Heteragrion albifrons Ris, 1918

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 : 19

Heteragrion albifrons Ris, 1918

( Figs. 8a–e )

[Key locator: Key to Group B species, couplet 10 (9’)]

Heteragrion albifrons: Ris 1918: 89 (description of ♁ holotype from Costa Rica, fig. 43);— Williamson 1919: 12, 15, 32–33 (key to species, ♁ in couplet c2, ♀ in couplet c1; mentions specimens in Calvert’s collections that match H. albifrons , considerations on similarities with H. erythrogastrum ; figs. 2, 32, 33, 61, 72, 86, 87, 148, 149);— Paulson 1981: 303–304 (behavior and coloration);— González-Soriano et al. 1982: 56 (recorded in Los Tuxtlas, Mexico);— Novelo-Gutiérrez 1987: 11–22 (description of F0 larvae);— Donnelly 1992: 58 (comparisons with H. rubrifulvum );— Ramírez 1992: 361, 364–365 (larval habitats and comparison with other known larvae in Costa Rica);— Ramírez et al. 2000: 247–254 ( Costa Rica);— Novelo-Gutiérrez 2007: 13 (listed among larvae described by Mexican authors);— Kalkman et al. 2010: 123 (listed among megapodagrionid known larvae);— Garrison et al. 2010: 88 (list of Heteragrion species);— Ramírez & Gutiérrez-Fonseca 2013: 100 (key to Heteragrion larvae from Costa Rica, couplet 3’);— Rodríguez-Tapia et al. 2022: 274 (listed among species with an index of environmental vulnerability).

Material examined. 1♁ MEXICO, Oaxaca, mountain road to Tuxtepec , 27.viii.1959, (545 m asl), G.H. & A.F. Beatty leg., ABMM ; 1♁ Veracruz, stream near Playa Escondida , 9–13.viii.1982, (18.5666, -95.0666), R.W. Garrison leg., ABMM (head missing) ; 1♁ COSTA RICA, Horquetas , 28.v.2013, (10.2836, -84.0468, 764m asl), A.C. Rivera leg., ECOEVO .

Known distribution. Costa Rica and Mexico.

Diagnosis and remarks. Robust and remarkable species, mainly for the male head coloration ( Fig. 8a ), which is paler than in any other species of the genus. According to Paulson (1981) and CBS (personal observation), the abdomen is entirey red, except for some yellowish on S1–2, as do some H. chrysops ( Williamson 1919) . Heteragrion albifrons can be separated from the remainder of Group B species by the following character combination: BP with a nearly straight margin ( Figs. 8c–e ); portions of cercus all subequal in size ( Fig. 8d ); ridge above ML straight, partially covering ML in dorsal and dorsolateral views, its apex forming a narrow tip ( Figs. 8c–e ); ML quite broad, its apex rounded ( Fig. 8e ); mouthparts and frons largely pale ( Fig. 8a ). Morphologically close to H. tricellulare .

Figures

FIGURE 8. Heteragrion albifrons: (a) anterior view of head; (b) lateral view of pterothorax; (c–e) cercus in mediodorsal view. BP: basal portion; MP: medial portion; AP: apical portion.