Tumulduria incomperta and the case for Tommotian trilobites

Bengtson, Stefan; Fedorov, Aleksandr B.; Missarzhevsky, Vladimir V.; Rozanov, A.Y.; Жегалло, Е. А.; Zhuravlev, A. Yu.

doi:10.1111/j.1502-3931.1987.tb00797.x

Cited by 11 publications

(8 citation statements)

References 5 publications

(1 reference statement)

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“…The botryoidal structure is observable on the internal surface of all available specimens, but is not apparent on external surfaces. This similarity in preservation of the shell structure was also noted by Bengtson et al (1987: 368) although the illustrated brachiopod valves were identified as belonging to Aldanotreta sunnaginensis (Bengtson et al 1987: fig. 7).…”

Section: Tumulduria As a Brachiopodsupporting

confidence: 58%

“…Consequently, any similarity of individual specimens to different parts of the trilobite carapace is superficial and Tumulduria has since been regarded as a problematic fossil (Rozanov et al 2010;Maloof et al 2010;Kouchinsky et al 2012). Bengtson et al (1987) compared the preservation of Tumulduria and co-occurring organophos-phatic brachiopods, but herein we show that Tumulduria incomperta more specifically represents the detached central portion of the ventral interarea of a paterinid brachiopod.…”

Section: Introductionmentioning

confidence: 89%

“…In the original description, Missarzhevsky (in Rozanov et al, 1969: 175) compared the bilaterally symmetrical plates of Tumulduria to chiton plates, but similar fossils were later interpreted as trilobite remains by Fedorov et al (1979), causing considerable interest in the palaeontological community as the oldest known trilobites (Repina 1981;Glaessner 1984;Khomentovsky 1986). However, based on detailed study of new material from Siberia, Bengtson et al (1987) were able to demonstrate unequivocally that Tumulduria is highly variable morphologically and that the plates grew by accretion. Consequently, any similarity of individual specimens to different parts of the trilobite carapace is superficial and Tumulduria has since been regarded as a problematic fossil (Rozanov et al 2010;Maloof et al 2010;Kouchinsky et al 2012).…”

Section: Introductionmentioning

confidence: 97%

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The problematic early Cambrian fossil Tumulduria incomperta represents the detached ventral interarea of a paterinid brachiopod

Skovsted

Kouchinsky

Bengtson

et al. 2012

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The organophosphatic early Cambrian (Terreneuvian, Cambrian Stage 2) fossil Tumulduria incomperta has been problematic ever since its original description in 1969. Comparison of abundant specimens from the Lower Cambrian of Siberia with co-occurring brachiopod valves show that T. incomperta represents the central portion of the ventral interarea of a paterinid brachiopod similar to Cryptotreta neguertchenensis, and that the domed central portion of typicalTumulduria specimens represents the ridge-like pseudodeltidium of the interarea.

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Section: Tumulduria As a Brachiopodsupporting

confidence: 58%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 97%

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The problematic early Cambrian fossil Tumulduria incomperta represents the detached ventral interarea of a paterinid brachiopod

Skovsted

Kouchinsky

Bengtson

et al. 2012

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“…2, fig. 8;Bengtson et al, 1987), but may be distinct from the verruculose texture in Cambrothyra and other coeloscleritophorans. The latter is generally much more ordered than typical diagenetic overgrowths, with the different verruculae remaining separate from each other rather than coalescing into a botryoidal mass (e.g., Figs.…”

Section: F I G U R E 11-chancelloriids and Sachitids From The Lower Cmentioning

confidence: 98%

Cambrothyra ampulliformis, an unusual coeloscleritophoran from the Lower Cambrian of Shaanxi Province, China

