nigricaudus, Axoclinus Allen [G. R.] & Robertson [D. R.] 1991:79, Fig. 1 [Revue française d'Aquariologie Herpétologie v. 18 (no. 3); ref. 19723] Near Pichilingue, Baja California, Mexico, about 24°16'N, 110°20'W, depth 0-3 meters. Holotype: USNM 316797. Paratypes: WAM P.30233-001 (1). Type catalog: Springer & Orrell 1996:28 [ref. 22274], Moore et al. 2008:40 [ref. 30117]. •Valid as Enneanectes nigricaudus (Allen & Robertson 1991) -- (De La Cruz Agüero et al. 1997:302 [ref. 24545], Fricke 1997:565 [ref. 23339]). •Valid as Axoclinus nigricaudus Allen & Robertson 1991 -- (Allen & Robertson 1994:220 [ref. 22193], Thomson et al. 2000:206 [ref. 25640], Smith & Williams 2002:8 [ref. 26427], Nelson et al. 2004:161 [ref. 27807], Love et al. 2005:151 [ref. 37547], Fricke 2009:35 [ref. 30394], Patzner et al. 2009:444 [ref. 30396], Page et al. 2013:166 [ref. 32708], Love et al. 2021:194 [ref. 39279]). Current status: Valid as Axoclinus nigricaudus Allen & Robertson 1991. Tripterygiidae: Tripterygiinae. Distribution: Eastern Pacific: southern tip of Baja California Sur (Mexico) and Gulf of California (Mexico). Habitat: marine.