4 new ANOM Lab articles in a special volume of Frontiers

ANOM Lab members published 4 articles on the Frontiers research topic “Insights on the Rise of Animal Life from Cambro-Ordovician Lagerstätten”. 3 articles report on fossil arthropods from the Fezouata Shale in Morocco. Potin et al. describe new suspension-feeding radiodonts from the Fezouata Shale (Fig. A), and discuss their ecological and evolutionary implications. Drage et al. document the moulting behavior of the Moroccan marrellid (Fig. B) and compare it to that of other marrellomorphs and modern arthropods. Laibl et al. also focus on marrellids, but this time characterizes the morphological changes occurring during their development based a nice set of juvenile and adult specimens including tiny immature stages (Fig. C). The fourth article, by Lustri et al., explores the environmental evolution of xiphosurids (Fig. D), and compare it to other euchelicerates groups.

Additional digital ressources:

A 3D model, based on µCT data, of one of the frontal appendage of the new taxon described by Potin et al. can be seen and manipulated online on Sketchfab.

A video presenting the three-dimensional rendering of the smallest immature stage of the Fezouata marrellid can be viewed here.

Gilsonicaris, not an Early Devonian anostracan but a polychaete annelid

In an article published today in Biology Letters, AnomLab postdoc Pierre Gueriau and his collaborators have resolved an 80-year-old mystery by deciphering the true nature of a 400-million-year-old marine creature from Germany. Since its initial description in 1943, this fossil, named Gilsonicaris rhenanus, has perplexed scientists who have alternatively interpreted it as an anostracan crustacean (‘fairy or brine shrimp’), a myriapod, or even a part of a starfish arm. Using a 3D X-ray scanner, the team reveals that Gilsonicaris is, in fact, a polychaete annelid (‘bristle worm’). This discovery unequivocally dismisses the existence of marine anostracans 400 million years ago, while also offering a wealth of new information regarding the early evolutionary history of bristle worms and their soft tissues.

A video summarizing the research

A 3D model that can be manipulated at will is available on Sketchfab.

Reference: Gueriau P., Parry L.A. & Rabet N. 2023. Gilsonicaris from the Lower Devonian Hunsrück slate is a eunicidan annelid and not the oldest crown anostracan crustacean. Biology Letters 19: 20230312. Find the article (Open Access) here.

New publication! A complete radiodont review is out

Gaëtan Potin and Allison Daley published today in Frontiers in Earth Science an exhaustive review paper focusing on radiodonts, an iconic Cambro-Ordovician arthropod group. This open-access article offers an in-depth summary of all research conducted on Anomalocaris, the earliest known apex predator, and its affiliated taxa. Many aspects are discussed, such as diversity, evolutionary implication, paleobiogeography and stratigraphic repartition… If you want to know more about these amazing animals, check out the article following this link: https://www.frontiersin.org/articles/10.3389/feart.2023.1160285/full.

Radiodont specimens with whole body preservation.
Image credits: (A–D) A. Daley, (E) P. Van Roy, (F) P. Cong