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19.
Anterior ends of the nasal bones
extend anteriorly, to overhang at least to some
extent, the posterior side of the dorsal narial openings [0]; or nasal bones retracted
posteriorly so as not to hang over the posterior side of the dorsal narial openings [1].
In the derived character state (for example as exists in
Zarhachis
flagellator,
see
Kellogg, 1926:pl. 2; and see Figure 9A herein), the nasal bones do not prevent
viewing the entire diameters of the dorsal narial passages in a standard dorsal view of
the cranium. (Character explained by Barnes, 2006:39, character 19.)
20.
Nasal bones elongate,
having a greater anteroposterior dimension than a transverse
dimension [0]; or nasal bones shortened and broadened, having lesser anteroposterior
dimension than transverse dimension [1]. The derived character state exists in
Zarhachis
flagellator
(example illustrated by Kellogg, 1926:pl. 2; and see Figure 9A
herein). (Character explained by Barnes, 2006:39, character 20).
21.
Premaxillary sac fossae
relatively narrow, being approximately the same width as
the more anterior parts of the premaxilla anterior to the narial region [0] (as in
Allodelphis
pratti,
see Figure 1A herein); or premaxilla wider in the area of the
premaxillary sac fossa on either side of the dorsal narial passages [1]. The derived
character state exists in
Prepomatodelphis
korneuburgensis
(see Barnes, 2006:
Figure 4), in
Araeodelphis,
cf.
A.
natator
(see Figure 7A herein), and in
Zarhachis
flagellator
(see Figure 9A herein). (See Barnes, 2006:39, character 21; modified
from Geisler & Sanders, 2003:98, character 8.)
22.
Rostrum
narrows in width anteriorly or anterior half of rostrum approximately the
same width as the posterior half [0]; or anterior end of rostrum widened transversely
[1], as in
Squalodon
(character explained by Muizon, 1991, 1994; Geisler & Sanders,
2003:98, character 2; and Barnes, 2006:39, character 22).
23.
Anterior end of zygomatic process of squamosal
not contacting the postorbital
process of the frontal [0]; or anterodorsal part of zygomatic process of squamosal
having a broad contact with ventral extremity of the postorbital process of frontal [1],
(Character defined by Barnes, 2006:39, character 23). The derived character state is
present in
Araeodelphis,
cf.
A.
natator
(see Figure 7B herein), in
Zarhachis
flagellator
(see Kellogg, 1926:pl. 4; and Figure 9B herein), and in
Platanista
gangetica
(see Van Beneden & Gervais, 1868-1880:pl. XXXI, Figures. 2, 9; Fraser
& Purves, 1960:pls. 17-18; and Figure 11 herein).
24.
Posterior ends of right and left maxillae
on posterior part of facial region
bilaterally symmetrical [0]; or posterior end of right maxilla, compared to posterior
end of left maxilla, curving farther medially toward the mid-line of the cranium [1].
The derived character state is present in
Notocetus
vanbenedeni
(see Fig. 6A herein),
in
Araeodelphis,
cf.
A.
natator
(see Fig. 7A herein), in
Zarhachis
flagellator
(see
Kellogg, 1926; and Fig. 9A herein), and in
Platanista gangetica
(see Van Beneden &
Gervais, 1868-1880:pl. XXXI, figs. 2a, 4, 9a; and Figure 11A herein). (Character
explained by Barnes, 2006:39, character 24.)
25.
Posterior ends of right and left maxillae
on posterior part of facial region both of
the same height [0]; or posterior end of right maxilla, compared to posterior end of
left maxilla, having a more concave dorsal surface in the area of the bone that is
medial to the temporal fossa [1]. The derived character state in some taxa of
Odontoceti is associated with the derived state of Character 24 (described above), but
it is not associated in all taxa, and it is thus regarded here as a separate character. The
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