Archaeogastroda Thiele, 1925

Popov, Leonid E., Ebbestad, Jan Ove R., Mambetov, Amanbek & Apayarov, Farid Kh., 2007, A low diversity shallow water lingulid brachiopod-gastropod association from the Upper Ordovician of Kyrgyz Range, Acta Palaeontologica Polonica 52 (1), pp. 27-40 : 32

Order Archaeogastroda Thiele, 1925 Family Holopeidae Wenz, 1938

Remarks.— Wagner (2002) emphasised a primitively expressed U−shaped sinus and simple growth lines for his “Holopeines” subclade within a “Raphistomatid” clade (informal notation, as indicated by the quotes; see Wagner 2002: 16). Traditionally, a number of Palaeozoic anisostrophically coiled gastropods showing these characters would be classified within the Late Cambrian to Early Ordovician Sinuopeidae Wenz, 1938 . Many of these genera are now placed in the family Holopeidae Wenz, 1938 (e.g., Raphistomina Ulrich and Scofield, 1897 ; Pachystrophia Perner, 1903 ; Sinutropis Perner, 1903 ; Umbospira Perner, 1903 ; Holopea Hall, 1847 ), and all are younger than the late Arenigian ( Wagner 2002). The genus discussed here, Ptychonema Perner, 1903 , is placed in Holopeidae by association with morphologically similar mid Ordovician to Silurian genera with a U−shaped sinus; Horný (1997) placed it within Eotomariidae Wenz, 1938 .