Odonalologica 18(2): 147-178 June I. 1989 Spines on the wing veins in Odonata 2. Anisozygoptera and Anisoptera * M. D’Andrea and S. Carfì Dipartimento di Biologia animale e Genetica, Università degli Studi di Firenze, Via Romana 17, I-50125 Firenze, Italy Received August 23, 1988 / Accepted September 18, 1988 The spines on the convex and concave wing nervures in Anisozygoplera and Anisoptera differ morphologically and, according to their location, also in distri- bution and size. The latter is correlated to the surface and wing chords. The relative the and and both of numbers ofspines on fore hind wings on surfaces the same wing constant in the two suborders. these are Comparing results with those on Zygoptera D’ANDREA & S. (M. CARFl, 1988, Odonatologica 17; 313-335) reveals a sub- stantial uniformity of this trait in the entire order of Odonata. INTRODUCTION The of the veins of presence spines on wing Odonata was noted by SEGUY in (1959) Cordulia aenea and by HERTEL (1966) in Aeshna cyanea, where he the says nervures are "covered above and below with small spurs (about0.015 in diameterand 0.15 but adds that ”we mm mm long)” cannot yet say what the function of these spurs is”. Finally, NEWMAN, SAVAGE & SCHOUELLA (1977) commented on the morphology and size of the spines in Aeshna in- but did their terrupta, not go beyond suggesting that function was to make the little is known about the wing aerodynamic. Thus, to date, more spines except that they exist. This follows paper our recent report on the wing spines in Zygoptera & (D’ANDREA CARFl, 1988), completing a preliminary study of these in Odonata. Our research data structures provides on the phylogeny, mor- phology and distribution of the spines, and tends of affirm their aerodynamic importance. * Study financed by the Ministero della Pubblica Istruzione (60%). 148 M. D'Andrea & S. Carfi The morphology and size of the spines were studied under a SEM and their distribution under a stereomicroscope. The nomenclature of the wing venation follows that of T1LLYARD & FRASER (1938-1940). GENERAL APPEARANCE IN ANISOZYGOPTERA AND ANISOPTERA The distinction morphological between the wing nervure spines in Zygoptera is these either short carinate quite simple: are (8-18 /am, small, stubby and teeths, termed S) or (20-70 long longitudinal grooved processes termed L) (D’ANDREA & CARFl, The L occur on the surface of 1988) 1. spines upper the (-) longitudinals and lower surface of the (+) longitudinals, while the S spines have the opposite distribution as shown in Figure 1. Fig. I. Morphology and distribution of the spines in Zygoptera. The of exist in The S same type spines Anisoptera. spines are usually less numerous and occasionally larger than those found in Zygoptera and occur on the upper surface of the (+) longitudinals and lower surface of the (-) longitu- dinals. The L spines occur on the opposite surfaces as well as on the lower side of the cross veins. The spines on the upper surface ofthe cross veins couldbe termed L spines ifnot for the following peculiarities: (a) they are smaller(1 /2 to 1 /3) than the — underlaying ones, particularly near the wing borders, (b) decrease in size in proximity to the anal field, particularly on the hind wing, until resembling small carinate which spines also occur on the hind borders, conferring (as in Zygoptera) denticulate — a profile to the wing nervure, (c) vary in size in relationship to the wing surface and chord like the carinate spines (Fig. 4), and they (d) resemble elongated spines in some primitive Zygoptera. Thus, these have been labelled S elongate (Se) spines. According to the distinctionbetween Se and Sc spines, the S spines occurring in Zygoptera are Sc spines. They occur in single rows on the M nervures, except on the upper surface ofthe R + where there are two parallel rows of S carinate (Sc) spines. The L shrink in size the spines towards margin, following the same gradient in do the Se the surface of the veins. seen Zygoptera, as spines on upper cross At the Sc w ing base the spines on both surfaces ofthe longitudinals appear as distinct Spines on Anisozygoptera and Anisoptera wing veins 149 ’’teeth”, shrinking towards the margins. In proximity to the hind margin they can thinner become and occasionally longer. The L spines on the upper (-) and lower surfaces of the (+) longitudinals are always longer than those on the adjacent cross veins. This fact, together with the variation in size occurring along it difficult the wing, makes to establish a norm for the size ofthe S and L spines which is indicative of entire the