Deciduous Tusks and Small Permanent Tusks of the Woolly Mammoth, Mammuthus primigenius (Blumenbach, 1799) Found on Beaches in The Netherlands - MDPI
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Article
Deciduous Tusks and Small Permanent Tusks of the
Woolly Mammoth, Mammuthus primigenius
(Blumenbach, 1799) Found on Beaches in
The Netherlands
Dick Mol 1, *, André Bijkerk 2 and Joanne P. Ballard 3
1 Natural History Museum Rotterdam, 3015 AA Rotterdam, The Netherlands
2 Independent Researcher, 2726 CP Zoetermeer, The Netherlands; andrebijkerk@gmail.com
3 Tennessee Valley Authority, Knoxville, TN 37902, USA; jpballard0@tva.gov
* Correspondence: dickmol@telfort.nl
Academic Editor: Maria Rita Palombo
Received: 25 March 2018; Accepted: 22 May 2018; Published: 28 May 2018
Abstract: Tusks of very young mammoths and other proboscideans are extremely rare in the fossil
record. This article presents all deciduous tusks and newly-developing permanent tusks of woolly
mammoths which are known from Dutch localities and the North Sea. Four deciduous tusks are from
The Netherlands and one is from Germany. Five specimens of newly-developing permanent tusks
are also discussed. In this article, we present several characteristics and details of those tusks such as
presence/absence of roots, and cementum and enamel layers that should facilitate an identification
when new findings are made. We also describe a dental element, a digitelle, that is easily mistaken for
a tusk of a juvenile woolly mammoth.
Keywords: proboscideans; dentition; milk tusk and permanent tusks; digitelle; North Sea; Maasvlakte;
Zandmotor; Rockanje
1. Introduction
The North Sea floor, located between the British Isles and the continent of Europe, is an important
source of fossil mammal remains from the entire Quaternary [1]. Several mammalian faunas inhabited
the area during various episodes of the Pleistocene. The terrestrial mammals from the North Sea
are divided into four fauna-associations which are regarded as groups of larger mammals with a
comparable age, although not necessarily regarded as contemporaneous [2].
The oldest, Early to Middle Pleistocene Fauna-associations I and II, contain heavily mineralized
and very dark fossils including the proboscideans Anancus arvernensis (Croizet and Jobert, 1828),
Mammuthus meridionalis (Nesti, 1825) and Mammuthus trogontherii (Pohlig, 1885). Fauna-association
III is much younger, of Late Pleistocene age, with Elephas antiquus (Falconer and Cautley, 1847)
and Mammuthus primigenius. The bulk of the radiocarbon dates fall within Maritime Isotope
Stage 3 (57–29 Ka cal BP). Fauna-association IV is Holocene, and does not contain any remains
of proboscideans.
The fossils of these mammals have routinely been brought up in the nets of fishing vessels such
as beam trawlers [3,4]. One of the best known and richest sources of fossils in the Southern Bight of
the North Sea is the Eurogeul area off the coast of the province of South Holland. These fossils are
found in fluvial sediments deposited in the former deltas of the Rhine and Meuse Rivers, before they
were flooded by rising sea levels at the end of the last ice age [5,6]. The Eurogeul, or Eurogully, is a
channel for large ships to enter the ports of Rotterdam (the Euro-Meuse channel). This channel fills
Quaternary 2018, 1, 7; doi:10.3390/quat1010007 www.mdpi.com/journal/quaternary
Quaternary 2018, 1, 7 2 of 14
Quaternary 2018, 2, x FOR PEER REVIEW 2 of 14
in with sediment, which must routinely be removed to maintain an adequate channel depth for the
passage of ships.
passage of ships. The
The fossil-rich
fossil-rich sediments
sediments are
are dredged
dredged and
and deposited
deposited along
along the
the coastline
coastline ofof The
The
Netherlands, which
Netherlands, which reinforces
reinforces and
and extends
extends the
the beaches.
beaches. The
The same
same process
process isis used
used for
for the
theconstruction
construction
of Maasvlakte 2, an artificial extension of the Rotterdam harbor (Figure 1). This results
of Maasvlakte 2, an artificial extension of the Rotterdam harbor (Figure 1). This results in the in the creation
creation
of new localities where the remains of Pleistocene and Holocene animals may be
of new localities where the remains of Pleistocene and Holocene animals may be discovered. discovered.
Figure 1. Map of the Eurogeul area that ships pass through on their approach to Rotterdam. Pale
Figure 1. Map of the Eurogeul area that ships pass through on their approach to Rotterdam. Pale yellow
yellow represents the dredged area. The popular Maasvlakte 2 fossil-hunting beach is marked in
represents the dredged area. The popular Maasvlakte 2 fossil-hunting beach is marked in medium
medium yellow—this is where the dredged sediment is deposited on the beach. The green silhouette
yellow—this is where the dredged sediment is deposited on the beach. The green silhouette in the
in the upper right is The Netherlands with the Eurogeul area marked with a red dot.
upper right is The Netherlands with the Eurogeul area marked with a red dot.
In recent years, many private collectors have created collections of various fossils found on the
In recent
seashore. Theseyears,
beaches many
are aprivate collectors
rich source have created
of well-preserved collections
skeletal oflarge
parts of various fossils mammals
terrestrial found on
the seashore. These beaches are a rich source of well-preserved skeletal
such as woolly mammoths and woolly rhinoceroses of the mammoth fauna. However, remains of parts of large terrestrial
mammals
small such as
terrestrial, woolly
marine, andmammoths
freshwaterand woolly
aquatic rhinoceroses
mammals such asofbeavers
the mammoth
and ottersfauna.
have However,
also been
remains of small terrestrial, marine, and freshwater aquatic mammals such as beavers
collected. Other interesting finds include insect remains, birds, fish, and even coprolites of hyenas and otters have
[7–
also been collected. Other interesting finds include insect remains, birds, fish, and
14]. These fossil finds are often well documented, and reveal many previously unknown details about even coprolites of
hyenas [7–14]. These fossil finds are often well documented, and reveal many previously
the individuals and their species, as well as their habitat and faunal assemblages. Through amateur unknown
detailscollecting,
beach about theimportant
individuals and have
insights their been
species,
made asfor
well
theas their habitat
deciduous and theandvery
faunal
smallassemblages.
permanent
Through amateur beach collecting, important insights have been
tusks of woolly mammoths. Little was known about these deciduous tusks and the made for the deciduous and theearly
very
small permanent tusks of woolly mammoths.
development of the permanent tusks of these proboscideans.Little was known about these deciduous tusks and the
earlyThe
development of the permanent tusks of these proboscideans.
juvenile deciduous and permanent tusks described here are identified as belonging to the
The juvenile deciduous
late Pleistocene-age Mammuthus andprimigenius,
permanent based tusks described here are identified
on their morphology [15–17].asEarly
belonging to the
and middle
late Pleistocene-age Mammuthus primigenius, based on their morphology [15–17].
Pleistocene faunal remains from the bottom of the North Sea can easily be distinguished from late Early and middle
Pleistocene remains
Pleistocene faunal remains
by theirfrom themineralized
heavily bottom of the North
state Sea can easily
of preservation be distinguished from late
[1,8,9,18].
