Heteragrion icterops Selys, 1862

Vilela, Diogo Silva, Lencioni, Frederico A. A., Bota-Sierra, Cornelio A., Ware, Jessica L. & Bispo, Pitágoras C., 2023, Taxonomic revision of the Neotropical genus Heteragrion Selys, 1862 (Zygoptera: Heteragrionidae): male morphology, new species and illustrated key, Zootaxa 5356 (1), pp. 1-96 : 55

Heteragrion icterops Selys, 1862

( Figs. 39a–f , 40a–f , 41a–b )

[Key locator: Key to Group B species, couplet 5 (3’)]

Heteragrion icterops: Selys 1862: 27 (description of ♁ from Santarém, Pará state, Brazil; comparison with Oxystigma petiolatum );— Selys 1886: 65–66 (additions to the original description; ♀ description; specimens probably represent H. inca );— Calvert 1909: 110–111 (compares H. inca with H. icterops );— Williamson 1919: 10, 13, 51 (key to species, couplet d2; taxonomic history, inconsistencies and comparison with H. inca );— De Marmels 1987: 227– 229 (propose H. romani as junior synonym of H. icterops ; states also similarities with H. simulatum ; figs. 8–12, 46);— von Ellenrieder & Garrison 2007: 8 (taxonomic uncertainties; brief synonymic list; figs. 2g –i);— Garrison et al., 2010: 88, 90 (list of Heteragrion species; figs. 375, 381–382);— Vilela et al. 2019a: 187–194 (description of ♀; comparison with H. angustipenne and H. bariai ; key to Group B female Heteragrion found in Brazil, couplet 2’; figs. 3, 6, 7–10, 12);— Stand-Pérez et al. 2019: 107 (mentions taxonomic uncertainty and comparisons with H. inca ).

Heteragrion romani: Sjöstedt 1918: 8–10 (description of ♁ from Manaus);— Williamson 1919: 64 (comparison with H. simulatum ).

Material examined. 1♁ BRAZIL, Amazonas state, Manaus, Campus UFAM, Terra Firme , 21.iv.2008, H. Gasca leg., INPA ; 1♁ Novo Airão , 20.viii.2008, INPA ; 1♁ Rio Preto da Eva , 25.ix.2008, (-2.6191, -59.7427), INPA ; 2♁♁ Pará state, Tailândia, Agropalma, F 9 Novo , 4.xi.2016, (-2.3568, -48.7190), D.S. Vilela leg., LESTES ; 2♁♁ Tailândia , Agropalma, H 48H50, 25.x.2016, (-2.6183, -48.8301), D.S. Vilela leg., LESTES ; 3♁♁ Tailândia , Agropalma, P 24- 14, 21.x.2016, (-2.5737, -48.8174), D.S. Vilela, A. Rivas-Torres, A. Cordero-Rivera leg., ECOEVO ; 1♁ Rondônia state, Porto Velho, Rio Caracol (Cachoeira Rio Bonito ), 30.iii.2004, N. Hamada, R.L.M. Ferreira, J.O. Silva & J. Pinto leg. , FAAL (3845).

Synonyms. Heteragrion romani Sj ̂stedt, 1918 ( De Marmels 1987).

Known distribution. Brazil (states of Amazonas, Pará and Rondônia).

