Holotype of Anguiscolex africanus. Credit: Complutense University of Madrid
A research study led by the Complutense University of Madrid (UCM) and the Institute of Geoscience (IGEO, CSIC-UCM) has actually revealed two well-preserved types of marine worms from the Palaeozoic period (Ordovician period) 455 million years back at the Tafilalt Biota website in Morocco.
These worms represent the new genus and types Anguiscolex africanus, and the brand-new species Wronascolex superstes.
Palaeoscolecid worms are not unusual in the Paleozoic; the problem is that 99.99% of the fossil record comprises their sclerites (hard plates embedded in the cuticle) in isolation, which typically develop in particular limestone rocks. To put it simply, this kind of worm lived in all the seas of the globe, but there is no evidence of their fossils besides at a small fraction of sites.
The worm fossils at the Moroccan website were articulated and well maintained in lutites (fine-grained rocks) and in an ecological context dominated by turbulent waters, which makes the finding, according to the UCM and IGEO paleontologist Juan Carlos Gutiérrez Marco, a “palaeontological surprise in a far from favorable geological context”.
The cuticle of these marine worms, explained in Historical Biology, was covered in phosphatic microsclerites (determining 20-100 thousandths of a millimeter), organized in rings on the succeeding segments, their preservation being helped with by fast burying, having actually initially been safeguarded underneath bacterial veils which sped up iron sulfides.
These 2 individuals are now contributed to the finding made some years back, at the same site and by the same research study team, of the worm Gamascolex vanroyi.
Worms that lived when Morocco was “polar”.
Another of the conclusions highlighted by the study is the “gigantism” of the three worms known in the Tafilalt Biota, which are 2 to 3 times bigger than the global record of palaeoscolecids in Australia, North America, and Central-Western Europe. “This scenario might be linked with metabolic factors involved in what is called “polar gigantism”, as Morocco was very close to the Earths South Pole throughout the Ordovician Period,” Gutiérrez Marco explains.
This is the third of these organisms to be found in the Tafilalt Biota, an outstandingly well-preserved site including a mix of fossils from groups with difficult parts (trilobites, mollusks, echinoderms) and others with a soft to weakly mineralized body (unusual arthropods, worms, paropsonemid discs …).
The finding forms part of the ongoing research into the Ordovician in Morocco in connection with a series of tasks under the National Plan (Ministry of Science and Innovation), with 15-day field seasons being organized in the desert surface a couple of times a year.
If they find anything of note, the scientists also have a network of partners who locate fossils throughout the year and contact them.
” We are trying to rebuild the environments and organisms of the past, and the information acquired assistance, in this case, to improve the geological connection of the fossil-bearing units of Morocco with other synchronous units found on the marine rack of the former continent of Gondwana”, the UCM scientist emphasizes.
Recommendation: “Polar gigantism and impressive taxonomic longevity in new palaeoscolecid worms from the Late Ordovician Tafilalt Lagerstätte of Morocco” by Diego C. García-Bellido and Juan Carlos Gutiérrez-Marco, 29 October 2022, Historical Biology.DOI: 10.1080/ 08912963.2022.2131404.