Pleistocene remains by their heavily mineralized state of preservation [1,8,9,18].
2. Literature Review for Deciduous and Permanent Tusks
Several publications describe details about deciduous and permanent tusks of Mammuthus
primigenius [10,15–17,19,20]. However, the number of reported specimens is limited.
Quaternary 2018, 1, 7 3 of 14
2. Literature Review for Deciduous and Permanent Tusks
Several publications describe details about deciduous and permanent tusks of Mammuthus
primigenius [10,15–17,19,20]. However, the number of reported specimens is limited.
Rountrey et al. [17] stressed the importance of finding additional tusk specimens in their landmark
research on early tooth development, gestation, and season of birth in mammoths regarding these
dental elements. In their conclusion they stated:
This work shows the potential value of detailed individual life history studies using
teeth. With work on additional specimens, these techniques could lead to construction
of an accurate tooth development schedule for mammoths, and this information is critical
for studies of mammoth life history that will help elucidate ecological factors associated
with extinction.
Every find of deciduous tusks and small permanent tusks of extremely young mammoths can
contribute greatly to our scientific understanding in this area of study, and should be recorded.
Hence, the amateur collectors of fossil remains on Dutch beaches deserve support and should be
encouraged both to learn to recognize these rare specimens and to have opportunities to present them
to paleontologists for examination. This paper intends to contribute to this effort, with a short overview
of the literature and a discussion of both the known deciduous tusks and the smallest permanent
tusks of juvenile mammoths from the environment of The Netherlands, which have been identified in
recent years.
There are other dental elements and parts thereof that can be easily confused with the smallest
tusks. One of these confounding fossils is presented here, a fossil digitelle (“finger”) of a plate of a
premolar of a juvenile woolly mammoth, which was considered to be a possible small tusk. Mammoths
and modern elephants go through a series of six sets of adult molars in their lifetime. The molars are
classified with capital letters for upper molars and lower case letters for lower jaw molars (Table 1).
Table 1. The dental formulae (following Sikes [21]) used for Mammuthus primigenius and recent African
and Asian elephants for each side.
1I 0C 3 dP 3M
Maxilla (Upper Jaw)
(1× Incisive) (No Canines) (3 Deciduous Premolars) (3 Molars)
0i 0c 3 dp 3m
Mandibula (Lower jaw)
(No incisives) (no canines) (3 deciduous premolars) (3 molars)
The uppercase letters I, C, P, and M are used to designate the upper jaw; and the lowercase letters i, c, p, and m are
used for the lower jaw.
Recognizing and determining fossils to species level requires comparison with known specimens.
Because of the rarity and the difficulty in recognizing the deciduous and juvenile permanent tusks
of Mammuthus primigenius, the fossil record is very limited. Sikes [21] discussed details about these
teeth from the African elephant, Loxodonta africana (Blumenbach, 1797), providing useful specimens
for comparison. Mashchenko [15] described several of these juvenile tusks, and concluded that both
deciduous tusks and permanent tusks develop in the fetus during the earliest stages simultaneously
and that the former were merely rudimentary without any function, being quickly replaced by the
permanent tusks.
Rountrey et al. [17] published a detailed analysis of two extraordinary late Pleistocene juvenile
mammoth mummies from Siberia, giving a comprehensive description of their dental elements.
One complete mummy was Lyuba from Yamal, a female individual who died when she was one month
old. Remarkably, she was missing both permanent tusks. The other was Oimyakon from Yakutia,
a partial mummy with the right permanent tusk, the left one being lost. Its gender is unknown and
it was approximately seven months old at time of death. It had already lost the deciduous tusks,
described and photographed by Maschenko et al. [16]. In cross-section, the oval-shaped permanent
Quaternary 2018, 1, 7 4 of 14
tusk measured 76 mm in length and was entirely covered with cementum and characterized by the tip
of the tusk being covered with an enamel cap.
Van der Plicht et al. [10] described a somewhat larger juvenile skull with a right permanent tusk
Quaternary 2018, 2,in
still anchored the alveolus.
x FOR This skull was trawled from the North Sea floor in the Eurogeul.4 of
PEER REVIEW It 14
is
mentioned here to illustrate the typical black enamel, which eventually becomes worn down due to
usage (Figure 2). TheseThese publications
publications are
are useful
useful references
references for identifying
identifying and analyzing
analyzing these rare
dental elements.
Figure
Figure 2.
2. Incomplete
Incomplete cranium
cranium of of aa juvenile
juvenile Mammuthus
Mammuthus primigenius
primigenius with
with the
the right
right permanent
permanent tusk
tusk in
in
anatomical position. For details and measurements see Van der Plicht et al. [10]. Locality: Euro-
anatomical position. For details and measurements see Van der Plicht et al. [10]. Locality: Euro-Maasgeul,
Maasgeul,
North Sea. North Sea. Collection:
Collection: Klaas Post,Klaas Post, Urk.
Urk. Photo: HansPhoto: Hans Wildschut.
Wildschut.
3. Review of Deciduous and Permanent Tusk Collections in The Netherlands
3. Review of Deciduous and Permanent Tusk Collections in The Netherlands
The
The following
following is
is aa brief
brief overview
overview of all known
of all known fossil
fossil deciduous
deciduous and permanent tusks
and permanent tusks of
of
Mammuthus primigenius in or close to The Netherlands.
Mammuthus primigenius in or close to The Netherlands.
3.1.
3.1. Terra Maris Museum
Terra Maris Museum Collection
Collection in
in Oostkapelle
Oostkapelle
A
A deciduous
deciduous tusk
tusk in
in the
the collection
collection of
of the
the Museum
Museum Terra
Terra Maris
Maris (Oostkapelle)
(Oostkapelle) was
was found
found on on aa trail
trail
consisting
consisting ofof sea
sea shells
shells in
in Zeeland
Zeeland near
near Veere in the
Veere in the late
late 1980s.
1980s. The
The very
very small
small and
and fragile
fragile specimen
specimen
shows
shows the
the typical
typical well-developed
well-developed root
root and
and has
has been
been described
described by
by Langeveld and Mol
Langeveld and Mol [22].
[22]. It
It belonged
belonged
to
to a very young Mammuthus primigenius, probably only a couple of months old at the time ofits
a very young Mammuthus primigenius, probably only a couple of months old at the time of itsdeath.
death.
3.2. Collection of Jan van der Steeg
A perfectly
perfectlypreserved
preserved deciduous
deciduous tusktusk
was was
foundfound
in the in the Holt-und-Haar
Holt-und-Haar sand pit,sand
close pit, close to
to Gildehaus
Gildehaus
in Germanyinnear
Germany nearborder.
the Dutch the Dutch
It isborder. It is catalogued
catalogued as number
as number P00170 in theP00170 in theofcollection
collection Jan van derof
Jan van
Steeg inder SteegMeijer
Losser. in Losser. Meijer [23]more
[23] provided provided
detailsmore details
about about
the site andthe
its site and its mammalian
mammalian fauna. Thefauna.
entire
The entire is
specimen specimen
somewhatis somewhat
club shapedclubhasshaped
a veryhasweak
a veryS-curve.
weak S-curve. The specimen
The specimen was described
was described and
and photographed
photographed by Mol
by Mol and Boeskorov
and Boeskorov [24]. [24]. No traces
No traces of wear
of wear are visible,
are visible, indicating
indicating that itthat
mustit must
have
have been embedded
been embedded entirelyentirely in the alveolus.
in the alveolus. Mol andMol and Boeskorov
Boeskorov [24] suggested
[24] suggested that this
that this animal mustanimal
have
must have died
died before before
the age the year.
of one age ofThe
onetusk
year. The tusk69.9
measures measures
mm in 69.9 mmThe
length. in length. The tipwith
tip is covered is covered
a thin
with a thin enamel layer which in turn is covered by a very thin layer of cementum. The diameter of
the enamel cap is between 7.1 and 14 mm.