Diagnosis and remarks. This species was described in 1862, based on a single male lacking the superior appendages, and with the paraptocts “ courts, finissant subitement en pointe noire ”, that is, “short, suddenly ending in a black tip” ( Selys 1862). In a further treatment, Selys (1886) made additions to the original description of H. icterops , including the ♀ description, based on a series from three different countries: Venezuela, Ecuador, and Peru. In this treatment, Selys (1886) describes the inferior appendages of the examined males, which were quite differently from the type specimen: “ les inférieurs très courts, cylindriques ”, that is, “the inferiors short, cylindrical”. The paraprocts of the species treated here as H. icterops are not cylindrical, but enlarged at their base, tapering to an acute point, nearly at 1/2 of cercus length ( Figs. 39e , 40e ). On the other hand, the paraprocts of H. inca are, in fact, short and cylindrical ( Figs. 42j–m ). This is the first evidence that the specimens studied in 1862 and 1886 may represent different species. Calvert (1909) described H. inca based on specimens from Peru, compares it with H. icterops , and among other morphological differences such as body size, pterostigma shape and head coloration, he also notices the differences on the paraprocts. Williamson (1919) added information on this species, also stating that “it seems possible there have been some misidentifications” [in the material examined by Selys] and pointing some inconsistencies concerning the identity of some specimens assigned as H. icterops in Selys’s collection. Further, in the taxonomic history of this taxon, De Marmels (1987, 1989) suggested the synonymy of H. romani with H. icterops , based on coloration characters, mentioning that the type specimen “lacks the superior appendages”. De Marmels (2004) also made considerations about the unlikely presence of H. icterops on Venezuela, suggesting confusion with the locality labels. Von Ellenrieder & Garrison (2007) examined the type material housed at RBINS, including the same H. icterops male examined by De Marmels, and the holotype of H. romani . In their rationale, von Ellenrieder and Garrison argue that there is a “small series from São João Del-Rei which are not H. icterops ”. This makes total sense, first taxonomically, and second because H. icterops is an Amazonian species, restricted to its lowlands; and the small series examined by von Ellenrieder and Garrison is from São João Del-Rei, Minas Gerais state, located at the Atlantic Forest and Cerrado biomes at nearly 1000m asl, separated by at least 2.500 km from the Amazonian region. Stand-Pérez et al. (2019) also mentioned the problem concerning these two species, and correctly assigns their examined specimens to H. inca , based on the accurate head description of Williamson (1919). Although some studies have helped to clarifying some taxonomic aspects, doubts about what really is H. icterops have remained over the years, and we have some considerations about this issue: (i) there is a male specimen depicted by Menger (in Williamson 1919) as being H. icterops (Plate X, figs. 117-118) and this specimen is really similar to what we consider to be H. inca , both in dorsal and lateral views (see Fig. 42 ); (ii) specimens assigned to H. icterops in the NHMUK are, in fact, H. inca ( Figs. 42l–m , compared in this plate with a male from Colombia in Figs. 42j–k ), and definitely not part of any type series ( Fig. 42n ; in fact, not listed as a type series by Kimmins 1970); (iii) FAAL borrowed and drew the type of H. icterops ( Fig. 40 ) from the RBINS and, although missing the cercus, it has the paraprocts, and they did match those of H. icterops and H. romani , its junior synonym ( Fig. 40e ), matching also regarding the coloration, as argued by De Marmels (1987). In fact, Williamson (1919) and De Marmels (1987) have stated that the male “lacks the superior appendages”, and not all appendages. Furthermore, Williamson (1919) comments that “Menger’s drawings of a male in the Selys collection is one of these specimens (possibly H. icterops posteriorly collected in Venezuela, Ecuador and Peru), but the drawings do not indicate which one”, and “were it certain that the specimen figured by Menger is conspecific with de Se1ys’ type of icterops , I should conclude that inca Calvert is a synonym of icterops ” ( Williamson 1919). These statements by Williamson, and the different description of male paraprocts by Selys in 1862 and 1886, clearly pose a severe doubt about the specimen drawn by Menger really representing H. icterops . From all this, we can conclude that: (i) the synonymy applied by De Marmels concerning H. icterops and H. romani (junior synonym) is correct, concerning coloration and morphology, as the paraprocts of the type specimen of H. icterops are typically enlarged ( Fig. 40e ), contrasting with those of H. inca , which are greatly reduced ( Fig. 42j–m ); (ii) the specimen depicted by Menger ( Williamson 1919, Plate X, figs. 117-118) does not belong to H. icterops , but in fact is part of a series of H. inca ( Ecuador and Peru are within the range of H. inca , while H. icterops is restricted to Brazil, and has never been collected in those aforementioned countries, despite large collection efforts in the last century) ( De Marmels 1987; Vilela et al. 2019a; Stand-Pérez et al. 2019); (iii) H. inca is definitely not a junior synonym of H. icterops and this possibility was only raised due to an error of labeling or identification (whether by Menger or Selys), that caused many specimens of H. inca to be labeled as H. icterops over the decades (e.g., the NHMUK specimens); (iv) apart from the coloration and anal appendages morphology, comparisons between the accessory structures of the genital fossa of the two species allow us to see the differences between them, mainly in the sclerotization of the structures and size of the vesica spermalis ( Figs. 41a–c ). The following character combination distinguishes H. icterops from H. inca and all other Group B species: ridge above ML long, sinuous consisting of small teeth, and a marked carina ( Figs. 39d–f ); in lateral view, ML bent downwards ( Fig. 39f ); AP the shortest ( Fig. 39d ); S9–10 almost entirely black or dark brown.

Figures

FIGURE 39. Heteragrion icterops: (a) anterior view of head; (b–c) lateral view of pterothorax; (d, f) mediodorsal view of cercus; (e) dorsal view of anal appendages. ML: medial lobe. Figures e–f provided by Rosser Garrison and Natalia von Ellenrieder.

FIGURE 40. Heteragrion icterops: (a) anterior view of head; (b) dorsal view of prothorax; (c) dorsal view of pterothorax; (d) lateral view of pterothorax and S1–4; (e) lateral view of S5–10, including the right paraproct; (f) dorsal view of male type, with the original labels at RBINS.

FIGURE 41. Ventral view of male genital fossae, showing the accessory structures and secondary genitalia of: (a–b) Heteragrion icterops, and (c) H. inca.

FIGURE 42. Heteragrion inca: (a–c) anterior view of head; (d) lateral view of pterothorax; (e–f, h) mediodorsal view of cercus; (g, i) close up showing the two MP ridges above ML; (c) adapted from the drawing by Williamson (1919). MP: medial portion of cercus; ML: medial lobe. Figures h–i provided by Rosser Garrison and Natalia von Ellenrieder.