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1926:pl. 6; and Figure 9 herein), and in
Platanista gangetica
(see Fraser & Purves,
1960:pl.18; and Figure 11 herein), and was described by Fordyce (1994:75, character
9) and by Barnes (2006:39, character 31). The derived character state is clearly
shown in an illustration of a skull of
Steno bredanensis
that was published by Fraser
& Purves (1960: pl. 24).
32.
Anterior end of tympanic bulla
rounded [0]; or having an elongate and pointed
anterior process or spine [1]. The derived character state is shown in illustrations of
Platanista gangetica
(see Van Beneden & Gervais, 1868-1880:pl. XXXI, Figures 7,
7a, 7b; Kellogg, 1924:pl. 7, Figures. 1-4; Fraser & Purves, 1960:pl. 18; and Figure
11C herein), and was explained by Fordyce (1994:176, character 45), and by Barnes
(2002b: 409; 2006:39, character 32). Although the petrosal and tympanic bulla are
not known for several fossil species of platanistoids, this very distinctive platanistoid
character is included in this analysis because an anterior bullar spine is present in all
known species of Platanistoidea for which a bulla is known.
33.
Symphyseal portion of mandible
not greatly elongated anteroposteriorly [0]; or
symphyseal portion of mandible anteroposteriorly elongated [1]. The symphyseal
portion of the mandible is considered to be elongated in Cetacea when it is more than
one-half of the total length of the mandible (for example as it is in
Platanista
gangetica
[see illustrations by Van Beneden & Gervais, 1868-1880:pl. XXXI, Figure
3], and in
Zarhachis
flagellator
[Kellogg, 1924:pl. 3]), and was defined by Barnes
(2006:39-40, character 33).
34.
Mandibular symphysis:
unfused [0]; or firmly ankylosed [1], (as shown on a
referred specimen of
Zarhachis
flagellator
[see Kellogg, 1924: pl. 3]; and described
by Fordyce [1994:175, character 5] and Barnes [2006:40, character 34].
35.
Cheek teeth
posterior to the first premolar having at least two roots [0], or all
premolars and molars single-rooted [1]. The homologies of the teeth in heterodont
dentitions of primitive Cetacea are clearly demonstrated by the Archaeoceti (see
Kellogg, 1936: Figures. 30, 31a), and the canine tooth, as is typical for Mammalia, is
the anterior-most tooth that is rooted in the maxilla. The tooth following the P1 is in
the Archaeoceti a single-rooted tooth, or is in some taxa a double-rooted tooth. We
consider that a single-rooted P1 (and also the p1) is the plesiomorphic character state
for Cetacea. In all species of Archaeoceti, the P2 (and p2) are two-rooted teeth (see
Kellogg, 1936: Figure 31a), and the presence of single-rooted second premolars, and
subsequent premolars and molars, in other Cetacea is the derived character state, and
this is a step in the development of homodonty (Barnes, 2006:40, character 35).
36.
Facial surface of cranium
not arched transversely in the area of the dorsal narial
openings; may be nearly flat transversely or may be ascending posteriorly [0]; or
arched transversely across the area of the narial openings and the cranial vertex, and
sloping laterally onto the supraorbital process [1]. The derived character state is
present in
Allodelphis pratti
and
Zarhinocetus errabundus
(see Figures 1-3 herein;
character defined by Barnes, 2006:40, character 36).
37.
Fossa in the anterior side of the paroccipital process
marking the presence in life
of a posterior sinus of the middle ear sinus system; absent [0] (as in
Allodelphis
pratti
[Figure 1C]); or present [1] (as in
Prepomatodelphis
korneuburgensis
[see Barnes,
2006: Figure 6]). The fossa for this sinus is also present in various genera of
Odontoceti as shown by
Fraser & Purves
(1960:pls. 13
[Monodon],
15
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