South American Ordovician phyllocarids (Crustacea, Malacostraca)

Rachebœuf, Patrick R.; Crasquin, Sylvie; Brussa, Edsel D.

doi:10.3140/bull.geosci.1126

Cited by 13 publications

(15 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Rolfecaris lethiersi was tentatively placed within Ceratiocarididae due to several inconsistencies with the diagnosis of this family, including the more-oval general outline, the apparent lack of a rostral plate, and a lack of a carapace horn. It was noted by Racheboeuf et al (2009) that the ornament was quite similar to that of Gonatocaris but that R. lethiersi lacked large ('optic') tubercles. The lack of tubercles is not necessarily problematic for placement within Gonaticaris; significant evidence exists within thin-shelled taxa (notably Ceratiocaris) to suggest that the 'optic tubercle' is likely an artefact of a relatively thin, pliable cuticle draping over a more robustly mineralized mandibular process (Rolfe, 1962;Collette and Rudkin, 2010).…”

Section: Discussionmentioning

confidence: 99%

Redescription, paleogeography, and experimental paleoecology of the Silurian phyllocaridGonatocaris

Collette¹,

Plotnick²

2020

J. Paleontol.

View full text Add to dashboard Cite

Gonatocaris decora (Clarke, 1901) is an unusual, highly ornamented Silurian phyllocarid from the Pittsford Shale Member of the Vernon Formation, Salina Group of New York, that has been allied with Emmelezoe in the past due to the possession of an ‘optic tubercle.’ The systematic positions of Gonatocaris and Emmelezoe have been difficult to assess due to the lack of complete remains, attributions based on spurious characters, and missing and unfigured specimens. Relatively recent collections of Gonatocaris decora, along with a relocation of the original type material of Emmelezoe, have allowed a reexamination of all relevant genera and a more robust systematic placement for G. decora. Characters of generic importance for Gonatocaris include a greatly elongated abdomen; an acute angle of the ventral carapace margin separating distinct anteroventral and posteroventral margins from each other; and distinctive, multiscale horizontal ridge-like ornament of the carapace valves. Growth was found to be isometric. Experimental work done using a model of the scale-like ornament and multiple grain sizes of substrate indicates that cuticle ornament may have served to increase friction between the animal and a fine sand substrate, although resistance to predation is the currently favored hypothesis. Because Gonatocaris species are currently known only from the eastern margin of Laurentia and northern South China, it is likely that this genus was nektonic. Accumulations of similarly sized carapaces and other disarticulated sclerites in shallow-water settings may indicate spawning events following molting en masse.

show abstract

Section: Discussionmentioning

confidence: 99%

Redescription, paleogeography, and experimental paleoecology of the Silurian phyllocaridGonatocaris

Collette¹,

Plotnick²

2020

J. Paleontol.

View full text Add to dashboard Cite

show abstract

“…The taphonomic history of the Winneshiek SCFs that allowed their preservation with finest details may have been similar to that of crustacean remains from the Cambrian of Canada reported from the Mount Cap Formation (lower Cambrian), the Deadwood Formation (middle-upper Cambrian), the Earlie Formation (middle Cambrian) and the Nolichucky Shale (middle-upper Cambrian) (Harvey & Butterfield 2008;Harvey et al 2012a,b;Harvey & Pedder 2013). The fossil record of crustaceans in the Ordovician is largely represented by easily preserved ostracod shells and phyllocarid carapaces (Sepkoski 2000;Vannier et al 2003;Racheboeuf et al 2009;Perrier et al 2015). Exceptionally preserved specimens from Konservat-Lagerst€ atten can contribute enormously to fill some gaps in the fossil record.…”

Section: Discussionmentioning

confidence: 99%

Exceptionally preserved arthropodan microfossils from the Middle Ordovician Winneshiek Lagerstätte, Iowa, USA

Nowak

Harvey

Liu

et al. 2018

LET

View full text Add to dashboard Cite

The Middle Ordovician (Darriwilian) Winneshiek Shale from Winneshiek County, Iowa, USA, hosts a Konservat‐Lagerstätte that has yielded a diverse fauna including soft‐bodied fossils. The shale is rich in organic content; in particular, algal material and fragmentary cuticular remains. Palynological acid treatment alongside modified, low‐manipulation processing enables the extraction of these ‘small carbonaceous fossils’ (SCFs) from the matrix, allowing a more detailed view of their morphology. Together these methods have yielded exceptionally well‐preserved crustacean‐type setae and a population of distinctive microfossils which we identify as the feeding appendages of a small‐bodied arthropod. We present two hypotheses for their identity: as either pancrustacean mandibles, or euchelicerate coxae. Overall, the detailed topological similarities and implied functional equivalence to the coxae of xiphosurid chelicerates, in particular, outweigh the resemblance to certain branchiopodan and hexapodan mandibles. In turn, however, the restricted size range and lack of associated limb or carapace fragments pose a taphonomic conundrum, suggesting an extreme biostratinomic bias. By comparison with previously described arthropodan SCFs from the Cambrian of Canada, the Winneshiek fossils extend the geographic, palaeoenvironmental and temporal range of this taphonomic window and provide a complementary tool for reconstructing the diversity and ecology of the Winneshiek biota.

show abstract

Section: Taxonomic Discussionmentioning

confidence: 99%

“…Species of the Ordovician genera Pumilocaris Racheboeuf et al ., and Rolfecaris Racheboeuf et al ., have different carapace shapes and body proportions, respectively (see Racheboeuf et al . ). Species of Emmelezoe Jones, clearly differ in their greatly elongated pleomeres and distinct carapace ornamentation (see Collette & Hagadorn ).…”

Section: Taxonomic Discussionmentioning

confidence: 99%

Appendages, functional morphology and possible sexual dimorphism in a new ceratiocaridid (Malacostraca, Phyllocarida) from the Early Devonian Hunsrück Slate (south‐western Germany)

Poschmann

Bergmann

Kühl

2018

Papers in Palaeontology

View full text Add to dashboard Cite

We describe a new archaeostracan phyllocarid from the famous Early Devonian Hunsr€ uck Slate, Germany. Morphological features suggest a new ceratiocaridid species for which we propose the name Ceratiocaris harpago sp. nov. The exceptionally well-preserved holotype specimen is the most completely known ceratiocaridid with an almost entire set of appendages including biflagellate antenniform antennules, robust uniramous antennae with hook-like flagellum, thoracopods densely covered with setae and probably six pairs of pleopods. A nectobenthic lifestyle is considered the most probable and the clasper-like morphology of the antennae suggests the presence of a sexual dimorphism in this taxon, with the holotype specimen being a male individual.

show abstract

South American Ordovician phyllocarids (Crustacea, Malacostraca)

Cited by 13 publications

References 16 publications

Redescription, paleogeography, and experimental paleoecology of the Silurian phyllocaridGonatocaris

Redescription, paleogeography, and experimental paleoecology of the Silurian phyllocaridGonatocaris

Exceptionally preserved arthropodan microfossils from the Middle Ordovician Winneshiek Lagerstätte, Iowa, USA

Appendages, functional morphology and possible sexual dimorphism in a new ceratiocaridid (Malacostraca, Phyllocarida) from the Early Devonian Hunsrück Slate (south‐western Germany)

Contact Info

Product

Resources

About