wing. Thus the dimensions given in Table IX are calculated in the central of fore means zone the wing at the level of the nodus. The difference in size between the S and L tends in spines to disappear step with the reduction in morphological differences between the (+) and (-) longitu- dinals, typically at the margins (where the lower L spines are always slightly thanthe S and in the transition longer upper spines) zone at the convex base ofthe intercalaries on the upper surface (and vice versa on the lower surface) where the L spines shrink to the size of S spines (as in Zygoptera). Some longitudinal nervures occasionally show a slight incavation in which case the Sc spines ap- longer and aciform (base of the R on the lower surface, and now pear 3 and then on other nervures). There is interindividual an ample variability in the quantity of spines on the in wing surface, as Zygoptera, but the ratio between the fore and hind wings and between the surfaces ofthe is two same wing roughly the same in bothconspecific and This in ratio intraspecific specimens. similarity allows a preliminary eva- luation ofthe without statistical of phenomenon a analysis the many specimens of each species. the veins Tiny spines on cross adjacent to the insertion point ofthe (+) and (-) similar those observed in longitudinals, to Zygoptera, are present up to but not beyond the distal half of the wing. The specimen of Epiophlebia superstes, which does not differ substantially from the above, has Se spines on the cross veins ofthe upper wing surface. The Sc on the spines longitudinal nervures are small and dense; denticulated as in Zygoptera, and grow in size in proximity to the margin. APPEARANCE IN ANISOZYGOPTERA AND ANISOPTERA FAMILIES Anisozygoptera EPIOPHLEBIIDAE Epiophlebia superstes (Selys, 1889) I <3, Japan surface. — A few Sc the Upper tiny spines are present on R+M, R and R, Pt Distinct and IR (from on). spines occur on R and a transition zone the 2 3 along 150 M. D’Andrea & S. Carfi base of IR A has between the base and discoidal cell and 2 . , large "teeth”(Sc) (DC) is thereafter. about AThefirstthird smooth Tiny spines reappear halfway along of Ma is also smooth. Tiny L spines on Sc vein, Rs and R .R *s appear 2+3 2 smooth almost up to the Pt. Several L appear on R (at about the long spines 2 level of the Pt), R R and CuP. The cross veins have Se which are 3 , 4+5 spines tiny hind at the first veins of field at the margins and apex. The 5-6 cross the anal are smooth while those between R and Rs have several tiny spines. Ans and Pns have evident spines between C and Sc and between R, and f^. in Fig. 2. Ratios between fore/hind (f/h) and upper/lower (u/1) Epiophlebia superstes and some h: — 1: lower surface; — f: fore — hind Aeshnoidea. — [u: upper wing surface; wing wing; wing]. and veins 151 Spines on Anisozygoptera Anisoptera wing Lower surface. — R and R have Sc entire tiny spines along the nervure, R 2 3 4+5 is smooth to the level ofthe nodus and then like CuP up appears the above. has is denticulate about a dozen spines after DC and feebly on the margin. Sc vein is smooth. All the (+) longitudinals have L spines except R+M, R and the first fourth of R,. The distribution and morphology of the L spines on the cross veins is like that of the overlying Se spines. in in The spines E. superstes are greatest number and equally dense on the upper hindand lower fore wing surface (Tab. 1). The fore/hind ratio is higher for the lower wing surface in all sectors except GG (Ans). The high valueof AA (that is, more spines in the posterior anal field) and low value of GG on the lower surface (that is, many more spines on the hind Ans) does not occur in Anisoptera (Tab. 111. Fig. 2). The upper/lower ratio (between the upper surface Se spines lower surface maximum and L spines) reaches a in DD (between R, and RJ in the hind and minimumin EE and This — wing, a (Pns R, prior to the Pt). trend ofa minimumAA, maximum DD, minimum EE and slight increase in values in FF — is common for both wings in Anisoptera (cf. Tabs V, VI, Figs 2, 3). Anisoptera PETALURIDAE Uropetala carovei (White, 1843) I <J, Australia — Sc in size after Upper surface. Large spines are present on R, (shrinking the the initial tract of IR and MA, the basal tract of and CuP, the Pt), 3 A, (for A, tract leading up to the DC will hereafterbe referred to as "basal” and that follo- wing the DC as ”distal”). Smaller and occasionally thinnerspines occur on R, the distal tracts of IR MA and A,. Several L spines are on the 3, present (-) longitudinals, except on Sc and Rs which are smooth.