Thamnosophis infrasignatus

{{Short description|Species of snake}}

{{Speciesbox

| image = Forest_Water_Snake_(Thamnosophis_infrasignatus)_(9657296102).jpg

| image_caption =

| status = LC

| status_system = IUCN3.1

| status_ref = {{cite journal | title = Thamnosophis infrasignatus | journal = IUCN Red List of Threatened Species | volume= 2011 | year = 2011 | doi = 10.2305/IUCN.UK.2011-2.RLTS.T172936A6944525.en | doi-access = free }}

| genus = Thamnosophis

| species = infrasignatus

| authority = (Günther, 1882)

| synonyms = * Ptyas infrasignatus Günther, 1882

• Liopholidophis thieli Domergue, 1972
• Liopholidophis infrasignatus (Günther, 1882)

| range_map =

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Thamnosophis infrasignatus, commonly known as the forest water snake, is a species of snake in the family Pseudoxyrhophiidae. It is endemic to Madagascar.