21.   Evolutionary biologists had always ascribed such difficulties to the famous incompleteness of the fossil record.

22.   For some dinosaur species, the fossil record contains only one skeleton, which is usually incomplete.

23.   Fossil records show the gator simply moved south as ice sheets advanced, and then north again when they receded.

24.   From that point forward, they began to dominate the fossil record of animal life.

25.   He said the fossil record for H. habilis was too scant to tie it to the A. africanus lineage.

26.   Her find filled a wide gap in the fossil record.

27.   Here, of course, the fossil record is of little help.

28.   Instead, they said the fossil record seemed to indicate that evolution proceeded with rapid bursts of change punctuating prolonged periods in which species were relatively unaltered.

29.   In these databases, he recorded when groups of organisms first appeared in the fossil record and when they disappeared or became extinct.

30.   It is not certain exactly when tails disappeared or why, he said, as tails do not readily show up in the fossil record.