Paleontologists have described a new genus and species of Jurassic cockroach, Alderblattina simmsi, based on an isolated wing found in Gloucestershire, the United Kingdom.
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Alderblattina simmsi: (A) dry specimen; (B) specimen wetted with ethanol; note the prominence of the two subspherical maculae (spots) and distal coloration at the wing tip. Scale bar – 1 mm. Image credit: Swaby et al., doi: 10.1002/spp2.1598.
“Insects are the most diverse group of terrestrial organisms in the history of life and have been fundamental components of terrestrial ecosystems since the Early Devonian,” said Open University paleontologist Emily Swaby and her colleagues from the Open University and the National Museum of Scotland.
“As primarily detritivores (decomposers), cockroaches play a crucial role in nutrient cycling in ecosystems, through the decomposition of organic matter, and are a critical food source for many predators including birds, lizards and other mammals.”
“Cockroaches (Blattodea), which are part of the superorder Dictyoptera, originated during the Bashkirian age (Carboniferous period) and rapidly diversified during the late part of the Moscovian age and penultimate Kasimovian age of the Carboniferous.”
“Further diversification occurred during the Early and Middle Permian.”
“Although the number of cockroaches sharply decreased following the end-Permian mass extinction, they flourished again in the Triassic period.”
The newly-described cockroach species lived during the Toarcian age of the Early Jurassic epoch, some 180 million years ago.
Named Alderblattina simmsi, it had a relatively small size and distinct wing coloration.
“Color patterning in insects, including on their wings, is primarily interpreted to be a physiological adaptation and/or used for protection against predation, or sexual signaling,” the paleontologists said.
“Today, cockroach species display a wide variety of color patterning, the functions of which include communication, protection against predation, sexual signaling and cuticle sclerotization.”
“Alderblattina simmsi is the second species of cockroach to unambiguously possess wing coloration patterns from the Toarcian.”
The authors assigned Alderblattina simmsi to the cockroach family Rhipidoblattinidae.
“Alderblattina simmsi differs considerably from all other Jurassic cockroaches due to the presence on the forewing of the two distinct subspherical maculae and coloration at the wing tip,” they said.
The Alderblattina simmsi fossil was collected in January 1984 by geologist Mike J. Simms.
The specimen came from Alderton Hill, which is part of the Whitby Mudstone Formation.
“We hypothesize that the extreme environmental conditions associated with the Toarcian Oceanic Anoxic Event drove competition for resources and/or evolutionary changes in predators, which in turn led to the development of aposematic coloration in two insect orders at this time,” the researchers said.
“Alderblattina simmsi is the seventh valid blattodean species from the Toarcian of Europe, and furthers our knowledge of the Toarcian cockroach faunas of Europe.”
“This unique specimen adds a pivotal point to the record of wing coloration patterns in Mesozoic cockroaches, and provides important evidence for further understanding of the evolution of aposematic color patterning in Blattodea.”
A paper on the findings was published in the journal Papers in Palaeontology.
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Emily J. Swaby et al. 2024. A new cockroach (Blattodea, Rhipidoblattinidae) from the Toarcian (Lower Jurassic) of Alderton Hill, Gloucestershire, UK, and the earliest likely occurrence of aposematic colouration in cockroaches. Papers in Palaeontology 10 (5): e1598; doi: 10.1002/spp2.1598
