancestors of present-day
white sharks and megatooth sharks [5].
Central Europe experienced a tropical climate during
the Middle Eocene and many terrestrial mammal groups
were already well developed at this time. These are, to date,
mainly known from the German fluvial and freshwater
lake sites at Messel and Geiseltal (Figure 1(a)) [8], from
which no seal ancestors have been recorded, nor have
any early phocids been reported from other Eocene ma-
rine vertebrate fossil localities of the European pre-North
Sea basin in France, Belgium, or England (Figure 1(a)).
2. MATERIALS AND METHODS
A two-day excavation of a field site at Dalum was

C. Diedrich / Natural Science 3 (2011) 914-920
915915
(a)
(b)
(c)
Figure 1. (a) Important Eocene marine and terrestrial vertebrate fossil sites in Europe; (b)
Middle Eocene seal delta and beaches on the north-western Rhenish Massif, in the
southern pre-North Sea basin; (c) Modern common seal Phoca vitulina Linnaeus,
1758 colony on the German Helgoland Düne sand bank (Photo A. Trepte).

C. Diedrich / Natural Science 3 (2011) 914-920 916
performed in May 2011, using large earth-moving ma-
chinery [5]. Sections were drawn up as part of strati-
graphic and sedimentological studies on the Fürstenau
Formation sequence at Dalum, which has been dated as
Early Eocene (Ypresian) to basal Middle Eocene (Lu-
tetian). A total of 180 cubic meters of phosphorite con-
glomerate from the early Lutetian transgression was ob-
tained for sieving three size fractions using 1 and 4 mm
sieves, the finer fraction being discarded. Only 0.1% of
the recovered material has yet been sieved [5], but this
has already yielded 14,440 fossils, of which 95% are
sharks’ teeth. Half of these 13,690 selachian teeth could
be identified at species level. Less well represented are
the teeth and fin spines of rays and the teeth and bones
of bone fish. The finer material (less than 4 mm) con-
tains many additional species that remain to be examined
in the future. Less then 0.1% of the fossils are from
mammals and these are mostly highly fragmented and
rounded usually rendering them impossible to identify.
Several terrestrial mammals that were identified just
from their teeth are similar to those in the Messel fauna
and of similar age; they include early horses and tapirs
[9]. Marine mammals have now also been identified,
although only from their postcranial bones. At least one
unidentified distal humerus fragment from a pachyos-
totic, marine mammal was found during this program,
proving the significance of this site with regard to the
evolution of marine mammals. The femur illustrated in
Figure 2 was actually found was actually found in these
gravels during the 1980s, and has prompted a major
program seeking to understand the biodiversity of ma-
rine vertebrates in Europe during the Eocene, in relation
to that of the terrestrial vertebrates. This femur, together
with all material from the 2011 excavations, is housed in
the Shark Center at Bippen (SCB) in north-west Ger-
many, a public visitor center and museum in the UNESCO-
supported “Geo and Naturpark TERRA. Vita”. Other seal
femora [10] have also been studied with respect to their
measurements [11], including bone material in the Uni-
versity of Alaska Museum (UAM), Oligocene remains
housed in the Dobergmuseum, Bünde (DMB) in Ger-
many, Miocene material from the Oertijdmuseum de
Groene Poort, Boxtel (MAB) in the Netherlands, and
finally, modern seal remains from the southern North
Sea Basin at the Seehundstation, Friedrichskoog (SFI) in
Germany.
3. THE WORLD’S EARLIEST PHOCID
FOSSIL
Suborder Pinnipedia Illiger, 1811
Family Phocidae Gray, 1821
Genus Praephoca nov. gen.
Praephoca bendullensis nov. spec.
Holotype. Half right femur (Figure 1(a)).
Type stratum. Marine transgression gravels of the Für-
stenau Formation, Early Lutetian, early Middle Eocene,
Paleogene, 45 - 49 Ma.
Type locality. Dalum, north-west Germany, southern
pre-North Sea basin.
