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NUMBER 89
FIGURE 3.—Chaunoides antiquus, n. gen. n. sp., holotype, left coracoid (MNRJ
4619-V), coated with ammonium chloride: A, ventral view; B, dorsal view.
(Scale bar= 1 cm.)
a large pneumatic foramen in the sterno-coracoidal fossa, a
large procoracoid foramen, and a large transverse procoracoid
process. The coracoid differs from that of Anhima by having a
(1) narrower head; (2) glenoid facet with the transverse width
Measurement
Coracoid
midshaft width
acrocoracoid apex to internal angle
Femur
top of head to internal condyle
least width midshaft
Radius
greatest width, distal end
Tarsometatarsus
width of proximal articular surface
Tibiotarsus
width immediately above tendinal
bridge
Ulna
greatest width of external condyle
225
greater than the length, also easily observed in ventral view
(Figures 3A, 5) because of its lateral expansion (similar to
Chauna); (3) larger and deeper scapular facet; and (4) larger
pneumatic foramen, with rounded borders, in the sterno-coracoidal
fossa. The coracoid differs from that of Chauna torquata
and C. chavaria by having (1) a smaller acrocoracoid process;
(2) the scapular facet more rounded and deeper; (3) the dorsal
surface less swollen; and (4) the large pneumatic foramen in
the sterno-coracoidal fossa wider and dorsoventrally more
compressed, with a small process in the dorsal border.
Chaunoides antiquus, new species
HOLOTYPE.—Nearly complete left coracoid, lacking only the
tip of the head, tip of the procoracoid process, and the sternocoracoidal
process (Figure 3). Vertebrate paleontology collections
of Museu Nacional de Historia Natural da Universidade
Federal do Rio de Janeiro, MNRJ 4619-V.
TYPE LOCALITY.—Santa Fe Farm, 2 km north of Tremembe,
Sao Paulo State, Brazil (22°30'S, 45°32'W) (Figure 1).
Montmorillonitic clay, about 4 m below the most superficial
level of shales.
HORIZON AND AGE.—Tremembe Formation, Taubate basin,
upper Oligocene or lower Miocene.
MEASUREMENTS OF HOLOTYPE.—See Table 1.
PARATYPES.—Another left coracoid lacking the sternal end
(MNRJ 4620-V), identical in morphology to the holotype, associated
with an almost complete left femur (MNRJ 4621-V);
the distal end of a left ulna (MNRJ 4622-V); the distal end of a
right radius (MNRJ 4623-V); a left radius lacking the proximal
end (MNRJ 4624-V); a left ulna lacking the proximal end
(MNRJ 4632-V), associated with a segment of distal shaft of a
left tibiotarsus (MNRJ 4631-V); and two segments of the distal
end of left tibiotarsi (MNRJ 4625-V, MNRJ 4629-V), the last
being associated with the proximal end of a left tarsometatarsus
TABLE 1.—Measurements (mm) of Chaunoides antiquus, n. gen. n. sp., compared with other Anhimidae.
Holotype,
MNRJ4619-V
12.3
66.1
-
-
-
-
-
-
Chaunoides antiquus, n. gen. n. sp.
Paratypes
MNRJ-4620-V
11.7
-
MNRJ 4621-V
89.7
10.0
MNRJ 4623-V, 4624-V
12.2, 12.5
MNRJ 4630-V
21.05
MNRJ 4625-4629-V, 4631-V
14,2, 14.0, 14.5, 15.0, 13.8, 14.1
MNRJ 4622-V, 4632-V
14.4,16.1
Chauna chavaria
USNM 347738
(sex indet.)
11.3
65.8
92.5
11.5
15.5
23.1
15.8
17.6
Chauna torquata
HA 41 HA 389 HA 702
(female) ( sex indet.) (male)
15.4
71.1
97.1
12.9
17.0
23.8
17.8
19.6
11.6
62.6
88.6
10.6
14.0
22.0
15.0
17.2
15.7
68.0
101.0
13.7
16.1
26.1
17.9
20.1
Anhima
HA 40
(female)
13.9
64.8
93.2
12.0
15.4
21.7
16.1
18.3
cornuta
HA 902
(female)
13.6
69.5
94.3
14.4
16.4
23.0
20.3
18.1