1036


Journal of Paleontology


(type species P. anglicana Tillyard, 1925) were included in the family by Tillyard (1925). Liassophlebia originally comprised four species based on wings: L. magnifica Tillyard, 1925, L. batheri Tillyard, 1925, L. withersi Tillyard, 1925, and L. west- woodi (Hagen, 1850), and two possible species based on partial abdomens: L. (?) clavigaster Tillyard, 1925 and L. (?) hopei (Brodie, 1845). Liassophlebia westwoodi was described from a specimen previously figured by Brodie (1845, pl. 10, fig. 8) and named Heterophlebia westwoodi by Hagen (1850, p. 359); it was later transferred to Tarsophlebia Hagen, 1866 by Hagen


(1866). Liassophlebia (?) hopei was described from a specimen figured and named Libellula hopei by Brodie (1845, pl. 10, fig. 3); it was later transferred to Heterophlebia Westwood, 1849 by Selys-Longchamps and Hagen (1850) and then ‘(Anisozy- gopteron?)’ by Handlirsch (1906). Petrophlebia was transferred to Architemistidae Tillyard, 1917 by Fraser (1957) and then to Campterophlebiidae Handlirsch, 1920 by Nel et al. (1993). Although Bechly (2016) proposed to transfer it back to Archi-


temistidae, its position in the Campterophlebiidae was con- firmed by revision of the family by Kelly and Nel (2017). The diagnosis of Liassophlebiidae was slightly emended by


Zeuner (1962) to include species with a discoidal cell closed basally. Petrophlebia anglicanopsis Zeuner, 1962, Liassophlebia jacksoni Zeuner, 1962, and L. gigantea Zeuner, 1962 were also described. Additional specimens were identified as L. magnifica from the Jackson collection of the lower Lias of Dorset. The Jackson collection was re-examined by Whalley (1985) who altered some of Zeuner’s species descriptions, transferred P. anglicanopsis to Liassophlebia and described L. pseudomagnifica Whalley, 1985 from one of Zeuner’s L. magnifica specimens. Liassophlebia anglicanopsis was considered an uncertain taxon in Liassophlebiidae by Nel et al. (1993). Additional genera were included from continental Europe,


CentralAsia, China, andAntarctica, which are not known from the British deposits: (1) Caraphlebia Carpenter, 1969 from South Victoria Land, Antarctica was considered possibly referable to Turanothemistidae Pritykina, 1968 by Nel et al. (1993) but was transferred to Selenothemistidae Handlirsch, 1939 by Bechly (2016); (2) Ferganophlebia Pritykina, 1970 fromthe Early Jurassic of Kyrgyzstan; (3) Paraliassophlebia Hong, 1983 from theMiddle Jurassic of China was considered as Epiprocta incertae sedis by Nel et al. (1993) but was tentatively transferred to Selenothemistidae by Bechly (2016); and (4) Grimmenopteron Ansorge, 1996 and Bavarophlebia Nel and Petrulevičius, 2005, both from the Toar- cian of Germany, each with one associated species. A further specimen was identified as Liassophlebia sp. from the Early Jur- assic of Austria by Kohli et al. (2016). Liassophlebiidae was reported to be known from the Early


Jurassic, Hettangian-Toarcian, by Nicholson et al. (2015, sup- plementary data) but this disregards the four species described by Tillyard (1925) from the Penarth Group of Strensham, Eng- land, which is Late Triassic: Rhaetian. This locality was repor- ted as Rhaetian by Nicholson et al. (2015) for other families but Tillyard’s book was not cited so these species must have been missed. The inclusion of this omission changes the dynamics of the family across the TJB because including these four species extends the family to before the boundary, indicating that the family survived the extinction event rather than originating in the subsequent stage.


Geological setting


The specimens discussed herein are from the Late Triassic to Early Jurassic of England (Fig. 1). They are mostly found in shallow marine limestones; these rocks are fine-grained enough to generally preserve insects well. The living insects were not necessarily associated with the marine environment but were


transported from their terrestrial or freshwater habitat through fluvial systems to their final deposition in the marine shallows. The Late Triassic material was collected from bed 18 of the Penarth Group at the historical locality of Strensham in the county of Worcestershire (Brodie, 1845) and was updated to current geological nomenclature by Kelly et al. (2017) who found the horizon to lie within the Lilstock Formation, Cotham Member, which is Rhaetian in age. The Early Jurassic fossils were collected from three localities Binton in the county of Warwickshire, another historical locality, exposed several insect-bearing horizons, which Brodie (1845) originally described and Kelly et al. (2018) found to correspond to the Planorbis Chronozone (Blue Lias Formation, Wilmcote Lime- stone Member) of the Hettangian. The other two localities— Stonebarrow and Catherston Lane—are very similar and are found at or near the Dorset coast. Stonebarrow is still actively collected from and Catherston Lane was active for a short time during the construction of the Charmouth bypass. There are several insect-bearing horizons; the insects discussed herein were collected from the ‘flatstones’ (bed 83/83h), which is a local name for a horizon found in the Obtusum Chronozone, Obtusum Subchronozone (Charmouth Mudstone Formation, Black Ven Mudstone Member) (Page, 2010; Kelly et al., 2017). Caraphlebia antarctica Carpenter, 1969 was described


from the Jurassic ‘Mawson Tillite’ on Carapace Nunatak, South Victoria Land, Antarctica (Carpenter, 1969).Mawson Tillite is a historical name for the Mawson Diamictite of the Ferrar Group (Balance and Watters, 1971), now known as the Mawson For- mation (Elliot and Hanson, 2001). Based on U/Pb and 40Ar/39Ar analysis of volcanic rocks in North Victoria Land, Musumeci et al. (2004) concluded that the pyroclastic event that led to the formation of the Prebble, Mawson, and Exposure Hill forma- tions occurred between the Hettangian and lower Pliensbachian. However, given the sizable hiatus of Lower Jurassic rocks in South Victoria Land (Ribecai, 2007; Schöner et al., 2011), any fossils from the Mawson Formation in this area are likely to have been deposited later within this estimation. The Mawson Formation is unconformably overlain by the


Carapace Sandstone Formation, which is not present in all areas (Ribecai, 2007). However, the insect was collected on Carapace Nunatak where the formation is present and has been estimated to have been deposited during the upper Sinemurian to lower Pliensbachian (Ribecai, 2007). This means that the age estima- tion for the Mawson Formation in this area could lie within the later Hettangian to early late Sinemurian, making them of similar age to the English specimens.


Materials and methods


Collections of English material were examined from The Natural History Museum, London (NHMUK), the National Museum of


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