The following verse is claimed to be variously from the Padma purāṇa, the Garuḍa purāṇa and the Visṇu purāṇa.
jalajā nava-lakṣāṇi sthāvarā lakṣa-viṁśati kṛmayo rudra-saṅkhyakāḥ
pakṣiṇāṁ daśa-lakṣaṇam triṁśal-lakṣāṇi paśavaḥ catur-lakṣāṇi mānuṣāḥ
I have tried to find this verse in these claimed sources but have been unable to do so. My working hypothesis is that the verse is not authentic.
My translation is:
There are 9 lakh marine animal forms, 20 lakh trees, 11 lakh worms, 10 lakh birds and 30 lakh four-legged animal forms. There are four lakh humans.
This verse is claimed by proponents to represent the number of species of each type, and evidence that the scriptures already contain the knowledge of modern science. This is because modern science estimates the total number of species at around 8.7 million. See here: https://www.nature.com/articles/news.2011.498. The total number of forms in the above verse is 8.4 million.
Problems with the claim
There are a number of problems with this claim. First, unlike the verse, modern science estimates the number of human species at around 20. There is no way there were 400,000 human species on earth – the fossil evidence simply does not support it.
Second, by definition, the word ‘species’ in science refers to a group of organisms that can reproduce with one another. What is the definition of ‘species’ in the verse above (if we translate the verse to include the word ‘species’)? If we say that the devas are a distinct species of humans according to the above verse, it is well known that devas can beget children with humans. So such a classification does not match the definition of species in science.
The classification in the verse, assuming the verse is even authentic, is entirely undefined. It is a mistake to interpret it to mean the scientific notion of species, and to then take credit for the estimate (as modern Caitanya sects love to do).
Śrī Jīva Goswami’s view
In Anuchheda 108 of the Bhakti Sandarbha, Śrī Jīva cites three verses from the Brahma-vaivarta purāṇa:
prāpyāpi durlabhataraṁ mānuṣyaṁ vibudhepsitam yair āśrito na govindas tair ātmā vañcitaś ciram
aśītiṁ caturaś caiva lakṣāṁs tān jīva-jātiṣu bhramadbhiḥ puruṣaiḥ prāpya mānuṣyaṁ janma-paryayāt tad apy aphalatāṁ jātaṁ teṣām ātmābhimāninām varākāṇām anāśritya govinda-caraṇa-dvayam
Those who have not taken shelter of Bhagavān Govinda, even after obtaining this human birth, which is exceedingly rare and aspired for by the devas, have effectively cheated their true selves over a vast sequence of time. After evolving successively through eight million, four hundred thousand species of life, a person finally attains a human birth. But that too is rendered futile by the self-conceited, wretched souls who do not take shelter of Govinda’s lotus feet. (Brahma-vaivarta Purāna)
From the bolded sentence above, it is evident there is only one human ‘species’!