3.3. Collection of Walter Langendoen
Another right deciduous tusk of a Mammuthus primigenius was collected on May 2014 on the
man-made beach of Maasvlakte 2 and added as specimen number WL0181 to the collection of Walter
Quaternary 2018, 1, 7 5 of 14
enamel layer which in turn is covered by a very thin layer of cementum. The diameter of the enamel
cap is between 7.1 and 14 mm.
Quaternary 2018, 2, x FOR PEER REVIEW 5 of 14
3.3. Collection of Walter Langendoen
reasonably
Another rightwell preserved.tusk
deciduous Its tipofconsists of dentin primigenius
a Mammuthus covered by a was
cap ofcollected
enamel. The
on root
Mayis2014
damaged
on the
in the area of the pulp cavity and the exact original length cannot be determined. This specimen is
man-made beach of Maasvlakte 2 and added as specimen number WL0181 to the collection of Walter
practically straight and has a preserved length of 46 mm. The enamel cap’s length is 17 mm and its
Langendoen (Figure 3). It is currently on display in the Historyland museum in Hellevoetsluis.
diameter varies between 6 and 9 mm.
Mol et al. [9], Langeveld
The and
original tusk wasMol [22]
used to and
makeMolsome [18] described
casts. this small
Unfortunately, deciduous
it broke tusk,the
in half along which
lengthwas
reasonably
of thewell
axispreserved. Its tip consists
during the production of theof dentin
casting covered
mold. by a cap
However, of enamel.
this accident The root
provided is damaged
insight in the
in the area of the
interior, pulp
which cavity
shows theand the exact
different toothoriginal lengthindicating
tissues clearly cannot bedentin,
determined.
cementum This specimen
and enamel. is
practically straight
The depth andstill-open
of the has a preserved
pulp cavity,length of 46 mm.
the volume The enamel
of dentin and the cap’s length
cementum andisenamel
17 mmcover
and its
are visible in Figure 3H.
diameter varies between 6 and 9 mm.The tusk was eventually restored.
Figure 3. Right deciduous tusk of Mammuthus primigenius. Locality: Beach of Maasvlakte. Collection:
Figure 3. Right deciduous tusk of Mammuthus primigenius. Locality: Beach of Maasvlakte. Collection:
Walter Langendoen (Hellevoetsluis) WL0181. Scale bar: 5 cm. Photo: Hans Wildschut. (A) Medial
Walter Langendoen (Hellevoetsluis) WL0181. Scale bar: 5 cm. Photo: Hans Wildschut. (A) Medial view;
view; (B) cranial view; (C) lateral view; (D) anterior view conical cap (tip of the tusk); (E) posterior
(B) cranial view; (C) lateral view; (D) anterior view conical cap (tip of the tusk); (E) posterior view,
view, circumference of the root including the cross section of the pulp cavity; (F) interior view after
circumference
breakageof the root
medial including
half; (G) the after
interior view crossbreakage
sectionlateral
of thehalf;
pulpandcavity; (F)ofinterior
(H) details view
the anterior after
view.
breakage medial half;
c: cementum; (G) interior
d: dentine; view
e: enamel; pc:after
pulpbreakage lateral
cavity. Photo: Hanshalf; and (H) details of the anterior
Wildschut.
view. c: cementum; d: dentine; e: enamel; pc: pulp cavity. Photo: Hans Wildschut.
Quaternary 2018, 1, 7 6 of 14
The original tusk was used to make some casts. Unfortunately, it broke in half along the length
of the axis during the production of the casting mold. However, this accident provided insight in
the interior, which shows the different tooth tissues clearly indicating dentin, cementum and enamel.
The depth of the still-open pulp cavity, the volume of dentin and the cementum and enamel cover are
Quaternary 2018, 2, x FOR PEER REVIEW 6 of 14
visible in Figure 3H. The tusk was eventually restored.
3.4.Collection
3.4. CollectionofofPeter
PeterSoeters
Soeters
AAcomplete
completeright
rightdeciduous
deciduoustusktuskwas
wasfound
foundon onthe
thebeach
beachof ofRockanje
Rockanje(South
(SouthHolland
HollandProvince)
Province)
ininMay
May20082008and
andititwas
wasadded
addedtotothe
thecollection
collectionofofPeter
PeterSoeters
SoetersininDelft
Delft(Figure
(Figure4).
4).Its
Itsroot
rootisissomewhat
somewhat
curved and has a rather small pulp cavity. The tusk is slightly incurvate as well
curved and has a rather small pulp cavity. The tusk is slightly incurvate as well and has a pristine and has a pristine
cap
ofcap of black
black enamel.
enamel. It has Ita shallow,
has a shallow, weakly-developed
weakly-developed groovegroove on the medial
on the medial side. Theside. The maximum
maximum length
islength
52 mm is and
52 mmthe and the thickness
thickness is 6 mmismeasured
6 mm measured in the middle
in the middle of the flattened
of the flattened root. Theroot. The crown
crown has a
has a lateral length of 9 mm and a medial
lateral length of 9 mm and a medial length of 7 mm. length of 7 mm.
Figure 4. Right deciduous tusk of Mammuthus primigenius. Locality: Beach of Rockanje. Collection:
Peter Soeters
Figure (Delft).
4. Right Scale bar:
deciduous tusk 5ofcm. Photo: Hans
Mammuthus Wildschut:
primigenius. (A) Medial
Locality: view;
Beach of (B) lateral
Rockanje. view;
Collection:
and (C)Soeters
Peter cranial(Delft).
view. Scale bar: 5 cm. Photo: Hans Wildschut: (A) Medial view; (B) lateral view; and
(C) cranial view.
3.5. Collection of Donny Chrispijn
3.5. Collection of Donny Chrispijn
A complete right deciduous tusk was found by Peter Soeters on the beach of Rockanje in April
A complete
2008, and it was addedrighttodeciduous tuskofwas
the collection found
Donny by Peter
Chrispijn inSoeters
Hoek van onHolland
the beach of Rockanje
(Figure 5). The in April
typical
2008, and
groove it wason
is visible added to theside,
the medial collection of Donny
facilitating Chrispijn in Hoek
the determination. van Holland
The smaller length(Figure
compared 5). The
to
typical
the groove
specimen is visible
in Section 3.4on the medial
is noted, whichside, facilitating
is probably due totheresorption
determination. The smaller
in the growing processlength
of
compared
the permanent to the
tuskspecimen
behind init. Section 3.4 is length
The original noted, must
whichhaveis probably due to resorption
been distinctly longer. This in the
wouldgrowing
also
process
mean thatofthe
thepermanent
permanenttusk tuskwasbehind it. The
present original
during length
the first must
year have
of the been
calf’s lifedistinctly longer.
