Theriodictis Mercerat, 1891

TEDFORD R. H., WANG X. & TAYLOR B. E., 2009, Phylogenetic Systematics Of The North American Fossil Caninae (Carnivora: Canidae), Bulletin of the American Museum of Natural History 2009 (325), pp. 1-218 : 88

Theriodictis Mercerat, 1891 Figure 32G–L; appendix 3

Dinocynops F. Ameghino, 1898 .

Pleurocyon Mercerat, 1917 .

Canis (Theriodictis) L. Kraglievich, 1928 .

Type Species: Theriodictis platensis Mercerat, 1891 .

Included Species: T. tarijensis (Ameghino), 1902 , and T.? floridanus, n. sp.

Distribution: For T. platensis , Argentina, Ensenadan and Lujanian (medial to late Pleistocene); for T. tarijensis , Bolivia, late Ensenadan and/or early Lujanian; for Theriodictis sp. (formerly Amphicyon argentinus F. Ameghino, 1904 ), Argentina, possibly Montehermosan (Pliocene), but more likely Ensenadan (medial Pleistocene) fide Berta (1988: 76); and for T.? floridanus, southeastern United States, late Blancan and early Irvingtonian.

Revised Diagnosis ( Berta, 1988: 64): Frontal sinus penetrates postorbital process and extends to frontoparietal suture; deep zygoma with wide masseteric scar; palatines extend posteriorly beyond toothrow; M1– M2 hypocones reduced; M2 small relative to M1 with reduced metacone; coronoid process anteroposteriorly long, dorsoventrally low; angular process expanded dorsoventrally; large fossa for inferior branch of medial pterygoid; m1 lacks metaconid but retains small entoconid; m2 small relative to m1, lacking anterolabial cingulum, strong paracristid and relatively unreduced metaconid.

Discussion: Recognition of the presence of this genus or a closely related taxon is based on two specimens, both elements of the lower jaw, from late Pliocene and medial Pleistocene deposits in Florida. Fortunately these specimens contain some of the more diagnostic features of the Cerdocyonina , particularly the hypercarnivorous adaptations within the clade that also contains the extinct Protocyon and the recently extirpated Falkland Island fox ( Dusicyon ).