Description: This type shares the characteristic markings of larval and transitional Sparisoma. Recruits become distinct from S. viride early as melanophores extend onto the base of the central caudal fin rays and divide the light bar on the tail. The melanophores extending into the caudal bar extend further below the midline than above (vs. equal above and below in S. chrysopterum/rubripinne). Small juveniles tend to have dark patches along the lateral midline mostly below the level of the lateral line and do not develop an obvious white tail bar. Some individuals develop a marked bicolor pattern of light above the lateral line and dark below. Later juveniles are variably mottled with some light striping and spotting and are only identified by process of exclusion (or DNA sequence analysis). Individuals from Noronha in Brazil show a pattern of reduced body markings and intensified black markings on the fins.
Diagnosis: The larvae of all Sparisoma may well be identical, and DNA sequencing is required to identify species. Transitional recruits develop the basic markings probably shared by all members of the genus, but small juveniles of Sparisoma acquire distinct patterns that separate most, if not all, regional species. The DNA sequence of the juvenile specimen from Noronha in Brazil confirms that it is S. radians (Bernardi et al 2005), even though it displays a peculiar pattern of markings. S. atomarium may be indistinguishable from S. radians when juvenile specimens are found in the same habitat.