[16]. Sikes This
[21] also
would also mean that the permanent tusk was present during the first year
described this growing process for African elephants. The maximum length of this specimen is 37 mm of the calf’s life [16]. Sikes
[21]the
and also described
thickness is 7this
mmgrowing
measured process
in thefor African
middle elephants.
of the flattenedThe maximum
root. The crown length of this the
has almost specimen
same
is 37 mm and
dimensions the
as in thickness
Section is 7 amm
3.4, has measured
lateral length ofin 9the
mm middle
and a of the flattened
medial length ofroot.7 mm.TheThecrown
enamel has
almost
cap thepreserved
is well same dimensions as in is
and its width Section
12 mm3.4, has a lateral
laterally and 11length of 9 mm and a medial length of 7
mm medially.
mm. The enamel cap is well preserved and its width is 12 mm laterally and 11 mm medially.
Quaternary 2018, 1, 7 7 of 14
Quaternary 2018, 2, x FOR PEER REVIEW 7 of 14
Quaternary 2018, 2, x FOR PEER REVIEW 7 of 14
Figure
Figure 5. 5. Right
Right deciduoustusk
deciduous tuskofofMammuthus
Mammuthus primigenius.
primigenius. Locality:
Locality:Beach
BeachofofRockanje.
Rockanje.Collection:
Collection:
Donny
Figure
Donny 5.Chrispijn
Chrispijn (Hoekvan
Right deciduous
(Hoek van Holland).
tusk Scale
Scalebar:
of Mammuthus
Holland). 5 cm. Photo:
primigenius.
bar: 5 cm. Hans
Locality:
Photo: Wildschut.
HansBeach (A) Medial
of Rockanje.
Wildschut. view; (B)
(A) Collection:
Medial view;
lateral
Donny view; and
Chrispijn (C)
(Hoekcranial
van view.
Holland).
(B) lateral view; and (C) cranial view. Scale bar: 5 cm. Photo: Hans Wildschut. (A) Medial view; (B)
lateral view; and (C) cranial view.
3.6. Collection of Hansjorg Ahrens
3.6. Collection of Hansjorg Ahrens
3.6. Collection of Hansjorg Ahrens
Hansjorg Ahrens from Leiden collected a small permanent right tusk of a very young woolly
Hansjorg Ahrens from Leiden collected a small permanent right tusk of a very young woolly
mammoth
Hansjorg on Ahrens
the beach of De
from Zandmotor,
Leiden collected which is anpermanent
a small artificial extension
right tusk ofof
thea coastline
very young at the coast
woolly
mammoth
of Monster
mammoth
onon
the
(South beach
Holland
the beach
of DeProvince).
of De
Zandmotor,
Zandmotor,
which
Except
which aissmall
for is an artificial extension
indentation
an artificial on the
extension
of thecavity,
of pulp
coastline
the coastline the at the
tusk
at the iscoast
coast in
ofof
Monster
superb
Monster (South
state Holland
of preservation
(South Province).
(Figure 6).Except
Holland Province). Except
The tusk for
for is a small
straight
a small indentation
and slightly
indentation on the
on flattened pulp cavity,
giving an
the pulp cavity, theovalthe is in is
tusk
tuskcross-
insuperb
superbstate
section. state
It isof of
coveredpreservation
in a thin
preservation (Figure
film
(Figure 6). tusk
of6).black
The The
enameltusk
is is straight
with
straight the
and and slightly
exception
slightly of a small
flattened flattened
sectionan
giving giving
of an oval
the medial
oval cross-
cross-section.
side which
section. It is isIttan
is colored.
covered covered
in a thin infilm
The alateral
thin
of blackfilm of blacksurface
and enamel
medial enamel
with withtusk
theofexception
this theofisexception
arough
smalldue oftoaasmall
section thin
of section
medial of
theirregular
the medial
layerwhich
side side
of enamel. which
is tan The is
typical
colored. tan colored.
Thegroove
lateralisand The lateral
visible on the
medial and medial
medial
surface surface
side.tusk
of this of
Thisispermanent this tusk
rough duetusk is rough
to a belonged due
to an
thin irregular to a
thin irregular
unborn
layer of enamel.layer
or newborn Theoftypical
enamel.
individual. The
grooveIt istypical
isthe groove
smallest
visible ismedial
known
on the visible on the
specimen
side. medial
with
This side.tusk
a maximum
permanent This permanent
length of 37tomm.
belonged an tusk
belonged
The depth
unborn tonewborn
or an unborn
of the pulp or newborn
cavity
individual. is It
22ismm. individual.
the It is the
The maximum
smallest known smallestwith
circumference
specimen knownata the specimen with
base of length
maximum the pulpa maximum
of cavity
37 mm.is
length
The of 37
43 mm;
depth mm.
theof the The
pulpdepth
diameter is
cavity ofisthe
16 mm, 22andpulp
mm. cavity
it measures
The is922
maximum mm mm.fromThethemaximum
circumferenceaxis to thecircumference
atthe lateral
base ofside.
the pulp at cavity
the base is of
43pulp
the mm;cavity
the diameter
is 43 mm; is 16 mm,
the and it measures
diameter is 16 mm,9and mmitfrom the axis
measures to the
9 mm lateral
from the side.
axis to the lateral side.
Figure 6. Right permanent tusk of Mammuthus primigenius. Locality: Beach of de Zandmotor.
Figure Right
Figure6. 6.
Collection: permanent
Hansjorg
Right Ahrens
permanent of Mammuthus
tusktusk
(Leiden). primigenius.
Scale bar:
of Mammuthus Locality:
5 primigenius.
cm. Photo: Hans Beach of de Zandmotor.
Wildschut.
Locality: Beach (A)
of Lateral Collection:
view;
de Zandmotor. (B)
Hansjorg
medial Ahrens
view; (C)(Leiden).
cranial Scale
view; bar:
and 5
(D) cm. Photo: Hans
circumference Wildschut.
pulp cavity. (A) Lateral view; (B) medial
Collection: Hansjorg Ahrens (Leiden). Scale bar: 5 cm. Photo: Hans Wildschut. (A) Lateral view; (B) view;
(C) cranial view; and (D) circumference pulp cavity.
medial view; (C) cranial view; and (D) circumference pulp cavity.
Quaternary 2018, 1, 7 8 of 14
Quaternary 2018, 2, x FOR PEER REVIEW 8 of 14
3.7.
