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162 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
TABLE 2.—Chronology and location of fossils samples (including ones discussed from literature).
Site
Remouchamps, Belgium
Merlin's Cave, England
Mamutowa Cave, Poland
Pin Hole Cave, England
La Balme-les-Grottes, France
La Colombiere, France
Gigny, France
La Fage, France
Westbury-sub-Mendip, England
Rebielice Krolewskie, Poland
late glacial
Stratigraphic Position
late glacial
Vistulian (Upper pleniglacial)
Devensian
"Wurm IV" (late glacial)
"Wurm IV" (late glacial)
"Wurm II"
"Rissian"
Early Anglian (oxygen isotope stage 12)
Biozone MNI6
Laura Kaagan and Simeon Mellalieu for help with the final version
of this paper, and to Janet Stacey for much support and encouragement.
The following people and institutions deserve
thanks for allowing access to both modern and fossil Lagopus
used in this analysis: Mark Adams, Don Smith, and Robert
Prys-Jones (Subdepartment of Ornithology, Natural History
Museum, Tring); Sandra Chapman and Andy Currant (Palaeontology
Department, The Natural History Museum, London); Per
Ericson (Naturhistoriska Riksmuseet, Stockholm); Jon Fjeldsa
(Zoologisk Museum, Copenhagen); Derek Yalden (University
of Manchester); Cecile Mourer-Chauvire (Universite Claude-
Bernard, Lyon); Michel Phillipe (Museum d'Histoire Naturelle
de Lyon); Zygmunt Bocheriski (Institute of Systematics and
Evolution of Animals, Kracow); John Nudds (Manchester City
Museum); Chris Hawkes (University of Bristol Speleological
Society Museum); the Musee Royaux d'Art d'Histoire,
Bruxelle; and Ruth Charles (University of Oxford). Finally, I
would like to acknowledge the support of the Natural Environment
Research Council (NERC) for funding this research and to
acknowledge the financial support from NERC as well as the
Graduate School of University College London, which allowed
me to present these results at the fourth international meeting of
the Society of Avian Paleontology and Evolution.
Results
In Lagopus mutus, there is a noticeable difference in the
mean size of the tarsometatarsi among modern subspecies in
Europe (see Table 1). The Scottish subspecies {L. mutus millaisi)
is larger than populations from Scandinavia {L. m. mutus) or
the Alps (L. m. helveticus). This difference is perhaps best seen
in the length, although the bones appear to be isometric. This
confirms the findings of Bocheriski (1974), although differences
in the means calculated in our two studies exist. Kraft
(1972) alleged differences between nominate L. m. mutus from
Scandinavia and L. m. helveticus from the Alps, but this could
not be confirmed in the present study due to small sample size.
With Lagopus lagopus there appears to be greater overlap
between the samples, although L. I. scoticus is slightly larger
than nominate L. 1. lagopus. The single specimen of L. I. major
Reference
Hedges etal., 1994
Housley, 1991
Bocheriski, 1974
Jacobi, pers. comm., 1996
Mourer-Chauvire, 1975a
Mourer-Chauvire, 1975a
Mourer-Chauvire, 1975a
Chaline, 1975
Currant, pers. comm ., 1996
Bocheriski, 1991
Age
10,330±110yrs. BP
and 10,800±1I10
yrs. BP
10,020±120yrs. BP
ca. 30-15 Ka
ca.100-10 Ka
ca. 15-10 Ka
13,390±300yrs. BP
ca. 30-20 Ka
ca. 300-150 Ka
ca. 500-450 Ka
ca. 3.6-2.4 Ma
is very much larger, although sample size prevents reliable
consideration of this subspecies, which is, however, regarded
as larger by ornithologists (Dement'ev and Gladkov, 1967).
The most apparent difference between modern and fossil
samples of both species of Lagopus is the difference in their
tarsometatarsal-shaft widths (Figure 2). This is almost ubiquitous,
which is important because the modern samples are geographically
widely spaced, and the fossils come from sites of
significantly different ages as well as being widely spaced geographically.
In addition, there is a tendency for fossils of both
taxa from the last glaciation to have shorter tarsometatarsi, thus
making these bones very robust (Figure 2). An exception to
this pattern is provided by the study made by Mourer-Chauvire
(1975a) on a sample from Gigny in France, which, although
from the last (Wurm) glaciation, had relatively long tarsometatarsi.
Tarsometatarsi from La Fage (Rissian) also show this tendency
(Mourer-Chauvire, 1975a; Figure 2). Therefore, length
is probably more variable among fossil populations than is
shaft width.
Given the consistency of greater robustness in Pleistocene
tarsometatarsi of Lagopus, an explanation should be sought.
Although it is conceivable that the species may have changed
through evolution or replacement, both L. lagopus and L. mutus
can be traced from the Pleistocene, suggesting intraspecific
adaptational changes. Research into bovid limbs and the variables
affecting their morphology has shown that shaft width is
closely correlated with body mass (Scott, 1985) because of
weight-bearing constraints, so the greater robustness of the fossil
tarsometatarsi of Lagopus may reflect greater mean body
weight. To test this hypothesis an attempt was made to assess
the degree to which tarsometatarsal dimensions are correlated
with body weight in modern Lagopus.
Both species of Lagopus are included in this analysis to augment
the size and range of samples. This approach is considered
valid because the relationship should be strictly mechanical
and thus comparable between closely related taxa; it would
seem unlikely that bones of L. lagopus and L. mutus possess
significantly different mechanical properties. Figure 3 shows
that there is a close, positive correlation between bird weights
and their tarsometatarsal-shaft widths (correlation coefficient