PDF (Lo-Res) - Smithsonian Institution Libraries

NUMBER 89 51
TABLE 4.—Measurements (mm) of fossil tarsometatarsi of Pterodroma baraui compared with modem specimens.
Catalog number
Fossil
site 8.8
site 8.5
Modem
MNZ 23831
Paris, number 772
Paris, number 2601
Paris, number 2603
Length
38.2
38.1
38.2
36.8
37.3
39.8
Mascarene Petrel {Pterodroma aterrima) that compare well
with those of the more complete specimen (MNZ S34852,
measurements given second): length from nostrils 20 mm vs.
-22 mm; length of nostril 10 mm vs. 12 mm; length to angle
gape 34 mm vs. 35 mm; depth at proximal end of nostril 11
mm vs. 10 mm. The width of MNZ S34852 at the angle gape is
16.5 mm.
Pachyptila macgillivrayi
FIGURES 9,10
One species of prion that now breeds on Amsterdam Island is
currently referred to Pachyptila salvini macgillivrayi (Roux et
al., 1986; Jouventin, 1994; Micol and Jouventin, 1995), although
previously it was referred to as a subspecies of the
Proximal width
6.3
_
6.8
6.3
6.9
6.4
Shaft width
2.8
3.2
2.8
2.8
3.2
2.8
Distal width
6.1
6.6
6.7
5.8
6.3
6.2
Broad-billed Prion (P vittata) (e.g., Jouanin, 1953; Paulian,
1960; Roux and Martinez, 1987), presumably because of its
similarly broad bill. It was allied with Salvin's Prion (P. salvini)
on account of its similar size, its breeding cycle (which is
more aligned with that of P. salvini), and its blue bill, as opposed
to the "steel-grey bills" of P. vittata (Roux and Martinez,
1987).
Prion bones are very numerous in most sites. Their measurements
exhibit an apparently normal, unimodal size distribution
(Figure 10, Appendix 3), so we refer the bones in this size
range to a single taxon with which we associate the numerous
cranial remains characterized by very broad bills that are found
in the same sites. The bones of this Amsterdam prion cannot be
referred to either P. vittata or P. salvini for the following rea-
FlGURE 9.—Photographs of Pachyptila skulls in dorsal (left) and ventral (right) views. A,C, modem P. vittata,
MNZ 12667, New Zealand; B,D, fossil P. macgillivrayi from site 18.7. Scale bar=5 cm.