Sublethal and lethal injuries of Pennsylvanian conulariids from Oklahoma

Abstract

Many specimens of the conulariid Paraconularia magna (Ries) from the Tackett Formation (Upper Pennsylvanian, Missourian) of Oklahoma exhibit repaired or unrepaired injured exoskeletons. Scalloped, cleft, and embayed patterns are interpreted to be repaired sublethal damages produced by unknown events or organisms. Punctures, which are the first reported in conulariids, were not followed by exoskeletal repair and were probably lethal. Cladodont sharks are implicated as possible predators of P. magna because of a close correspondence in size and pattern between the dentition of some sharks and the punctures preserved in conulariid exoskeletons.

Threat-protection mechanics of an armored fish

“…For predatory fish, the biomechanics of biting and the generation of bite forces has been considered (Westneat, 2004), for example for the placoderm Dunkleosteus terrelli by analyzing the anatomical configurations of the skull, thoracic shield, mandible and jaw depressor muscle (Anderson and Westneat, 2006). Evidence for predation-related exoskeletal penetration and repair in armored fish has been reported in the literature (Reimchen, 1988;Mapes et al, 1989;Mcclanahan and Muthiga, 1989;Kodera, 1994). A substantial literature also exists on the origins of natural armor strength and toughness (Currey and Taylor, 1974;Bruet et al, 2005;Barthelat and Espinosa, 2007).…”

“…While the predator and prey under investigation in this study (both P. senegalus) are comparable, parametric simulations enabled assessment of asymmetric situations (inequality, where the armor or threat are significantly weaker or stronger relative to each other) and specifically, the determination of under what conditions and how the offensive threat or defensive protection would dominate in the interaction. Failure of the armor could result in internal soft tissue and organ damage leading to death, infection, as well as subsequent predatory and territorial fighting vulnerability (Reimchen, 1988;Mapes et al, 1989;Mcclanahan and Muthiga, 1989;Kodera, 1994;Zuschin et al, 2003). Failure of a tooth can lead to reduced feeding rates and territorial fighting vulnerability (Magalhaes, 1948;Kent, 1983;Geller, 1990).…”

The Fossil Record of Shell-Breaking Predation on Marine Bivalves and Gastropods

“…The truncated valve margin exposes the mantle edge (Colton, 1908;Magalhaes, 1948;Carriker, 1951). The above categorization has been applied to repaired bivalves (Dietl et al, 2000;Alexander and Dietl, 200 I), brachiopods (Alexander, 1986), conularids (Mapes et al, 1989) and could be applied to scars in gastropod aperturallips (Fig. 9).…”

Armoured test of Early Devonian Mesoconularia (Conulariida) from the Prague Basin (Czech Republic): probable adaptation to increased predation pressure

“…brachiopod shells (Conway Morris & Bengtson 1994) or conulariids (Bischoff 1973, Mapes et al 1989. Hardness itself may provide enough protection against drilling or peeling by smaller predators, for example gastropods or small cephalopods, although the hardness of radular teeth is comparable to that of calcium phosphate shells (Lowenstam 1962).…”

“…The interspaces were more flexible but likely more prone to breakage by predators than the transverse ridges. There are various types of breakages observed in conulariids (Babcock et al 1987, Mapes et al 1989, Brabcová 2002, and some of them may have been caused by jawed predators (cephalopods and vertebrates). The evolutionary response of conulariids to increased durophagy could not have been general reinforcement of the entire shell wall, as this would have resulted in reduced flexibility of the shell and thus loss of the ability to close the aperture by means of lappets.…”