3.7. Collection
Collection of
of Dick
Dick Mol
Mol
Peter
Peter Soeters from Delft
Soeters from Delft collected
collectedaapermanent
permanenttusk
tuskofofaajuvenile
juvenilewoolly
woollymammoth
mammoth onon
thethe beach
beach of
of Rockanje in August 2013, which he then donated to the first author. This well preserved
Rockanje in August 2013, which he then donated to the first author. This well preserved tusk is straighttusk is
straight with no curvation (Figure 7). It also shows the characteristic groove indicating
with no curvation (Figure 7). It also shows the characteristic groove indicating that it originated from
that it
originated from the left upper jaw. Most of this gray-brown to yellow-brown specimen is covered
the left upper jaw. Most of this gray-brown to yellow-brown specimen is covered with a wafer-thin
with a wafer-thin layer of enamel. When compared to the specimens described by Machenko [15], it
layer of enamel. When compared to the specimens described by Machenko [15], it can be concluded
can be concluded that the animal was only a few months old when it died. The maximum length is
that the animal was only a few months old when it died. The maximum length is 49 mm. The depth of
49 mm. The depth of the pulp cavity measures 24 mm. Posterior of the pulp cavity, the circumference
the pulp cavity measures 24 mm. Posterior of the pulp cavity, the circumference of the tusk is 48 mm.
of the tusk is 48 mm. Measured from the back to the front, the diameter here is 17 mm, and measures
Measured from the back to the front, the diameter here is 17 mm, and measures 12 mm from medial
12 mm from medial to lateral.
to lateral.
Figure 7. Left permanent tusk of Mammuthus primigenius. Locality: Beach of Rockanje. Collection:
Figure 7. Left permanent tusk of Mammuthus primigenius. Locality: Beach of Rockanje. Collection: Dick
Dick Mol (Hoofddorp). Scale bar: 5 cm. Photo: Hans Wildschut. (A) Lateral view; (B) medial view;
Mol (Hoofddorp). Scale bar: 5 cm. Photo: Hans Wildschut. (A) Lateral view; (B) medial view; (C)
(C) cranial view; and (D) circumference pulp cavity.
cranial view; and (D) circumference pulp cavity.
3.8. Collection of Willy van Wingerden
3.8. Collection of Willy van Wingerden
On 24 February 2017, Willy van Wingerden from Honselersdijk picked up a permanent tusk of
On 24 February 2017, Willy van Wingerden from Honselersdijk picked up a permanent tusk of
a woolly mammoth from the beach of De Zandmotor. The shape of the tusk is straight (Figure 8).
a woolly mammoth from the beach of De Zandmotor. The shape of the tusk is straight (Figure 8). The
The tip is covered with a thin layer of enamel and the transition from the enamel to the dentin is
tip is covered with a thin layer of enamel and the transition from the enamel to the dentin is clearly
clearly visible. The previously described groove located on the medial side of the tusk facilitates
visible. The previously described groove located on the medial side of the tusk facilitates the
the determination as a left permanent tusk. The tusk is tan colored and the enamel tends to a dark
determination as a left permanent tusk. The tusk is tan colored and the enamel tends to a dark brown
brown color. Resembling the specimen from Dick Mol’s collection found on the beach of Rockanje
color. Resembling the specimen from Dick Mol’s collection found on the beach of Rockanje (Item 3.7),
(Item 3.7), this tusk must have belonged to a juvenile Mammuthus primigenius just a couple of months
this tusk must have belonged to a juvenile Mammuthus primigenius just a couple of months old. The
old. The maximum length is 53 mm and the pulp cavity is 21 mm deep.
maximum length is 53 mm and the pulp cavity is 21 mm deep.
Quaternary 2018, 1, 7 9 of 14
Quaternary 2018, 2, x FOR PEER REVIEW 9 of 14
Quaternary 2018, 2, x FOR PEER REVIEW 9 of 14
Figure 8.8.Left
Figure Leftpermanent
permanenttusk of Mammuthus
tusk of primigenius.Locality:
Mammuthus primigenius. Locality:Beach
Beachofof
dede Zandmotor.
Zandmotor. Collection:
Collection:
Figure
Willy van 8. Left permanent
Wingerden tusk of Mammuthus
(Honselersdijk). Scale primigenius.
bar: 5 cm. Locality:
Photo: Beach
Hans of de Zandmotor.
Wildschut. (A) Collection:
Lateral
Willy van Wingerden (Honselersdijk). Scale bar: 5 cm. Photo: Hans Wildschut. (A) Lateral view; (B) view;
Willy
(B)medial
medialvan Wingerden
view; (C) (Honselersdijk).
cranial view; and (D)Scale bar: 5 cm.
circumference Photo:
pulp
view; (C) cranial view; and (D) circumference pulp cavity. Hans
cavity.Wildschut. (A) Lateral view; (B)
medial view; (C) cranial view; and (D) circumference pulp cavity.
3.9.
3.9. CollectionofofMartien
Collection MartienLelijLelij
3.9. Collection of Martien Lelij
AA superbspecimen
superb specimenof ofaapermanent
permanent tusk of of aa woolly
woollymammoth
mammothwas wasfound
found bybythethelate Martien
late Martien
Lelij A superb
from Hoek specimen
van Holland of aon permanent tusk ofina March
woolly2012.
mammoth was from
foundthe byupper
the late Martien
Lelij from Hoek van Holland on thethe local
local beach
beach in March 2012. It Itis isa tusk
a tusk from the upper right right jawand
jaw
Lelijitfrom
and is Hoek curved
slightly van Holland
(Figure on9).
theItlocal beach
clearly has in March
the 2012. It isgroove
characteristic a tusk onfromthe the upperside.
medial rightThe
jaw
it is slightly curved (Figure 9). It clearly has the characteristic groove on the medial side. The brown
and it is slightly curved (Figure 9). It clearly has the characteristic groove on the medial side. The
to brown
dark brown to darkenamel brown layer
enamel is layer is substantial
substantial in thickness.
in thickness. The cementum
The cementum layerlayer
andand the the transition
transition from
brown
from the tocementum
dark brown to enamel
the layer
dentin areis clearly
substantial in thickness.
visible. Because Thetip
the cementum
of this layer
tusk is and
not the polished
yet transition
thefrom
cementumthe to
cementum the dentin
to the are
dentinclearly visible.
are clearly Because
visible. the
Because tiptheofof this
tipthe tusk
ofliving is
this tusk not yet
is not polished
yetitpolished due
due
to use, to use, it is likely that it was completely hidden in the alveolus animal. If so, would
due it
imply
is
tothat
use,likely
this
that itthat
it istusk
likely wasit completely
belonged wasto acompletely
hidden
woolly mammoth hiddenin the
inthatalveolus
the alveolus
must
ofofthe
have theliving
died living
within
animal.
animal.
the firstIfIfso,
so,ititwould
year
would
of its
implyimplythat this tusk belonged to a woolly mammoth that must have died within the first year ofofitsits
first year
life. Thisthat this tusk belonged
undamaged tusk has atolength
a woolly mammoth
of 102 mm. At that mustofhave
the end the pulpdied cavity,
within thethe circumference
life.life.
This undamaged tusk hashasa alength of 102
102mm. At
At the
theisend of the the pulp
pulpcavity,
cavity,the the circumference
of theThis tuskundamaged
is 55 mm. The tuskdiameter length
of theofoval mm. cavity
pulp end
19 ofmm at maximum. The circumference
enamel layer
of the
of tusk
the tuskis 55is mm.
55 mm.The Thediameter
diameter ofofthetheoval
oval pulp
pulp cavity
cavity is
is 19
19 mm
mm at maximum.
at maximum.The Theenamel
enamellayer layer
measures from the tip of the tusk to the rear over a maximum length of 66 mm.
measures from the tip of the tusk to the rear over
measures from the tip of the tusk to the rear over a maximum length a maximum length of 66 mm.
mm.
