Janusiscus

Janusiscus schultzei was a gnathostome (jawed vertebrate) dating from the Early Devonian period in Siberia, approximately 415 million years ago. It may be a common ancestor of either Chondrichthyes (cartilaginous fish) or Osteichthyes (bony fish) or both. If it is an ancestor to both types of fish, then J. schultzei would also be a common ancestor to all living jawed vertebrates. The species name is in honor of Hans-Peter Schultze; the genus named after Janus, the Roman god of duality.[1]

Janusiscus
Temporal range: 415 Ma
↓
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Infraphylum: Gnathostomata
Genus: †Janusiscus
Giles et al., 2015
Species:
†J. schultzei
Binomial name
†Janusiscus schultzei
Giles et al., 2015

Taxonomy

The following cladogram is simplified from Giles et al., 2015:[1]

 
 

 †Galeaspida

 
 
 

 †Osteostraci

 
 Gnathostomata 
 

 †Antiarchi

 
 
 

 †Petalichthyida

 
 
 

 †Ptyctodontida

 
 
 

 †Rhenanida

 
 

 †Arthrodira

 
 
 

 †Janusiscus schultzei

 
 
 

 Osteichthyes (Bony fish and tetrapods)

 
 
 

 †Acanthodii

 
 

 Chondrichthyes (Cartilaginous fish)

 
 
 
 
 
 
 
 
 
 

References
  1. Giles, Sam; Friedman, Matt; Brazeau, Martin D. (2015-01-12). "Osteichthyan-like cranial conditions in an Early Devonian stem gnathostome". Nature. 520 (7545): 82–85. doi:10.1038/nature14065. ISSN 1476-4687. PMC 5536226. PMID 25581798.


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