Baissoptera? cretaceoelectra Perez-de la Fuente, Penalver , Delclos & Engel

Fuente, Ricardo Perez-de la, Penalver, Enrique, Delclos, Xavier & Engel, Michael S., 2012, Snakefly diversity in Early Cretaceous amber from Spain (Neuropterida, Raphidioptera), ZooKeys 204, pp. 1-40 : 6-7

Baissoptera? cretaceoelectra Perez-de la Fuente, Penalver, Delclos & Engel sp. n. Figs 2, 3

Holotype.

MCNA 12068.4, from Peñacerrada I amber; fore- and hind wing distal fragments. Three associated hymenopterans are preserved as syninclusions.

Diagnosis.

Fore- and hind wing with a relatively long pterostigma with a strongly oblique and slightly sinusoid pterostigmal crossvein placed beyond pterostigmal midlength; fore- and hind wing with one closed radial cell distal to pterostigma; forewing Rs with six branches; forewing with at least eight closed subradial cells.

Description.

Sex unknown. Veins with some strong, very short setae preserved, membrane hyaline. Forewing.Length of preserved fragment 6.4,maximum width 2.8;wing apex relatively rounded; pterostigma relatively long (2.4 long, length ca. eight times basal pterostigmal width), slightly widening distally, not conspicuously infumate as preserved; pterostigma with a strongly oblique and slightly sinusoid pterostigmal crossvein placed beyond pterostigmal midlength, basally closed by a crossvein; pterostigma longer than any radial cell; R with two branches beyond pterostigma;at least three radial cells present, one closed radial cell partly distal to pterostigma; Rs with six branches and at least eight closed subradial cells;MA at least with two branches; gradate seriesveryregular, almost following a staircase-like pattern. Hind wing.Length of preserved fragment 5.9,maximum width as preserved 2.7;wing apex more pointed than in forewing;costal field distinctly narrower than in forewing; one c-sc crossvein preserved;pterostigma relatively long (2.5 long, length ca. 10 times basal pterostigmal width), slightly widening distally, not conspicuously infumate as preserved, starting 0.5 (twice pterostigmal basal width) beyond termination of Sc; pterostigma with a strongly oblique and slightly sinusoid pterostigmal crossvein placed beyond pterostigmal midlength, basally closed by a crossvein;pterostigma longer than any radial cell;R with two branches beyond pterostigma;at least five radial cells present, one small closed radial cell distal to pterostigma;Rs with five branches and at least seven closed subradial cells; MA at least with two branches; gradate seriesveryregular, almost following a staircase-like pattern.

Etymology.

The specific epithet is a combination of the Greek words cretaceus (taken from the period name, although specifically meaning “chalky”) and elektron, meaning “amber”.

Comments.

Within the current taxonomic framework, the numerous crossveins of MCNA 12068.4 are indicative of placement in the Baissopteridae . Unfortunately, neither base of the wing is preserved, thus important characters such as the maximum width of the costal field, the pattern of distribution of c-sc crossveins (= costal crossveins), the separation between M and CuA in the forewing, and the shape of the basal piece of MA, are unknown. Also, the infumation of the pterostigma is not evident in the holotype, but it is uncertain if this could have been caused by taphonomical processes and is, therefore, not used as a diagnostic character although if the absence of infumation is true of the species in life, then it would represent a remarkable difference from all other described baissopterids. Fortunately, the pterostigma can be delimited thanks to the relative parallelness of C and R (R tends to conspicuously change its slope beyond the pterostigma in the other baissopterids) and also the greater thickness of both veins.

