Wikipedia, I am ignorant of biology. What delineates a 'species'?
"differing measures are often used, such as [...] morphology"
Okay. Please enlighten me as to the meaning of 'morphology'?
Morphology "includes aspects of the outward appearance (shape, structure, colour, pattern)"
So two organisms classified into different species might only differ in terms of outward appearance, such as colour? Surprising.
Thank you Wikipedia, you may go now.