Original description of Anchura ? ciboloensis by Stephenson, 1941
- "Shell of moderate size, thin, turreted. Spire about half the total height of the shell; apical angle about 30 degrees. Whorls six, slightly convex to almost flat on the sides. Suture closely appressed, distinctly but narrowly impressed. Protoconch simple, smooth, coiled three times, with apical angle corresponding to that of the main shell. The surface is unevenly ornamented and varies markedly on different individuals; on the holotype the half of the body whorl nearest the aperture exhibits 3 to 6 widely spaced, low, dull axial ribs or folds which are strongest just below the suture and fade out downward, separated by broad shallow interspaces; this whorl is slightly constricted below the suture. The penultimate whorl and apparently the anterior half of the antepenultimate whorl are smooth, flattish to very slightly convex, and slightly constricted below the suture; the posterior half of the antepenultimate whorl, and two or three whorls back of that present numerous low rather sharp axial ribs; these have an extremely variable strength of development on different individuals and seem to be almost wanting in some. The aperture is elongated, with a distinct anal notch behind, and extends forward in a moderately long narrow, slightly sinuous canal. The inner lip is broadly excavated and forms a thick callus extending somewhat forward on the base; on some specimens this callus extends upward about halfway across the penultimate whorl; the outer lip is broken away on all the numerous specimens from the type locality and is evidently thin and frail; the holotype, however, and several other specimens show the beginning of an expanded lip, and a distinct reflection of the posterior margin of this lip onto the penultimate whorl."
Locus typicus: Cibolo Creek, 1.5 miles west of Zuehl, Bexar County, Texas, USA
Stratum typicum: Kemp clay, Navarro Group, Maastrichtian, upper Cretaceous
Types: holotype U.S.N.M. no. 76916; height about 31 mm, thickness exclusive of outerlip about 10 mm; paratypes, U.S.N.M. no. 76917 (figured); 20 selected paratypes, U.S.N.M. no. 76918.
Anchura ? ciboloensis in Stephenson, 1941; left holotype, right paratype U.S.N.M. no. 76917
- Image courtesy The University of Texas at Austin