Extra search - what is it?

Case 1

Your are searching for a species ("species 1"); its higher taxon's rank is a subgenus

Illustration:
case 1
You will get: Illustration:
Result for case 1


Case 2

Your are searching for a subspecies ("subspecies 1")

Illustration:
case 2
You will get: Illustration:
Result for case 2


Case 3

Your are searching for a species ("species 1"); its higher taxon's rank is a genus

Illustration:
case 3
You will get: Illustration:
Result for case 3


Case 4

Your are searching for a subgenus

Illustration:
case 4
You will get: Illustration:
Result for case 4


Case 5

Your are searching for a genus

For performance and pertinence reason, the extra search is not available for a genus.