Helicops carinicaudus

Helicops carinicaudus can be distinguished from all its congeners, except H. danieli, H. infrataeniatus, H. leopardinus and H. phantasma by the following combination of characteristics: 17–19 dorsal scale rows at mid-body, reducing to 17 anterior to cloaca (versus 17–20/17–19 in H. angulatus; 21–22/17–19 in H. apiaka; 25/21 in H. boitata; 19/19 in H. gomesi; 21–29/19–23 in H. hagmanni; 17–20/15–19 in H. modestus; 17/15 in H. nentur; 23–25/16–19 in H. pastazae; 21–23/16 in H. petersi; 23–26/17–21 in H. polylepis; 19–21/16–19 in H. scalaris; 19/17 in H. tapajonicus; 20–23/16–19 in H. trivittatus; 25–28/18–20 in H. yacu), 128–141 ventrals in males and 128–148 ventrals in females (versus ♂103–123♀104–125 in H. angulatus; ♂112–125♀112–124 in H. modestus; ♂110–119♀113–125 in H. scalaris; ♂118♀121–123 in H. tapajonicus). From H. danieli and H. leopardinus, it differs in having a striped or uniform dorsum versus blotched pattern in H. danieli and H. leopardinus. From H. infrataeniatus and H. phantasma, it differs in having a yellow or cream venter with two series of black semi-lunar marks, between these small, irregular black spots (for information on references, see Suppl. material 3).

The distribution of H. carinicaudus extends from the Estuary of the Rio de La Plata along the shoreline of Brazil to the Province Pernambuco (Fig. 1d).