CREATE TABLE table_name_67 (sequence_length__aa_ INT, common_name VARCHAR, divergence_from_human_lineage__mya_ VARCHAR)

What is the sequence length (aa) of the protein with the common name Purple Sea Urchin and a divergence from human lineage less than 742.9?
SELECT SUM(sequence_length__aa_) FROM table_name_67 WHERE common_name = "purple sea urchin" AND divergence_from_human_lineage__mya_ < 742.9
SELECT SUM("sequence_length__aa_") FROM "table_name_67" WHERE "common_name" = "purple sea urchin" AND "divergence_from_human_lineage__mya_" < 742.9