| Gettyia | |
|---|---|
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Avialae |
| Clade: | †Enantiornithes |
| Family: | †Avisauridae |
| Genus: | †Gettyia Atterholt, Hutchinson, and O'Connor, 2018 |
| Type species | |
| †Gettyia gloriae Atterholtt, Hutchinson, and O'Connor, 2018 | |
| Synonyms | |
Gettyia is anextinctgenus ofavisauridenantiornitheanbird from theLate Cretaceous ofNorth America.[1][2]
Gettyia is known from a single righttarsometatarsus. This bone was similar to that of other North American avisaurids such asAvisaurus andMirarce, but it was much smaller. Thesecond metatarsal had a tubercule (knob-like structure) on its front edge, which likely connected to thetibialis cranialis muscle which flexes the ankle. Other avisaurids typically had this tubercule located midway on the shaft of the metatarsal, or closer to the ankle than the toes.Gettyia, on the other hand, had itstibialis cranialis tubercule located more than halfway down the shaft.[1] The third and fourth metatarsals are more extensively fused than in other avisaurids, as fusion occurs not only near the ankle, but also near the toes.[2]
The more distally placedtibialis cranialis tubercule ofGettyia suggests that it had a more specialized lifestyle compared to other avisaurids. Zeffer & Norberg (2003) have found that living birds with a distally placedtibialis cranialis tubercules were biomechanically inclined to emphasize force of flexion, rather than speed.Birds of prey in particular utilize forceful flexion during their hunting behavior. Arborealparrots and other climbing birds also make use of forceful flexion to obtain stability while foraging or hanging from tree branches. More terrestrial birds typically need more speed and less force, to assist locomotion like walking and hopping.[3]
Gettyia is known from thehumid low-lying swamps, lakes, and river basins of the western shore of theWestern Interior Seaway, and from the much more arid uplands between that area and theCordilleran Overthrust Belt which eventually formed theRocky Mountains.
Gettyia was originally namedAvisaurus gloriae by Varrichio and Chiappe (1995) for MOR 553E/6.19.91.64, a tarsometatarsus from the lateCampanian UpperTwo Medicine Formation of Glacier County, Montana, USA. The species name honors Gloria Siebrecht, a volunteer fossil collector at the Museum of the Rockies who discovered the specimen.[2] A new partial skeleton of an enantiornithean that would come to be known asMirarce prompted Atterholtet al. (2018) to re-evaluate avisaurid taxonomy. They found thatMirarce was intermediate between "Avisaurus" gloriae andAvisaurus archibaldi, showing that the two "Avisaurus" species were not actually members of a single monophyletic genus. To solve this problem, they created the genus nameGettyia forAvisaurus gloriae, honoring the late Mike Getty.[1]
