taxonID	type	description	language	source
FAEB2F23C06F5F8AB166FDD9ACBBE3CF.taxon	type_taxon	Type species. Alligator mississippiensis [Daudin, 1802] from “ les bords du Mississipi ”.	en	Stout, Jeremy B., Massonne, Tobias, Samuels, Joshua X., Schubert, Blaine W. (2025): Small, enigmatic alligatoroid from the Middle Eocene Clarno Formation, John Day Fossil Beds, Oregon. Fossil Record 28 (2): 309-319, DOI: 10.3897/fr.28.169148
FAEB2F23C06F5F8AB166FDD9ACBBE3CF.taxon	description	Description. UCMP 164865 (Fig. 3) is the anterior-most portion of a reconstructed left dentary that measures 6.3 cm in length. The mandibular symphysis measures 2.4 cm long and extends posteriorly to the fourth dentary alveolus. UCMP 164865 does not preserve the alveoli immediately posterior to the first, though they are assumed to be alveoli two and three, as the next preserved tooth is the largest of the preserved dentary and spatially consistent with other known alligatoroids (Brochu 2004; Cossette and Tarailo 2024) and most members of Crocodylia as a whole (Brochu 1999). Furthermore, the assumed fourth alveolus is preserved along its anterior extent and is not confluent with another. Pursuant to the aforementioned assumption, counting anterior to posterior, the first and fourth through twelfth alveoli are preserved. Similar to other small-bodied alligatoroids of the time (Cossette and Tarailo 2024), the dentary curvature between the fourth and twelfth alveoli is deep, with a noticeable dorsal rise between the eleventh and twelfth alveoli. The height of the dentary at the first and fourth alveoli is approximately equal to the dorsal extent at the twelfth alveolus. The lingual side of UCMP 164865 is better preserved than the lateral. Though the splenial is not preserved, its presence can be inferred as a scar (Stout 2021) along the mandibular ramus and is well preserved. The splenial had a robust presence constituting the medial wall along the entirety of the anterior mandibular ramus. When present, the splenial appears to have reached and participated in the mandibular symphysis. The angle that the lingual margin of the mandibular ramus reaches the symphysis is exceptionally shallow. The Meckelian groove is preserved across most of the mandibular ramus and attenuates as it approaches the symphysis. In life, it may have been completely enclosed along its mesial margin by the splenial. With the exception of the mandibular symphysis and the inferred presence of the anterior portion of the splenial, no articulation with other bones of the mandible is preserved. Several openings of the mandible preserve important phylogenetic information in alligatoroids (Brochu 1999), but are not preserved in UCMP 164865: the mandibular fenestra and posterior foramen intermandibularis oralis existed posterior to the preserved portion and the anterior foramen intermandibularis oralis, if present, would be located on the splenial. Seven teeth are partially or wholly preserved in UCMP 164865: the first, fourth through sixth, seventh and ninth (partial) and twelfth. The largest tooth and its associated alveolus is the fourth, which is separated from the (not preserved) third. All teeth project dorsally or anterodorsally and each are pointed, except for the distinctly globidontan twelfth. All are unserrated, but possess anterior and posterior carinae. All possess some degree of labiolingual compression. A portion of the thirteenth alveolus is preserved at the posterior-most extent of UCMP 164865 and may have been much larger than the preceding eight. The teeth possess smooth carinae and robust basiapical ridges on their lingual margins.	en	Stout, Jeremy B., Massonne, Tobias, Samuels, Joshua X., Schubert, Blaine W. (2025): Small, enigmatic alligatoroid from the Middle Eocene Clarno Formation, John Day Fossil Beds, Oregon. Fossil Record 28 (2): 309-319, DOI: 10.3897/fr.28.169148
CCD4213F11F453958F9ECD3034DBDB2F.taxon	type_taxon	Type species. Indeterminate.	en	Stout, Jeremy B., Massonne, Tobias, Samuels, Joshua X., Schubert, Blaine W. (2025): Small, enigmatic alligatoroid from the Middle Eocene Clarno Formation, John Day Fossil Beds, Oregon. Fossil Record 28 (2): 309-319, DOI: 10.3897/fr.28.169148
CCD4213F11F453958F9ECD3034DBDB2F.taxon	description	Description. UCMP 164866 is a right humerus from the Hancock Mammal Quarry that represents the only crocodylian postcranial element recovered from the upper section of the Clarno Formation (Fig. 4). It measures 10.5 cm in straight-line length. The proximally projecting deltopectoral crest offers some phylogenetic information (Brochu 1999), but it is not preserved in UCMP 164866. It is figured herein only as representative eusuchian postcranial material and is not assumed to be associated with the taxon or individual of UCMP 164865, though the relative size of each does not negate the possibility.	en	Stout, Jeremy B., Massonne, Tobias, Samuels, Joshua X., Schubert, Blaine W. (2025): Small, enigmatic alligatoroid from the Middle Eocene Clarno Formation, John Day Fossil Beds, Oregon. Fossil Record 28 (2): 309-319, DOI: 10.3897/fr.28.169148
