Systematics of pterobranchs from the Cambrian Period Burgess Shales of Canada and the early evolution of graptolites

Ramirez-Guerrero, Greta Margarita; Cameron, Christopher B.

doi:10.3140/bull.geosci.1797

Cited by 8 publications

(14 citation statements)

References 37 publications

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“…( iii ) Similarly, the early tube record suggests that the initial diversification of the pterobranchs occurred along the benthos, with fully planktonic Graptoloidea exploding in diversity during the Ordovician (Sadler, Cooper & Melchin, 2011; Cooper et al ., 2014). ( iv ) Finally, the ubiquity of the stolon system in well‐preserved Cambrian graptolites suggests that obligate colonial‐living forms evolved early in the evolutionary history of this group (Ramírez‐Guerrero & Cameron, 2021).…”

Section: Phylum Hemichordatamentioning

confidence: 99%

“…Two related questions are the timing of coloniality and miniaturization within Hemichordata, and how these ecologically significant morphological steps were achieved. Minimally, we know that some middle Cambrian pterobranchs were already colonial, based on the preservation of the stolon system (Ramírez‐Guerrero & Cameron, 2021), and miniaturized, based on micrometer‐scale tubes (Harvey et al ., 2011; Maletz, 2019). The builders of these earliest pterobranch tube fragments are not preserved, but have been tentatively assigned a cephalodiscid rather than a rhabdopleurid affinity based on the tube morphology (Maletz, 2019).…”

Section: Phylum Hemichordatamentioning

confidence: 99%

“…two feeding arms). ( ii ) The size of the earliest recognizable pterobranch tubes (Harvey et al ., 2011; Maletz, 2019), including a wide variety of benthic forms from the middle Cambrian (Ramírez‐Guerrero & Cameron, 2021), suggests that the inhabitants themselves had already undergone miniaturization. ( iii ) Similarly, the early tube record suggests that the initial diversification of the pterobranchs occurred along the benthos, with fully planktonic Graptoloidea exploding in diversity during the Ordovician (Sadler, Cooper & Melchin, 2011; Cooper et al ., 2014).…”

Section: Phylum Hemichordatamentioning

confidence: 99%

“…Spartobranchus lacks similar specializations and was likely a deposit feeder (Caron et al ., 2013). Despite lacking direct evidence of the zooids, the rhabdopleurid affinities of the Cambrian graptolite tubes suggest that they were tentaculate suspension feeders (Maletz, 2017; Ramírez‐Guerrero & Cameron, 2021). Gyaltsenglossus appears to have been able to employ a combination of both tentaculate filter feeding and deposit feeding moderated by its long, Saccoglossus ‐like proboscis (Nanglu et al ., 2020 a ).…”

Section: Phylum Hemichordatamentioning

confidence: 99%

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Worms and gills, plates and spines: the evolutionary origins and incredible disparity of deuterostomes revealed by fossils, genes, and development

et al. 2022

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Deuterostomes are the major division of animal life which includes sea stars, acorn worms, and humans, among a wide variety of ecologically and morphologically disparate taxa. However, their early evolution is poorly understood, due in part to their disparity, which makes identifying commonalities difficult, as well as their relatively poor early fossil record. Here, we review the available morphological, palaeontological, developmental, and molecular data to establish a framework for exploring the origins of this important and enigmatic group. Recent fossil discoveries strongly support a vermiform ancestor to the group Hemichordata, and a fusiform active swimmer as ancestor to Chordata. The diverse and anatomically bewildering variety of forms among the early echinoderms show evidence of both bilateral and radial symmetry. We consider four characteristics most critical for understanding the form and function of the last common ancestor to Deuterostomia: Hox gene expression patterns, larval morphology, the capacity for biomineralization, and the morphology of the pharyngeal region. We posit a deuterostome last common ancestor with a similar antero‐posterior gene regulatory system to that found in modern acorn worms and cephalochordates, a simple planktonic larval form, which was later elaborated in the ambulacrarian lineage, the ability to secrete calcium minerals in a limited fashion, and a pharyngeal respiratory region composed of simple pores. This animal was likely to be motile in adult form, as opposed to the sessile origins that have been historically suggested. Recent debates regarding deuterostome monophyly as well as the wide array of deuterostome‐affiliated problematica further suggest the possibility that those features were not only present in the last common ancestor of Deuterostomia, but potentially in the ur‐bilaterian. The morphology and development of the early deuterostomes, therefore, underpin some of the most significant questions in the study of metazoan evolution.

