PDF (Lo-Res) - Smithsonian Institution Libraries

NUMBER 89 17
cal in shape and dimensions to that from Mauritius and therefore
must belong to the same species.
Compared with living forms of Anas from Madagascar, A.
theodori is larger than A. bernieri (Hartlaub) (Figure 5, Table 7)
and smaller than A. melleri P.L. Sclater (Howard, 1964). We
compared it in the USNM with various species of Anas. The one
it resembles most is Anas gibberifrons Muller, which lives in the
east and northeast of the Indian Ocean, from the Andaman Islands
to Indonesia and Australia, and on islands in the western
Pacific Ocean (Mayr and Cottrell, 1979). The common characteristics
and the differences between A. theodori and A. gibberi­
Measurement
Sternum
width (a)
keel depth (b)
Coracoid
internal length
proximal width
proximal depth
stemal-facet length
stemal-facet depth
minimum shaft width
depth at same level
Humerus
total length
proximal width
proximal depth
distal width
distal depth
midshaft width
midshaft depth
Ulna
total length
proximal width
proximal depth
distal width
depth external condyle
midshaft width
midshaft depth
Tibiotarsus
total length (c)
proximal width (c)
proximal depth (c)
distal width
distal depth
minimum shaft width
depth at same level
Tarsometatarsus
total length
proximal width
proximal depth
distal width
distal depth
midshaft width
midshaft depth
'Specimen very juvenile.
frons are as follows. If the anterior part of the sternum illustrated
by Newton and Gadow (1893, pl. 34: figs. 11, 12) is perfectly
preserved, the carina projects further anteriorly and the ventral
manubrial spine (spina externa of Newton and Gadow) is narrow
and elongated in A. gibberifrons and is more elongated than in A.
theodori. The coracoid of A. theodori looks very similar to that
of A. gibberifrons. On the internal side of the posterior face,
above the sternal facet, there is a small, proximally directed
spike, followed by a small depression, which also is present in A.
gibberifrons. On the anterior face, near the internal side of the
acrocoracoid, an almost circular muscular scar occurs in A. the-
TABLE 7.—Dimensions (mm) of the main bones of the extinct Anas theodori, from Mauritius and Reunion, compared
with modem Anas gibberifrons (USNM) and Anas bernieri (two specimens; Steve Goodman, pers. comm.,
1995). For Anas theodori from Mauritius, the dimensions are from material at MNHN (prefix MAD), from Newton
and Gadow (N. & G., 1893), or measured from their figures; Reunion dimensions are from material at
MHNR (prefix FE-O). (a=width of front part of sternum, measured between the two lateral intermuscular lines;
b=stemum-keel depth, from dorsal surface of sternum to ventral tip of keel; c=measured without cnemial crests;
d=measured with cnemial crests; «=number of specimens.)
Reunion
FE-O-1810
-63
7.5
7.0
6.0
7.1
4.4
3.9
FE-O-1894
71.0
8.5
9.7
8.0
-
3.8
3.0
Mauritius
MAD-4057 (cast)
27.7
21.7
MAD-4993
41.1
-9
8.3
-16
3.6
4.3
3.5
MAD-4988
73.0
-16
-
11.2
6.6
5.2
4.5
MAD-7161
71.0
8.6
9.2
8.0
9.0
3.7
3.2
MAD-4992*
-42
-
-
-
4.2
3.6
Anas theodori
Mauritius
N. &G., 1893
42.5
-8
-
17.2
-
4.1
-
MAD-4989
69.6
15.5
7.9
11.3
6.5
5.2
4.2
N. &G., 1893
42.0
9.2
8.3
9.2
-
4.3
-
Mauritius
MAD-4991
73.1
16.1
8.2
11.6
6.5
5.6
4.6
Anas bernieri
-30.9,-31.2
-
-
-
-
-
64.5, 66.5
13.3, 13.5
-
10.0, 10.3
- --
58.0, 60.6
7.4, 7.6
-
6.0,6.1
-
-
65.1, 67.6(d)
6.7, 6.8
-
6.7, 6.8
-
-
-
38.7, 39.3
7.0, 7.3
-
7.3, 7.5
-
-
mean (n=4)
24.25
20.78
37.55
8.03
7.20
15.33
2.98
3.80
2.98
69.93
15.18
7.68
10.75
6.50
5.33
4.50
61.55
7.45
6.88
5.98
6.50
3.95
4.00
64.38
7.50
8.53
6.78
7.58
3.08
2.68
36.15
7.48
6.83
7.70
5.48
3.35
2.93
Anas gibberifrons
range
23.2-25.8
19.4-21.8
35.1-38.9
7.4-8.4
6.8-7.6
14.5-16.3
2.7-3.2
3.7^t.O
2.6-3.2
-68-71.4
14.5-15.5
7.4-8.0
9.9-11.2
6.2-6.7
5.1-5.6
4.2^1.8
59.5-63.2
7.1-7.6
6.2-7.5
5.7-6.1
6.2-6.8
3.6-^.2
3.6-4.4
59.5-67.4
-7-7.9
-8-9.3
6.6-7.1
7.0-8.0
3.0-3.1
2.5-2.8
33.3-38.9
7.1-8.1
6.3-7.2
7.1-8.3
5.1-5.9
3.0-3.9
2.7-3.1