The u in anthuceros

heard as anthuceros

spelled anthoceros

It is an o: Anthoceros.

What the ear did

Unstressed, and therefore unhearable. Anthos ends in that o.

Sound decision: an unstressed vowel blurring. Said an-THOSS-er-oss.

A-N-T-H-O-C-E-R-O-S

The full entry for anthoceros covers the name itself.