The genus Erythrolamprus belongs to the subfamily Dipsadinae, which is sometimes referred to as the family Dipsadidae.

[3] The subspecific name, merremi is in honor of German herpetologist Blasius Merrem.

The former subspecies extending further south (southeastern Brazil, Paraguay, Uruguay and northeastern Argentina) is now recognized as a full species, Erythrolamprus semiaureus.

It occurs in both lowland tropical rainforest and Atlantic forest at elevations below 100–700 m (330–2,300 ft).

It is believed that body size may differ either because of local genetic modification or direct phenotypic effect of food availability on the growth rates.

[10] With respect to reproductive output in the northern and southern coast Atlantic forest, and the northern and southern inland forest, the reproductive output recorded for Erythrolamprus miliaris orinus and Erythrolamprus miliaris merremi were determined via number of eggs, size of eggs, and number of neonates.

The mean egg volume in the southern coast Atlantic forest was seen to be the largest of the four regions.

The reproductive frequency was lower in the northern coast Atlantic forest than the other regions.

Female reproductive status was unaffected by the level of infection, nor was the number of eggs she carried.