Cartilaginous fish There are 21 known species of
cartilaginous fishes from the Urumaco Formation, belonging to the orders
Lamniformes,
Carcharhiniformes,
Myliobatiformes and
Rajiformes.
Carcharhinus caquetius is an
endemic species of
predator shark from Urumaco. A large number of well-preserved
fossils of the
sawfish Pristis rostra have been found in the deposits. The
megalodon is also known from the Urumaco Formation. The coastal seas of Urumaco were further inhabited by species that still live in the
Caribbean Sea today, such as the
spotted eagle ray,
smooth hammerhead shark,
tiger shark and
bull shark.
Bony fish The
bony fishes from the Urumaco Formation include
groupers,
piranha-like fish such as
pacas,
cuttlefish,
thorny catfish and
red-tailed catfish.
Reptiles The Urumaco Formation has a great diversity of crocodilians with twelve known species. Seven species of
caimans have been described:
Caiman brevirostris,
C. latirostris,
Globidentosuchus brachyrostris,
Melanosuchus fisheri,
Mourasuchus arendsi,
M. nativus and
Purussaurus mirandai,
Gryposuchus croizati,
G. jessei,
Hesperogavialis cruxenti and
Ikanogavialis gameroi are the
gavials of Urumaco, a group that is no longer found in
South America today. The kinship of
Charactosuchus mendesi with the other crocodilians is considered unclear. Multiple species of crocodilians were able to live together because they focused on specific
niches, limiting infraspecific competition. For example, the
Mourasuchus arendsi had a
duck-like beak with which it caught
crustaceans, the fish-eating
Gryposuchus croizati, in length, lived particularly in estuaries, and
Purussaurus mirandai, in length, hunted a wide range of prey animals.
Stupendemys geographicus is the best-known turtle species from the Urumaco formation. This animal from the
American necked turtles family was one of the largest turtles ever with a shell long. Other turtles from Urumaco include several species of
Bairdemys, the
mata mata Chelus lewisi and
softshell turtles. In addition to the multiple crocodilians and turtles, vertebra of a
boa have also been found in the Urumaco Formation.
Mammals Phoberomys pattersoni is one of the largest known rodents ever. This three-meter-long relative of today's
pacarana had a lifestyle similar to that of the
capybara. Several species of
xenarthrans are known from the Urumaco Formation.
Urumaquia robusta was a
ground sloth from the
Megatheriidae weighing four tons. Others ground sloths from Urumaco are
Bolivartherium urumaquensis,
Urumacotherium garciai,
Eionaletherium tanycnemius, and
Pseudoprepotherium venezuelanum belonging to the
Mylodontidae.
Urumacocnus urbani and
Pattersonocnus diazgameroi are ground sloths from the
Megalonychidae.
Boreostemma pliocena is a
glyptodont.
Bounodus enigmaticus (
Proterotheriidae,
Litopterna) and
Gyrinodon (
Toxodontidae,
Notoungulata) are the South American ungulates of the Urumaco formation. In the waters of Urumaco lived the
freshwater dolphins Ischyrorhynchus vanbenedeni and
Saurodelphis and the
dugongs Nanosiren sanchezi and possibly
Metaxytherium. == References ==