Chilella rugella DeLong & Freytag, 1967

Gonçalves, Clayton C., Domahovski, Alexandre C., Mejdalani, Gabriel & Takiya, Daniela M., 2021, Three new genera from South America and some taxonomic changes in Gyponini (Insecta: Hemiptera: Cicadellidae), European Journal of Taxonomy 750, pp. 70-93 : 89-90

Chilella rugella DeLong & Freytag, 1967

Fig. 8

Material examined

Holotype

CHILE • ♀; Chile, Sin. Hem. ; 1956; E.C. Reed and C.J. Drake leg.; USNM.

Remarks

The monotypic genus Chilella was erected by DeLong & Freytag (1967) based on a single female specimen of Chilella rugella DeLong & Freytag, 1967 from Chile. According to the authors, Chilella differs from other genera of Gyponini by the following set of characteristics: (1) crown short and broad; (2) transition crown-face rounded, without defined margin; (3) ocelli distant from eyes, located on anterior portion of crown; (4) forewing rugose, corrugated and without an appendix; and (5) foreleg with metatibia intercalary setae between macrosetae.

Our study of the holotype of Chilella rugella ( Fig. 8A–E ) indicated that the position of the ocelli, which are located in the crown-face transition, is incongruent with the diagnoses proposed for Gyponini by DeLong (1942), Oman (1949), Linnavuori (1959), Dietrich (2005), and Krishnankutty et al. (2016). According to those authors, the ocelli in Gyponini are located on the crown, away from the anterior margin. Moreover, according to the key to the tribes of Iassinae proposed by Krishnankutty et al. (2016), Chilella rugella is classified as Selenomorphini Evans, 1974 , based on the following characteristics: (1) head with crown poorly delimited, rounded to face; (2) hind wing veins R4+5 and M1+2 separated distally, not confluent at apex; and (3) body pigmentation primarily pale green or stramineous.

However, morphological characteristics of C. rugella are not congruent with any genera currently included in Selenomorphini . Chilella differs from Selenomorphus Evans, 1974 and Linnavuoria Dai & Dietrich, 2015 in having the crown-face transition indistinct, whereas in the last two genera the crownface transition is distinctly angulated in profile. Also, Chilella differs from Pachyopsis Uhler, 1877 and Uhleriana Domahovski, 2019 in having the metatibiae with intercalary setae. In addition, it differs from Parapachyopsis Domahovski, 2019 in having the head narrower than the pronotum and from Scaroidana Osborn, 1938 by its smaller size (9.0 mm) and position of the ocelli mesad to the antennal pits ( Fig. 8C ), whereas in Scaroidana they are closer to the eyes and located above the antennal pits, in ventral view.

Unfortunately, the holotype of C. rugella lost its forewings, which could have provided useful information about its relationships with other genera of Selenomorphini . However, according to DeLong & Freytag (1967), the forewings are rugose and corrugated, two features not found in any other genus of the tribe. We propose the transfer of Chilella to Selenomorphini , maintaining it as a valid genus. However, the discovery of male specimens as well as phylogenetic studies on the tribe are necessary to confirm our proposal.

Figures

Fig. 8. Chilella rugella DeLong & Freytag, 1967, holotype, ♀ (USNM). A. Habitus, dorsal view. B. Habitus, lateral view. C. Head, ventral view. D. Posterior portion of abdomen, ventrolateral view. E. Labels. Scale bars: A–B =2.0 mm; C–D= 1.0 mm.