Hipporex's Slightly-Inaccurate Photographic Guide to Crocodilia

Hipporex

Hipporex

Well-Known Member
5+ year member
After finishing my masterpiece of a thread, The Zoochat Photographic Guide to Tubulidentata, I decided to take this concept a little more seriously. I chose Crocodilia because I've always had a fascination with these living fossils that look like they're straight out of the Mesozoic Era (maybe that's because they are).
 
Last edited:
To get things started let's take a look at where Crocodilia lies on the tree of life (I'll be using phylogenetic bracketing rather than Linnaean taxonomy as it is most accurate):
  • Life
  • Eukaryota
  • Animalia
  • Chordata
  • Vertebrata
  • Gnathostomata
  • Osteichthyes
  • Sarcopterygii
  • Tetrapodomorpha
  • Tetrapoda
  • Reptiliomorpha
  • Amniota
  • Sauropsida
  • Eureptilia
  • Sauria
  • Archosauromorpha
  • Archosauriformes
  • Archosauria
  • Pseudosuchia
  • Paracrocodylomorpha
  • Loricata
  • Crocodylomorpha
  • Crocodyliformes
  • Mesoeucrocodylia
  • Metasuchia
  • Neosuchia
  • Crocodilia
Crocodilians are the closest living relatives of avian dinosaurs (i.e. birds), as the two groups are the only known survivors of the Archosauria. And as @TeaLovingDave points out below, the second closest living relatives of the crocodilians appears to be Testudines (the turtles), as all three groups (Aves, Crocodilia, and Testudines) are the only living members of Archosauromorpha.

 
Last edited:
Hipporex said:
Crocodilians are the closest living relatives of avian dinosaurs (i.e. birds), as the two groups are the only known survivors of the Archosauria.
Click to expand...

With, interestingly enough, the Testudines as the next extant outgroup - after decades of debate and rather a lot of moving the group to-and-fro within the Sauropsida, it now appears very likely that they belong within the Archosauromorpha.
 
According to the latest research, extant Crocodilia includes 3 families, 5 subfamiles, 9 genera, 25 species, and a partridge in a pear tree.

Family Alligatoridae
Subfamily Alligatorinae
Genus Alligator
  • Species Alligator mississippiensis
  • Species Alligator sinensis
Subfamily Caimaninae
Genus Caiman
  • Species Caiman crocodilus
  • Species Caiman latirostris
  • Species Caiman yacare
Genus Melanosuchus
  • Species Melanosuchus niger
Genus Paleosuchus
  • Species Paleosuchus palpebrosus
  • Species Paleosuchus trigonatus

Extant Alligatoridae are two species in the genus Alligator, and six species of caimans grouped into three genera. They can be recognized by the broad snout, in which the fourth tooth of the lower jaw cannot be seen when the mouth is closed.

Family Crocodylidae
Crocodylinae
Genus Crocodylus
  • Species Crocodylus acutus
  • Species Crocodylus intermedius
  • Species Crocodylus johnsoni
  • Species Crocodylus mindorensis
  • Species Crocodylus moreletii
  • Species Crocodylus niloticus
  • Species Crocodylus novaeguineae
  • Species Crocodylus palustris
  • Species Crocodylus porosus
  • Species Crocodylus rhombifer
  • Species Crocodylus siamensis
  • Species Crocodylus suchus
Genus Mecistops
  • Species Mecistops cataphractus
  • Species Mecistops leptorhynchus
Genus Osteolaemus
  • Species Osteolaemus tetraspis

Extant Crocodylidae contains 15 species, with twelve in the genus Crocodylus, and three species in other genera. They have a variety of snout shapes, but can be recognized because the fourth tooth of the lower jaw is visible when the mouth is closed.

Family Gavialidae
Subfamily Gavialinae
Genus Gavialis
  • Species Gavialis gangeticus
Subfamily Tomistominae
Genus Tomistoma
  • Species Tomistoma schlegelii
There are two extant species of Gavialidae. They can be recognized by the long narrow snout, with an enlarged boss at the tip.


The relationships of crocodilians has been the subject of debate and conflicting results. Many studies and their resulting cladograms, have found the "short-snouted" families of Crocodylidae and Alligatoridae to be close relatives, with the long-snouted Gavialidae as a divergent branch of the tree. However, in 2012, Erickson et al. produced a phylogeny formed from DNA sequencing to give a maximum likelihood cladogram of the relationships among living crocodilians, and his results suggested Crocodylidae was more cloesly related to Gavialidae and that Alligatoridae was the outlier.
 
Hipporex said:
Extant Crocodylidae contains 15 species, with twelve in the genus Crocodylus, and three species in other genera.
Click to expand...

Hipporex said:
Genus Osteolaemus
  • Species Osteolaemus tetraspis
Click to expand...

Or not :p the complexity of this one, and the fact upcoming research hasn't been completed and published as yet, is a big reason why none of us have touched the crocodilians as yet as regards a photographic thread.
 
