WoRMS
www.marinespecies.org
The World Register of Marine Species REST services from the Flanders Marine Institute: authoritative marine taxonomy with AphiaIDs, synonymy, classification trees, vernacular names, and recorded distributions, used as the taxonomic backbone by OBIS and many other marine systems.
GET /v1/data/worms/children1Request
AphiaID of the parent taxon. Use a family or genus: a species with no children answers 204 with an empty body.
curl "https://api.fastcrw.com/v1/data/worms/children?id=125469" \ -H "Authorization: Bearer $FASTCRW_API_KEY"
2Response example
A sample shape. Press Run to see live data from WoRMS.
[
{
"AphiaID": 295924,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=295924",
"scientificname": "Aeglefinus",
"authority": "Malm, 1877",
"status": "unaccepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125733,
"valid_name": "Melanogrammus",
"valid_authority": "Gill, 1862",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Aeglefinus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Aeglefinus Malm, 1877. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=295924 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:295924",
"isMarine": 1,
"isBrackish": null,
"isFreshwater": null,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2015-04-23T06:36:07.833Z"
},
{
"AphiaID": 125728,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=125728",
"scientificname": "Arctogadus",
"authority": "Dryagin, 1932",
"status": "accepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125728,
"valid_name": "Arctogadus",
"valid_authority": "Dryagin, 1932",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Arctogadus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Arctogadus Dryagin, 1932. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=125728 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:125728",
"isMarine": 1,
"isBrackish": 0,
"isFreshwater": 0,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2014-11-21T13:09:37.943Z"
},
{
"AphiaID": 296060,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=296060",
"scientificname": "Asellus",
"authority": "Valenciennes, 1838",
"status": "unaccepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125769,
"valid_name": "Mora",
"valid_authority": "Risso, 1827",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Asellus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Asellus Valenciennes, 1838. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=296060 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:296060",
"isMarine": 1,
"isBrackish": null,
"isFreshwater": null,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2008-02-21T16:46:40.470Z"
},
{
"AphiaID": 125729,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=125729",
"scientificname": "Boreogadus",
"authority": "Günther, 1862",
"status": "accepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125729,
"valid_name": "Boreogadus",
"valid_authority": "Günther, 1862",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Boreogadus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Boreogadus Günther, 1862. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=125729 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:125729",
"isMarine": 1,
"isBrackish": 1,
"isFreshwater": 0,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2014-11-21T13:09:37.943Z"
},
{
"AphiaID": 296194,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=296194",
"scientificname": "Brachygadus",
"authority": "Gill, 1862",
"status": "unaccepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125739,
"valid_name": "Trisopterus",
"valid_authority": "Rafinesque, 1814",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Brachygadus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Brachygadus Gill, 1862. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=296194 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:296194",
"isMarine": 1,
"isBrackish": null,
"isFreshwater": null,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2015-04-23T06:36:07.833Z"
},
{
"AphiaID": 125730,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=125730",
"scientificname": "Eleginus",
"authority": "Fischer, 1813",
"status": "accepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125730,
"valid_name": "Eleginus",
"valid_authority": "Fischer, 1813",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Eleginus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Eleginus Fischer, 1813. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=125730 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:125730",
"isMarine": 1,
"isBrackish": 1,
"isFreshwater": 1,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2014-11-21T13:09:37.943Z"
},
{
"AphiaID": 125731,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=125731",
"scientificname": "Gadiculus",
"authority": "Guichenot, 1850",
"status": "accepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125731,
"valid_name": "Gadiculus",
"valid_authority": "Guichenot, 1850",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Gadiculus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Gadiculus Guichenot, 1850. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=125731 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:125731",
"isMarine": 1,
"isBrackish": 0,
"isFreshwater": 0,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2014-11-21T13:09:37.943Z"
