iBet uBet web content aggregator. Adding the entire web to your favor.
iBet uBet web content aggregator. Adding the entire web to your favor.



Link to original content: https://pubmed.ncbi.nlm.nih.gov/32742697
A miniature Ordovician hurdiid from Wales demonstrates the adaptability of Radiodonta - PubMed Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Jun 3;7(6):200459.
doi: 10.1098/rsos.200459. eCollection 2020 Jun.

A miniature Ordovician hurdiid from Wales demonstrates the adaptability of Radiodonta

Stephen Pates  1 , Joseph P Botting  2   3 , Lucy M E McCobb  2 , Lucy A Muir  2
Affiliations

A miniature Ordovician hurdiid from Wales demonstrates the adaptability of Radiodonta

Stephen Pates et al. R Soc Open Sci. .

Abstract

Originally considered as large, solely Cambrian apex predators, Radiodonta-a clade of stem-group euarthropods including Anomalocaris-now comprises a diverse group of predators, sediment sifters and filter feeders. These animals are only known from deposits preserving non-biomineralized material, with radiodonts often the first and/or only taxa known from such deposits. Despite the widespread and diverse nature of the group, only a handful of radiodonts are known from post-Cambrian deposits, and all originate from deposits or localities rich in other total-group euarthropods. In this contribution, we describe the first radiodont from the UK, an isolated hurdiid frontal appendage from the Tremadocian (Lower Ordovician) Dol-cyn-Afon Formation, Wales, UK. This finding is unusual in two major aspects: firstly, the appendage (1.8 mm in size) is less than half the size of the next smallest radiodont frontal appendage known, and probably belonged to an animal between 6 and 15 mm in length; secondly, it was discovered in the sponge-dominated Afon Gam Biota, one of only a handful of non-biomineralized total-group euarthropods known from this deposit. This Welsh hurdiid breaks new ground for Radiodonta in terms of both its small size and sponge-dominated habitat. This occurrence demonstrates the adaptability of the group in response to the partitioning of ecosystems and environments in the late Cambrian and Early Ordovician world.

Keywords: Afon Gam Biota; Dol-cyn-Afon Formation; Hurdiidae; Lagerstätten; Ordovician; Radiodonta.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1.
Figure 1.
Geographical (a) and palaeogeographical (b) location of the Afon Gam Biota, Wales, UK. (a) Redrawn from [49]; (b) constructed using GPlates [50]. Av, Avalonia; Ba, Baltica; La, Laurentia; SP, South Pole.
Figure 2.
Figure 2.
NMW 2012.36G.90a from the Afon Gam Biota, Dol-cyn-Afon Formation, Wales, UK. Accumulation of fossil material in burrow, including hurdiid radiodont frontal appendage. (a) Photograph of specimen, taken under water; (b) interpretative drawing. B, edge of burrow. Scale bars: 5 mm.
Figure 3.
Figure 3.
Close-up of hurdiid frontal appendage from figure 2. (a) Counterpart NMW 2012.36G.90b; (b) part NMW 2012.36G.90a; (c) area indicated by black arrow in (a), white arrows indicate auxiliary spines on endite 3, black arrows indicated auxiliary spines on endite 4; (d) interpretative drawing of the part. aux, auxiliary spines; ds, dorsal spines; en, endite; pd, podomere; ts, terminal spine. Scale bars: (a,b,d) 0.5 mm; (c) 0.1 mm.
Figure 4.
Figure 4.
Comparison of an idealized hurdiid appendage and black silhouette illustrating terminology of distal, proximal, dorsal and ventral (a) with a reconstruction of the Afon Gam hurdiid (b). Colours indicate the proposed homologous parts of the appendage, as labelled in (a). 1–5, five podomeres bearing broad recurved endites; S, shaft region.
Figure 5.
Figure 5.
Comparison of distal regions of eurypterid spiniferous prosomal appendages (a) and hurdiid radiodont frontal appendages (b). Appendages orientated to provide best possible comparison with NMW 2012.36G.90. Reconstructions of Carcinosoma-type (taxa such as the Ordovocian Orcanopterus manitoulinensis), Hughmilleria-type (taxa such as the Ordovician Paraeurypterus anatolensis) and Megalograptus-type (taxa such as the Ordovician Pentecopterus decorahensis) eurypterid spiny appendages redrawn from [: fig. 9]. Reproduced with permission. Cyrtoctenus wittebergensis reconstruction created using data from [70]. Note the finger-like movable spine visible (yellow) underneath the filamentous structures for Cyrtoctenus wittebergensis, and comparable structures on two podomeres which do not bear combs proximally. The distalmost two podomeres (seven and eight; brown) are not known in this species, and so reconstruction of this part is speculative.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Conway Morris S. 1989. The persistence of Burgess Shale-type faunas: implications for the evolution of deeper-water faunas. Earth Environ. Sci. Trans. R. Soc. Edinb. 80, 271–283. (10.1017/S0263593300028716) - DOI
    1. Gaines RR. 2014. Burgess Shale-type preservation and its distribution in space and time. Paleontol. Soc. Pap. 20, 123–146. (10.1017/S1089332600002837) - DOI
    1. Muscente AD, et al. 2017. Exceptionally preserved fossil assemblages through geologic time and space. Gondwana Res. 48, 164–188. (10.1016/j.gr.2017.04.020) - DOI
    1. Daley AC, Antcliffe JB, Drage HB, Pates S. 2018. Early fossil record of Euarthropoda and the Cambrian Explosion. Proc. Natl Acad. Sci. USA 115, 5323–5331. (10.1073/pnas.1719962115) - DOI - PMC - PubMed
    1. Briggs DEG. 1979. Anomalocaris, the largest known Cambrian arthropod. Palaeontology 22, 631–664.

LinkOut - more resources