Wealden insects: An artist’s update (Part 4)

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Biddy and Ed Jarzembowski (UK)

An ‘artist’s impression’ of Wealden insects, inspired by the original work of Neil Watson, appeared in a three-part mini-series in Deposits issues 47 to 49. Since then, the discovery of a number of species new to science (belonging to diverse groups) has meant that an update was needed. Here are some completely new watercolours by Biddy, including the first true bug (heteropteran) from the Wealden, and the first Wealden earwig (dermapteran). Insects are arthropods and an accompanying Wealden crustacean is added this time. Photographs of actual fossils found in the Weald Clay Formation of Lower Cretaceous (Hauterivian and Barremian) age are provided too. We are indebted to Fred Clouter, Terry Keenan, Tony Mitchell and Pete Austen (UK) for help with these images.

As before, Ed has supplied some explanatory notes to accompany the pictures, with more on the way. We have incorporated some new ideas on established species, such as different interpretations of the fossil lifestyle in the case of the ‘moss’ bug. Wealden insects are often disarticulated (due to transport in water).

Where intact relatives are known from other contemporary deposits (especially Asia and Spain), these have been referred to, as well as recent representatives. While we can now recognise the commoner insect groups from the late age of the dinosaurs, continuing fieldwork shows that others remain to be unearthed. The artist’s job is ongoing, like that of the specialist and collector. We shall continue to periodically share the finds with you as a new generation of artist’s impressions.

Fig. 15(a). Extinct earwig, Valdopteron woodi Kelly, Ross & Jarzembowski. This earwig differs from recent ones because it lacks forceps and has segmented ‘tails’ instead; also, the wing cases (tegmina) are not smooth and have veins. This is because it is not only a dermapteran (earwig), but an archidermapteran (archaic earwig). The body is therefore based on Jurassic Palaeodermapteron Zhao, Shih & Ren from China. The colour scheme, however, was inspired by the Australian Brown Earwig and Apachyus species.
Fig. 15(b). Voldopteron woodi, left temen, 6mm long, preserved as organic (carbonaceous) impression (adpression) in sideritic ironstone concretion.
Fig. 16(a). Extinct moss bug, Yuripopovia woottoni Jarzembowski. Only known from the Wealden with more than one included species, the genus Yuripopovia Jarzembowski belongs to a widespread extinct family, the progonocimicids. It is a Mesozoic relative of living peloridiids – the moss bugs – which have a limited distribution in the Southern Hemisphere. According to bug specialist (palaeohemipterist) Jacek Szwedo, Cretaceous progonocimicids lived on trees rather than on mosses. Thus, two different colour schemes are offered here: brown on bark (top) and green on foliage (bottom). The body is based on Mesocimex Hong from the Chinese Jurassic.
Fig. 16(b). Yuripopovia woottoni, right tegmen part and counterpart, 5mm long, preserved as an impression with some brown colouration in calcareous siltstone (scour fill).
Fig. 17(a). Large water bug, Iberonepa species Jarzembowski & Coram. This is an extinct true bug from the Wealden and Purbeck, known from modified forewings (hemelytra) in the UK, which are very similar to those of complete fossils of Iberonepa romerali Martínez-Delclòs, Nel & Popov from the Spanish Lower Cretaceous. A predator, it had front legs adapted for catching prey and back legs flattened for swimming, like recent belostomatids. The latter are still found in the UK and exotic species are known to pinch the toes of swimmers in warmer climes plus be a pest of fish farms. The males, however, are also known for their parental care.
Fig. 17(b). Iberonepa sp hemelytron (tegmen with membranous tip), 2cm long, preserved as organic impression in phosphatic concretion.
Fig. 18(a). Pine flower weevil, Oxycorynoides bucklowae Legalov & Jarzembowski. Weevils are the most diverse family group in the animal kingdom, often with a characteristic long nose (rostrum). Feeding on plants, gardeners sometimes claim (in despair) that there is one for every flower. The colour of this extinct species is based on living nemonychids, with a touch of Acorn Weevil.
Fig. 18(b). Oxycorynoides bucklowae, wetted body part and counterpart, 6mm long, preserved as an adpression in sideritic ironstone concretion.
Fig. 19(a). Aquatic isopod, Cymothoidana websteri Jarzembowski, Wang, Fang & Zhang. During the search for insects, some new Wealden crustaceans have also been found. This one lived in the water where insect remains were deposited. It belongs to the living cymothoid isopods and is modelled on Harford’s Isopod from intertidal North America and the Speckled Sea Louse from British estuaries.
Fig. 19(b). Cymothoidana websteri, hindbody, 5mm long, preserved as an irony (ferruginous) impression in calcareous siltstone (scour fill).

Specimens are deposited in the Natural History Museum, London; Booth Museum of Natural History Brighton; and Maidstone Museum and Bentlif Art Gallery, UK.

Other articles in this series comprise:
Wealden insects: An artist’s impression (Part 1)
Wealden insects: An artist’s impression (Part 2)
Wealden insects: An artist’s impression (Part 3)
Wealden insects: An artist’s update (Part 4)

Further reading

English Wealden fossils, Palaeontological Association Field Guide to Fossils No 14, edited by David J Batten, The Palaeontological Association, London (2011), 769 pages (Paperback), ISBN: 978-14-44367-11-9.

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