Heteragrion silvarum Sjöstedt, 1918

LENCIONI, F. A. A., 2013, <p> <strong> Diagnoses and discussion of the group 1 and 2 Brazilian species of <em> Heteragrion </ em>, with descriptions of four new species (Odonata: Megapodagrionidae) </ strong> </ p>, Zootaxa 3685 (1), pp. 1-80 : 13

Heteragrion silvarum Sjöstedt, 1918

Figs. 23 (♂ app), 33D–F (♂ thx), 54C (♂ habitus), 72 (map)

Heteragrion silvarum Sjöstedt 1918: 4 , Fig. 10 (male and female description, illustration of male appendages in dorsal view); Williamson 1919: 63–64 (discussion of species); De Marmels 1987: 229–231, Figs. 13–19, 47–48 (redescription of holotype and female paratype, differences from H. ictericum , illustration of male and female head and prothorax, male thorax, female S 8–10 in lateral view, female S 9–10 in ventral view); Lencioni 2005: 141, Figs. 88A–J (data on description and distribution, illustration from Sjöstedt 1918 and De Marmels 1987); Garrison et al 2010: 88 (list).

Types. Holotype and Allotype in NRM (not examined) .

Additional material examined. 2♂. Brazil: Amazonas State: Reserva Ducke—Bacia Acará —AC22— Segmento 14, 16-II-2005 , 1♂, leg. Juen, L.; Rondônia State: Porto Velho , 8º45'S, 63º54'W, 100 m, 03-V-1922 , 1♂, leg. J. H. Williamson & J. W. Strohm.

Illustration made from following specimens. 1 ♂ (Fig. 23A, 23B, 33D, 33E, 33F, 54C)— Brazil: Rondônia State: Porto Velho , 03-V-1922, leg. J. H. Williamson & J. W. Strohm. ( NC 4223 ) .

Distribution. Brazil (states of Amazonas and Rondônia).

Diagnosis. Male: Color pattern very close to that of H. ictericum (Figs. 33A–B). Cercus in lateral view: dorsobasal expansion absent. Ventrobasal expansion present but very small. Straight (Fig. 23B). Cercus in mediodorsal view: basal portion longest. 1/2 its length, medial and apical portions subequal. Medial process triangular plate, sclerotized ridge crossing process on its inner side. Apical portion pointed (Fig. 23A).

Remarks. —R. W. Garrison (pers. comm.) wrote to me about this species. He compared the holotype male of H. silvarum with material, most collected by the Williamsons, that he considered to represent H. silvarum from several localities in Brazil. Garrison examined a male (Reserva Ducke, 26 km E Manaus) that fits the incomplete holotype of H. silvarum perfectly as to body maculation and noted representatives from other populations (Belem, Porto Velho). The appendage morphology for all agreed well with Sjöstedt's figures for H. silvarum (Sjöstedt 1918) . Other material from Manaus (paratype of H. melanurum ) is close to H. silvarum , as noted by De Marmels (1987). All comparisons with the morphology of the appendages was based on Sjöstedt's figures, as the appendages were missing when De Marmels examined the holotype in 1987. Based on his examination, Garrison agrees with De Marmels that H. melanurum = H. silvarum but acknowledges that this species is wide-ranging and variable as to color. The specimen in the Lencioni collection from Porto Velho includes a note from R. Garrison: "specimens darker than normal H. silvarum but agree with appendage morphology to topotypical material."

Figures

FIGURE 7–10. Appendage structure (7 lateral view, 8 mediodorsal view, 9–10 ventral view): (D) ridge, (E) medial process, (J) external wall, (K) ventral surface of cercus, (L) medial wall, (N) ventrobasal expansion, (Q) ventrobasal apophysis.