Paragonophlebia, Nel, 2009

Nel, André, 2009, A new Odonata family from the Jurassic of Central Asia (Odonata: Epiproctophora), Journal of Natural History 43 (1 - 2), pp. 57-64 : 58-59

Type genus Paragonophlebia gen. nov.

Diagnosis

(1) Hind wing anal area very long, narrow, and unicellular; male anal angle present but smooth; (2) hind wing subdiscoidal space transverse, hypertrophied and posteriorly opened; (3) numerous secondary antenodal cross-veins of first row distal of Ax 2 in forewing and hind wing; (4) forewing discoidal cell basally opened; (5) forewing MAb aligned with basal part of arculus and CuA; (6) forewing subdiscoidal space not transverse; (7) postdiscoidal area distally narrowed, with one row of cells; (8) MP straight; (9) CuAa short and distally zigzagged and vanishing in area between MP and posterior wing margin.

Discussion

Only two groups of Epiproctophora have a hypertrophied hind wing subdiscoidal space, transverse and posteriorly opened, reaching the posterior wing margin, i.e. the Isophlebiida: Isophlebioidea and the Parazygoptera: Triassolestidae Tillyard, 1918 (sensu Bechly 1997, 1999). This last author characterized the Triassolestidae by the following autapomorphies: (1) ‘hind wing AA+CuP and MP+CuA partly fused basal of arculus’. This character is unique within the Odonata , and known in Progonophlebia Tillyard, 1925 , Triassolestodes Pritykina, 1981 , ‘ Sogdopteron ’ legibile Pritykina, 1980, Italophlebia Whalley, 1986 , and Germanophlebia Nel et al., 2003 ( Nel et al. 2003); (2) ‘hind wing distal part free part of AA+CuP not longitudinal and fusing with CuAb but perpendicular (aligned with arculus) and directed towards posterior margin: subdiscoidal cell posteriorly open’; ‘characteristic kink in CuA between gaff-portion and CuAb in hind wing’. This character would need to be confirmed because such a kink is not visible in Progonophlebia and should be verified in Triassolestes and Triassolestodes .

Nevertheless, if Paragonophlebia has the character ‘2’ listed above, it does not have character ‘1’, which is the main, unique autapomorphy of the Triassolestidae sensu Bechly (1997) (see also Nel et al. 2003). Lastly, Paragonophlebia does not have the main ‘autapomorphy’ of the Parazygoptera within the Isophlebioptera, sensu Bechly, i.e. ‘RP2 arising distinctly distal of subnodus’. Note that this character is subject to numerous convergences and reversals within the whole clade Epiproctophora. Also, it is not present in the triassolestid genus Germanophlebia . The large clade Parazygoptera is rather weakly supported.

If Paragonophlebia has the ‘hypertrophied hind wing subdiscoidal space, transverse and posteriorly opened, reaching the posterior wing margin’ of the Isophlebioidea (and more precisely the Isophlebiidae Handlirsch, 1906 , but also some Campterophlebiidae Handlirsch, 1920 ), it can be easily separated from these families by the following characters.

‘Presence of numerous secondary antenodal cross-veins of first row distal of Ax 2 in fore and hind wing’. Bechly (1996) considered the absence of these cross-veins as an autapomorphy of the Isophlebioptera, but he noted that it is ‘apparently reversed in several species’. Karatawia turanica Martynov, 1925 , Progonophlebia woodwardi Tillyard, 1925 and Selenothemis liadis Handlirsch, 1920 could have such secondary antenodal cross-veins. However, this part of the wing is poorly preserved in the type specimen of P. woodwardi , the type specimen of K. turanica is also a very poorly preserved wing, and the type specimen of S. liadis would need re-examination. Furthermore, these three taxa strongly differ from Paragonophlebia gen. nov. in the shape of their subdiscoidal spaces;

‘Hind wing anal area not greatly widened, unicellular and very elongate’. The anal area of Paragonophlebia is unicellular and elongate, unlike those of the whole clade Isophlebiida;

‘Forewing discoidal cell basally opened and MAb aligned with basal part of arculus and basal free part of CuA’. This structure of Paragonophlebia is a plesiomorphy also present in the Campterophlebiidae , but not in the Isophlebiidae ;

‘Postdiscoidal area distally narrowed, with one row of cells between MAa and MP’. This structure is also present in Archithemis Handlirsch, 1908 (Isophlebiida: Architemistidae). Nevertheless, Paragonophlebia does not have the potential synapomorphies of the Architemistidae, as proposed by Bechly (1996), namely, ‘a single row of very long and oblique cross-veins in postdiscoidal area of hind wing’, and ‘IR2 apparently originating on RP3/4’.

Lastly, Paragonophlebia does not have the potential synapomorphies of the Isophlebiida: Campterophlebiidae , as proposed by Bechly (1996), ‘male hind wing with a very acute or even hook-like projecting anal angle’; ‘hind wing longitudinal veins (especially RP3/4) distinctly undulate’; ‘space between MA and MP distally constricted by an opposite curvature of these two veins’.