Racelda alternans Signoret, 1863

Gil-Santana, Helcio R. & Oliveira, Jader, 2022, A new species of Racelda Signoret, with taxonomical notes and a key to the males of the genus (Hemiptera, Reduviidae, Ectrichodiinae, Ectrichodiini), ZooKeys 1122, pp. 53-79 : 53

Racelda alternans Signoret, 1863

Figs 3-8

Type material examined.

Racelda alternans . Male syntype: Racelda alternans [handwritten] / det. Signoret. [printed] // Chile [handwritten] / Coll. Signoret. [printed] // [printed red label]: Typus / Racelda / Racelda alternans Signoret, 1863 / etik. Hecher 1996 / REDV. 102/1; Male [potential] syntype: Racelda alternans [handwritten] / det. Signoret. [printed] // Chile [handwritten] / Coll. Signoret. [printed] // [printed red label]: Typus? / etik. Hecher 1996 (NHMW).

Racelda alternans was described from Chile ( Signoret 1863), and it is the type species of Racelda by monotypy ( Maldonado 1990). It was also recorded from Argentina by Dougherty (1995).

A male syntype is deposited in NHMW (Figs 3-5 ). Besides this syntype, another male deposited in the same collection and with same data is considered as a potential (probable) or doubtful ( “?”) syntype of R. alternans ( Sehnal 2000) (Figs 6-8 ). The position of uncertainty of Sehnal (2000) about this potential syntype was based mainly on the supposed divergence between the coloration of the pronotum of this specimen and the original description of R. alternans by Signoret (1863). His description stated the following: prothorax [pronotum] brownish with two large lateral yellow markings, which meet almost at level of anterior furrow. This description seems to be in accordance with both specimens, possibly, even more with that which was considered as a doubtful syntype by Sehnal (2000) (Fig. 6 ). In the recognized syntype there are only lateral pale markings on hind lobe of pronotum which are far from meeting at the level of the transverse furrow (Fig. 3 ), while in the doubtful syntype, besides similar lateral pale markings on hind lobe, the fore lobe is almost completely pale, a coloration only interrupted by the mid-longitudinal furrow (Fig. 6 ). It is noteworthy that the drawing of the habitus (dorsal view) of R. alternans which accompanies the original description ("fig. 6") clearly shows a pair of pale rounded markings on fore lobe of pronotum, although smaller than what is seen in the “?” syntype, in which almost all the fore lobe (except the median sulcus) is pale (Fig. 6 ). It is possible that more than these two type specimens existed when Signoret described the species, but the figure makes it clear that another specimen, with pale portions on the fore lobe of the pronotum, which are not observed in the syntype recognized by Sehnal (2000), was drawn and therefore considered by Signoret (1863) as belonging to this species. On the other hand, it is noteworthy that the quality of details and precision of the drawings in Signoret’s paper are not those required today for a scientific drawing of a specimen. Thus, it is possible that the pale markings of the pronotum had not been well depicted and the pale markings were represented smaller than they are in the “?” syntype. The lack of precision in the mentioned drawing is suggested by the pattern of the lateral pale markings of the hind lobe, which were drawn as a pair of parallel lines meeting at their apices, while in reality they are continuous markings at each side of hind lobe. Therefore, this evidence and the fact that the original labels of both type specimens are very similar and with the same handwriting (Figs 5 , 8 ), suggest that both specimens should be considered and possibly recognized as syntypes of R. alternans .

Melo and Faúndez (2015) argued that R. alternans could be easily distinguished by the characteristic coloration of the thorax of the males. The pronotum of the male photographed by them (their fig. 11) presented a general dark coloration with a relatively large median pale marking on each side of fore lobe and the hind lobe with lateral pale markings similar to those of the syntype considered as doubtful by Sehnal (2000) (Fig. 6 ).

Figures

Figures 1 - 10. 1, 2 Racelda aberlenci Berenger & Gil-Santana, 2005, male from French Guiana. 1 dorsal view 2 abdomen, ventral view. 3 - 8 Racelda alternans Signoret, 1863, male specimens deposited in NHMW. 3 - 5 syntype 3 dorsal view 4 ventral view 5 labels 6 - 8 potential syntype 6 dorsal view 7 ventral view 8 labels. 9, 10 Racelda moerens Breddin, 1898, male holotype deposited in SDEI 9 dorsal view 10 labels. Scale bars: 2.0 mm (2, 3, 6); 1.0 mm (1).