Biology:Osteolaeminae

Short description: Subfamily of crocodiles

Osteolaeminae Temporal range: Eocene–Holocene, 38–0 Ma PreЄ Є O S D C P T J K Pg N
West African dwarf crocodile (Osteolaemus tetraspis)
Central African slender-snouted crocodile (Mecistops leptorhynchus)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	Archosauriformes
Order:	Crocodilia
Family:	Crocodylidae
Subfamily:	Osteolaeminae Brochu, 2003
Genera
Osteolaemus Mecistops? †Aldabrachampsus? †Brochuchus †Euthecodon †Kinyang †Rimasuchus

Osteolaeminae is a subfamily of true crocodiles within the family Crocodylidae containing the dwarf crocodiles and slender-snouted crocodiles, and is the sister taxon to Crocodylinae.

Taxonomy

Osteolaeminae was named by Christopher Brochu in 2003 as a subfamily of Crocodylidae separate from Crocodylinae, and is cladistically defined as Osteolaemus tetraspis (the Dwarf crocodile) and all crocodylians more closely related to it than to Crocodylus niloticus (the Nile crocodile). This is a stem-based definition, and is the sister taxon to Crocodylinae. Osteolaeminae contains the two extant genera Osteolaemus and Mecistops, along with several extinct genera, although the number of extant species within Osteolaeminae is currently in question.

Phylogeny

The cladogram below is based on two studies that combined morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data.

Crocodylidae

Osteolaeminae     Mecistops cataphractus West African slender-snouted crocodile     Euthecodon†         Brochuchus†       Rimasuchus†       Osteolaemus osborni Osborn’s dwarf crocodile     Osteolaemus tetraspis Dwarf crocodile           Crocodylinae   Voay†   Crocodylus       Crocodylus anthropophagus†     Crocodylus thorbjarnarsoni†         Crocodylus palaeindicus†     Crocodylus Tirari Desert†               Crocodylus johnstoni Freshwater crocodile       Crocodylus novaeguineae New Guinea crocodile     Crocodylus mindorensis Philippine crocodile           Crocodylus porosus Saltwater crocodile       Crocodylus siamensis Siamese crocodile     Crocodylus palustris Mugger crocodile               Crocodylus checchiai†     Crocodylus falconensis†         Crocodylus suchus West African crocodile       Crocodylus niloticus Nile crocodile         Crocodylus moreletii Morelet's crocodile     Crocodylus rhombifer Cuban crocodile         Crocodylus intermedius Orinoco crocodile     Crocodylus acutus American crocodile

(crown group)

Alternatively, other morphological studies have recovered Mecistops as a basal member of Crocodylinae, more closely related to Crocodylus than to Osteolaemus and the other members of Osteolaeminae, as shown in the cladogram below.

Crocodylidae	Osteolaeminae   Rimasuchus lloydi†       Voay robustus†       Osteolaemus osborni Osborn’s dwarf crocodile     Osteolaemus tetraspis Dwarf crocodile           "Crocodylus" gariepensis†         Brochuchus parvidens†     Brochuchus pigotti†         Euthecodon arambourgi†     Euthecodon brumpti†           Crocodylinae   Mecistops cataphractus West African slender-snouted crocodile         Crocodylus thorbjarnarsoni†     Crocodylus anthropophagus†         Crocodylus niloticus Nile crocodile       Crocodylus checchiai†     Crocodylus moreletii Morelet's crocodile     Crocodylus intermedius Orinoco crocodile     Crocodylus acutus American crocodile     Crocodylus rhombifer Cuban crocodile       Crocodylus palaeindicus†       Crocodylus palustris Mugger crocodile         Crocodylus ossifragus†     Crocodylus siamensis Siamese crocodile         Crocodylus mindorensis Philippine crocodile     Crocodylus johnstoni Freshwater crocodile     Crocodylus porosus Saltwater crocodile       Crocodylus raninus Borneo crocodile     Crocodylus novaeguineae New Guinea crocodile

Species list

• Subfamily Osteolaeminae
  • Genus Osteolaemus
    • Osteolaemus osborni, Osborn’s dwarf crocodile
    • Osteolaemus tetraspis, dwarf crocodile (There has been controversy as to whether or not this is actually two species; recent (2010) DNA analysis indicate three distinct species: O. tetraspis, O. osborni and a third, currently unnamed.)
  • Genus Mecistops
    • Mecistops cataphractus, West African slender-snouted crocodile
    • Mecistops leptorhynchus, Central African slender-snouted crocodile
  • Genus Brochuchus†
    • Brochuchus pigotti† (formerly Crocodylus pigotti)
    • Brochuchus parvidens†
  • Genus Euthecodon†
    • Euthecodon nitriae†
    • Euthecodon brumpti†
    • Euthecodon arambourgi†
  • Genus Rimasuchus†
    • Rimasuchus lloydi† (formerly Crocodylus lloydi)

References

Wikidata ☰ Q21541686 entry