Hetaerina americana, Fabricius, 1798

Vega-Sánchez, Yesenia Margarita, Mendoza-Cuenca, Luis Felipe & Rodríguez, Antonio González-, 2020, Hetaerina calverti (Odonata: Zygoptera: Calopterygidae) sp. nov., a new cryptic species of the American Rubyspot complex, Zootaxa 4766 (3), pp. 485-497 : 489

3.1. Hetaerina americana taxonomic history

The original description of H. americana (and until 1853) only included few aspects of the male coloration (Fabricius 1789). Selys-Longchamps (1853, 1854) made a more precise description of the species including a small description of the females. The first illustration of the cerci of H. americana was included in Selys-Longchamps (1854; Plate 12, Fig. 3 , pp. 331). The author described the appendages as follows:

“ Anal appendages yellow, black at their extremities; the superiors cylindrical, arched, little toothed on the outside; the superior ridge ends in a semicircle before the tip, which is a little thicker, cylindrical, obtuse, a little depressed on the inner lower edge that offers, from the middle to a little before the tip, a very strong dilatation flattened, which is preceded by an excavation below. This dentate dilation in the middle, in profile view, is a fairly large obtuse medial tooth, ending in a very small and rounded tooth.

Inferior appendages are shorter than half of the superior ones, straight, cylindrical, obtuse, separated; its internal angle is weak, with a hair brush ”.

After these descriptions, Hagen in Selys-Longchamps (1859) delved into the variation existing within H. americana and suggested two new species: H. californica and H. basalis . The first species differs in the shape of the cerci, which is quadrangular, and also in that the pterostigma is absent. This species is restricted to Northern California. The second species, H. basalis , is characterized by having a much larger red wing spot than Hagen’s definition of H. americana (i.e. reaching the node) and a triangular median lobe in the cerci. Hagen suggested that this is a ‘race’ of H. americana .

Walsh (1863) suggested three new species from the review of several specimens of H. americana : H. texana , H. scelerata and H. pseudoamericana . In general, these species differ, according to Walsh, in small variations of the cerci as well as in the extension and coloration of the red spot and in the presence and coloration of the pterostigma. It should be noted that all the individuals reviewed by Walsh were from USA populations.

Finally, Calvert (1901) included the first specimens from Mexico and Guatemala, and in his Plate II, figures 6, 11 and 15, drew the appendages of what we suggest is the here described new species. Calvert commented that, in a population from Tamaulipas he examined individuals that showed cerci of this shape, as well as others such as those shown in figure 16 that correspond to H. americana sensu stricto (i.e. they were in sympatry). The difference between individuals was only recognized by this character, since the coloration and extension of the red spot in the two types were identical.

Calvert suggested that the variation in the shape of the cerci was not correlated with the geographical location or the season in which the individuals were collected. Finally, Calvert suggested that all the aforementioned species belong to a single H. americana species, which is very variable.

From this review, we found no evidence that any of the synonyms that were described for H. americana match the new species suggested by Vega-Sánchez et al. (2019). The only report that included illustrations of the cerci of this new species is the work of Calvert (1901), nevertheless it is in this paper that the author synonymized all species in H. americana .

Figures

FIGURE 3. Variation between H. calverti and H. americana males. Male cerci (dorsal and mediodorsal view) of H. calverti (A) and H. americana (B). The illustrations are not at scale.