The Earliest Damselfly-Like Insect and the Origin of Modern Dragonflies (Insecta: Odonatoptera: Protozygoptera)

Home , Damselfly, Meganeura, Meganisoptera, Odonatoptera

SHORT COMMUNICAnON The earliest damselfly-like insect and the origin of modern dragonflies (Insecta: Odonatoptera: Protozygoptera)

E. A. .Iarzembowski' and A. Nel2

JA RZEMBOWSKI,E.A. & NEL, A. 2002. The earliest damse lfly-like insect and the origin of modern dragonflies (Insecta: Odonatoptera: Pro tozygoptera). Proceedings of the Geologists' Associatio n, 113, 165-1 69. The first Carboniferous protozygopteran is forma lly described from the late Westp halian Coal Measures of southern England. Bechlya ericrobinsoni gen. et sp. nov. (Bechlyidae fam. nov.) is the oldest represent ative of a lineage which includ es all living dragonflies and damselflies. This discovery shows that small, damse lfly-like forms co-existed with the giant dragonflies of the Eura merican coal swamps .

IMaidstone Mus eum & Bentlif Ar t Gallery, St. Faith's St reet, Maidsto ne, Kent MEl4 lLH and PRIS, The University, Reading RG6 2AB, UK "Laboratoire d'Entomologie and CNRS UM R 8569. Mus eum Nati onal d'Histoire Naturelle, 45 rue Buffo n, F-75005, Paris, France

1. INTROD UCTION Format ion (Upper Westphalian D: Dicksonites plueck enetii Subzo ne; Thomas & Cleal, 1994), probab ly fro m The insect order Odona toptera (damselflies, dragon above the No. 10 Coal Seam (Jarzembowski, 1989). flies and their extinct relatives, i.e. dragonflies sensu The insect is associated with plant compression fossils lata) is an ancient one first appearing in the Upper interpreted as representing the litter of a lycopsid forest Ca rboniferous (Upper Na murian B of Ger many and dominated by the arbo rescent clubm oss Lepidodendron Argentina: Brauckmann et al., 1985; Gutierrez et al., aculeatum (Proc tor & Jarzembowski, 1999) which was 2000). The Carboniferous Odonatop tera include the deposited on an upp er delta floodpl ain (Assemblage 4 celebrated giant dragonflies (Meganisop tera), some of of Proctor. 1994). Od onatoptera are rare in this facies, which attained wingspans of c. 70 em, exceeding that as in ot her Euramerican coalfields, on ly a single of any living insect (Ca rpenter, 1992). However, the megan isopteran having been described previo usly from discovery of a small odona topteran with an estima ted the Fo reland Basin (Bolton. 1914). wingspan of under 6 em in the Upper Carbonifero us of southern England shows that small species also existed. Moreover, it is a significant find because this fossil is 3. SYSTEMATIC PALAEONTOLOGY the earliest representative of the Protozygoptera, the We follow the wing venation nomenclature of Riek sister group of the Panodonata - a clade which in (1976), Riek & Kukalova-Peck (1984) and Kukalova cludes all living dragonflies and damselflies (Bechly, Peck (1991), emended by Nel et al. (1993) and 1996). Triassic fossils show that Protozygoptera were Bechly (1996), and the phylogenetic classification of slender, damselfly-like insects (Fig. I). Odonatoptera prop osed by Bechly (1996). Order Odo natoptera Martyn ov, 1932 2. GEOLOGY Clade Stigmoptera Bechly, 1996 The new find, a unique wing, represe nts eighteen years Suborder Prot ozygoptera Tillyard, 1925 ofcollecting by amateur and professional geologists on Superfa mily Archizygopteroidea Handl irsch, 1906 the site of a form er colliery tip, now a SSSIIRIGS, Family Bechlyidae fam. nov. known as Writhlington Geological Nature Reserve at Lower Writhlington, near Radstock, (Bath & NE) Diagosis Somerset [National Grid Reference ST 703 553). Over Three strong antenodal crossveins present between C 1000 insect fossils belon ging to ot her gro ups have been and ScP cor responding to AxO, Ax I and Ax2; anteno recovere d here over the same period . The reserve lies in dal crossveins in second row (between ScP and RA) the Rad stock Syncline of the Westphalian Fo reland no t well aligned with Ax I and Ax2; AxO strongly Basin in southern England and the wing is preserved as curved ; vein MAb strong but directed towards wing an impression in grey roof shale from the Farrington base and not aligned with free base of CuA; true nod us

Fig. 1. General habitus of Protozygoptera by Carlo Pesarini, courtesy Prof. J.-c. Gall.

