Ptychomphalus wehenkeli ( Terquem and Piette, 1865 )

Monari, Stefano, Valentini, Mara & Conti, Maria Alessandra, 2011, Earliest Jurassic patellogastropod, vetigastropod, and neritimorph gastropods from Luxembourg with considerations on the Triassic-Jurassic faunal turnover, Acta Palaeontologica Polonica 56 (2), pp. 349-384 : 371-372

publication ID	https://doi.org/ 10.4202/app.2010.0098
publication LSID	lsid:zoobank.org:pub:D91ACB86-86DD-4730-B5CA-4FA96152EEBF
persistent identifier	https://treatment.plazi.org/id/03ECFA40-FFAE-1C09-3C48-FD84FB5D0752
treatment provided by	Felipe
scientific name	Ptychomphalus wehenkeli ( Terquem and Piette, 1865 )
status

Treatment

Ptychomphalus wehenkeli ( Terquem and Piette, 1865)

Fig. 14 View Fig .

1865 Pleurotomaria wehenkeli sp. nov.; Terquem and Piette 1865: 61, pl. 4: 29–31.

1988 Ptychomphalus caepa (Eudes−Deslongchamps) ; Meier and Meiers 1988: 31–32, pl. 7: 14a, b.

Material.—Forty−five specimens: MNHNL BR 103, MNHNL BR 116−1, MNHNL BR 118−2, MNHNL BR 123, MNHNL

doi:10.4202/app.2010.0098

BR 161, MNHNL BR 176, MNHNL BR 206, MNHNL BR 221−1, MNHNL BR 225, MNHNL BR 233, MNHNL BR 259, MNHNL BR 270, MNHNL BR 276, MNHNL BR 279, MNHNL BR 305−2, MNHNL BR 306−1, MNHNL BR 317, MNHNL BR 341 (two specimens), MNHNL BR 368, MNHNL BR 455−1, MNHNL BR 456, MNHNL BR 467 (two specimens), MNHNL BR 470, MNHNL BR 472−2, MNHNL BR 486, MNHNL BR 499−1, MNHNL BR 545, MNHNL BR 562−2, MNHNL BR 564, MNHNL BR 656, MNHNL BR 661, MNHNL BR 694, MNHNL BR 714, MNHNL BR 717, MNHNL BR 740 (two specimens), MNHNL HE 101−1, MNHNL HE 129, MNHNL HE 144, MNHNL HE 146, MNHNL HE 147, MNHNL HE 159, MNHNL HE 178, Brouch, Upper Hettangian ( Schlotheimia angulata Zone , Schlotheimia complanata Subzone ). One specimen: MNHNL GL379−2, Brouch, Luxembourg Sandstone Formation, exact stratigraphical level unknown.

Dimensions.—See Table 2.

Description.—Low−turbiniform, sublenticular−globose shell. Teleoconch composed of about five whorls. Surface of the whorls concave. Sutures slightly impressed. Periphery smoothly angulated, not exposed on the spire. Selenizone moderately wide, with its lower rim running along the line of the periphery. Surface of the selenizone flush on the juvenile and adult shell, becoming slightly convex to relatively prominent on the last whorl. Labial slit short, extending about one tenth of the length of the last whorl. Base convex, rather swollen. Aperture subcircular, with marked sutural corner. Peristome prosocline, discontinuous on the parietal lip. Inner lip arched, smoothly passing to the basal lip. Inner lip strengthened by a strong callus which extends to and covers the basal cavity. Early whorls sculptured with a smooth, bulge−shaped, subsutural spiral carina. On the post−juvenile shell, the carina bears strong, closely spaced, slightly prosocline nodes. Spire otherwise smooth. Selenizone smooth, delimited by very thin marginal spiral threads. Base smooth. Growth striae feeble, prosocline, evenly and markedly prosocyrt on the surface of the whorls, prosocyrt on the peripheral band below the selenizone, opisthocyrt on the base.

Remarks.—In Ptychomphalus wehenkeli ( Terquem and Piette, 1865) the height to width ratio of the shell is moderately variable. Moreover, the nodes on the sutural bulge can be variably spaced and sized and they appear at different stages during the growth. The species differs from Ptychomphalus caepa ( Eudes−Deslongchamps, 1849) in having a lower spire and the sutural spiral bulge ornamented with nodes. Moreover, the surface of the whorls is narrower and more concave.

Ptychomphalus wehenkeli represents the most abundant pleurotomarioidean species from Luxembourg. Joly (1907, 1908, 1936) reported it from several localities of Belgium and France. However, that author did not provide any illustration of his material.

Stratigraphic and geographic range.—Late Hettangian ( Schlotheimia angulata Zone ), Ardennes ( France); Late

Hettangian ( Schlotheimia angulata Zone , Schlotheimia complanata Subzone ), Brouch ( Luxembourg).