Ancient DNA and dating of cave bear remains from Niedzwiedzia Cave
suggest early appearance of Ursus ingressus in Sudetes
Mateusz Baca a,*, Pawe1 Mackiewicz h,*, Anna Stankovic b,e
, Danijela Popovic c
,
Krzysztof Stefaniak d
, Kinga Czarnogórska e
, Adam Nadachowski f
, Micha1 Ga˛siorowski g
,
Helena Hercman g
, Piotr Weglenski b,c
a Center for Precolumbian Studies, University of Warsaw, Krakowskie Przedmiescie 26/28, 00-927 Warsaw, Poland b Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawinskiego 5a, 02-106 Warsaw, Poland
c Centre of New Technologies, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
dDepartment of Evolutionary Biology and Ecology, University of Wrocław, Sienkiewicza 21, Wrocław 50-335, Poland e Institute of Genetics and Biotechnology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland
f
Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Cracow, Poland g Institute of Geological Sciences, Polish Academy of Sciences, Twarda 51/55, 00-818 Warsaw, Poland
hDepartment of Genomics, Faculty of Biotechnology, University of Wrocław, Przybyszewskiego 63/77, 51-148 Wrocław, Poland
abstract
The migration of Ursus ingressus from Southern to Western Europe, where it replaced native forms of
Ursus spelaeus, is well documented. However, its occurrence in Central and Eastern European countries is
unexplored. We have characterized the cave bear population inhabiting the Sudetes Mountains during
the Late Pleistocene. DNA analyses were performed on 39 cave bear specimens from the Niedzwiedzia
Cave. Ten successfully yielded the 254-bp sequences of an mtDNA control region. Phylogenetic analyses
allowed assignment of nine samples to the U. ingressus haplogroup and one to brown bear (Ursus arctos).
The mtDNA haplotypes of U. ingressus formed a single cluster and differed from haplotypes obtained for
cave bears from other excavation sites in Europe. Uraniumethorium and radiocarbon dating of selected
samples has shown that U. ingressus appeared in the Sudetes region at least 80,000 years ago. This
finding may suggest that the appearance of U. ingressus in this area resulted from migration that occurred
earlier than the colonization of the Alps and Swabian Jura. It is possible that migration of U. ingressus
proceeded along the Carpathian and Sudetes arc.
It is widely accepted that two main forms of cave bear, Ursus
ingressus and Ursus spelaeus, inhabited Europe during the Late
Pleistocene (Rabeder, 1995; Rabeder et al., 2000, 2004a, 2004b;
Rabeder and Hofreiter, 2004; Hofreiter et al., 2004b) (Fig. 1).
However, the taxonomical position of these forms is still under
debate: they are considered either as separate species (Rabeder,
1995; Rabeder and Hofreiter, 2004; Rabeder et al., 2004a, 2004b;
Hofreiter et al., 2004b) or as U. s. spelaeus and U. s. ingressus, subspecies
of U. spelaeus (Baryshnikov and Puzachenko, 2011).
U. spelaeus has been further divided into ‘classic’ U. s. spelaeus and
two high-Alpine forms with reduced body size, U. s. eremus and U. s.
ladinicus (Rabeder et al., 2004b, 2008). U. spelaeus remains have
been found in Spain, France, Germany, Belgium, Italy, and Austria,
while U. ingressus inhabited mostly Eastern Europe and has been
discovered in Romania, Slovenia, Ukraine, Czech Republic, Slovakia,
and Greece but also in Switzerland, Austria, and Germany. Divergence
of these two forms took place 173e414 ka (Knapp et al.,
2009). The place of U. ingressus origin remains unknown: however,
the basal position of haplotypes from the Romanian site Pes¸ tera
cu Oase in phylogenetic trees suggests Southeastern Europe (Baca
et al., 2012). It has been proposed that the westward migration of
U. ingressus started ca. 60,000 years ago (Rabeder and Hofreiter,
2004; Münzel et al., 2011). The presence of U. ingressus was
genetically confirmed in several sites in Austria (Gamssulzen,
Nixloch, and Herdengel caves), and its first appearance has been
dated to ca. 50,000 years ago (Rabeder and Hofreiter, 2004;
Hofreiter et al., 2004a, 2004b). U. ingressus cohabited with Alpine
forms of U. spelaeus for some time and ultimately replaced it.
Further migration of U. ingressus to the Swabian Jura ca. 32,000
years ago probably also resulted in the final replacement of
U. spelaeus ca. 28,000 years ago (Hofreiter et al., 2007; Münzel et al.,
2011).
We previously reported two aDNA sequences of this species
from Niedzwiedzia Cave in Poland, moving its range northwards
(Baca et al., 2012). The taxonomical affiliation of these samples was
confirmed by phylogenetic and morphometric analyses. One sample
was found to be over 49,000 years old, indicating an earlierthan-expected
migration of U. ingressus into the Sudetes region.
To verify this interesting hypothesis and to assess the genetic diversity
of cave bears from this region, we have carried out aDNA
analyses on a larger sample and applied uraniumethorium dating
of bone collagen to obtain the precise age of the studied samples.
"...Interestingly, one sequence obtained from a III metatarsal (KLEVI_22)
excavated in Niedzwiedzia Cave clusters with sequences of
brown bear (U. arctos) (Fig. 3). This positioning confirms previous
biometrical and morphological analyses indicating that this bear
species also inhabited this cave in the Late Pleistocene
(Wiszniowska, 1989; Wiszniowska et al., 1996; Bieronski et al., 2009)..."
