PDF (Lo-Res) - Smithsonian Institution Libraries

Intraspecific Variation in Modern and Quaternary
European Lagopus
ABSTRACT
Skeletal proportions of modem European populations of Lagopus
lagopus (Linnaeus) and L. mutus (Montin) from Britain, Iceland,
Scandinavia, northern Russia, and the Alps are compared
with their Quaternary fossil counterparts from Britain, Poland,
France, and Belgium. Lagopus lagopus and L. mutus from most
pre-Holocene deposits are found to differ allometrically from
modem samples. This difference is best seen in the tarsometatarsus,
which often is more robust in both species in the Pleistocene
and in turn may reflect greater body weight. Possible correlations
between this phenomenon and the climatic and ecological conditions
of the past, as well as the possibility that these birds were less
sedentary, are discussed.
Introduction
Previous workers, such as Newton (1924), Mourer-Chauvire
(1975a, 1975b), Janossy (1974, 1976), Bochehski (1974,
1985, 1991), Harrison (1980), Potapova (1986), and Bocheriski
and Tomek (1994) have described differently sized
and proportioned postcranial bones of both Lagopus mutus
(Montin) and Lagopus lagopus (Linnaeus) from the fossil
record of Europe. Specifically, samples of both species from
the Pleistocene were seen to differ in size and allometry from
skeletons of their recent counterparts. These allometric differences
were seen in the relative proportions of their tarsometatarsi,
carpometacarpi, phalanx 1 digit III pedis, and phalanx 1
digit II alae, as well as in cranial elements.
Newton, who was probably the first to note the occurrence of
anomalously proportioned Lagopus fossils of Pleistocene age,
believed that a third species had existed (Newton, 1924). He referred
to this species, found at Merlin's Cave, a late Pleistocene
site in Britain, as a "small ptarmigan" and never named it as a
distinct form, which is how many authors have dealt with these
John R. Stewart, The McDonald Institute for Archaeological Research,
Downing Street, Cambridge CB2 3ER, England.
John R. Stewart
159
anomalies since. Exceptions are the species Lagopus atavus
Janossy (1974) from the late Pliocene of Poland (Janossy,
1976; Bocheriski, 1991) and the subspecies L. lagopus noaillensis
Mourer-Chauvire (1975a) and L. mutus correzensis
Mourer-Chauvire (1975a) from La Fage, a Rissian (middle
Pleistocene) site in France.
Lagopus lagopus noaillensis and L. mutus correzensis were
described by Mourer-Chauvire as being distinguished by the
robustness of their tarsometatarsi as compared to modern populations.
She also plotted the mean lengths and shaft widths of
tarsometatarsi of both species from La Colombiere and Gigny,
two assemblages of different ages from the last glacial of
France, together with the two named subspecies from La Fage.
This showed that they, too, had relatively robust tarsometatarsi,
although their lengths varied, producing allometric-shape variation.
The most detailed study of Lagopus fossils to date was that
by Bocheriski (1974). In his book he compared a number of
Polish fossil populations of both species from the last glaciation
with samples from much of their modern European distribution.
He concluded that the fossil birds possessed longer carpometacarpi
and humeri but shorter tarsometatarsi than their modern
counterparts, and that the articular ends of the humeri, tarsometatarsi,
and coracoids were more massive. Bocheriski interpreted
the differences in the wing-bone lengths as indicating
that the primary feathers of both species had become shorter,
thus reducing wing-surface area over time. This, together with
the change in bone robustness, especially that of the coracoid,
indicated to him that the two species had maintained, or had
only slightly reduced, their body size over time. Later, Bocheriski
(1985) showed that Pleistocene L. lagopus in Poland
had longer distal-wing bones (carpometacarpi and phalanx 1
digit II alae) and shorter distal-leg elements (tarsometatarsi and
phalanx 1 digit III pedis) when compared to modern birds. Subsequently,
Bocheriski and Tomek (1994) focused on the relative
lengths of postcranial bones of Pleistocene L. mutus in
Austria and showed that they differed from modern alpine birds
in having shorter tarsometatarsi but longer carpometacarpi.