This confirms my suspicion that it takes a diapsid to know one.    From Wordnik.com.  [New evidence that natural selection is a general driving force behind the origin of species - The Panda's Thumb] Reference

Birds are also clearly diapsids and if every living amniote that isnt a mammal is a diapsid then birds are diapsid reptiles too.    From Wordnik.com.  [Drawing a Line in the Academic Sand - The Panda's Thumb] Reference

Perhaps the confusion here is the similarity to the term “theropod” which always refers to a diapsid except when it refers to Lenny. ben.    From Wordnik.com.  [Controversies in Evolution: 'Jurassic beaver' unearthed in China - The Panda's Thumb] Reference

This is where Lenny caustically suggested that I was a YEC for not knowing that turtles had been reclassified as diapsids with a secondarily anapsid appearing skull I hope that embryologically turtle skulls start off as diapsid and then change but I dont really know.    From Wordnik.com.  [Drawing a Line in the Academic Sand - The Panda's Thumb] Reference

Well, diapsid reptiles .... but birds are diapsids, too.    From Wordnik.com.  [freshnews.org - most clicked links] Reference

Mesozoic, and Hyphalosaurus sinohydrosaurus (Nature 401, 262, 1999) a long-necked diapsid reptile.    From Wordnik.com.  [WN.com - Articles related to Summary Box: Drop in home sales hurts stock market] Reference

Edit perhaps this isnt the correct place to ask this question, but I’ve had difficulty with these high-in-the-classification-system words and perhaps someone knows the exact evolutionary definitions and how they compare to each other: “reptile”, “sauropsid” and “diapsid”.    From Wordnik.com.  [Down with phyla! (episode II) - The Panda's Thumb] Reference

I think i’ve got this now: basal anapsid reptiles (which presumably gave rise to synapsid and sauropsid lineages) died out leaving no descendants. turtles, full diapsid reptiles closely allied to crocodiles, secondarily developed a seemingly (but not osteogenically identical) anapsid skull structure subsequently.    From Wordnik.com.  [Report on the 2005 Creation Mega Conference, Part Four - The Panda's Thumb] Reference

Also re: ‘reptile’, ‘sauropsid’ and ‘diapsid’.    From Wordnik.com.  [Down with phyla! (episode II) - The Panda's Thumb] Reference

'diapsid status' of the skull was used in the title, as if it were one of the most significant details of the specimen).    From Wordnik.com.  [ScienceBlogs Channel : Life Science] Reference

401, 262, 1999) a long-necked diapsid reptile.    From Wordnik.com.  [WN.com - Articles related to Summary Box: Drop in home sales hurts stock market] Reference

While I think it went ok, I hope I didn’t overwhelm my students: the idea for the first teaching session was to quickly run through Palaeozoic and Mesozoic tetrapod history, looking at the major clades, so we dashed through tetrapod origins, lepospondyls, temnospondyls, the living amphibian groups, anthracosaurs, amniote origins, Palaeozoic synapsids, the turtle origins controversy, and diapsid diversity.    From Wordnik.com.  [Archive 2006-10-01] Reference