The specimen is tentatively classified within the genus Baissoptera as it has the pterostigmal crossvein most similar to the diversity found within this genus. Today just two of the 12 species currently classified within the genus Baissoptera , i.e., Baissoptera brasiliensis Oswald, 1990 and Baissoptera lisae Jepson, Ansorge & Jarzembowski, 2011, lack a pterostigmal crossvein in both fore- and hind wings ( Oswald 1990: p. 156, figs 3, 4; Jepson et al. 2011: p. 393, text-figs 6A, B). Some genera can even show an additional, straight pterostigmal crossvein in a more basal position at least in the hind wing, i.e., Baissoptera kolosnitsynae Martynova, 1961 and Baissoptera pulchra (Martins-Neto and Nel, 1992) ( Martynova 1961: p. 81, fig. 7; Martins-Neto and Nel 1992: p. 428, figs 2, 3). Regarding the other taxa currently classified within the Baissopteridae , the genera Lugala and Cretoraphidia lack a pterostigmal crossvein, at least in the hind wing ( Ponomarenko 1988: p. 75, fig. 4; 1993: p. 70, figs 7, 9, 10); whereas the genera Cretoraphidiopsis and Austroraphidia , althoughshowing a pterostigmal crossvein situated beyond pterostigmal midlength, have it not as strongly oblique as in Baissoptera? cretaceoelectra sp. n., both showing irregular gradate series in both wings and a much lesser number of Rs branches in the forewing (three in Austroraphidia , four in Cretoraphidiopsis ). Cretinocellia cellulosa Ponomarenko, 1988 has been recently transferred from the Baissopteridae to the Mesoraphidiidae by Bechly and Wolf-Schwenninger (2011) based on its lack of pterostigmal crossvein(s) and a Sc ending about midwing length. Although these two characters are also present in Cretoraphidia certa Ponomarenko, 1993 and Cretoraphidia magna Ponomarenko, 1993 ( Ponomarenko 1993: p. 70, figs 7, 10), in both, the crossvenation is relatively higher than in Cretoraphidia cellulosa and should therefore remain in Baissopteridae for the moment. Consequently, Bechly and Wolf-Schwenninger (2011) also noted that the genus Cretinocellia might occupy a basalmost position within Mesoraphidiidae according to its relatively high crossvenation compared to the other mesoraphidiids. On the other hand, we still consider Arariperaphidia rochai Martins-Neto and Vulcano, 1989 as incertae sedis rather than as a baissopterid (contra Bechly and Wolf-Schwenninger 2011), owing to its lack of preserved characters indicating a more conclusive assignment. The shape and location of the pterostigmal crossvein is quite diagnostic for Baissoptera? cretaceoelectra . Only Baissoptera minima Ponomarenko, 1993 shows such a strongly oblique pterostigmal crossvein within the family, even slightly sinusoid as in the new species, in a relatively elongate pterostigma (length ca. eight times basal pterostigmal width) ( Ponomarenko 1993: p. 64, fig. 2). However, the pterostigmal crossvein is located before pterostigmal midlength and Rs is poorly branched in Baissoptera minima . Baissoptera? cretaceoelectra has Rs in the forewing with more branches currently described within the genus. The remaining Baissoptera species always show a lesser number of branches of Rs in the forewing, i.e., five ( Baissoptera brasiliensis , Baissoptera grandis Ren in Ren et al. 1995, Baissoptera liaoningensis Ren, 1994, Baissoptera lisae , and Baissoptera sibirica Ponomarenko, 1993), four ( Baissoptera elongata Ponomarenko, 1993, Baissoptera euneura Ren, 1997, Baissoptera kolosnitsynae , and Baissoptera martinsoni Martynova, 1961), or three Rs branches ( Baissoptera pulchra and Baissoptera minima ) ( Martynova 1961; Oswald 1990; Martins-Neto and Nel 1992; Ponomarenko 1993; Ren 1994, 1997; Ren et al. 1995; Jepson et al. 2011). Although Baissoptera cellulosa Ponomarenko, 1993 (based on a forewing lacking the apex) could also possess six branches of Rs and does have a sinuate pterostigmal crossvein presumably beyond pterostigmal midlength ( Ponomarenko 1993: p. 65, fig. 3), it differs from Baissoptera? cretaceoelectra in that the pterostigmal crossvein is just slightly oblique and the more abundant crossvenation. The only other described baissopterid with such an elevated number of branches of Rs is Cretoraphidia certa , but it lacks a pterostigmal crossvein as has been discussed, and in addition Sc ends in a more basal position. Furthermore, the pterostigmal length of the new species is elongate when compared to the other lengths shown by the other species within the genus Baissoptera . Only Baissoptera grandis has a longer pterostigma, its length about 11 times its basal pterostigmal width ( Ren et al. 1995: p. 175, fig. 2). The shortest pterostigmata within the genus are found in Baissoptera martinsoni and Baissoptera elongata , their lengths ca. four and six times their basal pterostigmal widths, respectively ( Martynova 1961: p. 80, fig. 6; Ponomarenko 1993: p. 67, fig. 5). Naturally, our placement of this species in Baissoptera is a conservative position based on the lack of complete material. More completely-preserved specimens, in which the wing base characters noted above could be assessed, may force a reconsideration of the generic assignment.