what does its name mean?
'Platypus' is the latinisation of the Greek word, 'flat-footed'
Platypus
The common name "platypus" is the latinisation of the Greek word ('), "flat-footed", from ('), "broad, wide, flat" and ('), "foot".
are platypus the only mammals that lay eggs No - The four extant species of echidnas also lay eggs.
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Platypus [SEP] Taxonomy and etymology
Shaw even took a pair of scissors to the dried skin to check for stitches. The common name "platypus" is the latinisation of the Greek word ('), "flat-footed", from ('), "broad, wide, flat" and ('), "foot". Shaw assigned the species the Linnaean name "Platypus anatinus" when he initially described it, but the genus term was quickly discovered to already be in use as the name of the wood-boring ambrosia beetle genus "Platypus". It was independently described as "Ornithorhynchus paradoxus" by Johann Blumenbach in 1800 (from a specimen given to him by Sir Joseph Banks) and following the rules of priority of nomenclature, it was later officially recognised as "Ornithorhynchus anatinus".