 The genus name Nebrius is derived from the Greek word nebris or nebridos , meaning the skin of a fawn . The specific epithet ferrugineus is Latin for " rust @-@ colored " . Other common names for this species include giant sleepy shark , Madame X ( a name coined by the shark fisherman Norman Caldwell in the 1930s for the then @-@ unidentified Australian specimens ) , nurse shark , rusty catshark , rusty shark , sleepy shark , spitting shark , and tawny shark . Based on morphological similarities , Nebrius is believed to be the sister genus of Ginglymostoma , with both being placed in a clade that also contains the short @-@ tail nurse shark ( Pseudoginglymostoma brevicaudatum ) , the whale shark ( Rhincodon typus ) , and the zebra shark ( Stegostoma fasciatum ) . 
 The genus name Nebrius is derived from the Greek word nebris or nebridos , meaning the skin of a fawn . The specific epithet ferrugineus <a href='drop_aux' title='1'><mark>is</mark></a>Latin for " rust @-@ colored " . Other common names for this species include giant sleepy shark , Madame X ( a name coined by the shark fisherman Norman Caldwell in the 1930s for the then @-@ unidentified Australian specimens ) , nurse shark , rusty catshark , rusty shark , sleepy shark , spitting shark , and tawny shark . Based on morphological similarities , Nebrius is believed to be the sister genus of Ginglymostoma , with both being placed in a clade <a href='null_relcl' title='2'><mark>that</mark></a>also <a href='uninflect' title='3'><mark>contains</mark></a> the short @-@ tail nurse shark ( Pseudoginglymostoma brevicaudatum ) , the whale shark ( Rhincodon typus ) , and the zebra shark ( Stegostoma fasciatum ) . 
The genus name Nebrius is derived from da Greek word nebris or nebridos , meaning the skin of a fawn . The specific epithet ferrugineus Latin fa " rust @-@ colored " . Other common names for dis species include giant sleepy shark , Madame X ( a name coined by the shark fisherman Norman Caldwell in the 1930s for the then @-@ unidentified Australian specimens ) , nurse shark , rusty catshark , rusty shark , sleepy shark , spitting shark , and tawny shark . Based on morphological similarities , Nebrius is believed to be the sis genus of Ginglymostoma , with both bein placed in a clade also contain tdashort @-@ tail nurse shark ( Pseudoginglymostoma brevicaudatum ) , the whale shark ( Rhincodon typus ) , and the zebra shark ( Stegostoma fasciatum ) .