A new arthropod resting trace and associated suite of trace fossils from the Lower Jurassic of Warwickshire, England

Abstract:  A new suite of arthropod trace fossils, attributed to a decapod crustacean, is described from the Lower Jurassic Saltford Shale Member of the Blue Lias Formation of Southam Cement Works Quarry, eastern Warwickshire, England. Solusichnium southamensis igen. et isp. nov. consists of small, isolated, bilaterally symmetrical, suboval hypichnia, comprising three regions. The concave anterior region contains imprints of chelate appendages, antennae and antennules. The elongate middle region contains abdominal appendage imprints that extend laterally, separated by a bifurcated medial imprint. The convex posterior region terminates in a globular V-shaped telson imprint. The large sample size and range of trace morphologies allows identification of five morphotypes within a taphoseries. S. southamensis is found on the base of siltstone lenses in what is otherwise a dysaerobic laminated mudstone unit, associated with epichnial Rusophycus , and the suite of trace fossils is interpreted as the resting traces (Cubichnia) and escape reactions (Fugichnia) of small decapods that were trapped below a distal storm deposit. The producer of S. southamensis was possibly an Eryon -like decapod, similar to those known from the slightly older Wilmcote Limestone Member of southwestern Warwickshire.