Williston (1903) originally diagnosed Dolichorhynchops as follows: “Head elongate, the facial region much attenuated; teeth nearly uniform in size, small; prefrontals and postfrontal bones not joined; parietals extending into a high crest; supraocciptial bones separated; internal nares small, included between the vomer and the palatine only; palatines broadly separated throughout; a large vacuity between the pterygoids anteriorly; quadrate process of pterygoids short; neck but little longer than the head, composed of 19 or 20 vertebrae; all presacral vertebrae of nearly equal length, moderately concave, with vascular foramina below; spines short, uniform in length; diapophyses of the dorsal vertebrae situated high up; coracoids with long epicoracoid process; clavicles and scapula free; episternum with an emargination in front and behind, the latter forming part of a large interclavicular foramen; three epipodial bones, all broader than long; ischium elongated; length 10 feet”