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Section: Phylum Hemichordatamentioning

confidence: 99%

Section: Phylum Hemichordatamentioning

confidence: 99%

Section: Phylum Hemichordatamentioning

confidence: 99%

Section: Phylum Hemichordatamentioning

confidence: 99%

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Worms and gills, plates and spines: the evolutionary origins and incredible disparity of deuterostomes revealed by fossils, genes, and development

et al. 2022

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“…Similar specimens from other Cambrian localities were assigned mainly to Yuknessia simplex Walcott, 1919, which was originally described from the Burgess Shale and interpreted by Walcott (1919) as an alga. LoDuca et al (2015a) showed that most of Walcott's Burgess Shale specimens preserve banding on the cuticle and identified them as a benthic colonial pterobranch hemichordate (see also Ramírez-Guerrero and Cameron, 2021); just a few of Walcott's specimens turned out to be algal. However, LoDuca et al (2015b) also investigated specimens attributed to Yuknessia from the Chengjiang biota in China and other Cambrian Lagerstätten in North America, and assigned them to the alga Fuxianospora Chen and Zhou, 1997.…”

Section: Systematic Paleontologymentioning

confidence: 99%

The soft-bodied biota of the Cambrian Series 2 Parker Quarry Lagerstätte of northwestern Vermont, USA

Pari¹,

Briggs

Gaines

2022

J. Paleontol.

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A non-biomineralized arthropod, Protocaris marshi, was described from the lower Cambrian (Dyeran Series 2, Stage 4) of Parker's Cobble in northwestern Vermont in 1884. It represents the first fossil exhibiting Burgess Shale-type preservation to have been discovered. The locality was presumed to have been worked out and was not collected in a significant way for more than 100 years. Rediscovery of productive layers has yielded soft-bodied and lightly sclerotized taxa new to the locality, including the alga Fuxianospora, a possible priapulid, a radiodont, and a specimen tentatively assigned to Herpetogaster. New specimens of the sponge Leptomitus zitteli, the bivalved arthropod Tuzoia, and the chordate Emmonsaspis cambrensis provide additional information on those taxa, and multiple specimens allow a bivalved arthropod, Vermontcaris montcalmi new genus, new species, to be described. The primary mode of fossil preservation is as carbonaceous compressions. The Parker Quarry Lagerstätte complements the Kinzers Formation of Pennsylvania (also Series 2, Stage 4) in revealing the diversity of soft-bodied taxa on the southern margin of the paleocontinent Laurentia. UUID: http://zoobank.org/2eb3ae7c-6579-403e-a9ab-654c05af4a1b

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Benthic pterobranchs from the Cambrian (Drumian) Marjum Konservat‐Lagerstätte of Utah

Lerosey‐Aubril,

Maletz,

Coleman

et al. 2024

Papers in Palaeontology

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Pterobranchs are rare in Cambrian strata of North America despite discoveries of more than 30 exceptionally preserved fossil biotas. Miaolingian pterobranchs from this continent typically form low‐diversity and low‐abundance assemblages. Here we describe an abundant pterobranch material from the Drumian Marjum Formation recently collected at the Gray Marjum Quarry in the House Range of Utah, USA. The faunule is composed of two new species: Sphenoecium marjumensis, an encrusting representative forming compact bushy colonies of more than 80 tubes with poorly developed rhizomes, and Tarnagraptus cupidus, an erect growing taxon characterized by intertwining stems and a monopodial colonial growth. Known in extant rhabdopleurids, this mode of colonial growth had hitherto never been observed in fossil pterobranchs. Its documentation in a c. 500‐myr‐old taxon attests to its deep origin in the evolutionary history of the group. Although the new species almost exclusively occur in the Marjum strata, this pterobranch faunule is broadly similar to those recovered from other Miaolingian Burgess Shale‐type deposits of North America in terms of genus‐level composition, species richness, and ecological structure. This may indicate that pterobranchs were poorly diverse components of animal communities at that time, or that they mostly thrived in more proximal shelf environments where conditions conducive to their preservation rarely developed. The common co‐occurrence of taxa with fundamentally different ecomorphotypes in the Miaolingian Series of North America strongly suggests an earlier phase of morphological diversification of benthic pterobranchs during the early Cambrian, which remains insufficiently documented by fossils.

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Systematics of pterobranchs from the Cambrian Period Burgess Shales of Canada and the early evolution of graptolites

Cited by 8 publications

References 37 publications

Worms and gills, plates and spines: the evolutionary origins and incredible disparity of deuterostomes revealed by fossils, genes, and development

Worms and gills, plates and spines: the evolutionary origins and incredible disparity of deuterostomes revealed by fossils, genes, and development

The soft-bodied biota of the Cambrian Series 2 Parker Quarry Lagerstätte of northwestern Vermont, USA

Benthic pterobranchs from the Cambrian (Drumian) Marjum Konservat‐Lagerstätte of Utah

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