Search for 8.4 million (or 84 lakh) species in Google, and several sources (mostly from Hare Krishna/ISKCON websites) claim that Padma Puranam states this shloka:
jalaja nava-laksani sthavara laksa-vimsati krmayo rudra-sankhyakah
paksinam dasa-laksanam trimsal-laksani pasavah catur-laksani manusah
9,00,000 species of aquatics 20,00,000 species of plants 11,00,000 species of insects/worms/reptiles 10,00,000 species of birds 30,00,000 species of animals 4,00,000 species of humans
I tried searching for this shloka but I can only find sanskrit text pdf - vedicilluminations.com/downloads/Puranas/Padma%20Purana/padma_purana_1srishti.pdf or english translation online, not english 'transliteration'.
A previous question provides links to all but the first 2 volumes of unabridged english translation.. which is probably where the source for this shloka lies since it is in Srishti (creation) khand.
Does anyone have an actual source for this shloka ? and the further breakdown of species ?