Segesta riograndensis, new genus and species of an Atalophlebiinae (Ephemeroptera: Leptophlebiidae) mayfly from southern Brazil Author Siegloch, Ana E. Author Polegatto, Cleber M. Author Froehlich, Claudio G. text Zootaxa 2006 1299 35 43 journal article 10.5281/zenodo.173598 fe8c12db-8d4a-45cc-9dd9-f12b75cb68ef 1175­5326 173598 Segesta Siegloch & Polegatto n. gen. Nymph, mature, female. Head . Prognathous. Clypeus ( Fig. 1 ): narrower than labrum, i.e. width ca. 2/3 of the width of labrum, with slightly divergent and sinuous margins. Labrum ( Fig. 1 ): expanded laterally, with rounded margins, anterior margin with shallow emargination; three rounded denticles on anterior emargination ( Fig. 2 ); length of labrum 1/3 of width; large dorsal row of fine setae closer to anterior margin and a group of setae on dorsal surface; on ventral surface, anterior and middle area with short setae, relatively long setae at wide area of margins. Mandibles ( Figs. 3–6 ): Semilunar in shape and with round margins; setae present on whole extension of lateral margin; a small ventral V shaped row of fine setae ( Fig. 5 ); right mandible with relatively slender incisors, the anterior one with three apical denticles, the posterior one with two apical denticles and minute marginal spines; prostheca slender with two portions, one long hard spine­like setae, and one group of fine setae on a projected base ( Fig. 6 ); a row of about 9 setae closer to mola; left mandible with more robust incisors, both with three apical denticles, the posterior one with minute marginal spines; prostheca with two portions, one projection with a pectinate and a simple setae, and one projection with a group of fine setae; setae closer to mola absent. Maxillae ( Figs. 7–9 ): General shape rectangular, stipes with minute posterior prominence on outer margin, brush of setae on apical margin of galealacinia and fine median setae as found in other Atalophlebiinae ; maxillary palp well developed, attached at mid length of maxillae, with various setae, long and short, curved inwards; first segment with rectangular shape, with margins slightly curved; second segment subequal in size to first segment; third segment about two times the length of second segment; third segment with row of long fine setae on lateral margin, same kind of setae on ventral surface, and relatively short setae on median margin in two different rows; third segment curved inwards ( Fig. 8 ). Hypopharynx: Lingua and superliguae as in Fig. 10 . Labium ( Fig.11 ): Glossae with numerous ventral short setae and some dorsal short setae; paraglossae with dorsal rows of setae of different sizes and ventral row of subequal fine setae; prementum small, with labial palps attached at anterior area of lateral margin; postmentum without lateral setae, with minute ventral setae on posterior area; length of paraglossae about half of width; labial palp well developed, first segment long and rectangular, length slightly larger than width of paraglossae; second segment very long, about two times the first segment and curved inwards, with long fine setae on lateral margin and other setae as in Fig. 11 ; third segment reduced to about 1/6 of length of first segment, with few fine setae ( Fig 12 ). Thorax . Legs: Forelegs with long fine setae on femur, and hard spatulate setae of varied sizes, long fine setae on tibiae and tarsi, other short setae as in Fig. 13 . Midlegs and hindlegs similar to forelegs, but with spatulate setae on hind tibiae ( Figs. 14, 15 ). Tarsal claws ( Fig. 16 ) with small subequal denticles, without large subapical denticle. Hind wingpads present. Abdomen . Posterolateral spines on segments 2 to 9, those on 7 to 9 progressively larger. Gills on segments 1 to 7; gills slender, with main tracheae visible without ramifications, minute setae on margins of gills ( Fig. 20 ). The new genus can be distinguished from other genera of Atalophlebiinae by the following combination of characters: clypeus slightly divergent with sinuous margin; labrum with shallow emargination and three non­prominent denticles; maxillary palp very large and curved with setae in varied combinations; labial palp very long and curved, with long setae; paraglossae wider than long; abdominal posterolateral spines gradually longer posteriorly. Type­species : Segesta riograndensis Adults : unknown Etymology : Segesta is a goddess of harvests; the name refers to shape of the maxillary and labial palps, that recalls sickles used in harvesting.