Segesta riograndensis Siegloch & Polegatto,

Siegloch, Ana E., Polegatto, Cleber M. & Froehlich, Claudio G., 2006, Segesta riograndensis, new genus and species of an Atalophlebiinae (Ephemeroptera: Leptophlebiidae) mayfly from southern Brazil, Zootaxa 1299, pp. 35-43: 38-41

publication ID 10.5281/zenodo.173598

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Segesta riograndensis Siegloch & Polegatto

n. sp.

Segesta riograndensis Siegloch & Polegatto  n. sp.

Nymph, mature, female (in alcohol). Body length: 6mm; terminal filament: 7mm, cerci: about 6 / 7 of length of terminal filament; general coloration gray spotted.

Head. Dorsum of head orange­brown, with a narrow transverse dark brown band between ocelli extending to anterior base of eyes. Mouthparts: orange­brown, lighter in ventral surface; cardo and base of mandibles darker. Labrum ( Fig. 1View FIGURES 1 – 12): dorsal row of about 50 long fine setae, very close to anterior margin; a group of about 9 dorsal curved setae on each half. Mandibles as in figures 3–6. Maxillae ( Figs. 7–9View FIGURES 1 – 12): Cardo with about 6 short setae; stipes with minute basal posterior prominence on outer margin; anterior margin of galealacinia completely occupied by hard brush of setae; in ventral anteromedian area, about 15 pectinate setae, with apical comb, and one large pectinate setae with complete comb ( Fig. 9View FIGURES 1 – 12). Hypopharynx as in Fig. 10View FIGURES 1 – 12. Labium as in Fig. 11View FIGURES 1 – 12.

Thorax. Dorsum of thorax orange­brown with dark spots at anterior and posterolateral margins of pronotum, and at the base of fore wingpad. Pronotum with row of about 8 spine­like setae on anterolateral margin. Legs: Orange­brown, dorsal surface of coxae with small dark spots; ventral surface of fore femora with two basal gray spots and two other apical; ventral surface of middle and hind femora with an apical gray spot. Forelegs ( Fig. 13View FIGURES 13 – 16) with long fine setae on posterior margin of femora, and hard spatulate setae of various sizes, ca. 6 long, and ca. 14 short; short setae on anterior margin of femora and short spatulate setae on dorsal surface; long fine setae on posterior margin of tibiae and tarsi, and short spine­like setae on anterior margin of tibiae and tarsi; midlegs ( Fig. 14View FIGURES 13 – 16) similar to forelegs, but femora with ca. 8 long and ca. 3 short spatulate setae on femora; hindlegs ( Fig. 15View FIGURES 13 – 16) similar to those described before, but femora with ca. 8 long and ca. 14 short spatulate setae, and spatulate setae also on tibiae, ca. 6 long and 8 short. Tarsal claws ( Fig. 16View FIGURES 13 – 16) with small subequal denticles, about 6 apical and 6 basal; a big subapical denticle absent; apical denticle curved.

Abdomen. Gray spotted, as in Fig. 17View FIGURES 17 – 20. Margin of tergum 5 as in Fig. 19View FIGURES 17 – 20. Shape of caudal filaments as in Fig. 18View FIGURES 17 – 20.

Nymph, mature, male. Eye. Lower portion black, upper portion orange­brown. Body length 6,3mm.

Adults: unknown.

Material examined: Holotype, female nymph, Brazil, State of Rio Grande do Sul, Independência, Santa Rosa River, A.E. Siegloch, I. 2005, deposited at MZSP. Paratypes, 7 nymphs; 2 nymphs same data as holotype, but 1 male and 4 female, XIII. 2005; 1 male and 2 female deposited in MZSP, and 4 female at MSNZRS.

Geographical distribution: The type­species was collected in northwestern Rio Grande do Sul, southern Brazil. There is also a record of a similar nymph (undescribed) for Nova Xavantina, State of Mato Grosso, western Brazil.

Habitat: The nymphs were found on rocks and stones in the river, at an altitude of about 300 m.

Etymology: The epithet riograndensis  refers to State of Rio Grande do Sul, where the species was collected.


Sao Paulo, Museu de Zoologia da Universidade de Sao Paulo