So, having read that describing a bone is one of the best ways to learn its features well, this is something I wrote up last night. Obviously it's a cast, but it's a very well done cast, so most of the features I describe should be in the real bone.
I'll note that because my access to the kind of literature I need to make any kind of comparative basis is currently limited (at least until the Fall), I've only focused on the features of the claw itself, and not how they relate to other theropod dinosaur groups.
With that said, I'd appreciate any comments/tips you may have!
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The element, a robust left manual ungual I missing the distal tip (which is fractured at a point transversely distal from the ventral margin of the articular facet and flexor tubercle), measures 190 mm in a line perpendicular to the articular facet and 305 mm across its convex, recurved dorsal margin. Its ventral portion, with the exception of the flexor tubercle (which is convex and robust in form), is flattened across its length. Distinctive rugosities cover the ungual's surface, though they are most apparent on the posterior regions. Possibly due to erosion, these pits are shallower on the medial side of the bone than on the lateral one.
A deep groove extends from the dorsomedial margin of the flexor tubercle, terminating just posterior to the missing distal tip. At its inception, this groove is placed in the lower 1/3 of the dorso-ventral complex, a form maintained for 3/4 of the claw’s curvature. However, this placement rapidly migrates dorsally at the 3/4 point until it reaches the top 1/3 of the bone. The groove reaches its maximum width halfway through the claw’s total length. A similar groove can be found on the lateral side of the claw. However, this groove is much deeper, a feature that may also be in part due to erosion of the medial surface. The lateral groove differs substantially from the medial one in that it thins radically to a ‘crack-like’ form 3/4 of the way through the medial groove’s duration.
The flexor tubercle is large and robust, being subequal in width to the dorsal margin of the articular facet. Its form, whose posterior margin is placed anterior to the articular facet, is subtriangular in both posterior and ventral views. A deep, median ridge divides the articular facet, which is oval-shaped in posterior view. The ventral portion of this ridge is especially bulky, being twice as thick as the maximum width reached by the midline. The articular surface for the condyles of the penultimate phalanx is deeper on the medial side than its lateral counterpart. Given the overall proportions of the ungual and its articular surfaces, the phalanx to which it was connected in life was likely equally robust.
So, having read that describing a bone is one of the best ways to learn its features well, this is something I wrote up last night. Obviously it's a cast, but it's a very well done cast, so most of the features I describe should be in the real bone.