. Discussion
Paleogenetic characterization of the cave bear in Europe is still
incomplete. While the distribution and phylogeography of cave
bear haplotypes in Western Europe are well documented, the north
and northeastern parts of its range are poorly characterized. Our
analyses of aDNA from Niedzwiedzia Cave, which is located north
from the Carpathian arc, at least partially fill this gap. Phylogenetic
analysis of 12 DNA samples obtained from remains excavated from
distinct excavation profiles of different geological ages indicated
that they undoubtedly belong to the U. ingressus group; an exception
was one sample that was clearly affiliated with the brown bear.
No sequences related to U. spelaeus were identified, suggesting that
U. ingressus was the only form of cave bear inhabiting the cave for at
least 40,000 years. The population of U. ingressus from
Niedzwiedzia Cave appears quite divergent from other European
samples. These findings plus the age of samples (up to ca.
80,000 BP) indicate an early separation of this population from
other European U. ingressus. Afterwards, the range of the Carpathians
may have played the role of an insulating barrier because no
evidence of gene flow has been identified between populations
from both sides of this mountain range.
The presence of only the U. ingressus haplotype and the lack of
U. spelaeus during the Early Weichselian in the Sudetes differ from
other central European sites located in the Austrian Alps and
Swabian Jura, to which migration of U. ingressus from Southeastern
Europe was associated with replacement of U. spelaeus (Rabeder
and Hofreiter, 2004; Rabeder et al., 2008; Münzel et al., 2011). It
was proposed that U. ingressus was ecologically better adapted to
continental environments and could outperform U. spelaeus
(Baryshnikov and Puzachenko, 2011). Morphological studies of cave
bears from Alpine caves revealed improved masticatory performance
of U. ingressus in comparison to U. spelaeus, which allowed
for more efficient food intake and processing (Rabeder et al., 2008).
Greater morphological variability of U. ingressus also suggests its
better adaptational abilities (Rabeder et al., 2008). The earliest
known samples of Alpine U. ingressus came from Gamssulzen Cave
and are dated to 47,300 BP (Bocherens et al., 2011), i.e., from the
beginning of high climate fluctuations during MIS 3. This context
may suggest that because of better adaptation skills, U. ingressus
could successfully compete with U. spelaeus during sudden and
severe climate oscillations. It cannot be excluded that these adaptations
also facilitated its migration north to the Carpathians, where
U. spelaeus was not reported. According to dating of specimens from
Niedzwiedzia Cave, U. ingressus appeared in the Sudetes at least
20,000 years earlier than in the Austrian Alps, during MIS 5a.
In this context, it is interesting to consider if potential differences
in dietary habits between U. ingressus and U. spelaeus
contributed to their different distribution. It has been assumed that
the cave bear was generally adapted to a herbivorous diet. The
herbivory of the cave bear is well supported by many craniodental
features (see e.g., Kurtén, 1976; Mattson, 1998; Rabeder et al., 2000;
Grandal-D’Anglade and López González, 2004), the relatively thic
dental enamel cap (Mackiewicz et al., 2010), several adaptations in
enamel structure (Wiszniowska et al., 2010), and numerous stable
isotope studies (e.g., Bocherens, 1990; Bocherens et al., 1994, 2006;
Nelson et al., 1998; Vila-Taboada et al., 1999; Fernández-Mosquera
et al., 2001).
Isotope analyses of samples with confirmed haplotype affiliation
based on DNA showed that both U. spelaeus and U. ingressus
were vegetarians (Bocherens et al., 2011; Bon et al., 2011; Münzel
et al., 2011). Interestingly, studies of cave bears from two closely
located caves in Austria showed that U. spelaeus eremus and
U. ingressus probably consumed different plant types from different
habitats (Bocherens et al., 2011). Recent analyses based on large
isotopic data sets revealed that the cave bear isotopic profile does
not differ from that of the grizzly bear (U. arctos horribilis), accustomed
to a diversified diet that varies from vegetarian to carnivorous
(Robu et al., 2013). Moreover, samples from Southeastern
European (Carpathian) sites, probably related to U. ingressus,
showed higher values of the nitrogen stable isotope, which suggests
a greater abundance of animal protein in their diet. In
agreement with that, studies of U. ingressus samples from Greece
indicated that this bear was mainly vegetarian but with a variable
component of what was likely aquatic animal protein (Dotsika et al.,
2011). Therefore, it cannot be excluded that U. ingressus was more
flexible than U. spelaeus in its dietary habits, which facilitated its
migration, especially to colder ecozones, e.g., northwards from the
Sudetes and the Carpathians, as our studies have indicated
5. Conclusions
Phylogenetic analyses of specimens from Niedzwiedzia Cave in
the Sudetes showed that this cave, located north of the Carpathian
arc, was inhabited for at least 40,000 years by only one taxon of
cave bear, U. ingressus. Dating of some samples (ca. 80,000 BP) indicates
that the appearance of U. ingressus in the Sudetes took place
earlier than in Western Europe. In agreement, the haplotypes from
Niedzwiedzia are divergent from those from other Western European
sites. The Niedzwiedzia Cave population was probably isolated
from other Western European cave bear populations because
the identified haplotypes were not detected in other excavation
sites.
www.smorfland.uni.wroc.pl/uploads/Main/1-s2.0-S1040618213006538-main.pdfSkeleton of cave bear Ursus speleaus in the the pavilion of the Bear Cave Kletno,Poland.
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