TeaLovingDave said:
Or not :p the complexity of this one, and the fact upcoming research hasn't been completed and published as yet, is a big reason why none of us have touched the crocodilians as yet as regards a photographic thread.
Click to expand...
Oh...well since I already started I feel like I should finish. I suppose when I get to O. tetraspis I'll refer to it as such for consistency but I put a note saying something along the lines of "the taxonomy of this animal is not fully understood and this part of the thread will likely be inaccurate in the near future." Yeah I remember reading something about the two valid subspecies possibly being there own full on species, plus the possibility of a third species from West Africa.
 
Alligator mississippiensis
  • Meaning of Scientific Name: "The lizard from the Mississippi River"
  • Common Name(s): American alligator, gator, common alligator
  • Species Authority: François Marie Daudin, 1802
  • Distribution: U.S. states of Alabama, Arkansas, Florida, Georgia, Louisiana, Oklahoma, Mississippi, North Carolina, South Carolina, Texas, and Virginia
  • Length (Males): 3.4 to 4.6 meters (11.2 to 15.1 feet)
  • Length (Females): 2.6 to 3 meters (8.5 to 9.8 feet)
  • IUCN Conservation Status: Least Concern (LC)
  • Fun Fact: This species is the state reptile of 3 U.S. states: Florida, Louisiana, and Mississippi
full

Normal variant (photo by @Tomek)

full

Albino variant (photo by @geomorph)
 
Alligator sinensis
  • Meaning of Scientific Name: "The lizard from China"
  • Common Name(s): Chinese alligator, Yangtze alligator, China alligator
  • Species Authority: Albert-Auguste Fauvel, 1879
  • Distribution: Eastern China
  • Length: 5 to 7 feet (1.5 to 2.1 meters)
  • IUCN Conservation Status: Critically Endangered (CR)
  • Fun Fact: This is the only species in the family Alligatoridae that lives on a continent other than North or South America.
full

(photo by @alexkant)
 
Caiman crocodilus
  • Meaning of Scientific Name: Caiman is Spanish for "alligator" and crocodilus is Latin for "a crocodile"
  • Common Name(s): Spectacled caiman, white caiman, brown caiman, common caiman
  • Species Authority: Carl Linnaeus, 1758
  • Distribution (Native): Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad, Tobago, and Venezuela
  • Distribution (Introduced): Cuba, Florida, and Puerto Rico
  • Length (Males): 5.9 to 6.6 feet (1.8 to 2.0 meters)
  • Length (Females): 3.9 to 4.6 feet (1.2 to 1.4 meters)
  • IUCN Conservation Status: Least Concern (LC)
  • Fun Fact: The species' common name comes from a bony ridge between the eyes, which gives the appearance of a pair of spectacles.
full

(photo by @ThylacineAlive)
 
Caiman latirostris
  • Meaning of Scientific Name: "Wide-nosed alligator"
  • Common Name(s): Broad-snouted caiman
  • Species Authority: François Marie Daudin, 1802
  • Distribution: South America (Southeastern Brazil, northern Argentina, Uruguay, Paraguay, Bolivia)
  • Length: 2 to 2.5 meters (6.6 to 8.2 feet)
  • IUCN Conservation Status: Least Concern (LC)
  • Fun Fact: A 2013 concluded that Caiman latirostris and its relatives are obligate omnivores, and play an important role in the dispersal of plant seeds in their habitats
full

(photo by @geomorph)
 
Caiman yacare
  • Meaning of Scientific Name: Caiman is Spanish for "alligator" and yacare is a regional term for "alligator," so Caiman yacare literally means "alligator alligator"
  • Common Name(s): Yacare caiman, Paraguayan caiman, Red caiman, Piranha caiman
  • Species Authority: François Marie Daudin, 1802
  • Distribution: South America (northeastern Argentina, Uruguay, southeastern Peru, eastern Bolivia, central/southwest, Brazil and Paraguay)
  • Length (Males): 2 or 2.5 meters (6.6 or 8.2 feet)
  • Length (Females): average of 1.4 meters (4.6 feet)
  • IUCN Conservation Status: Least Concern (LC)
  • Fun Fact: This species has the southernmost distribution of all allagtorids.
full

Yacare caimans at the Blackpool Zoo in Blackpool, England (photo by @Jordan-Jaguar97)
 
Melanosuchus niger
  • Meaning of Scientific Name: Melanosuchus means "black crocodile," derived from the Greek melas ("black") + Greek soukhos ("crocodile"); niger is Latin for "black"
  • Common Name(s): Black caiman
  • Species Authority: Johann Baptist Ritter von Spix, 1825
  • Distribution: South America (Bolivia, Brazil; Colombia; Ecuador; French Guiana; Guyana; Peru)
  • Length: 2.2 to 4.3 meters (7 feet 3 inches to 14 feet 1 inches)
  • IUCN Conservation Status: Lower Risk - Conservation Dependent (CD)
  • Fun Fact: Melanosuchus niger is structurally dissimilar to other caiman species, particularly in the shape of the skull. Compared to other caimans, it has distinctly larger eyes. Although the snout is relatively narrow, the skull (given the species' considerably larger size) is much larger overall than other caimans.
full