Figure 9. Right permanent tusk of Mammuthus primigenius. Locality: Beach of Hoek van Holland.
Figure
Figure 9. Right
9. Right
Collection: permanent
permanent
Martien tusk
tusk
Lelij (Hoek ofofMammuthus
van Mammuthus
Holland). primigenius.
Scale bar: 5 cm.Locality:
primigenius. Locality: Beach
Beach
Photo: Hans ofofHoek
Hoekvan
Wildschut. vanHolland.
(A) Holland.
Lateral
Collection: Martien
view; (B) Martien
Collection: Lelij
medial view; (Hoek
(C) cranial
Lelij (Hoek van Holland).
van view; and (D)
Holland). Scale bar: 5
circumference
Scale cm. Photo: Hans
pulp cavity.
bar: 5 cm. Photo: Wildschut. (A) Lateral
Hans Wildschut. (A) Lateral view;
view; (B) medial view; (C) cranial view; and (D) circumference pulp cavity.
(B) medial view; (C) cranial view; and (D) circumference pulp cavity.
Quaternary
Quaternary 2018,
2018, 2,
1, x7 FOR PEER REVIEW 10
10 of
of 14
14
3.10. Collection of Trudy Langeveld
3.10. Collection of Trudy Langeveld
A right permanent juvenile tusk was collected by Trudy Langeveld from Voorhout in January
A right
2011 on permanent
the beach of Hoek juvenile tusk was
van Holland. Thecollected by Trudy
sand originated Langeveld
from from Voorhout
the extraction areas to the in north
Januaryof
2011 on the beach of Hoek van Holland. The sand originated from the extraction
the Euro-Maasgeul, off the coast of South Holland. It has been added to her collection under catalog areas to the north of
the Euro-Maasgeul,
number 141. off the coast of South Holland. It has been added to her collection under catalog
numberThis141.
larger specimen, mostly yellow-brown colored, is slightly damaged; the tip has been broken
Thispossibly
recently, larger specimen,
due to the mostly yellow-brown
suction action of the colored, is slightlymachine
sand dredging damaged;(Figure
the tip10).
has It been broken
is slightly
recently, possibly
rounded medially,due to thethe
showing suction action of groove.
characteristic the sandDeposits
dredging ofmachine
wafer-thin (Figure
black10).
enamelIt is are
slightly
still
roundedonmedially,
present showing
the lateral side of the
thischaracteristic
tusk. The marks groove.
of thisDeposits
permanent of wafer-thin
tusk suggest black
thatenamel are still
it had already
present on
emerged the lateral
from the tuskside of this
socket andtusk.
mustThe marks
have been ofvisible
this permanent
in the living tuskanimal.
suggestWhenthat itcompared
had already to
emerged
the specimenfromdescribed
the tusk socket
by Vananddermust have
Plicht been
et al. ([10]visible in the2)
see Figure living
it cananimal. When compared
be concluded to the
that the animal
specimen
was 12–24described
months byoldVan der Plicht
at time et al. ([10]
of death. see Figure has
The specimen 2) it acan be concluded
preserved lengththatofthe102animal
mm, wasbut
12–24 months old
reconstructing theat time
total of death.
length usingThe
thespecimen
specimenhas a preserved
from the collectionlength of of 102 mm,
Martien but
Lelij forreconstructing
comparison,
theleast
at total30length
mm isusing the specimen
missing. The depthfrom
of thethe collection
pulp of84
cavity is Martien
mm and Lelij
its for comparison,
maximum at least
diameter 30 mm
measures
is missing.
28 mm. The depth of the pulp cavity is 84 mm and its maximum diameter measures 28 mm.
Figure
Figure 10.
10. Right
Right permanent
permanent tusk
tusk of
of Mammuthus
Mammuthus primigenius.
primigenius. Locality:
Locality: Beach
Beachof
ofHoek
Hoek van
van Holland.
Holland.
Collection:
Collection: Trudy Langeveld (Voorhout). Scale bar: 5 cm. Photo: Hans Wildschut. (A) Medial view;
Trudy Langeveld (Voorhout). Scale bar: 5 cm. Photo: Hans Wildschut. (A) Medial view;
(B)
(B) lateral
lateral view;
view; (C)
(C) cranial
cranial view;
view; and
and (D)
(D) circumference pulp cavity.
circumference pulp cavity.
3.11.
3.11. Collection
Collection of
of Henk
Henk Mulder
Mulder
In
In November
November 2017,
2017, Henk
Henk Mulder
Mulder from
from Monster
Monster picked
picked up
up aa left
left permanent
permanent tusktusk of
of aa young
young
woolly mammoth from the beach of De Zandmotor. Unfortunately, the tip of the tusk
woolly mammoth from the beach of De Zandmotor. Unfortunately, the tip of the tusk was broken was broken
due
due to mechanical
to mechanical action.
action. However,
However, thecavity
the pulp pulp was
cavity wasThis
intact. intact.
tuskThis
was tusk
fromwas fromindividual
an older an older
individual than thefrom
than the specimen specimen from theofcollection
the collection of Trudy(Item
Trudy Langeveld Langeveld (Item
3.10). The 3.10).isThe
length length
about is about
150 mm and
150 mm and the depth of the pulp cavity
the depth of the pulp cavity is 55 mm. is 55 mm.
4.
4. The
The Juvenile
Juvenile Tusk Look-Alike
Tusk Look-Alike
The
The preceding
preceding text
text gives
gives an
an overview
overview of
of known
known deciduous
deciduous tusks
tusks and
and permanent
permanent tusks
tusks of
of very
very
young
young woolly
woolly mammoths.
mammoths. TheThe knowledge
knowledge is
is valuable
valuable as
as aa reference
reference collection,
collection, and
and also
also to
to distinguish
distinguish
them from confounding elements that look similar but yet have a different origin; in particular, the
following dental element.Quaternary 2018, 1, 7 11 of 14
them from
Quaternary confounding
2018, 2, x FOR PEERelements
REVIEW that look similar but yet have a different origin; in particular, 11 of 14
the following dental element.
Erwinvan
Erwin vander derLee
Leefound
foundaafragment
fragmentof ofaadental
dentalelement
elementin inthe
thesupplemented
supplementedsand sandof ofthe
thebeach
beach
ofHoek
of Hoekvan vanHolland
Hollandin inAugust
August2017 2017(Figure
(Figure11).
11).The
Thespecimen
specimenhas hassome
somecharacteristics
characteristicsof ofaatusk
tuskof of
aajuvenile
juvenilemammoth.
mammoth. It It is
is fragile,
fragile, not
not fully
fully developed,
developed, without a root and a very very deep
deep pulp cavity.
cavity.
