Scurriopsis Gemmellaro, 1879

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 : 352-355

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-FFBB-1C18-3F44-F8FAFD99002A
treatment provided by	Felipe
scientific name	Scurriopsis Gemmellaro, 1879
status

Treatment

Subgenus Scurriopsis Gemmellaro, 1879

Type species: as for the genus.

Remarks.—The genus Scurriopsis Gemmellaro, 1879 is assigned here to the suborder Patellina von Ihering, 1876 because of the presence of an horseshoe−shaped muscle scar in the type species, Scurriopsis neumayri Gemmellaro, 1879 (Gemmellaro 1879: 381, pl. 29: 5, 6; Cox and Keen 1960). The same character was described by Terquem (1855: 281, pl. 18: 2) for Scurriopsis (Hennocquia) hettangiensis ( Terquem 1855) . The lack of information on the protoconch and microstructure of the shell, which are fundamental aspects for the systematic placement of the limpet−shaped gastropods (see Hedegaard et al. 1997; Fuchigami and Sasaki 2005 and references therein) leaves the superfamily and family position uncertain.

Scurriopsis (Scurriopsis) schmidti ( Dunker, 1844) View in CoL Fig. 5A–C View Fig .

1844 Patella schmidtii sp. nov.; Dunker 1844: 187.

1847 Patella schmidtii Dunker ; Dunker 1847: 113, pl. 13: 17a–c.

1855 Patella schmidtii Dunker ; Terquem 1855: 281–282, pl. 18: 4, 4a, 4b.

1884 Patella schmidtii Dunker ; Quenstedt 1884: 756, pl. 215: 35.

?1901 Patella delgadoi sp. nov.; Böhm 1901: 213, pl. 8: 1, 2.

1902 Patella schmidti Dunker ; Cossmann in Chartron and Cossmann 1902: 201, pl. 3: 34, 35.

1932 Acmaea schmidti (Dunker) ; Haber 1932: 164–166.

1988 Scurriopsis schmidtii (Dunker) View in CoL ; Meier and Meiers 1988: 25, pl. 2: 4a, b.

Material.— Fourteen specimens: MNHNL BR 109, MNHNL BR 180, MNHNL BR 190, MNHNL BR 222, MNHNL BR 360, MNHNL BR 493, MNHNL BR 495 (three specimens), MNHNL BR 501, MNHNL BR 502, MNHNL BR 506, MNHNL BR 580, MNHNL BR 672, Brouch, Upper Hettangian ( Schlotheimia angulata Zone , Schlotheimia complanata Subzone ) . Two specimens: MNHNL HE138 , MNHNL HE149 , Brouch, Hettangian , exact stratigraphical level unknown .

Dimensions.—See Table 1. Description.—Limpet−shaped shell. Peristome moderately elliptical, tending to subrectangular, slightly wider in the posterior region. Width of peristome 77–93% of its length. Shell moderately to rather high, with height varying 37–52% of the shell length. Apical shell slightly coeloconical and rather high. Apex weakly pointing anteriorward and placed anteriorly at 57–67% of the shell length. Posterior outline of shell in lateral view convex. Anterior outline from convex to moderately concave. Sculpture made of sharp and rounded radial ribs on the entire surface. Juvenile shell bearing 20 to 25 radial ribs. Adult shell ornamented with 40 to 60 radial ribs consisting of two orders of alternating ribs which make the peristomal edge slightly undulated. Ribs are commonly denser on the lateral regions of the shell where they are separated by thinner intervals. Primary ribs appear at a short distance from the apex. Secondary ribs rapidly reach the same size of the primary ribs during the growth. Intercalation of primary and secondary ribs well visible on the posterior area where the intervals between the primary ribs are wider. Radial ribs strongly roughed by intersection with marked and dense growth striae.

Remarks.—The original name given by Dunker (1844) to this species, Patella schmidtii , was corrected by Cossmann (in Chartron and Cossmann 1902) to Patella schmidti . This correction was confirmed by Haber (1932) in his revision of Dunker’s (1844) species.

Dunker (1847) described small shells of Scurriopsis (Scurriopsis) schmidti ( Dunker, 1844) corresponding well to the juvenile specimens described here. In Dunker’s specimens the shape of the shell is rather high and the ornament is made of about twenty radial ribs. The juvenile part of the shell of the specimens from Luxembourg have the same shape and ornament.

The material shows a relatively high intraspecific variation. It includes specimens of two different adult shapes which are clearly in morphological continuity. A first morphology consists of moderately high shells with slightly concave anterior slope. These specimens are the most similar to the shells ascribed by Terquem (1855) and Cossmann (in Chartron and Cossmann, 1902) to S. (S.) schmidti . The other morphology is more globose due to the convex anterior slope. The ornament of the adult shell is rather variable as well, the number of primary and secondary ribs ranging from about 40 to 60. Finally, the anterior position of the apex is also variable.

Patella delgadoi Böhm, 1901 from the earliest Jurassic of doi:10.4202/app.2010.0098

the Lusitanian Basin ( Portugal), differs from S. (S.) schmidti View in CoL only in its higher shell. The other differences mentioned by Böhm (1901), such as the larger size and the stronger ornament fall within the field of variability of S. (S.) schmidti View in CoL as here described. This leaves open the possibility that P. delgadoi is a synonym of Dunker’s (1844) species.

Helcion discrepans de Ryckholt, 1852 ( Ryckholt 1852: 61, pl. 2: 24, 25; Chapuis and Dewalque 1853: 109, pl. 14: 7; Haber 1932: 155), from the Luxembourg Sandstone Formation, differs from S. (S.) schmidti View in CoL in having an almost circular peristome, and a radial ornament composed of much stronger radial ribs which make the peristomal rim strongly crenulated.

Stratigraphic and geographic range.—Early Hettangian ( Psiloceras planorbis Zone View in CoL ), Halberstadt (Saxony−Anhalt, Germany); Hettangian, Hettange−Grande (Lorraine, France); Late Hettangian ( Schlotheimia angulata Zone , Schlotheimia complanata Subzone ), Brouch ( Luxembourg); Hettangian, Le Simon−la−Vineuse (Vendée, France);?Early Sinemurian, Coimbra (Lusitanian Basin, Portugal).