(N) present with nodal crossvein Cr and oblique sub Name nodus (Sn); all main longitudinal veins with no second After Dr E. Robinson, a 'true spirit' of the Geologists' ary branches except CuA; petiole long and narrow Association. with AA completely fused with AP (A); CuP reduced to a short crossvein between MP+CuA and anal Description margin; wing slender with few long cells. Part and countpart of a basally complete wing with the wing tip missing; petiolate base and wing corrugation Possible autapomorphies well preserved; no trace of colour pattern; length, Antenodal crossvein AxO incomplete, i.e. there is no 24.4 rnm, width opposite nodus N, 4.5 mm; distance corresponding subantenodal crossvein between ScP from base to N, 13.9 mm; exact position of N relative and R+MA; arculus lying midway between Axl to wing apex and pterostigma unknown; some five and Ax2 (convergently acquired by Odonata: antenodal crossveins between Costa C and ScP; basal Epiproctophora). antenodal crossvein AxO very strong and curved, 1.6 mm from wing base, without any corresponding Type genus antenodal crossvein in second row between ScP and R+MA; second antenodal crossvein Axl and third Bechlya gen. nov. Ax2 stronger than two distal secondary antenodal Genus Bechlya gen. nov. crossveins; Axl 4. I mm distal ofAxO and Ax2 2.5 mm distal of Ax I; five antenodal crossveins in second row Diagnosis between ScP and RA/R+MA; second row of anteno As for family. daIs distinctly weaker and not aligned with first row; two antesubnodal crossveins between RA and RP; Name very oblique arculus present, i.e. RP+ MA separating After Dr G. Bechly, odonatopterist. from RA between Axl and Ax2; RP separating from MA 0.6 mm distal of base ofarculus; no posterior part Type species of arculus, only a strong oblique vein between MA and MP corresponding to MAb, 1.0 mm distal of base of Bechlya ericrobinsoni gen. et sp. nov. RP; space between ScP and C in N sclerotized; strong Bechlya ericrobinsoni gen. et sp. nov. nodal crossvein Cr forming posterior part of N; strong, (Fig. 2) oblique subnodus Sn, I. I mm distal of Cr; four post nodal crossveins preserved, curved/oblique but not Diagnosis aligned with three corresponding postsubnodal cross As for genus. veins between RA and RPI; branches of RP poorly THE EARLIEST DAMSELFLY-LIKE INSECT 167

AX2 AX1

RPI RP2 CuP

Fig. 2. Bechlya ericrohinsoni: gen. et sp. nov.: (a) part, BMB 018498; (b) counterpart. BMB 018499 (scale line 2 mm), photographed by R. Stutely: (c) venation diagram preserved. base of proximal concave branch RP3/4 Horizon and locality nearly opposite N; base of convex IR2 about 5.3 mm Upper Westphalian D, Writhlington Geological distally; base of RP2 visible 3.0 mm distally; branches Nature Reserve. of RP. MA, MP and CuA nearly straight and more or less parallel; one crossvein between MA and RP basal Holotype of base of RP3/4; comparatively few, non-aligned BMB 018498.-9 [W477 a.b], colI. E. A. Jarzembowski, crossveins between main longitudinal veins; MP+Cu Booth Museum Brighton. UK. straight in its proximal part; CuP a short crossvein near distal end of petiole, very similar to that ofRecent Discussion Odonata, 0.3 mm long; distance from wing base to The unique type has been examined under alcohol and CuP. 4.2 mm; MP+CuA with a distinct curve distal of coated with ammonium chloride. It is impossible to CuP, MP and CuA separating 1.5 mm distally, 1.0 mm determine whether the type is a fore- or hind wing. basal of arculus; AA and AP not separated; petiole Bechlya ericrobinsoni gen. et sp. nov. can be attributed very long. 5.5 mm long and 1.2 mm wide; cubital area to the Odonatoptera on the basis of the following broad. 1.4 mm wide. broader than all other areas synapomorphies: presence of antenodal crossvein AxO; between main veins; one row of cells in cubital area; MP unbranched; CuP joining A; ScP fused with C CuA with 5 preserved simple posterior branches, distinctly basal of wing apex. The basal fusions of MA directed obliquely towards posterior wing margin. with R and of MP with Cu are synapomorphies of 168 E. A. JARZEMBOWSKI AND A. NEL

