pterodactyl n.

Also petə-, Proto-Indo-European root meaning "to rush, to fly." 

It forms all or part of: accipiter; appetence; appetite; apterous; apteryx; archaeopteryx; asymptote; centripetal; Coleoptera; compete; competent; eurypterid; feather; helicopter; hippopotamus; Hymenoptera; impetigo; impetuous; impetus; iopterous; Lepidoptera; ornithopter; panache; panne; pen (n.1) "writing implement;" pennon; peripeteia; perpetual; perpetuity; petition; petulance; petulant; pin; pinion; pinnacle; pinnate; pinniped; potamo-; potamology; propitiation; propitious; ptero-; pterodactyl; ptomaine; ptosis; repeat; symptom.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit pattram "wing, feather, leaf," patara- "flying, fleeting;" Hittite pittar "wing;" Greek piptein "to fall," potamos "river, rushing water," pteron, pteryx "feather, wing," ptilon "soft feathers, down, plume;" Latin petere "to attack, assail; seek, strive after; ask for, beg; demand, require," penna "feather, wing;" Old Norse fjöðr, Old English feðer "feather;" Old Church Slavonic pero "feather;" Old Welsh eterin "bird."

metrical foot, late 14c., from Latin dactylus, from Greek daktylos, a unit of measure (a finger-breadth), also "a fruit of the date tree, a date," literally "finger" (also "toe"), a word of unknown origin. The metrical use (a long syllable followed by two short ones) is by analogy with the three joints of a finger. In English versification it refers to an accented syllable followed by two unaccented. The "date" sense also sometimes was used in early Modern English.

extinct flying reptile of the Cretaceous period, 1876 (Marsh), based on pterodactyl with the stem of Greek anodous "toothless," from an- "not, without" (see an- (1)) + odon (genitive odontos) "tooth" (from PIE root *dent- "tooth").

They are remarkable for their large size, some having a spread of wings not less than twenty-five feet. They differ widely from the Pterodactyls of the old world, especially in the absence of teeth, and hence have been placed by the writer in a new order, Pteranodontia, from the typical genus Pteranodon. [O.C. Marsh, "Principal Characters of American Pterodactyls," 1876]