Has anyone ever found a Conulaliid pearl

[howard_l]

I have seen literature that Conulariids created pearls like clams do. I find a lot of Conulariids but never any pearls associated with them. Hes anyone ever found or seen one.

[Ridgehiker]

I have seen literature that Conulariids created pearls like clams do. I find a lot of Conulariids but never any pearls associated with them. Hes anyone ever found or seen one.

Interesting question.

I haven't found 'lots' of conularians but perhaps a couple dozen. This fauna rare in most formations. We're these pearls found inside of the fossil specimens or somehow in association? I haven't found any pearls but must admit not even sure what to look for. It would also be interesting to know if anyone here has found peals in Paleozoic bivalves.

[BobWill]

Never heard that one. Do any other cnidarians (assuming they have that part right) make pearls?

[howard_l]

I believe they would have been in the top portion or the aperture. I have found some and some literature shows flaps covering the Aperture. You are right about them being fairly rare but there is one location in the lower Mississippian near Louisville where they are the dominant fauna.

[piranha]

Babcock, L.E. (1990).
Conulariid Pearls. pp. 68-71
IN: Evolutionary Paleobiology of Behavior and Coevolution.
Elsevier Scientific Publishing, 725 pp.



Pearls are reported here for the first time in the extinct animal phylum Conulariida. Representatives of the Conulariida are characterized by an elongate, four-sided pyramidal exoskeleton composed of calcium phosphate. The exoskeleton has a weak bilateral symmetry and numerous pairs of transverse rods supporting a multilayered integument (Babcock and Feldmann, 1986). Unquestioned conulariids have been found in rocks of Early Ordovician to Late Triassic age. Pearls (Fig. 52A-D) are rare and have been found in only two species, Paraconularia crustula (White) from the Pennsylvanian of Johnson County, Kansas (USNM 435350), and P. magna (Ries) from the Pennsylvanian of Okfuskee County, Oklahoma (USNM 435351, 435352). They are found adhering either to inner layers of integument in examples having a partially exfoliated exoskeleton (Fig. 52A, B,) or to steinkerns where the exoskeleton has been removed. Examined pearls seem to be of the blister type but some may have initially been cyst pearls that were later incorporated into the inner layers of the exoskeleton. The maximum number of pearls found in one specimen is three and the largest such structure is 2 mm in diameter. Conulariid pearls are composed of numerous fine concentric laminae (Fig. 52C, D) of calcium phosphate. Investigation under high magnification revealed that the laminae are cryptocrystalline. Evidently, these phosphatic concretions formed by the sequential deposition of thin layers of collophane around foreign irritants that affected either the internal exoskeletal surface or soft tissues that bounded it. The irritants that stimulated the formation of pearls are not known. By analogy with pearls formed naturally by present-day mollusks, however, it is probable that many developed around parasites or boring endobionts. Sediment grains may also have served as nuclei. The presence of pearls in conulariids supports evidence (Babcock et al., 1987) that a mantle or mantle-like tissue bounded the internal surface of the exoskeleton and was responsible for its secretion.

 

 

 

[Auspex]

I had no idea, and would have been highly skeptical, in the absence of evidence!