Neodonatoptera (sensu Bechly, 1996).The small size of recorded, showing that our current knowledge of fossil the wing, the presence of a true odonatan N with an Odonatoptera is patchy. oblique Sn, a strong nodal Cr crossvein, and a sclero tized space between ScP and C, together with the The problem of the first primary antenodal crossvein unbranched MA, exclude the new species from AxO. Meganisoptera and are synapomorphies of the more advanced clade Panodialata Nel et al., Bechly (1996) included in his list of synapomorphies of 1999 (=Lapeyriidae+Nodialata Bechly, 1996=Protan the Odonatoptera the following structure: 'a basal isoptera+Triadophlebioptera+Protozygoptera+Recent cross-vein between ScP and R+MA aligned with an Odonata). The presence of a typical odonatoid dis oblique branch of ScA between costal margin and ScP coidal cell closed distally by a strong, oblique vein ('basal brace') ...' (p. 355). There is a strong oblique MAb between MA and MP is a synapomorphy of the crossvein corresponding to the 'basal brace' (originally Discoidalia sensu Bechly (1996= Triadophlebioptera+ named AxO by Chao, 1951) in all Recent Odonata, but Protozygoptera+Recent Odonata) that excludes any it is also present in the Lower Permian meganeurid relationships with the Permian Lapeyriidae and Prota Megatypus schucherti Tillyard, 1925 and the Carbon nisoptera. Within the Discoidalia, the reduced 'reticu iferous Eugeropterum lunatum Riek, 1984 (based on lation', the non-basally recessed N, the low density of the reconstructions of Riek & Kukalova-Peck, 1984). postnodal crossveins, the absence ofbranches of RP3/4 Nevertheless, this 'basal brace' is not figured in nearly and MP are symplesiomorphies that would exclude all available reconstructions of described Carbonifer ous and Permian Odonatoptera. It is not visible in it from Triadophlebioptera sensu Bechly (1996= the wings of the various species of Meganeura in Triadotypidae + Piroutetiidae + Triadophlebiomorpha the collections of the Laboratory of Palaeontology, sensu Pritykina, 1981). Furthermore, the fusion of the National Museum of Natural History, Paris, because distal part of CuP with A, giving the former a of their poor preservation. Furthermore, the basal crossvein-like appearance, and CuA not resembling a crossvein between ScP and R+MA is absent in Bechlya crossvein basally parallel with CuP are synapomor ericrobinsoni gen. et sp. nov. Thus, it is not always phies of the Stigmoptera sensu Bechly (1996= present in Odonatoptera. We provisionally interpret Protozygoptera + Panodonata, = Archizygoptera + this absence of a crossvein between ScP and R+MA as Odonata). The pterostigma is unknown. B. ericrobin an autapomorphic reversal in Bechlya gen. nov., but soni gen. et sp. nov. lacks an alignment of MAb with the presence ofAxO needs to be investigated in all the free base of CuA which is a synapomorphy of the the known Carboniferous and Permian Odonatoptera. Panodonata. The long, petiolated wing with AA com For example, Bechly (1995, 1996) considered that AxO pletely fused with AP are synapomorphies of the (= basal brace ScA) in the Protanisoptera is in a very Protozygoptera sensu Bechly (1996, including Archi distal position, more or less exactly in the position of zygoptera, = Kennedyomorpha Pritykina, 1980), but Axl in Recent Odonata (and that there is actually no these characters have been convergently acquired by distal, strong antenodal crossvein homologous with Triadophlebiomorpha and many Recent Zygoptera Axl or Ax2). An examination of Polytaxineura stanleyi demonstrating that they are of little value for placing Tillyard, 1935 (Protanisoptera; Upper Permian, the new species in the Protozygoptera. B. ericrobinsoni Australia) shows that two strong antenodal crossveins gen. et sp. nov. shares with Protozygoptera the follow are clearly visible, exactly in the position of Ax I and ing characters that Bechly (1996) proposed as potential Ax2 of Recent Odonata. A basal brace is also present synapomorphies of this clade: nodal crossvein Cr not between C and ScP, prolonged between ScP and aligned with Sn; antenodal crossveins of first and R+MA, in well-preserved specimens of Protanisoptera second rows not aligned. This last character is not (Huguet et al., in press). It probably corresponds to shared by all Protozygoptera (A. Nel, pers. obs.). basal vein AxO. These characters are, however, also present in the more basal Lapeyriidae and Protanisoptera. Thus their 4. CONCLUSION polarity is questionable. According to Bechly, 'CuP shifted in a very basal position' would also be a Prior to the Writhlington find, the earliest Stigmoptera synapomorphy ofthe Protozygoptera. This structure is (Protozygoptera+Panodonata) were reported from the not preserved in many Protozygoptera but has nearly Permian. The new find shows that the stigmopteran the same position in the new species and several lineage leading to modern dragonflies and damselflies definite species of this suborder. Thus this character is had differentiated earlier, dating back to the earliest the best potential synapomorphy linking B. ericrobin known radiation of the winged insects, that of the soni gen. et sp. nov. with the Protozygoptera. Finally, non-Holometabola in the mid-late Carboniferous it may be noted that it does not share any synapomor (Jarzembowski & Ross, 1996). The damselfly-like phies with Odonata. Consequently it is the oldest habitus of Bechlya ericrobinsoni gen. et sp. nov. (small stigmopteran, implying that not only this clade, but size, petiolate wing base) is an ancient adaptation, also the Protanisoptera and Lapeyriidae existed by showing that narrow-winged Odonatoptera co-existed the Upper Carboniferous. They have not yet been with broad-winged Meganisoptera by the Upper T HE EARLI EST DAMSELFLY-LIKE INS E CT 169

