Araripeleon alphonsei

Millet, Johann & Nel, Andre, 2010, A new myrmeleontoid genus from the Crato Formation of Northeast Brazil (Lower Cretaceous) (Insecta: Neuroptera: Palaeoleontidae), Zootaxa 2353, pp. 49-54 : 49-53

Araripeleon alphonsei gen. et sp n.

( Figs. 1–3 )

Diagnosis. Costal area narrow; dense wing venation: numerous cross-veins throughout wings and numerous branches of Rs (21 to 23); first posterior branch of Rs close to stem of Rs; R1 and Rs relatively straight distally; absence of anterior Banksian fold in radial area; broad area of MP2 with posterior branch of MP2 relatively short and ending in CuA; anal area narrow.

Description. A nearly complete specimen with the four wings and at least the fore legs still connected to the body. The hind and fore wings of both sides are partly overlapping. A small beetle is fossilised in ventral view above the abdomen.

Head transverse, 2.3 mm long, 3.2 mm wide; dorsal surface missing so it is not possible to know if it had ocelli or not; eyes globular, nearly as long as head, 2 mm long, 1.1 mm wide, 1.9 mm apart in anterior part and 3.5 mm apart posteriorly; antenna 10.3 mm long, with 100 flagellomeres, nearly all identical, about as long as wide, apically thin, not clubbed, scape smaller than pedicel, pedicel very large and broad; mouthparts not visible. Thorax 13.1 mm long, 7.3 mm wide; pronotum trapezoidal elongate, 3.7 mm long, narrower in anterior part (2.5 mm) than in posterior part (4.5 mm); mesothorax 3.7 mm long, 7.3 mm wide; metathorax 5.7 mm long, 4.6 mm wide. Abdomen rather poorly preserved, with 7–8 visible segments, 25.4 mm long; max. width 3.4 mm; left ectoproct partly preserved, curved elongate, 5.1 mm long; a long oblong median structure is present at abdomen apex, 2.8 mm long. Fore femora broad and elongate, anteriorly directed, 5.4 mm long, 1.7 mm wide, longer than pronotum; fore tibiae partly visible, preserved under the femora, posteriorly directed, 0.35 mm wide; no spines or spurs visible on fore leg. Fore and hind wings nearly identical in size, shape and venation. It was possible to draw correctly the hind wing venation but that of forewing is more fragmentary. Hind wing 42.5 mm long, 10.0 mm wide; Sc distally fused with R1, 35.5 mm from wing base; area between Sc and anterior wing margin as broad as area between Sc and R1; 40 to 45 simple and short cross-veins between C and Sc between wing base and point of fusion between R1 and Sc; area between anterior wing margin and Sc+R1 greatly widened, with about 13 long secondary veins, some of them being dichotomously forked and divided into small veinlets near wing margin (end-twigging); area between Sc and R1 with several cross-veins (at least five are visible); base of Rs 2.5 mm from wing base; MA separating from Rs 1.0 mm distally, 3.5 mm from wing base; the area covered by the branches of Rs is the largest of the wing, covering wing surface from apex to mid part of posterior wing margin; Rs divided into numerous (at least 21 to 23) posterior branches, all slightly zigzagged but not curved, with nine to 12 rows of cross-veins between them; all branches of Rs apically forked close to posterior wing margin; MA curved, slightly zigzagged and with two distal subdivisions, covering a small area; 19 cross-veins between MA and MP1; MP divided into MP1 and MP2 at its base; MP1 simple, MP1 and MP2a parallel, curved, with 21 cross-veins between them; a small fork at their respective apices; fork of MP2 into MP2a and MP2b 12.9 mm from wing base; MP2b short, 2.1 mm long, reaching CuA; basal part of area between MP2 and CuA crossed by a row of eight cells; MP2a with three posterior branches reaching CuA and nine posterior branches reaching posterior wing margin; CuA and CuP separating 3.4 mm from wing base; CuA and CuP+1A parallel with several narrow cells between them; distal end of CuA vanishing in area of MP2a; apex of CuP+1A 12.6 mm from wing base; area between CuP+1A and posterior wing margin with 2–3 rows of cells; area between 2A, 3A, and posterior wing margin with two rows of three cells. In forewing, ‘oblique vein’ (posterior branch of M) between M and CuA well pronounced.

Etymology. Named after Araripe, and the suffix - leon of Palaeoleon .The species epithet is named after Alphonse Millet, son of the first author.

Discussion. The wing venation of Araripeleon gen. nov. resembles those of the recent Nymphidae , Ascalaphidae , and Myrmeleontidae . In the most recent phylogenetic analyses of the Neuroptera proposed by Aspöck et al. (2001, 2003), Aspöck (2002), and Aspöck & Aspöck (2008), these three families are grouped together in a subclade ( Nymphidae + ( Myrmeleontidae + Ascalaphidae )) of the Myrmeleontoidea.

Araripeleon differs from all the Myrmeleontoidea already described from the Crato Formation in its dense wing venation with very numerous cross-veins and branches of Rs (21 to 23), broad area of MP2 with posterior branch of MP2 ending in CuA ( Martins-Neto, 2000; Martins-Neto et al., 2007).