Holotype name. Genus after the ancestor of Phoca,
and species after the collector J. Bendull.
Description and differential diagnosis. Only the upper
half of the right femur is preserved (Figure 1). Com-
pared with Oligocene, but mainly with Miocene to pre-
sent-day phocid pinniped femora (Figures 2.2-2.4) the
femur joint is much more prominent and its plesiomor-
phic character relates more to terrestrial mammals such
as the Eocene mammals from Messel [8]. This promi-
nence generally reduces during the evolution of phocids,
as an aquatic adaptation (Figures 2.2-2.4) [10]. The dou-
ble-headed and narrower trochanter tertius of the Eocene
femur still has a low angle with the axis of the femur
(10˚), compared to the much larger angle (30˚ - 40˚) in
the Miocene to present-day phocids (Figures 2.2 and
2.3), which also have a flattened trochanter tertius. The
Trochanter tertius of P. bendullensis has the plesiomor-
phic characteristics of terrestrial mammals. The already
flattened and widened femur shaft (Figure 2.1(b)) is the
main apomorphic character and is typical of highly
evolved phocids that are already adapted to aquatic en-
vironments, as well as being found in Miocene to pre-
sent-day pinnipeds (Figures 2.2-2.4) [10,11]. Overall this
new Eocene femur reflects an intermediate stage be-
tween terrestrial mammals and the Miocene pinnipeds,
already exhibiting well-developed phocid characteristics.
Quite similar in shape to this Eocene femur are those of
the modern arctic Phoca hispida Schreber, 1775 (Figure
2.4), and in particular, the common seal Phoca vitulina.
Both of these present-day seals have a less distinct femur
head, and are distally wider with a smaller distal tibia/
fibula articulation surface (Figures 2.3 and 2.4).
4. DISCUSSION
4.1. The Evolutionary Beginnings of the
Earliest Phocids
The seal femur (Figure 2) is possibly even a little older
than Middle Eocene, and may derive from reworked
Lower Eocene marine sands [5], which would push back
the evolution of pinnipeds at least into the Paleocene.
The femur has been compared osteologically and
morphologically to those of Eocene terrestrial mammals
and Oligocene to present-day aquatic seals. It represents
an intermediate stage but has already developed a very
seal-like morphology [10]. The seal lineage must there-
fore be pushed back further than suggested in recent

C. Diedrich / Natural Science 3 (2011) 914-920
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Figure 2. The world’s oldest seal remains, from the Early Lutetian (early Middle Eo-
cene) marine gravels at Dalum (north-western Germany), in a deltaic environment of
the southern pre-North Sea basin, on the coast of central Europe. 1. Right half flattened
pachyostotic femur with distinct head of Praephoca bendullensis nov. gen. nov. spec.
(Holotype, SCB no. Mam-3), (a) cranial, (b) lateral inner view, (c) caudal. 3. Right fe-
mur of the Late Miocene seal Batavipusa neerlandica from the southern pre-North Sea
basin (MAB). 4. Right femur of the modern ringed seal Phoca hispida (UAM).
publications, from the Eocene [3,4] into the Paleocene
and even to the Early Paleocene (Danian), from which
no fossils of phocids or their ancestors have yet been
recorded anywhere in the world.
Eocene. The femur from Dalum is the world’s oldest
record of an almost fully aquatic marine phocid. Because
of the flattened and widened shape of the femur shaft the
evolution to such morphology must have already started
in the Paleocene, at the latest.
Oligocene. The oldest records of pinnipeds to have
been reported in previous publications were from the
Upper Oligocene (Chattian) of North America [1], but
these authors failed to recognize or discuss the published
phocid remains from the Upper Oligocene of northern
Germany (a solitary rib from the southern North Sea
basin at Bünde, in Doberg, Germany, was published
with an unidentified “phocid rib” [12]). Pinnipeds are
now well known from Upper Oligocene times in the
northern hemisphere, although the amount of material
recovered remains very limited.
