Caenis teipunensis sp. nov. (Figs. 1–6) Material. Venezuela, Estado Bolívar: 15 3 (slide 518) and 1 Ƥ imagos from Kavanayén stream, N 5° 37' 27" - W 61° 44' 37", 1355 m, 21/XI/2005, EG, AMO, CA and MEG cols.; 23 3 (slides 510, 516, 517) and 3 Ƥ imagos from Kako-Parú stream, N 4° 54' 0" – W 61° 5' 25", 913 m, 28/VI/2007, EG, AMO, CA and MEG cols. Holotype 3 imago, allotype Ƥ imago and 10 paratype 3 imagos at MLBV; 5 paratype 3 imagos at INPA; rest in IML. Male imago. Length (mm): body, 3.0–3.6; forewings, 2.5–2.9; foreleg (from base of trochanter to apex of claw), 1.8–2.3; caudal filaments, 6.5–9.0. General coloration yellowish light brown (Fig. 1). Head yellowish white shaded with gray widely except on a transversal pale band between anterior part of lateral ocelli; venter of head pale. Antennae: scape yellowish gray, pedicel yellowish translucent, flagellum hyaline. Thorax. Prothorax yellowish translucent shaded with gray dorsally, darker on a pair of submedian spots; presternal triangle anteriorly pointed (Fig. 2). Mesonotum and metanotum yellowish orange shaded with gray on carinae, pleurae and sterna paler. Wings hyaline, veins translucent except C, Sc and Rs grayish. Legs. All coxae, fore femora and base of fore tibiae yellowish; rest of foreleg and middle and hind legs whitish; median and subapical gray marks present on all femora, submedian gray mark also on middle and hind tibiae. Abdomen. Segments 1–8 whitish-translucent, 9–10 yellowish, without lateral or dorsal filaments; all terga shaded widely with gray, darker on terga 1–2 and lateral spots of terga 1–9; sterna translucent white with light gray marks on lateral margins of sterna 8–9. Genitalia (Figs. 3, 5– 6) with whitish membranes and yellowish sclerites; forceps orangeish, long and slender, apically pointed and sclerotized, generally sharpening abruptly at the apex, few setae and small tubercles present but variable (Figs. 6 a–f); penes (Figs. 3, 5) whitish with a yellowish V-shaped mark, ventral surface with small tubercles and shallow groove, lobes of the penes rounded laterally; styliger plate with elongated and oval central sclerite, apophyses strongly developed, wide and long (Figs. 3, 5). Caudal filaments whitish translucent. Female imago (Fig. 4). Length (mm): body, 3.0–3.5; forewings, 2.8–3.2; fore leg (from base of trochanter to apex of claw), 1.5; caudal filaments, 2.1–2.5. Color pattern as in male. Abdominal sternum 9 rounded, not projected. Eggs light yellow. Nymph. Unknown. Etymology. The specific epithet teipunensis is a combination of "tei-pun" (meaning “sabana”, according to the Pemon indigenous group from "La Gran Sabana", our study area) and the Latin suffix "-ensis" (denoting place or locality). Diagnosis. Male imagos of Caenis teipunensis sp. nov. can be distinguished from all other species in the genus by the following combination of characters: 1) length of body, 3.0– 3.6 mm, and of forewings, 2.5–2.9 mm; 2) presternal triangle anteriorly pointed (Fig. 2); 3) fore legs 0.6–0.7 times the length of body; 4) finger-like process on abdominal tergum 2 and lateral processes on other abdominal segments absent; 5) cerci 2.1–2.5 times the length of body; 6) styliger plate with elongated and oval central sclerite, apophyses strongly developed, wide and long (Figs. 3, 5); 7) penes (Figs. 3, 5) completely fused, laterally constricted, lateral lobes rounded, small tubercles and shallow grooves present on ventral surface; 8) forceps sclerotized, sharp, generally with small tubercles and setae on outer basal margin (Figs. 6 a–f), forceps 7.3–9.5 times longer than width at the middle. Discussion. Except for the extremely long apophyses of the styliger sclerite and shape of the forceps, Caenis teipunensis sp. nov. is similar to C. fittkaui Malzacher, and belongs to the same group of species defined by the apically pointed forceps (Malzacher 2001). Ecology. Imagos were collected along the stream margins, at night, and during the rainy season (November 2005 and June 2007), by using light traps. Streams flow through an upland undulating savanna ecosystem (913– 1355 m) and they were partially shaded (Kaku-Parú, Fig. 23) or not shaded at all (Kavanayén, Fig. 24). They were small to medium size streams (18–20 m wide), of low order (1st–2nd), with shallow (8–32 cm) and acidic (pH = 5) waters, and with bottoms mainly composed of bed-rock (Kavanayén) and gravels (Kaku-Parú).

Published as part of Molineri, Carlos, Grillet, Maria-Eugenia, Nieto, Carolina, Dominguez, Eduardo & Guerrero, Edmundo, 2011, New species and records for the mayfly families Caenidae, Leptohyphidae and Coryphoridae (Ephemeroptera, Pannota) from Venezuelan Guayana's Uplands, pp. 39-50 in Zootaxa 2750 on pages 40-43, DOI: 10.5281/zenodo.206964