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| An artist’s impression of Liassophlebia sp., resting on a frond of the palaeofern species Phlebopteris muensteri. in Swaby, Coe, Hutchinson, Riva & Nel, 2023. Artwork: Jules Kiely and Bristol Museum & Art Gallery. |
ABSTRACT
Liassophlebiidae is an extinct family of damsel-dragonflies found in Upper Triassic and Lower Jurassic strata of Europe, Asia and Antarctica. Whilst Liassophlebiidae is well represented by Lower Jurassic fossils, their lowest occurrence in the Upper Triassic has hitherto only been suggested by three fragmentary specimens. These were originally ascribed to two species: Liassophlebia withersi and Liassophlebia batheri, but the latter is now considered nomen dubium. Here we describe a fourth, better preserved specimen that is likely to be Rhaetian (Late Triassic) in age. The specimen, BRSMG Cg3101 a+b, was collected from Bowdens Quarry, Somerset, UK, from the lower part of the White Lias Formation. The specimen comprises an incomplete forewing attributed to Liassophlebia due to: the small number of antenodals, antesubnodals and crossveins between RP and MA based RP3/4 in the base of RP2 opposite the subnodus; a straight and elongate secondary longitudinal vein in the postdiscoidal area; numerous cells and secondary veins in radial and median areas. The specimen is likely to represent a new species and provides stronger evidence than the previous three specimens of the presence of Liassophlebiidae during the late Rhaetian. Its stratigraphical position suggests that Liassophlebiidae arose in the immediate aftermath of the Triassic-Jurassic mass extinction.
KEYWORDS: Insecta, Odonatoptera, stem Anisoptera, diversity, Triassic, Triassic-Jurassic mass extinction
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| An artist’s impression of Liassophlebia sp., resting on a frond of the palaeofern species Phlebopteris muensteri. the forewings are based on the specimen BRSMG Cg3101 a+b described herein. As the new specimen is incomplete, other specimens within the genera were used to create this artist’s impression as follows: the hindwing is based on the holotype specimen of Liassophlebia magnifica (NHMUK I.6648/I.10462); and the body proportions are based on the incomplete abdomens of the holotypes ‘Liassophlebia’ clavigaster (NHMUK I.10433) and ‘Liassophlebia’ hopei (OUMNH J.55084 a and b). The colour and body morphology, including resting wing posture is inferred from present day Anisoptera. © Jules Kiely and Bristol Museum & Art Gallery. |
Emily J. Swaby, Angela L. Coe, Deborah Hutchinson, Lee Riva and André Nel. 2023. A New Liassophlebiidae (Odonata: Heterophlebioidea) from Strata close to the Triassic-Jurassic Boundary in Somerset, UK. Historical Biology: An International Journal of Paleobiology. DOI: 10.1080/08912963.2023.2261957