Following the key to recent neuropteran families of New (1990), Araripeleon would fall near Nymphidae , the two other families being excluded for the long filiform antennae without club or apex broadened. Nevertheless Araripeleon falls in the Mesozoic family Palaeoleontidae Martins-Neto, 1992 because it has all the diagnostic characters of this family as redefined recently by Menon & Makarkin (2008), viz. ‘large myrmeleontoids (forewing 36–70 mm long) with relatively long antennae, unusually dense cross-venation in the majority of genera, easily distinguished from other myrmeleontoid families by the following combination of character states: (1) antennae long, filiform, neither dilated nor clavate distally [dilated distally in Myrmeleontidae , Araripeneuridae; clavate in Ascalaphidae ]; (2) origin of Rs situated near wing base in both wings [removed from base in Myrmeleontidae , Araripeneuridae, Ascalaphidae , Nemopteridae , Babinskaiidae ]; (3) presectorial cross-veins absent in both wings [present in Myrmeleontidae , Ascalaphidae , Nemopteridae , Babinskaiidae ]; (4) ‘oblique vein’ present in forewing [absent in Nymphidae ]’. Nevertheless all these characters can also be found in Nymphidae , except maybe the ‘oblique vein’ absent or less pronounced in Nymphidae than in Palaeoleontidae . It would be necessary to make a phylogenetic analysis to confirm the value of the separation between the two families. We provisionally include Araripeleon in the Palaeoleontidae for its pronounced ‘oblique vein’.

Menon & Makarkin (2008) gave a list of the genera currently included in this family. Araripeleon differs from Neurastenyx Martins-Neto & Vulcano, 1997, Baisopardus Ponomarenko, 1992 , Parapalaeoleon Menon & Makarkin, 2008 , and from Paraneurastenyx Martin-Neto, 1998 in the numerous and strictly parallel branches of Rs, absence of anterior Banksian fold in radial area, and the median vein more posteriorly curved ( Ponomarenko, 1992a; Martins-Neto, 2000; Heads et al., 2005; Menon & Makarkin, 2008). Araripeleon differs from Samsonileon Ponomarenko in Dobruskina et al., 1997 in the absence of a Banksian fold, a narrower anal area, and absence of a very strong fork of median vein ( Dobruskina et al., 1997). Araripeleon shares with Metahemerobius Makarkin, 1990 the absence of the Banksian fold and branches of Rs more or less parallel, but differs in the number of cross-veins between R1 and Rs, R1 and Rs less curved in their distal parts for Araripeleon , and presence of anterior branches of median vein in its distal part in Metahemerobius ( Makarkin, 1990). Several very important structures of the Palaeoleontidae are not preserved in the holotype of Palaeoleon Rice, 1969 , type genus of the family, i.e. the base of Rs and the oblique vein. Nevertheless, the Banksian fold is clearly visible in the photograph of this fossil ( Rice, 1969: plate 1). Note that the base of Rs and the oblique vein are not preserved in the holotype of Metahemerobius, and that the oblique vein is also not clearly figured for Baisopardus in Heads et al. (2005) and Ponomarenko (1992a).

Lastly Cretoleon Ponomarenko, 1992 was considered possibly to belong to Palaeoleontidae by Ponomarenko (in Dobruskina et al. 1997), listed among the genera of this family by Heads et al. (2005), but tentatively removed from this family by Menon & Makarkin (2008) for the following forewing characters: ‘costal space is broad; Rs originates relatively distant from the wing base; the anterior Banksian fold is absent; the subcostal veinlets in the pterostigmal region are very closely spaced and simple; cross-veins are rare in the distal portion of the wing’. All these characters, except the position of the origin of Rs, are not listed in the diagnosis of this family of these last authors. The origin of Rs in Cretoleon remains very basal if slightly less basal than in other Palaeoleontidae (unknown in the type genus of the family). Also the Banksian fold is absent in the palaeoleontid genus Metahemerobius. Thus the removal of Cretoleon from this family looks rather weakly supported. Araripeleon differs from Cretoleon in the first posterior branch of Rs close to base of Rs, more numerous cross-veins between R1 and Rs, and costal area narrower ( Ponomarenko, 1992b).

In conclusion Araripeleon has enough differences from all these genera to attribute it to a new genus. We tentatively attribute it to the Palaeoleontidae because it shares all the diagnostic characters of the family, even if it has not the Banksian fold present in nearly all the palaeoleontid genera. The confirmation of its position will need a phylogenetic analysis that would include all the Mesozoic myrmeleontoid taxa, and precise the limit of the Palaeoleontidae and the relationships between the families currently included in this superfamily.

Figures

FIGURE 1. Araripeleon alphonsei gen. nov., sp. nov., holotype SMNK 2358 PAL, photograph of general habitus (scale bar represents 10 mm).

FIGURE 2. Araripeleon alphonsei gen. nov., sp. nov., holotype SMNK 2358 PAL, drawing of general habitus, with the forewing details removed (scale bar represents 10 mm).

FIGURE 3. Araripeleon alphonsei gen. nov., sp. nov., holotype SMNK 2358 PAL, drawing of left forewing (scale bar represents 10 mm).