Miocene. A younger phocid fossil from the Early
Miocene (Burdigalian), which was found in the southern
pre-North Sea basin of central Europe, has been de-
scribed as Leptophoca amphiatlantica [13]. The Late
Miocene (Tortonian-Messinian) phocid Batavipusa neer-
landica [14] from the of the coast of the pre-North Sea
basin in the Netherlands was also found in fully marine
deposits, as described from the Paris Basin [15]. The
newly discovered Puijila darwini [2], which has been
suggested as a possible pinnniped ancestor, lived in the
Arctic during the Miocene. Although this species was
thought be a “missing link” it now seems likely that it
represents a later adaptation to the aquatic life style
within a separate lineage, which must have occurred
more than 25 million years later than the phocid seal
ancestor discovery reported herein, which has a mini-
mum age of between 47 and 51 Ma, indicating that the
pinnipeds must therefore have already been almost fully

C. Diedrich / Natural Science 3 (2011) 914-920 918
evolved by the middle of the Paleocene.
Pliocene. There is a much better fossil record for pho-
cids in the Pliocene, which has already been discussed in
several papers [3,6,10,16].
Pleistocene to Present-day. The phylogeny of the pin-
nipedia and the DNA of extant species have recently
been investigated by Arnaston et al. and Fukton et al.
[3,4]. In today’s southern North Sea basin two different
phocid seal species occupy the sand banks and shallow
marine environments, especially around the coastal is-
lands of northern Germany and the Baltic Sea, these be-
ing the common seal Phoca vitulina [17] (Figure 1(c))
and the grey seal Halichoerus grypus [18].
4.2. Palaeobiogeography and Habitat of
Early Seals
The presence of the earliest pinniped fossils on both
the Atlantic coast (the phocids) and the Pacific coast (the
otariids) of North America, together with the monophyly
of the pinnipedia indicated by DNA analyses, led re-
searchers to believe that they had originated on this con-
tinent [3,7]. However, the unrecognized fossil record
from Europe, together with the new Early to Middle
Eocene material, combine to suggest that they may have
originated in the more protected shallow marine pre-
North Sea Basin, with its extensive sandy coastlines,
rather than on the steeper and deeper North American
coastlines of the Middle Eocene that resulted from tec-
tonic break-up and the opening up of the Atlantic Ocean
[19]. The break-up of the American, European, and Af-
rican continents and the opening up of the northern At-
lantic Ocean [19] were certainly important factors in the
evolution and distribution of the earliest seals. These
seals may have originate in the cold Arctic regions and
subsequently migrated southward (possibly seasonally)
during the Early to Middle Eocene, through the North
Sea basin to northern Europe and across the North At-
lantic to the North American coast. The palaeobio-
geographic separation of two lineages, the Atlantic [3]
phocids and otariids [3] (including those from the North
Sea coastlines discussed herein) and the North American
Pacific coast phocids and otariids [3], may therefore
have occurred some time later, during the Oligocene.
Since the fossil phocid seal record in Europe now ex-
tends from the Early to Middle Eocene into the Oligo-
cene [10-12] and Miocene [13-15], the Phoca lineage
(the northern Atlantic and North Sea phocids) appears
more likely to have originated in Europe (in the southern
pre-North Sea basin, where the oldest Praephoca ben-
dullensis species was found) rather than in North Amer-
ica [3,4].
Previous studies of pinniped origins, irrespective of
whether they were based on their monophyly or diphyly
[3,4], have assumed that pinnipeds originated on the
shores of oceans or large bodies of water. This interpre-
tation is also supported by the new material from the
Eocene pre-North Sea basin presented herein, which was
found in a coastal delta environment (Figures 1(a) and
(b)). The sand and gravel banks that were present along
the entire coastlines of the Armorican Massif, the Rhen-
ish Massif, and the Bohemian Massif would have been
ideal areas, both for catching fish and for reproduction.
