Segesta 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 : 36-38

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.

Figures

FIGURES 1 – 12. Segesta riograndensis n. sp.: 1, labrum, left dorsal view, right ventral view. 2, anteromedian emargination of labrum; 3, left mandible, dorsal view. 4, right mandible, dorsal view. 5, right mandible, partial, ventral view. 6, mandibles details; left and right incisors and prostheca. 7, maxillae, ventral view. 8, maxillary palp, detail, dorsal view. 9, pectinate setae of galealacinia, ventral view. 10, hypopharynx, left ventral view, right dorsal view. 11, labium, left ventral view, right dorsal view, some setae omitted. 12, segment 3 of labial palp.

FIGURES 13 – 16. Segesta riograndensis n. sp.; 13, foreleg. 14, midleg. 15, hindleg. Legs in dorsal view. 16, Tarsal claw.

FIGURES 17 – 20. Segesta riograndensis n. sp.; 17, abdomen with color pattern. 18, base of caudal filaments. 19, posterior margin of tergum 5. 20, gill of first abdominal segment.