Heteragrion azulum Dunkle, 1989

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 : 25-26

Heteragrion azulum Dunkle, 1989

( Figs. 13a–f )

[Key locator: Key to Group B species, couplet 7 (3’)]

Heteragrion azulum: Dunkle 1989: 195–197 (Illustrated description of the ♁ holotype from Mexico);— Dunkle 1993: 353–356 (description of the ♀, no figs. Provided);— Garrison et al. 2010: 88 (list of Heteragrion species);— Machado & Souza 2014: 97 (comparisons with H. cyane );— Vilela et al. 2019b: 592 (listed among the “blue Heteragrion ”);— Novelo-Gutiérrez & Gómez-Anaya 2023: 195–200 (additions to the original description of ♀ and ♁).

Material examined. 1♁ (HOLOTYPE) MEXICO, Veracruz state, stream 2km E Coyame and 12.4 km ENE Catemaco, 18.viii.1976, J.A. Garrison leg., FSCA (examined through holotype photographs, the same of Fig. 13 ) .

Known distribution. Southeastern Mexico.

Diagnosis and remarks. Rare species, H. azulum was until recently known only from the type series and further female material ( Dunkle 1989, 1993; Novelo-Gutiérrez & Gómez-Anaya 2023). Novelo-Gutiérrez & Gómez-Anaya (2023) recently made additional collections of this species and provided remarks on the female description as well as great images of both sexes. This species can be separated from the remainder of Group B species by the following character combination: overall body coloration consisting of shades of blue and gray, with black background, S8– 10 yellow; ridge above ML long, straight, bearing strong teeth; ML broad, with blunt apex; AP with a medial depression. This species was assessed in the IUCN Red List as the Vulnerable (VU) category, for occurring in an area smaller than 6000 km ², always in small numbers and in only two localities (González-Soriano et al. 2021). In that assessment, the authors also state that H. azulum is threatened by “great pressure due to the conversion of the original vegetation for cattle or agriculture purposes”.

Figures

FIGURE 13. Heteragrion azulum: (a) anterior view of head; (b) lateral view of pterothorax; (c) dorsal view of cercus; (d) close up, MP-AP; (e) mediodorsal view of cercus; (f) close up, ridge and ML. MP: medial portion; AP: apical portions; ML: medial lobe. Figures a–f provided by Rosser Garrison and Natalia von Ellenrieder.