Black caiman at Crocodiles of the World in Brize Norton, England (photo by @Maguari)
 
Paleosuchus palpebrosus
  • Meaning of Scientific Name: "Ancient crocodile with full eyelids;" palaios (Greek for "ancient") + soukhos (Greek for "crocodile") + palpebra (Latin for "eyelid") + osus (Latin for "full of")
  • Common Name(s): Cuvier's dwarf caiman, Cuvier's smooth-fronted caiman, dwarf caiman, Cuvier's caiman, musky caiman,
  • Species Authority: Georges Cuvier, 1807
  • Distribution: South America (Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, Venezuela)
  • Length (Males): 1.4 meters (4.6 feet)
  • Length (Females): 1.2 meters (3.9 feet)
  • IUCN Conservation Status: Lower Risk - Least Concern (LC)
  • Fun Fact: Paleosuchus palpebrosus is not only the smallest extant species in Alligatoridae, but also the smallest of all crocodilians.
full

Cuvier's dwarf caimans at Tierpark und Fossilium Bochum in Bochum, Germany (photo by @Eagle)
 
Paleosuchus trigonatus
  • Meaning of Scientific Name: "Three-cornered ancient crocodile" palaios (Greek for "ancient") + soukhos (Greek for "crocodile") + trigonos (Greek for "three-cornered") + atus (Latin suffix meaning "provided with")
  • Common Name(s): Smooth-fronted caiman, Schneider's dwarf caiman, Schneider's smooth-fronted caiman
  • Species Authority: Johann Gottlob Theaenus Schneider, 1801
  • Distribution: South America (Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Venezuela)
  • Length: 1.2 to 1.6 meters (3.9 to 5.2 feet)
  • IUCN Conservation Status: Lower Risk - Least Concern (LC)
  • Fun Fact: The specific name, trigonatus, refers to the triangular shape of the head.
full

Smooth-fronted caiman at the Sacramento Zoo in Sacramento, California, U.S.A. (photo by @Great Argus)
 
Crocodylus acutus
  • Meaning of Scientific Name: "Sharp pebble worm" = kroko (Greek for "pebble") + deilos (Greek for "worm") + acutus (Latin for "sharp")
  • Common Name(s): American crocodile, American saltwater crocodile
  • Species Authority: Georges Cuvier, 1807
  • Distribution: North American and South America (Caribbean islands, southern Florida, the Greater Antilles, southern Mexico, Central America and the South American countries of Columbia and Ecuador)
  • Length: 2.9 to 4 meters (9 feet 6 inches to 13 feet 1 inches)
  • IUCN Conservation Status: Threatened - Vulnerable (VU)
  • Fun Fact: American crocodiles, unlike American alligators, are extremely susceptible to cold temperatures and live exclusively within tropical waters. During 2009, unusually cold weather in southern Florida resulted in the deaths of about 150 wild American crocodiles.

full

American crocodile in Parque Ecológico El Palapo in Mexico (photo by @Adam Khor)
 
Crocodylus intermedius
  • Meaning of Scientific Name: "Intermediate pebble worm" = kroko (Greek for "pebble") + deilos (Greek for "worm") + intermedius (Latin for "intermediate")
  • Common Name(s): Orinoco crocodile
  • Species Authority: Graves, 1819
  • Distribution: Endemic to the Orinoco River basin of Colombia and Venezuela
  • Length: Up to 4.1 meters (13 feet 5 inches) in modern times; they use to grow much bigger
  • IUCN Conservation Status: Threatened - Critically Endangered
  • Fun Fact: The biology of the Orinoco crocodile is poorly documented in the wild, mostly due its small population. It is thought to have a more piscivorous diet with an opportunistic nature resulting in a generalist predatory behavior.
full

Orinoco crocodile at the San Antonio Zoo in San Antonio, Texas, U.S.A. (photo by @jbnbsn99)
 
Crocodylus johnstoni
  • Meaning of Scientific Name: "Johnstone's pebble worm" = kroko (Greek for "pebble") + deilos (Greek for "worm") + johnstoni (honoring Robert Arthur Johnstone , the man who reported the existence of this species to Kreft)
  • Common Name(s): Freshwater crocodile, Australian freshwater crocodile, Johnstone's crocodile; Australians like to call this species the "Freshie"
  • Species Authority: Gerard Krefft, 1873
  • Distribution: Oceania (Endemic to the Australian states of Western Australia, Queensland, and Northern Territory)
  • Length (Males): average is 2.3 to 3 meters (7.5 to 9.8 feet), however... (see fun fact)
  • Length (Females): 2.1 meters (6.9 feet)
  • IUCN Conservation Status: Lower Risk - Least Concern (LC)
  • Fun Fact: In areas such as Lake Argyle and Katherine Gorge there exist a handful of confirmed 4 meters (13 feet) individuals.
full

"Freshie" at Queensland Zoo in Queensland, Australia (photo by @WhistlingKite24)

full

"Freshie" at Werribee Open Range Zoo in Victoria, Australia (photo by @Jambo)
 
Last edited:
You must log in or register to reply here.
Back
Top