Remains of subfossil birds from King George Island (South Shetland

Remains of subfossil birds from King George Island (South Shetland

ACTA ZOOL. CRACOV.
29
7
109-116
K R A K Ó W , 15. X I I . 1985
Zygm unt B o c h e ń s k i
Remains of subfossil birds from King George Island (South Shetland Islands)
[w ith P la te X I and 3 text-figs]
Szczątki kopalnych ptaków z Wyspy Króla Jerzego (Szetlandy Południowe)
A b s t r a c t . F ifty-tw o bones and th e ir fragm ents of subfossil birds were found in 1981 a t
Low H ead on K ing George Island (South Shetland Islands). T hey are determ ined as Pygoscelis
antarctica and Stercorarius skua an d d ated back to Younger Holocene.
Bird bones described in th e present paper were found on 2. II. 1981 on King
George Island (South Shetland Islands) by th e members of Polish A ntarctic
Expedition, Prof. D r K. B i r k e n m a j e r and D r B. J a b ł o ń s k i , and collected
by the latter. The bony m aterial was found a t Low H ead, th e locality pointed
a t th e sketch m ap (Fig. 1). Some of the bones were scattered on th e moraine
surface, b u t those under study were covered by about 10 cm stratu m of moraine
gravel, th e surface of which was hardened by clumps of moss and overgrown
by lichen Usnea antarctica. According to Prof. B i r k e n m a j e r (personal commu­
nication) th e bones come from th e tim e of Younger Holocene as they had lain
on the sea terrace, covered by moraine, 25 to 40 m above th e sea level. This
terrace originates from E arly to Middle Holocene and is homologous to the
terrace of th e same level from th e Penguin Island, described by B i r k e n m a j e r
(1982 b). On the other hand th e degree of covering of bony m aterial lying on
moraine surface by lichens suggests th a t it has lain intact for a t least several
hundered years. These two premises lim it th e tim e th e bones are coming from.
Penguin bones
All the m aterial collected consists of 51 bones or bony fragments. There were
found among them : 11 specimens of hum erus (6 complete), 1 coracoid, 12
femora (of them 5 complete or nearly complete), 7 tibiotarsi, 1 ulna, 1 fragm en­
ta ry sacrum and 1 vertebra. O ther bony pieces coming most probably of young
birds are so fragm entary and damaged th a t it is impossible to recognize them.
The greater p a rt of rem nants is strongly damaged, and on the other hand coming
from young birds, have not completely ossified articular parts. T hat is the
reason why only sixteen specimens can be studied in details and determined.
115
В. 1979. Vergleichende Osteologie der Pinguine. Mitt. zool. Mus. Berlin, 55, Suppl.:
Ann. Orn. 3: 3—98.
V o l k m a n N. J., W. T r i v e l p i e c e . 1981. Nest-site selection among Adeliae, Chinstrap and Gentoo
Penguins in mixed species rookeries. Wilson Bull., Lawrence, 93 (2): 243— 248.
W h i t e W . G., J . W . H. C o n r o y . 1975. Aspects of competition between pygoscelid penguins
at Signy Island, South Orkney Islands. Ibis, London, 117 (3): 371—373.
Stephan
STRESZCZENIE
2
lutego 1981 zostały znalezione w żwirze moreny (fot. 1), pokrywającej
morską terasę na Low Head, na Wyspie króla Jerzego (Szetlandy Południowe),
szczątki ptaków w postaci 52 kości, fragmentów i wiórów kostnych. Ich wiek
określony na młodszy holocen jest ograniczony z jednej strony przez wiek terasy
(starszy lub środkowy holocen), a z drugiej strony przez porosty, które rosły
na morenie nietknięte przynajmniej przez kilkaset lat. Większość szczątków
należy do pingwinów. Pomiary lepiej zachowanych 16 kości pingwinów (tab. I),
a także morfologia (fot. 2—7), szczególnie kości ramieniowych, wskazują bez­
spornie, że szczątki należały do gatunku Pygoscelis aniarctica.
W opisywanym materiale została także znaleziona pojedyncza kość ramie­
niowa (fot. 8, tab. II), oznaczona jako Stercorarius skua.
Żaden z obu wymienionych gatunków nie był dotychczas podawany ze sta­
nowisk kopalnych.
Redaktor pracy: prof. dr M. Młynarski
8*