Schmidtites Sous-embranchement (subphylum) des Linguliformea Classe des Lingulata Ordre des Lingulida Super-famille des Linguloidea Famille des Obolidae Sous-famille des Obolinae

Genus Schmiditites Schuchert & LeVene, 1929 nom. subst. pro Schmidtia Volborth, 1869 (non Balsamo-Crivelli, 1863) Schmidtia: Marshall, 1873 Schmidtia: Dall, 1877 Schmidtia: Hall & Clarke, 1892 Obolus (Schmidtia): Mickwitz, 1896 Obolus (Schmidtia): Walcott, 1908 Obolus (Schmidtia): Walcott, 1912 Schmidtites: nom. subst. Schuchert & Levene, 1929 Schmidtites: Rowell, 1965 Obolus (Schmidtites): Goryansky, 1969 1989 Schmidtites: Popov & Khazanovitch, p. 114. Schmidtites: Puura & Holmer, 1993 Schmidtites: Puura, 1996 Schmidtites: Bednarczyk, 1998 Schmidtites: Holmer & Popov, 2000 Previous diagnosis in the Treatise of Invertebrate Paleontology (2000)

[Schmidtites celatus (Volborth, 1869), originally described under the name Schmidtia celata Volborth, 1869, p. 732] New diagnosis (in Emig, 2006 - see reference below) Bi-symmetrical muscle arrangement (*) Ventral valve: Triangular umbonal region; pseudointerarea slightly concave with well-defined and slightly elevated flexure lines, and with a median narrow pedicle groove. Posterior adductor muscle unpaired. Dorsal valve: Rounded umbonal region; pseudointerarea with well-defined and elevated flexure lines. Posterior adductor muscle unpaired. Vascula media short, widely divergent. Vascula lateralia (main mantle canals) of both sides subparallel to slightly curved. Shell to subcircular to oval in outline. External surface smooth, with fine concentric growth. Upper Cambrian and Lower Ordovician (Tremadoc) (*) Nota : The Posterior Internal Oblique muscle (numbered 4": Emig 1982) is at present only known in Lingula, Glottidia and Lingularia, which have an asymmetrical muscle arrangement. This feature is probably for the family diagnosis (see above)

Emig C. C., 2006. Schmidtites celatus (Obolida, Brachiopoda) from the "Obolus sands" (Upper Cambrian - Lower Ordovician) of Estonia. Carnets de Géologie/Notebooks on Geology, Article 2006/04 (CG2006_A04)   [pdf].

Species of Schmidtites

Schmidtites celatus (Volborth, 1869) Synonyms: Schmidtia celata n. sp.: Volborth, 1869 Schmidtia celata: Hall & Clarke, 1892 Obolus celatus: Mickwitz, 1896 Obolus celatus var. orbiculatus n. var.: Mickwitz, 1896 Obolus celatus var. praecisus n. var.: Mickwitz, 1896 Obolus acuminatus n. sp.: Mickwitz, 1896 Obolus acuminatus var. alatus n. var.: Mickwitz, 1896 Obolus acuminatus var. humeratus n. var.: Mickwitz, 1896 Obolus acuminatus var. subtriangularis n. var.: Mickwitz, 1896 Obolus crassus n. sp.: Mickwitz, 1896 Obolus crassus var. angulatus n. var.: Mickwitz, 1896 Obolus (Lingulella) celatus: Walcott, 1898 Obolus (Schmidtia) celatus: Walcott, 1912 Obolus (Schmidtites) celatus: Goryansky, 1969 New Diagnosis (Emig, 2006) including the figure A (see below) Ventral valve Umbonal region with pseudointerarea forming a rounded beak, continuous with the posterolateral margins; Pseudointerarea limited laterally by well expressed and slightly elevated flexure lines and separated by a narrow subparallel pedicle groove; width about the half of the internal umbonal portion. Muscle arrangement as on figure A. Dorsal valve Pseudointerarea, slightly concave, width about one third of the umbonal region; limited laterally by well expressed and slightly elevated flexure lines. A median ridge extending over 0.6 to 1.5 millimetres at the level of the Anterior Oblique muscle scars. Muscle arrangement as on figure A. Anterior Adductor muscles slightly divergent anteriorly; the Anterior Internal Oblique (4) (and Median Internal Oblique, 4´) muscle and the Anterior Lateral Oblique muscle (2) form a composite muscle (2 + 4/4´) which is aligned with the close Median Lateral Oblique muscle (3). Vascula media short, widely divergent. Vascula lateralia, main mantle canals, are subparallel to slightly curved with a similar distance between the tip of the vascula lateralia to the anterior margin of the valve, on both ventral and dorsal sides. Shell ventri-biconvex, sometimes thick-shelled: the ventral valve is slightly higher than the dorsal valve, smooth with some concentric growth lines. Figure A Figure A: Muscle arrangement and disposition of the main mantle canals (their variability, left; in a specimen, right) and umbonal regions (internal view) in Schmidtites celatus (from Emig, 2006). NOTA : this figure A has to be included in the diagnosis because considered as part of this diagnosis.

Umbonal region of ventral valves (internal view)
Umbonal region of dorsal valves (internal view)