 The invisible rail is superficially similar to the purple swamphen , Porphyrio porphyrio , which has recently been found in Halmahera , but that species is larger , with a short , thick red bill and a red forehead shield ; it also has purple underparts and a white undertail . The invisible rail is different from the Calayan rail , Gallirallus calayanensis , in that it is larger and lacks the barred plumage of that species ; there is no overlap between the ranges of the two species . 
 The invisible rail is superficially similar to the purple swamphen , Porphyrio porphyrio , which <a href='been_done' title='1'><mark>has</mark></a> recently been found in Halmahera , but that species <a href='drop_aux' title='2'><mark>is</mark></a>larger , with a short , thick red bill and a red forehead shield ; it also <a href='got' title='3'><mark>has</mark></a> purple underparts and a white undertail . The invisible rail is different from the Calayan rail , Gallirallus calayanensis , in that it <a href='drop_aux' title='4'><mark>is</mark></a>larger and <a href='uninflect' title='5'><mark>lacks</mark></a> the barred plumage of that species ; <a href='dey_it' title='6'><mark>there</mark></a> is no overlap between the ranges of the two species . 
The invisible rail is superficially similar to da purple swamphen , Porphyrio porphyrio , which done recently been found in Halmahera , but dat species larger , with a short , thick red bill and a red forehead shield ; it also got purple underparts and a white undertail . The invisible rail is diff from the Calayan rail , Gallirallus calayanensis , in that it larger and lack tdabarred plumage of that species ; it ain't no overlap between the ranges of thdawo species .