Microbial Sealing in the Biostratinomy of Uintacrinus Lagerstatten in the Upper Cretaceous of Kansas and Colorado, USA

Meyer, David L.; Milsom, Clare

doi:10.2307/3515627

Cited by 9 publications

(10 citation statements)

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“…13). Carbon films have been reported in fossil crinoids (Springer, 1901;Meyer, Milson & Webber, 1999;Meyer & Milson, 2001), but these typically occur in a discrete layer rather than a diffused stain as described in this study. EDX analyses of a small portion of the slab containing two complete gogiids (Fig.…”

Section: Soft-part Preservationmentioning

confidence: 50%

Taphonomy, palaeoecological implications, and colouration of Cambrian gogiid echinoderms from Guizhou Province, China

et al. 2007

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Based on rich material (381 specimens examined) from two Cambrian echinoderm faunas, the early Cambrian Balang fauna and middle Cambrian Kaili fauna in Guizhou Province, South China, the taphonomy of gogiid echinoderms is described in detail, and the preservation of stereomic microstructure and organic remains of Cambrian gogiid echinoderms is reported here for the first time. Taphonomic considerations include entombment patterns, decay sequences, individualspecific diagenetic histories, unusual burial postures, selective disarticulation patterns, and postmortem elongation. In particular, five categories of gogiid entombment patterns are proposed to describe the multi-directional orientations recorded at the burial time of articulated gogiids. Gogiidbearing slabs of Guizhou material primarily (70 %) display the type 2 entombment pattern (articulated gogiids preserved with fan-shaped brachioles); thus, most Guizhou gogiids were buried with brachioles preserved in feeding posture during obrution events. Balang gogiid faunas contain the oldest evidence of palaeoecological interactions among echinoderms and other indigenous taxa. In addition to preburial and post-burial decay, other potential causes for unusual disarticulation patterns exhibited by the gogiids from the lower Cambrian Balang Formation include pre-burial bio-disturbance and post-burial bioturbation based on ichnogenera, including Rusophycus and Planolites. Chemical analyses reveal that carbon, calcium, manganese and iron are the major elements responsible for the variety of colours exhibited by Guizhou gogiids. Three-dimensional stereomic microstructure (mean stereom pore size = 8.4-8.7 µm; average trabecular thickness = 4.5-4.6 µm) occurs on the external surfaces of thecal plates in two gogiid species. Stereom preservation in calcite suggests that the dissolution of calcareous echinoderm plates, yielding characteristic mouldic preservation, is sub-Recent (after lithificaiton and exposure of gogiid-bearing, marine sedimentary successions on or near the land surface).

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Section: Soft-part Preservationmentioning

confidence: 50%

Taphonomy, palaeoecological implications, and colouration of Cambrian gogiid echinoderms from Guizhou Province, China

et al. 2007

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“…Perhaps unexpectedly, the special conditions leading to exceptional echinoderm specimens very rarely led to preservation of soft tissues. Organic films (Springer 1901; Meyer and Milsom 2001) can be associated with fossil crinoids, but certain identifiable soft parts are not known among them [see Ausich and Babcock (1998, 2000) and Sprinkle and Collins (1999) for a discussion of Echmatocrinus , now regarded to be a cnidarian].…”

Section: Discussionmentioning

confidence: 99%

Soft‐tissue Preservation of the Hind Gut in a New Genus of Cladid Crinoid From the Mississippian (Visean, Asbian) at St Andrews, Scotland

Kammer¹,

Ausich²

2007

Palaeontology

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Soft-tissue preservation of the hind gut, or anal sac, in the tegmen of Tubulusocrinus (gen. nov.) doliolus (Wright) from the Mississippian (Visean, Asbian) Pittenweem Formation at St Andrews, Scotland, is the first of its kind known in crinoids; it sheds important new light on the nature of the cladid tegmen. Many cladid crinoids had a calcite-plated anal sac that may have functioned like a chimney to prevent fouling of the ambulacra. The tubular, uncalcified anal sac of Tubulusocrinus may have functioned like a hose by pointing down current between the arms to avoid fouling of the ambulacra. Its smaller size may also have required less energy to produce than a heavy-plated sac. The hind gut is apparently preserved by haematite replacement, which was probably altered from original authigenic pyrite that formed soon after catastrophic burial.

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“…Although extremely rare, oral surfaces are preserved on Uintacrinus Grinnell, 1876 (Cretaceous). Uintacrinus is a relatively large articulate crinoid, and its oral surface was a soft-tissue structure with plates embedded in the soft tissue (Springer, 1901; Meyer and Milson, 2001, fig. 5D).…”

Section: Articulatesmentioning

confidence: 99%

Exaptation of pelmatozoan oral surfaces: constructional pathways in tegmen evolution

Ausich

Kammer

2016

J. Paleontol.

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The adoral surface of a crinoid theca has traditionally been called the tegmen, despite a wide range of morphologies; and, unfortunately, this has obscured the potential to recognize homologies between blastozoans and crinoids. With present recognition of these homologies, the constructional morphology of crinoid oral regions is explored, herein. Two major types of oral regions exist among crinoids: (1) an oral surface with the mouth exposed; and (2) a tegmen, in a restricted definition, with the mouth covered beneath solid plating. A tegmen is constructed by exaptation of oral surface plating and, commonly, other thecal plating. A pseudo-tegmen is an exaptation of aboral cup plates (i.e., radial plates). Tegmens or pseudo-tegmens evolved in all major crinoid clades at least once as an exaptation of oral surface plating. Tegmens evolved iteratively both between and within clades. In some cases, tegmen plates can be homologized with oral surface plates, but in other cases this is not apparent. Examples of tegmens that evolved many times include tegmens with an appearance of oral surface plates cemented in place; tegmens with fixed ambulacral cover plates and primary peristomial cover plates disproportionately enlarged; tegmens composed exclusively, or nearly so, of greatly enlarged primary peristomial cover plates; tegmens with tessellate plating but presumably with some flexibility; and tegmens constructed of innumerable undifferentiated plates. Most tegmens have all ambulacral cover plates fixed; but in some instances, the abaxial ambulacral cover plates remain moveable. Additionally, some lineages that possessed a tegmen evolved an oral surface secondarily, likely as an atavism. Based on this restricted definition of a tegmen, the hemicosmitid blastozoanCaryocrinitesalso evolved a tegmen. As known, tegmens dominated among camerate crinoids; and oral surfaces were more common among cladids, hybocrinids, disparids, flexibles, and articulates. However, oral surfaces evolved in some camerate lineages; tegmens evolved in some cladid, disparid, and articulate lineages; and pseudo-tegmens evolved in some flexible and articulate lineages.The iterative evolution of tegmens in crinoids and blastozoans is thought to be an adaptive response to cover the mouth and proximal ambulacra to protect this portion of the digestive tract from predation, scavenging, parasites, and disease causing agents.

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Microbial Sealing in the Biostratinomy of Uintacrinus Lagerstatten in the Upper Cretaceous of Kansas and Colorado, USA

Cited by 9 publications

References 0 publications

Taphonomy, palaeoecological implications, and colouration of Cambrian gogiid echinoderms from Guizhou Province, China

Taphonomy, palaeoecological implications, and colouration of Cambrian gogiid echinoderms from Guizhou Province, China

Soft‐tissue Preservation of the Hind Gut in a New Genus of Cladid Crinoid From the Mississippian (Visean, Asbian) at St Andrews, Scotland

Exaptation of pelmatozoan oral surfaces: constructional pathways in tegmen evolution

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