[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Claw function in Deinonychus



As total length is uncertain for all except a few complete dromaeosaur specimens, perhaps a comparison of ungual length to another element's length would be less prone to error. Here's data comparing ungual length to femoral and phalanx II-1 length. Velociraptor's and Deinonychus' femoral lengths are estimated from scaling similar-sized specimens, as no single specimen has been measured for all relevent elements. Utahraptor material is not articulated and lacks described pedal phalanges or femora. I included Archaeopteryx just to see where it'd go.

(Archaeopteryx
Berlin- ungual 12.5, phalanx 8.5, femur 52.6)
Microraptor zhaoianus
CAGS 20-7-004- ungual 13.24, phalanx 6.88, femur 64.26
CAGS 20-8-001- ungual 16.04, phalanx 6.91, femur 74.77
Rahonavis
holotype- ungual 19.7, phalanx 12, femur 88
Bambiraptor
holotype- ungual 46, phalanx 14.3, femur 118
Sinornithosaurus
holotype- ungual 35, phalanx 15, femur 148
Velociraptor
IGM 100/25- ungual 66, phalanx 21
IGM 100/985- ungual 64.8, phalanx 23.6
IGM 100/982- ungual 66.3, phalanx 23.9 (femur ~214)
Adasaurus
IGM 100/51- ungual 27, phalanx 26
Deinonychus
holotype- ungual ~137, phalanx 43.5 (femur ~328)

ungual/phalangeal ratios-
Microraptor (20-7-004) = 1.92
Microraptor (20-8-001) = 2.32
(Archaeopteryx = 1.47)
Rahonavis = 1.64
Bambiraptor = 3.22
Sinornithosaurus = 2.33
Velociraptor (25) = 3.14
Velociraptor (985) = 2.75
Velociraptor (982) = 2.77
Adasaurus = 1.04
Deinonychus (holo) = ~3.15

ungual/femoral ratios-
(Archaeopteryx = .24)
Microraptor (20-7-004) = .21
Microraptor (20-8-001) = .21
Rahonavis = .22
Bambiraptor = .39
Sinornithosaurus = .24
Velociraptor = .31
Deinonychus = .42

Based on this, I'd agree comparative ungual length increases with body size, albeit not by much. Bambiraptor has an unusually large ungual for its size, while Adasaurus has an unusually small one.

Mickey Mortimer