Americabaetis titthion Lugo-Ortiz & McCafferty 1996
Creators: name: Amaral, Igor Ferreira
name: Salles, Frederico Falcão
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Baetidae
Americabaetis
Americabaetis titthion

description: Americabaetis titthion Lugo-Ortiz & McCafferty, 1996
(Figs 1–5)
Americabaetis titthion Lugo-Ortiz & McCafferty 1996: 167; Francischetti et al. 2003: 69; Salles et al. 2004: 23; Domínguez et al. 2006: 72; Salles et al. 2010a: 302; Salles et al. 2010b: 26.
Diagnoses. Male adults (modified from Salles et al. 2004). 1) turbinate portion of eyes orange, separated by approximately the width of a lateral ocelli, upper surface ellipsoidal (Fig. 1b); 2) costal and subcostal area of fore wing tinged with reddish-brown (as in Fig. 2e); 3) pairs of soft, setose protuberances present on meso- and metasternum (Figs. 1a, c); 4) subgenital plate slightly concave (Fig. 1f); 5) forceps brown, with segment I/II slightly tapering medioapically and segment III light brown (Fig. 1f). Nymphs (modified from Domínguez et al., 2006 and Salles et al., 2010b). 1) frontal keel absent (Fig. 4b); 2) lingua broadly pointed apically (Fig. 3g); 3) labium with glossa 0.8× length of paraglossa (Fig. 3i); 4) apex of paraglossa with 3 rows of pectinate setae; 5) segment II of labial palp with a moderate distomedial projection (Fig. 3i); 6) meso and metasternum with a setose paired protuberance (Fig. 4c); 7) tarsal claw with 10–12 denticles; 8) posterior margin of abdominal terga with rounded spines (Fig. 5d).
Descriptions
Male imago (Fig. 1). Lengths (in mm). Body: 6.0; Forewings: 5.9. Head (Figs. 1a, b). Brown, with cream lateral mark. Antenna light yellowish-brown, flagellum thickened at the base. Lateral and middle ocelli surrounded with black. Ventral portion of compound eye gray. Turbinate eyes separated approximately by the width of lateral ocellus; upper surface ellipsoidal and orange, except for brown edges; basal ⅓ of stalk brown, remainder cream. Thorax (Figs. 1b, c). Pronotum brown with lateral margin cream. Mesoscutum predominantly brown; anteronotal protuberance with lateral cream mark; anteronotal transverse impression and medioscutum dark brown; sublateroscutum with anterior portion cream; scuto-scutellar impression cream. Katepisterna brown with cream spot; meso and metasterna light brown, both with pair of triangular protuberances covered with small setae. Wing. Forewing hyaline (as in Fig. 2e); costal, subcostal and basal area reddish-brown, more pigmented between Sc and RA; veins yellowish-brown; stigmatic area with 8–9 short veins, some incomplete; marginal intercalary veins paired, except between ICu2 and A. Legs. Foreleg 5.1 mm; coxa brown with cream marks; trochanter, femur, tibia and tarsi brown; tarsus segments in decreasing order: 2, 3, 4, 5, 1; mid and hindleg similar, cream; tarsal segments II, III and IV with ventral projection. Abdomen (Figs. 1d–f). Segments I–X brown, VII–X with white inclusions (on terga VI–IX they are absent medially and on sigilla); tracheation black and well visible. Cercus broken-off and lost. Genitalia. Forceps predominantly brown, lighter towards apex. Forceps base with distomedial projection; forceps segment I tapering towards fusion with segment II; forceps segment III elongate; posterior margin of subgenital plate slightly concave.
Female imago (Fig. 2). Length (in mm). Body: 6.0; Forewings: 6.6. Head (Fig. 2a). Cream; antenna and lateral and middle ocelli similar to male imago; compound eye gray; posterior margin of head elevated. Thorax (Figs. 2a, b). Predominantly light brown; prothorax with lateral margin cream; anteronotal transverse impression and anterolateroparapsidal suture brown; apex of scutellum and scuto-scutellar impression cream; meso and metathorax sterna light brown; Wing similar to male; Legs (Fig. 2c). foreleg 2.6 mm, light brown, slightly longer than mid and hindleg; mid and hindleg similar to male, tarsal segments light brown. Abdomen (Fig. 2d). Cercus reddish-brown.
Nymph. Length (in mm). Body: 7.00; Cerci: 3.8; Antenna: broken. Head (Fig. 4b). Labrum (Fig. 3a, b). 0.6× wider than long; dorsal surface with scattered short, fine, simple setae and pair of long, submedial simple setae; dorsolateral arc of setae composed of 6–9 + 1 long simple seta; ventral surface with 8–10 spine-like setae near lateral margin; lateral margin with short, fine, simple setae. Hypopharynx (Fig. 3g). Lingua longer than superlinguae, apex acute covered with fine setae; superlinguae expanded. Maxilla (Fig. 3h). Proximal inner margin of galealacinia with one row of 7–9 simple, fine setae. Labium (Fig. 3i). Glossa with 3–4 pectinate setae in distal outer margin; apex of paraglossa with pectinate setae. Abdomen. Gills II–V broader and larger than VI and VII, gills VII small and rounded (Figs. 4a, 5a); margins of sterna VII–IX with blunt spines (Figs. 5b).
Eggs (Figs. 5e, f): Diameter: 51.5 µm; Height: 103.7 µm. Oblong; chorion with small irregular cells net-like. Micropyle unknown.
Material examined: BRAZIL, Minas Gerais, Araponga, Pousada Remanso, 1 male imago and 2 female imagos; 20° 39’ 18’’ S 42° 27’ 12” W 1062 m.a.s.l.; 21/iii/2023; F.F. Salles col. BRAZIL, Minas Gerais, Araponga, Cachoeira do Boné, 2 nymphs; 20° 38’ 45’’ S 42° 27’ 26’’ W 945 m. a.s.l.; 24/ix/2018; F.F. Salles; D. Belicchi; M.I. Passos; J.F. Marulanda-Lopez cols. BRAZIL, Santa Catarina, São Joaquim, Rio Pelotas, 5 nymphs; 28° 26’ 50.3’’ S 49° 52’ 58.3’’ W 936 m.a.s.l.; 31/viii/2009; N. Hamada; P. Cruz; R. Boldrini.
description: Published as part of Amaral, Igor Ferreira & Salles, Frederico Falcão, 2024, Comprehensive description of new and known stages of Americabaetis titthion Lugo-Ortiz & McCafferty (Ephemeroptera: Baetidae), pp. 305-314 in Zootaxa 5536 (2) on pages 306-312, DOI: 10.11646/zootaxa.5536.2.6, http://zenodo.org/record/14033712