Pantherophis kansensis Gilmore, 1938

Jacisin Iii, John J. & Lawing, A. Michelle, 2024, Fossil snakes of the Penny Creek Local Fauna from Webster County, Nebraska, USA, and the first record of snakes from the Early Clarendonian (12.5 - 12 Ma) of North America, Palaeontologia Electronica (a 2) 27 (1), pp. 1-42 : 14-16

Pantherophis kansensis Gilmore, 1938 †

Figure 7

Material. UNSM 139983 (21 pre-cloacal trunk vertebrae).

Description. In anterior view, the neural spine is relatively low for a colubrid, the neural arch is moderately vaulted, and the zygosphene is convex dorsally. The zygosphenal articular facets are strongly tilted dorso-ventrally. The neural canal is rounded and slightly smaller than the cotyle, which is also round. The prezygapophyseal articular facets tilt slightly upward, and the diapophyses and parapophyses are rounded, distinct sections of the synapophyses.

In dorsal view, the neural spine is long and located in the middle of the vertebra. The anterior edge of the zygosphene is concave. The prezygapophyseal accessory processes are moderately pointed, the prezygapophyseal articular facets are rounded to oval and tilted slightly upward, and the epizygapophyseal spines are absent. The posterior edge of the neural arch in dorsal view is slightly rounded.

In lateral view, the neural spine is approximately twice as long as it is high. The condyle is tilted slightly forward. The hemal keel is distinct from the centrum, and the synapophyses can clearly be divided into diapophyseal and parapophyseal sections. The interzygapophyseal ridge is bowed downward, and the subcentral ridge is bowed upward.

In posterior view, the neural arch is somewhat vaulted. The condyle is round and approximately the same size as the neural canal, which is an inverted U-shape. The zygosphenal articular facets and the postzygapophyseal articular facets are all tilted sharply upward. The diapophyses and parapophyses are distinct parts of the synapophyses.

In ventral view, the centrum is triangular and bordered by visible subcentral ridges. The hemal keel is well-developed, moderately wide, and constricted in the middle relative to the ends. The prezygapophyseal accessory processes are distinct, oblique, and directed anterolaterally. As in other views, the synapophyses are distinctly divided into the diapophyses and parapophyses.

Remarks. Pantherophis kansensis has vertebrae with a lower neural spine and more anterolaterally directed prezygapophyseal accessory processes than any other known species of Pantherophis or Bogertophis . This neural spine is relatively taller in some specimens, and is more proportionally more similar to Pantherophis obsoletus in that regard; these vertebrae appear to be from a more anterior portion of the vertebral column.

Figures

FIGURE 7. Trunk vertebra of Pantherophis kansensis from the Penny Creek local fauna. From top left: dorsal, ventral, anterior, posterior, and lateral views (anterior to the left). Scale bar equals 1 mm.