SEM photographs of the Maastrichtian planktic foraminiferal species usually considered to be putative survivors of the KPB extinction. Specimen comparison from upper Maastrichtian and lower Danian samples at El Kef. Samples K numbered in cm from the KPB. Specimens in Maastrichtian samples: 1. Guembelitria cretacea (K-100); 2. Guembelitria blowi (K-750); 3. Muricohedbergella holmdelensis (K-400); 4. Muricohedbergella monmouthensis (K-70); 5. Heterohelix globulosa (K-400); 6. Heterohelix labellosa (K-400); 7. Heterohelix planata (K-400); 8. Heterohelix navarroensis (K-400); 9. Globigerinelloides yaucoensis (K-400); 10. Pseudoguembelina costulata (sample K-400); 11. Laeviheterohelix glabrans (K-400); 12. Globigerinelloides prairiehillensis (K-1100); 13. Globigerinelloides volutus (sample K-400); 14. Pseudoguembelina kempensis (sample K-400); 15. Pseudoguembelina costulata (K-400); 16. Rugoglobigerina rugosa (K-400). Specimens in Danian samples: 17. Guembelitria cretacea (K+5); 18. Guembelitria blowi (K+5); 19. Muricohedbergella holmdelensis (K+5); 20. Muricohedbergella monmouthensis (K+70); 21. Heterohelix globulosa (K+5); 22. Heterohelix labellosa (K+5); 23. Heterohelix planata (K+20); 24. Heterohelix navarroensis (K+5); 25. Globigerinelloides yaucoensis (K+5); 26. Laeviheterohelix pulchra (K+5); 27. Laeviheterohelix glabrans (K+5); 28. Globigerinelloides prairiehillensis (K+10); 29. Globigerinelloides volutus (K+5); 30. Pseudoguembelina kempensis (K+10); 31. Rugoglobigerina rugosa (K+5). Scale bars: 100 μm.