Tarphyceratida Flower 1950

Order Tarphyceratida Flower, 1950 Diagnosis (from Aubrechtová & Korn 2025) Multiceratoid cephalopods with coiled to gyroconic conchs of various whorl profile and simple transverse or slightly curved suture lines. Coiling planispiral, rarely torticonic; body chambers usually long, extending from a half to more than one complete whorl in length. Last whorl commonly slightly to greatly divergent from preceding coiled portions; terminal aperture commonly modified. Siphuncle varies in position; siphuncular segments tubular, nautilosiphonate, with orthochoanitic or loxochoanitic septal necks and thick connecting rings in stratigraphically earlier forms, and cyrtochoanitic septal necks and thin homogeneous rings in stratigraphically later forms. Muscle attachment scars ventromyarian or sometimes pleuromyarian. Thin cameral deposits present in some taxa. Shell surface smooth or ornamented with transverse lirae, ribs or annuli, or spiral ornament elements. Families included Barrandeoceratidae Foerste, 1925; Estonioceratidae Hyatt in Zittel, 1900; Ophioceratidae Hyatt, 1894; Plectoceratidae Hyatt in Zittel, 1900; Tarphyceratidae Hyatt, 1894; Trocholitidae Chapman, 1857.