Other authors [1] have suggested that the initial adap-
tation of the pinnipeds to an aquatic environment took
place in a more restricted (even genetically [3,4]) and
less exposed environment, and postulated that the pin-
nipeds entered the marine environment after an initial
non-marine (lacustrine, riverine, or estuarine) phase of
evolution, probably along the southern shores of North
America, with the ancestors of extant phocids taking an
eastward route into Atlantic waters and those of the
otariids dispersing westward into the Pacific [3,13]. This
model must now be revised on the basis of the palaeoen-
vironmental analyses completed on the Dalum site.
The earliest evidence of phocids with aquatic adapta-
tions from the Middle Eocene of the southern pre-North
Sea basin comes from the margins of a deltaic system, so
that these may have still been fresh water forms, or per-
haps have adapted to brackish water. In central Europe
the transition from a terrestrial to a marine life style does
not seem to be represented at Dalum as these Middle
Eocene seals appear to have already been fully adapted
shallow marine carnivores, but is supported by the evi-
dence from their predators (see below). This suggests
that their evolution may have started in the shallow ma-
rine pre-North Sea basin of central Europe, where many
terrestrial tropical mammals evolved at that time on the
mainland areas (Figure 1(a)), the fossils of which have
been found at the UNESCO-World Heritage Site at
Messel and at the Geiseltal fresh water lake site [8], both
in Germany. Since such terrestrial ancestors of phocids
are absent from the Middle Eocene at these sites, it can
be assumed that the early seals were, at that time, pin-
nipeds already adapted to shallow marine conditions.
This conclusion appears to be further supported by the
presence of their predators.
5. THE PHOCID PREDATORS
In addition to the ideal coastal habitat of the P. ben-
dullensis phocids, the suggestion that the Middle Eocene
seals were already fully adapted to shallow marine con-
ditions is supported by the abundant shark remains found
at Dalum. This site contains many teeth of a smaller an-
cestor to the “great white shark” Procarcharodon auricu-
latus, and also less common larger, serrated teeth from a
“megatooth shark” ancestor Carchharocles cf. sokolovi

C. Diedrich / Natural Science 3 (2011) 914-920
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[5]. It would appear that sand and gravel banks in the
coastal zones of the southern pre-North Sea basin may
have already been serving as breeding areas for seals
during the Eocene, as they have been from the Oligocene
up to the present [16-18] and offer the earliest evidence
of white shark hunting areas. This would also explain the
quite unusually high quantity of white shark teeth in the
Dalum region, which are much less well represented at
other Belgian, English and French shark sites [20,21].
The development of the white shark lineages now appear
to correlate very well with the appearance and evolution
of the first larger marine mammals, and especially the
seals, that formed their prey. The hunting of seals by
white sharks, which is well known at the present time
[22], thus appears to have had its origin in the Middle
Eocene. As has been demonstrated herein for the seals,
these predators also appeared after the Paleocene, and
the ancestors of both the white sharks and the megatooth
sharks [23] now appear to be well documented at the
same time from the Dalum site, during the Early to Mid-
dle Eocene. The earliest sirenians [24] and toothed
whales [25] also appeared at this time in the pre-North
Sea basin; their existence at the Dalum site has not yet
been proven, but is to be expected.
6. ACKNOWLEDGEMENTS
The discovery of the seal remain described herein was made by the
hobby palaeontologist Mr. J. Bendull, who kindly allowed the speci-
men to be studied and a cast to be made. The project was sponsored by
the Geopark TERRA. Vita (Mr. H. Escher), and the Osnabrück Landkreis.
The company PaleoLogic was responsible for the field work and scien-
tific research. I am grateful to The Kuhlhoff education center leaders
(Mr. A. Bruns and Mr. W. Hollermann), and the mayor of Bippen, Mr.
H. Tolsdorf, for managing the installation of a field sieving laboratory.
Finally, I would also like to thank H. Felker, another local hobby-
palaeontologist, who provided support, helped with sieving the mate-
rial, and allowed access to his large collection (obtained over 25 years
from both Dalum and Bippen localities) for comparisons, especially of
the white shark tooth material. Finally E. Manning supported much
with the spell-check.
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