Themaximum
The maximumlength lengthisis4646mm.mm.ItItappears
appearsto tobebecomplete,
complete,from
fromthethepulp
pulpcavity
cavityon
onthe
theposterior
posteriorside
side
tothe
to thetip
tipononthe
theanterior
anteriorside.
side.ItItisisslightly
slightlycurved
curvedand andstrongly
stronglyflattened
flattenedlaterally.
laterally.The
Thetiptipisiscovered
covered
by a thin cap. The circumference of this tusk is 28 mm at the pulp cavity and
by a thin cap. The circumference of this tusk is 28 mm at the pulp cavity and 26 mm in the middle of 26 mm in the middle of
thetusk.
the tusk.The
Thedepth
depthof ofthis
thiscavity
cavityappears
appearsto tobebe22
22mm.
mm.The Thespecimen
specimenconsists
consistsofofdentin
dentincompletely
completely
coveredwith
covered withaafilmfilmofofenamel,
enamel,whichwhichin inturn
turnisiscovered
coveredby byaathin
thinlayer
layerof ofcementum.
cementum.The Thecross-section
cross-section
ofthe
of thedental
dentalelement
elementisisflattened,
flattened,giving
givingan anoval
ovalshape
shapeover
overthetheentire
entirelength.
length.The
Themaximum
maximumdiameterdiameter
ofthe
of thetusk,
tusk,measured
measuredfrom fromfrontfronttotoback
backisis55mm,
mm,ininanatomical
anatomicalposition.
position.ItItmeasures
measures10 10mm mmfrom
from
medialto
medial tolateral.
lateral.TheThepulp
pulpcavity
cavityisisextremely
extremely small
small compared
compared to to all
all known
known small
small permanent
permanent tusks.
tusks.
Moreover,this
Moreover, thisspecimen
specimenisistoo tooflattened,
flattened,seen
seenfrom
fromfront
fronttotoback.
back. These
These are
arenot
notcharacteristics
characteristicsof of
newly-developed permanent
newly-developed permanent tusks.tusks. Furthermore, the morphology of the find find is
is too
too irregular
irregular in in
structure to be determined as a (permanent)
structure to be determined as a (permanent) tusk. tusk.
Figure11.
Figure 11.Digitelle
Digitelleof
ofaapremolar
premolarofofMammuthus primigenius. Locality:
Mammuthusprimigenius. Locality: Beach
Beach of
of Hoek
Hoek van
van Holland.
Holland.
Collection: Erwin van der Lee (Rotterdam). Photo: Hans Wildschut. (A) Caudal view; (B) cranial
Collection: Erwin van der Lee (Rotterdam). Photo: Hans Wildschut. (A) Caudal view; (B) cranial view; view;
(C)medial
(C) medialview;
view;(D)
(D)lateral
lateralview;
view;and
and(E)
(E)circumference
circumferencepulp
pulpcavity.
cavity.
This specimen must be identified as one of the digitelles, which is a part of lamella of a mammoth
This specimen must be identified as one of the digitelles, which is a part of lamella of a mammoth
molar. A pillar or a slat shows deep incisions. It appears that such a pillar is composed of several
molar. A pillar or a slat shows deep incisions. It appears that such a pillar is composed of several
adjacent, and, on the bottom, closely connected digits that are flattened from the front to the rear.
adjacent, and, on the bottom, closely connected digits that are flattened from the front to the rear. Such a
Such a pillar is made up of several varying digitelles. Several digits and the pillars form a plate. The
pillar is made up of several varying digitelles. Several digits and the pillars form a plate. The digits
digits are usually connected at the base. This is not always the case with premolars. The size of this
are usually connected at the base. This is not always the case with premolars. The size of this digitelle
digitelle suggests that this must have been part of a third or fourth premolar.
suggests that this must have been part of a third or fourth premolar.
5. Conclusions
The tusks of juvenile Mammuthus primigenius discussed in this paper are of great scientific value as
they are still very rare in the fossil record. Because of sand supplementation activities of the Dutch
beaches, deciduous tusks and very small permanent tusks are now occasionally found. These elements
are very important sources for mammalian paleontological research. However, the chance of recognitionQuaternary 2018, 1, 7 12 of 14
5. Conclusions
The tusks of juvenile Mammuthus primigenius discussed in this paper are of great scientific
value as they are still very rare in the fossil record. Because of sand supplementation activities
of the Dutch beaches, deciduous tusks and very small permanent tusks are now occasionally found.
These elements are very important sources for mammalian paleontological research. However,
the chance of recognition is also slim. The tusks described and illustrated here can aid in recognition
of these particular mammoth remains and increase the likelihood that they will be preserved for the
fossil record.
5.1. Basic Characteristics of Deciduous Tusks
A deciduous tusk is somewhat club shaped and has a relatively large root and a well-developed
cap on the tip, which is covered with a thin enamel layer that in turn is covered by a thin layer of
cementum. It may measure around 35–100 mm in length and usually nearly straight or only slightly
nonlinear. The cross-section is more or less oval shaped—the lateral side being more curved than the
medial side. A shallow groove may be visible on the medial side of the tusk (Figures 3A, 4A, 5A, 6B,
7B, 8B, 9B and 10A).
5.2. Basic Characteristics of Juvenile Permanent Tusks
The major distinction between the deciduous and permanent tusk is the relatively deep pulp
cavity, which may measure up to about half of its total length. Permanent tusks do not have a root.
The length of the smallest known specimen measures 37 mm and it is covered with a very thin layer of
enamel. The common features with deciduous tusks are the cross-section, the lateral side being more
curved compared to the medial side. The medial side of the tusk is characterized by a shallow groove.
However, a correct identification of fossil remains requires careful comparisons. To determine whether
the specimen is a deciduous tusk or a newly-developed permanent tusk, a thorough knowledge is
required of the tusk and the development of proboscideans. It was only after extensive comparisons
that the discovery of Erwin van der Lee could be definitively classified as a digitelle of a lamella or
plate of a Mammuthus primigenius, rather than a juvenile tusk.
Tusks of proboscideans have a complex structure with chevron shaped lines (Schreger lines) and
growth rings much like trees, which carry the complete life history. A detailed analysis of a tusk’s
interior would provide more information about the first years of life of mammoths which inhabited
the vast plains between the British Isles and the continent of Europe in the Late Pleistocene. Then,
we might be able to judge the rate at which newborn mammoth calves have grown, and whether or
not that matches what we know about elephants in Africa and Asia. Hopefully, more such finds will
be made in sufficient quantities to sacrifice one or more of good quality to be subjected to the required
destructive tests for that.
Author Contributions: The authors all contributed to the determinations, to the analysis of the results and to the
writing of the manuscript.
Funding: No funding was received for the production of this paper.
Acknowledgments: The authors would like to express their gratitude to Erwin van der Lee from Rotterdam for
making available his discovery of the digitelle of a premolar woolly mammoth for identification and research.
Once more, we would like to thank Jan van der Steeg in Losser and Walter Langendoen in Hellevoetsluis,
for making available the deciduous tusks in their care; Peter Soeters in Delft for his donation of a number
of mammoth finds, including the very small permanent tusk; the late Martien Lelij from Hoek of Holland,
Hansjorg Ahrens from Leiden, Trudy Langeveld from Voorhout, Henk Mulder from Monster, Donny Chrispijn
from Hoek van Holland and Willy van Wingerden from Honselersdijk for providing their exceptional finds of
very small permanent tusks for description; Hans Wildschut, Hoofddorp, for the photography; and Klaas Post
and Bram Langeveld (Natuurhistorisch Museum Rotterdam) for reviewing earlier drafts of this paper.
