Apertochrysa aspersa ( Wesmael, 1841 )

Duelli, Peter & Henry, Charles S., 2022, The Apertochrysa prasina group (Neuroptera: Chrysopidae), with a key to the European species, Zootaxa 5134 (1), pp. 61-91 : 86

Ap2: Apertochrysa aspersa ( Wesmael, 1841) ??

Chrysopa aspersa ( Wesmael, 1841) : original description

Synonymized with C. prasina Burmeister, 1839 by Brauer (1856).

The type specimen of Chrysopa aspersa is deposited in the Institut Royale des Sciences Naturelles de Belgiques (ISNB). It has a white label “ c. aspersa (mihi)”, and two pink labels “ TYPE ” and a note: “ Chrysopa aspersa , Type présumé, retrouvé in coll. Sélys - 1965, G. Demoulin”. The pink label “ TYPE ” has the same color as the note by Demoulin, so most probably it was not a type label by Wesmael himself. It is a female with a wing length of only 12 mm, which makes clear that it cannot be A. prasina s.s. (with a female wing length of 15.5–17.5 mm) under which it was synonymized by Brauer (1856). However, the type specimen apparently chosen as type by Desmoulin does not really agree with Wesmael’s original description in 1841: wing length 6.5-8.5 li. There had been different measures for designating “linea (li)” at that time, but none would go as low as 12 mm for 6.5 “linea”. If we take the size of the French or Rhinelandic measure (1 li = 2.26 mm or 2.18 mm), the range of wing lengths in the original description would be 14.7–19.2 mm or 14.2–18.3 mm, which are both far too large for the type specimen with a wing length of only 12 mm. The smallest “linea” at that time was the Spanish linea (1.9 mm), which would give a range of 12.3–16.2 mm for the original description, almost matching the range of the prasinoid specimens found in the tray. Belgium once was “Spanish Holland,” so Wesmael might indeed have used the Spanish measure.

In the tray with the type specimen at the museum in Brussels, we identified three prasinoid species collected around Brussels, all labelled as C. prasina or C. aspersa : four females and three males of A. prasina s.s, had wing lengths larger than the range characteristic of the other prasinoid species, while 25 females had wing lengths of less than 15.5 mm and thus were either Ap2 or Ap3. We assume that the Mediterranean Ap1 does not occur around Brussels. Three non-furwing males (certainly Ap3) with im cells> 15% dark and multiple dark portions were identified, as well as four Ap 2 males with furwings and im cells <15% dark, in mostly one portion (certainly Ap2). The designated female type of C. aspersa , with 12 mm wing length, can only be Ap2, because none of the females of Ap3 encountered in this study had a wing length of less than 12.5 mm. None of the specimens in Brussels had a red suture, which in the case of small males with furwings (certainly Ap2) must be interpreted as a color loss due to long preservation.

Quite obviously, Wesmael had written the original description for Apertochrysa aspersa based on a series of specimens belonging to three different species. From the range of sizes given in the original description it is not clear which of the specimens from the collection of Edm. de Sélys-Longchamps that Wesmael considered to be the type specimen. Demoulin in 1965 selected a type specimen, unfortunately a female, and the smallest of them all, which was smaller than the size range given in the original description by Wesmael. A lectotype has to be chosen, if possible, from the original set of described specimens. To save the name C. aspersa , and still recognize Demoulin’s choice, it should be an Ap 2 male with furwings to clearly separate it from Ap3. Plus, the wing length must be in the range given in the original description. From the use of the name C. aspersa by specialists such as Burmeister and Navás, we can infer what the original C. aspersa of Wesmael must have looked like. In the tray with the original type of C. prasina Burmeister, 1839 in Halle, Germany, there is a much smaller prasinoid with the label C. aspersa Wesm. , which still displays the red sutures under the antennae and clearly is Ap2. We assume that Burmeister himself had identified that specimen as C. aspersa before it was synonymized with C. prasina in 1856. He must have considered the two specimens in his tray as different species—and he was right. In the insect collection of the Natural History Museum of Basel, a small “ Chrysopa aspersa ” bears the label “det. L. Navás.” Navás had described several prasinoid varieties as looking similar to var. aspersa , or var. adspersa . They all were smaller than his C. mariana type specimen with a wing length of 16 mm, which became a junior synonym of the large A. prasina . For Navás, var. aspersa also was clearly different from Burmeister’s C. prasina .