et al. 2010

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Cambrothyra ampulliformis Qian and Zhang, 1983, is a jar- or vase-shaped fossil known from the Lower Cambrian of Shaanxi and Hubei provinces, China. It has been interpreted as a protistan test or cyst or a metazoan sclerite. A large collection of specimens from the Xihaoping Member of the Dengying Formation in southern Shaanxi Province permits its detailed redescription. These fossils are highly variable in shape but this variation is continuous and does not support the current recognition of multiple species for this material. They were originally hollow with a restricted basal foramen and a calcareous wall probably composed of fibrous aragonite. All of these features support the identification of Cambrothyra as sclerites of a coeloscleritophoran, a problematic group of Cambrian scleritome-bearing metazoans. Furthermore, the walls of Cambrothyra sclerites contain numerous pores, a feature shared with other coeloscleritophorans. Cambrothyra resembles chancelloriids in particular due to the shared presence of a verruculose texture around the foramen and the absence of mirror-image pairs of asymmetric sclerites. However, unlike chancelloriids, which have rosette-like compound sclerites, the scleritome of Cambrothyra was dominated by isolated sclerites, with only a few pairs and clusters of sclerites and twin sclerites. Consequently, we hypothesize that Cambrothyra forms a clade with other chancelloriids, but represents a basal lineage that plesiomorphically retained isolated sclerites. The morphology of Cambrothyra sclerites, which shares features with both chancelloriids and halkieriids, thus supports the hypothesis that all coeloscleritophorans form a natural group.

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“…2K; Bengtson et al, 1990;Conway Morris and Chen, 1991;, rows of spine-bearing plates called paracarinachitids (Fig. 2J;Qian and Bengtson, 1989;Conway Morris and Chen, 1991), the phosphatic plates of Tumulduria (Bengtson et al, 1987), and a variety of spine-or tooth-shaped fossils such as Cyrtochites, Fomitchella, Kaiyangites, Rhombocorniculum, and Yunnanodus (Bengtson, 1983;Qian and Bengtson, 1989;G. Li et al, 2003;Qian et al, 2004;Yao et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

The earliest Cambrian record of animals and ocean geochemical change

Maloof

Porter

Moore

et al. 2010

Geological Society of America Bulletin

346

314

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The Cambrian diversifi cation of animals was long thought to have begun with an explosive phase at the start of the Tommotian Age. Recent stratigraphic discoveries, however, suggest that many taxa appeared in the older Nemakit-Daldynian Age, and that the diversifi cation was more gradual. We map lowest Cambrian (Nemakit-Daldynian through Tommotian) records of δ 13 C CaCO 3 variability from Siberia, Mongolia, and China onto a Moroccan U/Pb-δ 13 C CaCO 3 age model constrained by fi ve U/Pb ages from inter bedded volcanic ashes. The δ 13 C CaCO 3 correlations ignore fossil tie points, so we assume synchro neity in δ 13 C trends rather than synchroneity in fi rst appearances of animal taxa. We pre sent new δ 13 C org , 87 Sr/ 86 Sr, uranium, and vanadium data from the same carbonate samples that defi ne the Moroccan δ 13 C CaCO 3 curve. The result is a new absolute time line for fi rst appearances of skeletal animals and for changes in the carbon, strontium, and redox chemistry of the ocean during the Nemakit-Daldynian and Tommotian ages at the beginning of the Cambrian. The time line suggests that the diversifi cation of skeletal animals began early in the Nemakit-Daldynian, with much of the diversity appearing by the middle of the age. Fossil fi rst appearances occurred in three pulses, with a small pulse in the earliest Nemakit-Daldynian (ca. 540-538 Ma), a larger pulse in the mid-to late Nemakit-Daldynian (ca. 534-530 Ma), and a moderate pulse in the Tommotian (ca. 524-522 Ma). These pulses are associated with rapid reorganizations of the carbon cycle, and are superimposed on long-term increases in sea level and the hydrothermal fl ux of Sr.

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Tumulduria incomperta and the case for Tommotian trilobites

Cited by 11 publications

References 5 publications

The problematic early Cambrian fossil Tumulduria incomperta represents the detached ventral interarea of a paterinid brachiopod

The problematic early Cambrian fossil Tumulduria incomperta represents the detached ventral interarea of a paterinid brachiopod

Cambrothyra ampulliformis, an unusual coeloscleritophoran from the Lower Cambrian of Shaanxi Province, China

The earliest Cambrian record of animals and ocean geochemical change

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