THE EVOLUTIONARY HISTORY AND PHYLOGENETIC RELATIONSHIPS OF THE SUPERFAMILY PLATANISTOIDEA - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 466

structure is characteristic of the Mysticeti and Odontoceti (Barnes, 2006:38, character
1).
2. Lacrimal foramen (or groove) present [0]; or absent [1]. (See Geisler & Sanders,
2003:102, character 52; and Barnes, 2006:38, character 2.)
3. Zygomatic portion of jugal bone thick both dorsoventrally and transversely, as in
terrestrial mammals and as in the Archaeoceti [0]; or narrower, thin, and rod-like [1].
(See Miller, 1923; Geisler and Sanders, 2003:102, character 56; and Barnes, 2006:38,
character 3.) The zygomatic arch of the jugal may be secondarily modified, as
explained for character 61, described below.
4. Dorsal infraorbital foramen (anterior maxillary foramina for cranial nerve V 2 )
having a single dorsal aperture [0]; or having multiple dorsal apertures [1]. (See
Geisler and Sanders, 2003:103, character 64; illustrated by Rommel, 1990: Figure 2;
Barnes, 2006:38, character 4.)
5. Lacrimal and jugal bones distinguishable as separate bones [0]; or fused [1]. (See
Miller, 1923; Heyning, 1989; Barnes, 1990:21, node 10; 2006:38, character 5; and
Geisler and Sanders, 2003:102, character 53.)
6. Antorbital notch absent [0]; or present [1]. The antorbital notch is formed between
the base of the rostrum and the enlarged anterolateral corner of the supraorbital
process, and the opening of this notch faces either anteriorly or anterolaterally. This
is a character that is present in all Odontoceti (see Barnes, 1990:21, node 10;
2006:38, character 6; and Rommel, 1990: Figure 2; modified from Geisler and
Sanders, 2003:102, character 49).
7. Ascending (or frontal) process of the maxilla abuts the anterior edge of the
supraorbital process of the frontal [0]; or the ascending process of the maxilla to
some degree covers the dorsal surface of the supraorbital process of the frontal [1].
The derived state is a character present in all Odontoceti, and any posterior extension
of the maxilla over the dorsal surface of the frontal bone is considered to represent
the derived character state. (See Miller, 1923; Barnes, 1990:21, node 10; 2006:38,
character 7; modified from Fordyce, 1994:175, character 3; Rommel, 1990: Figures
1-2; and Geisler and Sanders, 2003:104, character 76).
8. Premaxillary foramen absent [0]; or present [1]. The derived state is a character of
all Odontoceti, and there is usually a single foramen in each premaxilla (Barnes,
1990:21, node 10; 2006:38, character 8; modified from Geisler and Sanders,
2003:103, character 69). The foramen, however, may have more than one aperture,
and in some members of the superfamily Physeteroidea (sperm whales and pygmy
sperm whales) there may be two or three apertures in the right premaxilla, and none
in the left premaxilla, the latter being the result of secondary loss.
9. Posterior maxillary foramen absent [0]; or present [1]. This is the foramen that
carries the posterior branches of the internal maxillary artery and the maxillary
division of the infraorbital nerve. This is a character of all Odontoceti (Barnes, 1990;
2006:38, character 9; modified from Geisler & Sanders, 2003:104, character 75).
10. Premaxillary sac fossa absent [0]; or present [1]. The premaxillary sac fossa (see
Rommel, 1990: Figure 2) is formed on the dorsal surface of the posterior part of the
premaxilla that is anterolateral to, or adjacent to, each dorsal narial opening, and
posterior to the premaxillary foramen. The ventral wall of the premaxillary sac,
which is a diverticulum of the narial passage, lies directly upon this smooth and