Carboniferous. Interestingly, Campyloptera eatoni analysis of th e Protan isoptera (In secta: Od on at optera). Brongniart, 1893 from the Stephanian of Commentry Geobios. is also an odonatopteran with a systematic position Ja rzembowski, E.A. 1989. Wr ithl ington G eological Nat ure more basal than the Panodialata and rathe r large, Reserve. Proceedings 0/ the Geologists' Association. 100, 219- 234. sub-petolated wings (Nel & Huguet, under review). Jarzcmbowski, E.A. & Ross , A.J. 1996. In sect origination and Finally, this discovery implies that Lapeyriid ae, Pro extinction in the Phan erozoic. In (Hart, M.B.; ed.) Biotic tanisoptera and Triadophlebioptera, as well as Proto Recovery from Mass Ex tinction Events. G eological Society. zygoptera, had appeared by the Upper Carboniferous, Lond on . Special Publicati ons , 102. 65-78. and their discovery may be anticipated in the Coal Kukalova-Peck. J . 1991. Fossil history a nd the evo lution of Measures of Euramerica. hexapod structures. In (Naumann, I.D.: ed.) The insects of Australia, a textbookfor students and research workers (Znd edn). 1. Melbou rne Un ivers ity Press. Melbourne, 141-1 79. ACKNOWLEDGEMENTS Nel, A. & H uguet. A. under review. Revision of th e en ig This study is PRI S contribution no. 832 and was partly ma tic U pper Carboniferous insect Campyloptera eatoni supported by Royal Society research grant no. 18525 Bron gn iart , 1893 (In sect a: Od onat optera ). Organisms. (EAl). Diversitv & Evolution. Nel, A., Martinez-Delclos, X.. Pai cheler, J .-C & He nr ot ay. M. 1993. Les "Anisozygoptera" fossiles. Phylogenie et REFERENCES classification (Odon at a) , Martinia, 3. suppl., 1-311. Nel, A., Gand,G. & Garric, J. 1999. A new fam ily of Bechl y, G . 1995. Morphologische Untersuchungen am Flu gelgeader der rezenten Libellen und der en Stam mgrup Od ona to ptera from the continental Upper Permian : the penvertreter (In secta ; Pterygot a: Odonata) unter beson Lapeyriidae (Lode ve Basin, France). Geobios, 32. 63-72. derer Beriicksichtigun g der Phylogenet ischen Syste ma tik Pritykina, L.N. 1980. Odo nata. [In Ru ssian .] Historical de und des Grundplanes der "Odo nata. Petalura. special scription of the Class Insecta. Trudy Paleon tologicheskogo volume , I. 1- 341. lnstituta Akademii Nauk S.S.S.R.. 175. 128- 134. Bechly, G. 1996. MorphoJogische Untersuchungen am Prityki na, L.N . 1981. New Triassic Od ona ta of mid dle Asia. Flugelgeader del' rezent en Libellen und deren Starnmg rup [In Ru ssian.] New insectsfrom the territory ofthe U.S.S. R. pen vertreter (In secta. Ptcrygot a. Od on at a) un ter beson Trudy Paleon tologicheskogo Institut a A kademie Nau k de rer Ber ucksich tigun g der Ph ylogenetischen Systema tik S.S.S.R.. 183. 5-42. und des G run dp lanes der "Odonata. Petalura. special Proctor. CJ. 1994. Ca rbonifero us fossil plan t assembl ages

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Manu script received 8 September 1000; revised typescript accepted I February 2001