Here. Probably need to do some training down in Texas:
On September 9, 2016, the [Texas] Department’s attorney sent proper notice to the Bureau of Indian Affairs. The [Texas] Department [of Family and Protective Services] also sent a letter dated March 16, 2017, to the Secretary of the Interior, ICWA, and to the Bureau of Indian Affairs, stating that W.C. testified that his Indian tribe was “maybe Lakota Sioux.” According to the Department’s letter, that tribe is not federally recognized as eligible for services or, more particularly, is not an “Indian tribe” pursuant to the ICWA. See 25 U.S.C.A. § 1903(8) (Westlaw through Pub. L. No. 115-22).
Emphasis added.
Turtle Talk 
In this Texas case, the BIA erred here by the “Dept.” (BIA) sending a letter stating Lakota Sioux is not a Tribe. Rather than stating there is no “Lakota Sioux” tribe, the BIA should have realized they meant one of the federally recognized “Sioux” Tribes, and sent the notice to the Lakota Tribes or to all Sioux Tribes (Dakota, Lakota, and Nakota): Cheyenne River Sioux Tribe (SD), Crow Creek Sioux Tribe (SD), Flandreau Santee Sioux Tribe (SD), Fort Peck Assiniboine and
Sioux Tribes (MT), Lower Brule Sioux Tribe (SD), Lower Sioux Indian Community of Minnesota (MN), Oglala Sioux Tribe (SD), Prairie Island Indian Community Mdewakanton Dakota Sioux of Minnesota (MN), Rosebud Sioux Tribe (SD), Santee Sioux Nation (NE), Shakopee Mdewakanton Sioux Community (MN), Sisseton-Wahpeton Sioux Tribe (ND&SD), Spirit Lake Sioux Tribe (ND), Standing Rock Sioux Tribe (ND & SD),Upper Sioux Community of Minnesota (MN), and Yankton Sioux Tribe (SD).
The term Lakota Sioux generally refers to members of the Great Sioux Nation. Lakota is the proper word that our people generally call ourselves in our language (some are Dakota and/or Nakota). The term Lakota generally means the western bands of “Sioux” whose ancestors comprise the Great Sioux Nation (recognized by the 1851 and 1868 Fort Laramie Treaties), and it is our relatives who defended themselves on their homelands guaranteed by these Treaties when Lt. Col. George A. Custer attacked them at Greasy Grass, also known as Battle of the Little Big Horn, on June 25 1876 – just 8 years after making the 1868 Treaty. For example, I am a Lakota and a member of the Great Sioux Nation, although I am also an enrolled member of the “Cheyenne River Sioux Tribe,” Thank you. Thomas J. Van Norman, Attorney at Law, P.O. Box 700, Eagle Butte, SD 57625