THE EVOLUTIONARY HISTORY AND PHYLOGENETIC RELATIONSHIPS OF THE SUPERFAMILY PLATANISTOIDEA - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 473

transverse width is greater than its dorsoventral height [1]. This derived character
state is present in the pomatodelphinine platanistids, for example the species of
Prepomatodelphis, Zarhachis, and Pomatodelphis (see Barnes, 2006:41, character
51, Figure 8; Figure 8 herein). This derived character state could possibly be
combined with the preceding character, because in the Platanistidae the two appear to
be linked. However, the acquisition of the two characters may have occurred at
different times, so they are here listed separately.
52. Supraorbital process not significantly thickened, for example in Prepomatodelphis
korneuburgensis [0] (see Barnes, 2006: Figure 5); or supraorbital process
dorsoventrally thickened, involving parts of both the maxilla and frontal that are
dorsal to the orbit [1]. (See Van Beneden & Gervais, 1868-1880:pl. XXXI, Figures 2,
9; Kellogg, 1926:pl. 4; Figures 6, 7, 9, and 11 herein; character explained by Barnes,
2006:41, as character 52.)
53. Anterior end of zygomatic process of the squamosal not remarkably extended
anteriorly [0]; or anterior end of zygomatic process of the squamosal extended
anteriorly [1]. The derived character state is present in Platanista gangetica (see Van
Beneden & Gervais, 1868-1880: pl. XXX, Figure 1; pl. XXXI, Figures 2, 9; Kellogg,
1924:pl. 6; Fraser and Purves, 1960:pls. 17-18; and Geisler and Sanders,
2003:character 188, Figure 13b; Barnes, 2006:41, character 53; and Figure 11
herein.)
54. Cranial vertex symmetrical, with mid-line sutures between the right and left nasal
and frontal bones at the cranial vertex aligned with the mid-line sagittal plane of the
cranium [0]; or asymmetrical, with mid-line sutures between the nasal and frontal
bones and dorsal narial openings skewed asymmetrically to the left side of the mid-
line sagittal plane of the cranium [1]. (For the derived character state see Van
Beneden & Gervais, 1868-1880:pl. XXXI, Figures 2a, 4, 9a; and listed by Barnes,
1990:21, at node 13; Barnes, 2006:41, character 54; Figures 6A, 7A, 9A, and 11A
herein.)
55. Rostrum not transversely compressed [0]; or rostrum transversely compressed so
that for at least the proximal two-thirds of its length its transverse width is less than
its dorsoventral height [1]. The derived character state is present in Platanista
gangetica (see Van Beneden & Gervais, 1868-1880:pl. XXXI; and Figure 8 and 11
herein; and was described by Barnes (2006:41, character 55)).
56. Symphyseal portion of mandible not transversely compressed [0]; or symphyseal
portion of mandible transversely compressed so that in at least its middle one-half the
transverse width is less than its dorsoventral height [1]. The derived character state is
present in Platanista gangetica (see Van Beneden & Gervais, 1868-1880:pl. XXXI;
and Figure 8 herein), and in a probable platanistine of Early Miocene age from
Oregon (see Barnes, 2006: Figure 7c; and Figure 10D herein), and was described by
Barnes (2006:41, character 56).
57. Size of nasal bones: right and left nasal bones of normal size for an odontocete, the
transverse width of each bone being approximately equal to the width of the
corresponding dorsal narial opening [0]; or nasal bones greatly reduced in size [1].
The derived character state is present in Platanista gangetica, in which the nasal
bones are reduced to small tubercles on the anterodorsal surfaces of the frontal bones
posterior to the dorsal narial openings (see Van Beneden & Gervais, 1868-1880:pl.