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Georgiana Wingard, U.S. Geological Survey. Public domain.)
Taxonomy, Phylogeny & Etymology
The American crocodile whose scientific name is
acutus (pronounced krok-o-DIL-luss
is a reptile among the class
of snakes, lizards, turtles, tortoises and the lizard-like
Tuatara. It is one of about 26 crocodilians in the world, an
order which includes two temperate-zone alligators, one from
southeastern North America and a smaller one from China,
about 14 other tropical
crocodiles scattered about the globe, six alligator-like caimans from
the South and Central Americas and the tropical slender-snouted gharial and Tomistoma
crocodiles. You may review a complete list, and learn the basics
of taxonomy and its Latin word use,
Austrian naturalist and zoologist Josephus Nicolaus
Laurenti (1735-1805) named the genus Crocodylus in
1768, a designation which today applies to about
12 of the known "true" crocodiles.
Crocodylus is from Latin, meaning "crocodile" (which in turn
means "pebble worm"). The species name, acutus, Latin for "acute" or "sharp"
(describing the crocodile's snout shape) is credited to Georges
Cuvier (1769-1832), a French naturalist and zoologist who
applied the word in 1807.
The crocodile shown at left is
Crocodylus intermedius, an
endangered crocodile from Venezuela. A close relative of
acutus, it bears a striking
resemblance to it. (Image:
The species has been identified in the past with different
names, which are now considered junior synonyms; they include:
Crocodylus americanus (Laurenti, 1768), Lacerta
alligator (Blumenbach, 1779), Crocodylus caudiverbera
(Bonnaterre, 1789), and Crocodylus floridanus
(Hornaday, 1875), the last being considered by some a junior
It's origins in
the evolutionary timeline began, like the alligator's, with the
Archosaurs --"ruling reptiles"
-- about 200 milion years ago. From these, the
ancient and modern Crocodyloformes, through a clade called
Pseudosuchia (and modern birds from the other branch,
Ornithosuchia), derive. The
sprang from the ancient stock about 100 million years later, the
modern crocodilians of today.
Crocodylus genus also includes the living species
intermedius, johnsoni, mindorensis,
moreletii, suchus, novaeguineae, palustris, porosus, rhombifer,
and siamensis (and formerly cataphractus).
Additonally are six established extinct species (others are
suspected, but not confirmed): anthropophagus, bugtiensis,
checchaiai, falconensis, palaeindicus, and thorbjarnarsoni.
The artistic restoration shown below is of the
extinct - and massive- Crocodylus thorbjarnarsoni,
an ancient close relative of the American crocodile, the skull fossils of
which were discovered in Kenya. Note how broad its snout is
(resembling that of an alligator) compared to the American croc.
Note the notches near the tip, through which each fourth bottom
tooth protrudes, distinctive features of a true crocodile.
(Image: smokeybjb. Creative Commons
This living crocodile and its alligator relative with
which it shares habitat, are quite distant genetically in the
timeline described above, having diverged in evolution from a
common ancestor 66 to 100 million years ago
with the clade Brevirostres, named by German
palaeontologist Karl Alfred von Zittel (1839-1904) in 1890. Brevirostres
((loosely translated from Latin as "brief" or
"short" "snout") is placed in Late Cretaceous
(epoch year 100.5-66), and is believed to be the last common
point of the alligatoroids and crocodyloids, ancestors of the
crocodilian descendant neighbors inhabiting Florida today.
The acutus species is hybridizing
in other parts of the tropical Americas with two others of its genus,
moreletii in Belize and the Yucatan of Mexico
and with the endangered rhombifer
in Cuba, situations which complicate taxonomical identification
(and conservation) efforts for all
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