You can’t help but be impressed by the regeneration ability of young spiders. This Mexican red knee tarantula (Brachypelma smithi), identified as a female in the December 18, 2012 blog entry, emerged from its molt on October 16, 2012 with a distinctly mismatched leg. Immediately after the December molt the mismatched leg was proportionally much larger, more heavily pigmented (see above) and fully functional.
Leg loss/damage during the molting process is not uncommon. Both of my rapid growing Honduran curly hair tarantulas (Brachypelma albopilosum) have experienced leg issues during previous molts. You can read more about those molts and the resulting leg issues in the blog entry entitled “Honduran curlyhair tarantula (Brachypelma albopilosum) molting issues.”