},
{
"AphiaID": 296653,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=296653",
"scientificname": "Gadulus",
"authority": "Malm, 1877",
"status": "unaccepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125739,
"valid_name": "Trisopterus",
"valid_authority": "Rafinesque, 1814",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Gadulus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Gadulus Malm, 1877. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=296653 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:296653",
"isMarine": 1,
"isBrackish": null,
"isFreshwater": null,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2015-04-23T06:36:07.833Z"
},
{
"AphiaID": 125732,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=125732",
"scientificname": "Gadus",
"authority": "Linnaeus, 1758",
"status": "accepted",
"unacceptreason": null,
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125732,
"valid_name": "Gadus",
"valid_authority": "Linnaeus, 1758",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Gadus",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Gadus Linnaeus, 1758. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=125732 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:125732",
"isMarine": 1,
"isBrackish": 1,
"isFreshwater": 0,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2014-11-21T13:09:37.943Z"
},
{
"AphiaID": 397666,
"url": "https://www.marinespecies.org/aphia.php?p=taxdetails&id=397666",
"scientificname": "Melanogrammes",
"authority": null,
"status": "unaccepted",
"unacceptreason": "misspelling",
"taxonRankID": 180,
"rank": "Genus",
"valid_AphiaID": 125733,
"valid_name": "Melanogrammus",
"valid_authority": "Gill, 1862",
"parentNameUsageID": 125469,
"originalNameUsageID": null,
"kingdom": "Animalia",
"phylum": "Chordata",
"class": "Teleostei",
"order": "Gadiformes",
"family": "Gadidae",
"genus": "Melanogrammes",
"citation": "Froese, R. and D. Pauly. Editors. (2026). FishBase. Melanogrammes. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=397666 on 2026-10-23",
"lsid": "urn:lsid:marinespecies.org:taxname:397666",
"isMarine": 1,
"isBrackish": null,
"isFreshwater": null,
"isTerrestrial": 0,
"isExtinct": null,
"match_type": "exact",
"modified": "2013-02-28T11:26:06.007Z"
},
"… 14 more items"
]Attribution: Taxonomic data from WoRMS, World Register of Marine Species (Flanders Marine Institute), licensed CC BY. Cite WoRMS as described at marinespecies.org.
Licence: WoRMS states on its About page: "The text on the WoRMS pages is open-access under the terms of the Creative Commons Attribution License (CC-BY). This License permits unrestricted use, provided it is cited as requested on the WoRMS webpages, unless stated otherwise on the individual pages." It carves images out of that grant: "Images are by default open-access under the terms of the CC BY-NC-SA license, unless stated otherwise on the individual pages." The REST responses return the same taxonomic text, so CC BY applies: commercial use and redistribution are both permitted with attribution, and no images are served by these capabilities.
Ask with this source
A prompt for your agent that names this source and how to call it through the crw MCP.
Child taxa
Use WoRMS (worms) from fastCRW Pergamon, capability "Child taxa" (children). You are walking the tree downwards from a family or genus and need its member taxa. Example options: id=125469. Use the crw MCP tools: crw_find_data to confirm the source and its options, then crw_get_data with provider "worms" and capability "children". Tell me the credits used and cite the licence from the response. If the crw MCP tools are missing, install them with: npx -y crw-mcp install --api-key <your fastCRW API key>
Classification ancestry
Use WoRMS (worms) from fastCRW Pergamon, capability "Classification ancestry" (classification). You need a taxon's kingdom-to-species lineage, not its children or synonyms. Example options: id=127405. Use the crw MCP tools: crw_find_data to confirm the source and its options, then crw_get_data with provider "worms" and capability "classification". Tell me the credits used and cite the licence from the response. If the crw MCP tools are missing, install them with: npx -y crw-mcp install --api-key <your fastCRW API key>
Distribution records
Use WoRMS (worms) from fastCRW Pergamon, capability "Distribution records" (distributions). You want the geographic range a taxon is recorded in, as named localities rather than occurrence points. Example options: id=127405. Use the crw MCP tools: crw_find_data to confirm the source and its options, then crw_get_data with provider "worms" and capability "distributions". Tell me the credits used and cite the licence from the response. If the crw MCP tools are missing, install them with: npx -y crw-mcp install --api-key <your fastCRW API key>
Taxon record by AphiaID
Use WoRMS (worms) from fastCRW Pergamon, capability "Taxon record by AphiaID" (record). You already hold an AphiaID and need the current name, rank and validity behind it. Example options: id=127405. Use the crw MCP tools: crw_find_data to confirm the source and its options, then crw_get_data with provider "worms" and capability "record". Tell me the credits used and cite the licence from the response. If the crw MCP tools are missing, install them with: npx -y crw-mcp install --api-key <your fastCRW API key>