FRENGUELLIIDAE, Petrulevičius & Nel, 2003

Petrulevičius, J. F. & Nel, A., 2003, Frenguelliidae, a new family of dragonflies from the earliest Eocene of Argentina (Insecta: Odonata): phylogenetic relationships within Odonata, Journal of Natural History 37 (24), pp. 2909-2917 : 2910

Family FRENGUELLIIDAE fam. nov.

Type genus. Frenguellia gen. nov.

Phylogenetic definition. Frenguelliidae fam. nov. includes all damselflies that are more closely related to Frenguellia patagonica gen. et sp. nov. than to any of the type species of the other type genera of the Epiproctophora family-group taxa sensu Bechly (1996) (stem-based definition).

Diagnosis. All known characters are from the (fore?) wing (see below). (1) CuP curved, looking like an anterior branch of AA; (2) terminal kink of the CP very weak, not aligned with nodal Cr but in a very distal position, so that there is a basally open triangle between costal margin and ScP, distal to nodal Cr; (3) nodal furrow reduced; (4) ScP reaching costal very obliquely at nodus; (5) nodal Cr vertical; (6) subnodus vertical; (7) midfork symmetrical and recessed basally to a position between 12 and 26% of wing length (base of RP3/4 closer to arculus than to nodus); (8) base of IR2 between nodus and arculus, closer to nodus than to arculus; (9) pterostigmal brace vein obsolete; (10) pterostigma elongate and broad; (11) discoidal cell basally opened and very narrow; (12) MAb directly aligned with anterior part of arculus (RP+MA and MA); (13) lestine oblique vein present; (14) all secondary antenodal cross-veins between ScP and RA suppressed; (15) antesubnodal space without cross-veins; (16) cubito-anal area broad, with three rows of cells between CuA and posterior wing margin; (17) nodus in the basal third of the wing, postnodal area very elongate; (18) postnodal and postsubnodal cross-veins very numerous but not aligned; (19) petiole short and broad.

Character (1) is a potential synapomorphy with the Epiproctophora. Characters (5) and (6) are also present in the Sieblosiidae (potential synapomorphies). The terminal kink of CP in a very distal position relative to vein Cr and the presence of a long triangular zone between ScP and costal margin (character (2)) are correlated autapomorphies of Frenguellia . No other Zygoptera or Epiproctophora have such a particular nodal structure. The relative positions of Cr and kink of CP seem to vary greatly within the different groups of Protozygoptera . In the Protomyrmeleontidae , the kink of CP is rudimentary but aligned or nearly so with Cr, which is also not specialized into a strong vein between ScP and RA, but a small cross-vein (Nel, personal communication). In the Permagrionidae Tillyard, 1928 (Permian Permagrion falklandicus Tillyard 1928 ), the kink of CP is not clearly visible but the fusion of ScP with the costal margin is in a distal position relative to Cr (Nel, personal communication). In several other undescribed Permolestidae from the Russian Permian, the kink of CP is aligned with Cr. In the Permo- Triassic Triadophlebioptera, the kink of CP is more or less aligned with Cr (Nel et al., in press; Nel, personal communication). No known Protozygoptera or Triadophlebioptera has a nodus similar to that of Frenguelliidae .

Phylogenetic systematics. After the phylogenetic system proposed by Bechly (1996, 1997), the family Frenguelliidae fam. nov. has no potential synapomorphy of the Zygoptera among its known characters. Frenguellia shares with the Epiproctophora one potential synapomorphy, i.e. the presence of a curved CuP. In this way, it could be in the crown group of this clade, as it does not have the other main synapomorphies of the Epiproctophora (see below). Its exact position remains doubtful as its potential affinities with the Epiproctophora are supported by only one character.