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NUMBER 89 191
FIGURE 4.—Holotypical right carpometacarpus (UF 30015) of Aquila bivia
from Inglis IA, Citrus County, Florida, in internal (left) and external (right)
views. Scale=xl, bar=l cm.
UF 30031-30033; two proximal ends of right femora, UF
30020, 30021; distal end of right femur, UF 30022; left femur,
UF 30019 (Figure 5B; Table 2); right tibiotarsus, UF 30012
(Figure 5A; Table 2); proximal end of right fibula, UF 30013;
right metatarsal I, UF 30018; right phalanx 1 of digit I, UF
30016; left ungual phalanx of digit II, UF 30017; right phalanx
2 of digit II, UF 30045; left phalanx 1 of digit III, UF 30046;
phalanx 3 of digit III, UF 30044; phalanx 1 of digit IV, UF
30047; ungual phalanx of digit IV, UF 30048. At least two
adults represented.
Ill Ranch (East Ravine at Dry Mountain, Graham County,
Arizona (OMNH Locality V818; Figure 2)): Partial associated
skeleton (OMNH 50271) including proximal and distal ends
of a right carpometacarpus, right and left ulnares, right radiale,
proximal end of left tarsometatarsus; right metatarsal I, phalanx
1 and ungual of digit I, phalanx 2 and ungual of digit II, phalanges
1-3 and ungual of digit III, phalanges 2-4 and ungual of
digit IV; left metatarsal I and phalanx 1 of digit I, phalanx 2
and ungual of digit II, phalanx 3 (partial) of digit III, and phalanges
2-4 of digit IV.
This locality is within greenish clay in the Gila Conglomerate
at the approximate level of paleomagnetic samples 112 and
113, East Ravine, of Galusha et al. (1984). This section has reversed
polarity throughout and represents Chron C2r, or slightly
above the 2.47 Ma Dry Mountain Ash Bed (Izett, 1981; Galusha
et al., 1984; Tomida, 1987). One adult (from associated
material) is represented.
MEASUREMENTS OF PARATYPES.—See Table 1.
ETYMOLOGY.—From Latin, bivius, -a, -um, two-wayed, in
reference to the distribution of the fossil specimens in Florida
and Arizona.
DIAGNOSIS.—The species is diagnosed by the following
characters. Carpometacarpus (UF 30015, OMNH 50271; Figure
4) with relatively deep external ligamental attachment with
pronounced proximal border, metacarpal I relatively long and
robust, pit below pollical facet on metacarpal II, relatively
large prominence for muscle attachment of proximal internal
edge of metacarpal III (ligamental attachment shallow and
proximal border less pronounced, metacarpal I relatively shorter
and less robust, absence of pit below pollical facet on metacarpal
II, and prominence for muscle attachment small in Aquila
chrysaetos, A. rapax, A. heliaca, A. verreauxii, and A. audax).
Femur with relatively long and slender shaft (shaft shorter and
more robust in A. chrysaetos) and with broad, deeply excavated
popliteal area (area narrower and moderately excavated in A.
chrysaetos; Figure 5B). Tibiotarsus with relatively long, narrow
shaft (shaft shorter and more robust in A. chrysaetos; Figure
5A). Size relatively large compared with Aquila chrysaetos,
A. rapax, A. heliaca, A. verreauxii, or A. audax.
COMPARATIVE MATERIAL.—Haliaeetus leucocephalus (Linnaeus);
USNM 611999, USNM 489276, 1 male and 1 female.
Aquila rapax (Temminck), USNM 430406, 430532, 488147,
488148, 1 male, 3 females. Aquila heliaca Savigny, USNM
488808, female. Aquila chrysaetos (Linnaeus), UF 19399,
23961,23962,23964,1 male, 3 females; USNM 17721,17983,
18194, 18802, 19251, 19394, 19399, 19724, 19777,288513,
319967, 320978, 343130, 491476, 500354, 500355, 500367,
502292,612086, 5 males, 5 females, 9 unsexed; LACM 89953,
female. Aquila audax (Latham), USNM 344883, unsexed. Aquila
verreauxii Lesson, USNM 612539, unsexed.
STATUS.—Extinct, known from fossils only.
REMARKS.—Aquila bivia was a large eagle that was closely
related to the Golden Eagle {A. chrysaetos), but it was
10%-15% larger than females of that species and had limb elements
that do not overlap with those of A. chrysaetos in length
(Table 2). A large series of late Pleistocene eagle bones from
Rancho La Brea that Howard (1947) recognized as a larger
temporal form of A. chrysaetos also do not approach the length
of the Inglis specimens (Table 2). Howard (1932) noted that the
Rancho La Brea eagle had relatively longer wings and shorter
legs than did recent A chrysaetos, but with a larger series of recent
skeletons she later found that the limb proportions of the