Conflicts of Interest: The authors declare no conflict of interest.
Ethical Statement: In The Netherlands, collecting fossils from public places is legal. However, fossil collection
elsewhere may be limited or prohibited by law. Also none of the authors are a member of any professionalQuaternary 2018, 1, 7 13 of 14
society with a code of ethics that recommends against publishing work on specimens that are held in private
collections. Such a code would be counterproductive in The Netherlands. The vast public beaches contain an
abundance of small fossil remains. Over the years, the number of non-professional paleontologists has increased
steadily, and they may have collected many rare specimens that would not have been discovered otherwise.
Non-professionals are a valuable resource to the field of paleontology here. In the Netherlands we are facing a
unique situation. For almost four decades, professionals and non-professionals have been united in the active
Werkgroep Pleistocene Zoogdieren (working group Pleistocene Mammals, www.pleistocenemammals.com),
which organizes very well attended fossil determination sessions several times a year for their ever-increasing
collections. At these meetings, non-professionals can learn and have their fossil finds identified by professionals.
The professional scientific community benefits from these meetings in getting an overview of all the discoveries
made in the field. Knowledge and information is shared mutually. In this way, many rare specimens have emerged,
enriching the Pleistocene fauna of the North Sea. Often these collectors develop an interest in the whereabouts of
their finds and many educate themselves to become ‘citizen scientists’. In addition, the collectors are encouraged
to donate or loan their specimens to museums for availability for research. Moreover, replicas are routinely
produced for display. Most collectors are happy to have their specimens examined by scholars. Publicizing about
these noteworthy finds in leading international media is a logical part of this process.
References
1. Mol, D.; de Vos, J.; Bakker, R.; van Geel, B.; Glimmerveen, J.; van der Plicht, J.; Post, K. Kleine Encyclopedie Van
Het Leven in Het Pleistoceen—Mammoeten, Neushoorns en Andere Dieren van de Noordzeebodem; Uitgeverij Veen
Magazines B.V.: Diemen, The Netherlands, 2008; ISBN 9789085710981.
2. Van Kolfschoten, T.; Laban, C. Pleistocene terrestrial mammal faunas from the North Sea. Meded. Rijks
Geol. Dienst 1995, 52, 135–151.
3. Mol, D. Twee etmalen korren in de Eurogeul: trok de kotter OD7 door een mammoetkerkhof? Afzettingen
2012, 33, 7–10.
4. Mol, D.; Post, K. Gericht korren op de Noordzee voor de zoogdierpaleontologie: Een historisch overzicht
van de uitgevoerde expedities. Cranium 2010, 2, 14–28.
5. Laban, C.; Rijsdijk, K.F. De Rijn-Maasdelta’s in de Noordzee. Grondboor Hamer 2002, 56, 60–65.
6. Rijsdijk, K.F.; Kroon, I.C.; Meijer, T.; Passchier, S.; van Dijk, T.A.G.P.; Bunnik, F.P.M.; Janse, A.C. Reconstructing
Quaternary Rhine–Meuse dynamics in the southern North Sea: Architecture, seismolithofacies associations
and malacological biozonation. J. Quat. Sci. 2013, 28, 453–466. [CrossRef]
7. Post, K. A Weichselian marine mammal assemblage from the southern North Sea. Deinsea 2005, 11, 21–27.
8. Mol, D.; Borst, W.; Reumer, J. De eerste fossiele hyenakeutel uit de Noordzee. Straatgras 2010, 22, 91–93.
9. Mol, D.; Langeveld, B.; Janse, A.; Langendoen, W.; Smolarz, J. Determinatiedag fossiele strandvondsten van
Maasvlakte 2 in Futureland: Een verslag. Cranium 2015, 32, 49–58.
10. Van der Plicht, J.; Post, K.; Mol, D. Over aasvliegen en een mammoetkalf uit de Eurogeul. Cranium 2012,
29, 14–19.
11. Dieleman, F. Overzicht van strandvondsten van woelmuizen en andere kleine zoogdieren langs de
Nederlandse stranden: Stand van zaken 2013. Afzettingen 2013, 34, 144–172.
12. Langeveld, B. Trogontherium cuvieri Fischer (Castoridae) van het strand van Hoek van Holland en de
Zandmotor. Cranium 2013, 30, 8–12.
13. Langeveld, B. Fossiele omhulsels van poppen van de subarctische aasvlieg Protophormia terraenovae
Robineau-Desvoidy, 1830 voor het eerst van opgespoten stranden (Eurogeulgebied). Cranium 2015, 32, 34–38.
14. Langeveld, B. Vondsten van de reuzenalk Pinguinus impennis (Linnaeus, 1758) (Aves) uit het Eurogeulgebied.
Cranium 2015, 32, 19–27.
15. Maschenko, E.N. Individual development, biology and evolution of the woolly mammoth. Cranium 2002,
19, 4–120.
16. Maschenko, E.N.; Boeskorov, G.G.; Baranov, V.A. Morphology of a Mammoth Calf (Mammuthus prinigenius)
from Ol’chan (Oimiakon, Yakutia). Paleontol. J. 2013, 47, 425–438. [CrossRef]
17. Rountrey, A.N.; Fisher, D.C.; Tikhonov, A.N.; Kosintsev, P.A.; Lazarev, P.A.; Boeskorov, G.; Buigues, B. Early
tooth development, gestation, and season of birth in mammoths. Quat. Int. 2012, 255, 196–205. [CrossRef]
18. Mol, D. Mammoth fossils recovered from the seabed between the British Isles and the European continent.
Bulletin de Musée d’Anthropologie préhistorique de Monaco 2016, 6, 129–142.
19. Maschenko, E.; Tikhonov, A.N.; MacPhee, R.D. Mammoth calf from Bolshoi Lyakhovskii Island
(New Siberian Islands, Arctic Siberia). Russ. J. Theriol. 2005, 4, 79–88. [CrossRef]Quaternary 2018, 1, 7 14 of 14
20. Maschenko, E.N.; Gablina, S.S.; Tesakov, A.S.; Simakova, A.N. The Sevsk woolly mammoth
(Mammuthus primigenius) site in Russia: Taphonomic, biological and behavioral interpretations. Quat. Int.
2006, 142, 147–165. [CrossRef]
21. Sikes, S.K. The Natural History of the African Elephant; World Naturalist; Weidenfeld and Nicolson: London,
UK, 1971; pp. 1–397. ISBN 978-0297000297.
22. Langeveld, B.; Mol, D. Vanuit de zeebodem naar het strand: Een kennismaking met fossielen van
Maasvlakte 2 (deel 1). Spirifer 2015, 39, 2–19.
23. Meijer, H.J.M. Mammoeten moeten ook drinken. Een nieuwe visie op een Laat-Pleistoceen ecosysteem.
Cranium 2001, 18, 17–26.
24. Mol, D.; Boeskorov, G. Een merkwaardige slagtand van een wolharige mammoet, Mammuthus primigenius
(BLUMENBACH, 1799) uit de Noordzee en korte beschrijvingen van twee mammoettanden uit Europa en
Azië, met algemene opmerkingen over slagtanden. Cranium 2007, 24, 17–36.
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).You can also read
