TY - JOUR PY - 2012 J2 - Nature SN - 0028-0836 T2 - Nature VL - 484 IS - 7395 DO - 10.1038/484436a TI - RARE SPECIMENS UR - https://www.cheric.org/research/tech/periodicals/view.php?seq=1042127 AU - Whitfield J SP - 436 EP - 438 LA - English ER -