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
Author
Jacisin Iii, John J.
Author
Lawing, A. Michelle
text
Palaeontologia Electronica
2024
a 2
27
1
1
42
http://dx.doi.org/10.26879/1220
journal article
10.26879/1220
1094-8074
10962250
Genus
CHARINA
Gray, 1849
Diagnosis.
As diagnosed in
Head (2015)
,
Charina
possesses a lobate neural spine that is laterally expanded similar to other Charinainae, and the pterapophyses are anteriorly directed in caudal vertebrae (
Kluge, 1993
;
Szyndlar, 1994
).
Charina
also exhibits a non-U-shaped zygosphene in dorsal view, a strongly concave zygosphene in anterior view, a relatively depressed neural arch, an incised posterior edge of the neural arch, and no paracotylar foramina (
Holman, 2000
).
Remarks.
The fossils described here are similar in size and morphology to known species of
Charina
. The longer neural spine, the V-shaped (dorsal), strongly concave (anterior) zygosphene, and the depressed neural arch with a relatively deeply incised posterior edge suggest that these vertebrae do not belong to the genus
Lichanura
; however, it should be noted that
Bell and Mead (1996)
have observed some intraspecific variation in these characters. As in
Parmley and Walker (2003)
, we instead attribute this fossil to the genus
Charina
based on the relative length of the neural spine, which is greater than that of
Lichanura
, and the lack of juvenile characteristics despite being relatively small in size.
Parmley and Walker (2003)
have observed that
Lichanura
of a similar size show juvenile characteristics such as a short, high overall morphology, thin neural arch, thin and highly arched zygosphene, exceptionally short neural spine, enlarged neural canal, and a condyle that appears too large for the centrum, none of which are visible in this specimen.