Alloretochus sigillatus Molineri, 2014, new species
Creators: name: Molineri, C.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Caenidae
Alloretochus
Alloretochus sigillatus

description: Alloretochus sigillatus new species
(Figs. 2A –I, 3C)
Diagnosis. Adult size relatively large (male body ca. 4 mm, female ca. 5 mm); with characteristic blackish marks on abdominal terga (Figs. 2B–C, E); male subgenital plate broadly emarginated posteriorly as in Figs. 2D and 3C; ratios forceps length/subbasal width 8.9; female sternum IX produced distally reaching apex of segment X, tapering distally with rounded apex; egg with 4 costae in lateral half (Figs. 2F–G).
Type material. Holotype male imago (genitalia and legs on slide IBN421CM) from BOLIVIA, río Blanco, ca. de Once por Ciento, road between Sta. Cruz and Trinidad, S 15º 21' 39.7" — W 63º 17' 28.8", 250 m, 14/VI/2000, E. Domínguez col.; 2 male and 1 female imago paratypes same data as holotype. Holotype deposited in UMSS, remaining specimens in IBN.
Additional material. One male imago (IBN) from ECUADOR: Esmeralda Prov., Cantón Eloy Alfaro, Parroquia Telembí, Estero Arenales, N 00º 40' 05" — W 78º 59' 25", 80 m, 15/IV/2002, E. Domínguez col.
Male imago. Length (mm): body, 4.0–4.2; forewing, 3.0–3.2; caudal filaments, 9.0–10.0. General coloration yellowish white. Head (Fig. 2C) pale with diffuse gray shading between ocelli, and with paired sublateral black marks near hind margin; ratio pedicel/scape, 1.75. Thorax. Pronotum translucent white with medial, T-shaped black mark (Fig. 2C); mesonotum yellowish white with thin grayish medial line; metanotum yellowish white with whitish membranous posterior portion produced dorsally, forming gray-shaded, finger-like tubercle on hind margin (as pointed by arrow in Fig. 2A). Legs whitish except forefemur yellowish. Ratios of length of body: foreleg: midleg: hindleg - 1: 0.6: 0.4: 0.5. Ratios of length of forefemur: tibia: tarsus - 1: 2.2–2.4: 1.2–1.3. Ratios of length of foretarsus segment I: II: III: IV: V - 1: 3.0: 1.7: 1.4: 1.4. Wings with yellowish veins; length/max width 1.7. Abdomen (Fig. 2B) whitish turning yellowish white on segments IX–X; with blackish median marks of characteristic shape on terga I–II and VII–X; segments IV–VI with long, thin vestiges of posterolateral projections. Genitalia (Fig. 2D): subgenital plate and forceps yellowish, penes whitish. Ratios forceps length/ subbasal width 8.9. Caudal filaments whitish.
Female imago. Length: body, 4.7; forewing, 3.7; caudal filaments, 1.5. Similar to male except: occiput with a large black macula between the sublateral spots; lateral ocelli much more produced dorsally (Fig. 2E). Thorax without gray shading; metanotum without finger-like dorsal tubercle. Ratios of length of body: foreleg: midleg: hindleg - 1: 0.2: 0.4: 0.4. Wing length/max width 1.9. Abdomen (Fig. 2E) with reduced dorsal markings, only present on terga I, III and X; sternum IX produced distally reaching apex of segment X, tapering distally with rounded apex.
Egg (Figs. 2F–G). Shape elongate-ovate, ratios total length/maximum width: 3.1–4.3. Polar cap 1/10-1/5 of whole egg in length, without tubercles. Chorion with 4 costae in lateral half. Costae smooth, asymmetrical in crosssection (overlapping adjacent inter-costal groove on one side only). As described in the previous species, a thin layer covering the egg (probably not part of the egg) shows few small subcircular tubercles.
Etymology. From Latin " sigillatus " meaning "with small and distinct marks".
Discussion. The characteristic blackish marks on the abdomen steadily distinguish adults of Alloretochus sigillatus sp. n. from A. peruanicus and also other brachycercines known from adult stage.The larval stage may be associated in the future by these marks, since generally adults carry body pigments from the larval stage (Sun & McCafferty 2008). The presence of posteromedian projection on metanotum and vestiges of abdominal projections on segment IV–VI is shared with A. peruanicus as redescribed above. The character proposed by Sun & McCafferty (2008) as autapomorphic for the genus Alloretochus, the broadly emarginated apex of the subgenital plate, is also present in this species. Male foretarsi are relatively shorter in A. sigillatus (1.2–1.3 times the length of forefemora), comparing to those of A. peruanicus (1.5–1.7 times the length of forefemora). Eggs of A. sigillatus differ from those of A. peruanicus by having only 4 wide costae in lateral half (7–8 costae in A. peruanicus), which are similar to eggs of Cercobrachys etowah (figure 569 in Sun & McCafferty 2008). A reduced number of costae is also present in Latineosus colombianus (figure 566 in Sun & McCafferty 2008), but in that species costae are much narrower.
Distribution. Bolivia (Santa Cruz) and Ecuador (Esmeralda). Biology unknown.
description: Published as part of Molineri, C., 2014, Description of Alloretochus sigillatus new species with comments and new distributional records for Alloretochus peruanicus (Ephemeroptera, Caenidae, Brachycercinae), pp. 139-145 in Zootaxa 3821 (1) on pages 142-144, DOI: 10.11646/zootaxa.3821.1.11, http://zenodo.org/record/226219