The first zoeal stage of Calocarcinus africanus Calman, 1909 is for the first time described and illustrated from laboratory-hatched material. Its morphology is compared with other trapeziid first stage zoeas, including those described for Quadrella Dana, 1851, Tetralia Dana, 1851 and Trapezia Latreille, 1828. The setation pattern of Calocarcinus does not appear to share the zoeal characters common to these trapeziids, and this may indicate that the genus is erroneously assigned to the Trapeziidae Miers, 1886. A further comparison of Calocarcinus first stage zoeas with other known xanthoid larvae, including those of Eriphia Latreille, 1817, and Lydia Gistel, 1848 was undertaken. Although Calocarcinus first zoeas appear to share many characters with those of Eriphia and Lydia, affinities between these two genera are considered to be speculative at present because many xanthoidean zoeas still remain undescribed. However, the morphology of the first zoea of Calocarcinus does not support the inclusion of this genus in the Trapeziidae. For the present study a data matrix was constructed comprising 12 taxa and twenty-six characters. The resulting tree supported the morphological comparison based on similarity and difference in that Calocarcinus was not a trapezoid but more closely related to the xanthoidean taxon Eriphia.