Baetodes traverae Mayo, 1972

Velásquez-Rodríguez, Karen, Huamantinco, Ana A. & Nieto, Carolina, 2022, The imago of Baetodes traverae Mayo, 1972 (Ephemeroptera: Baetidae), with a redescription of the nymph, Zootaxa 5091 (4), pp. 567-572 : 567-570

Baetodes traverae Mayo, 1972

Nymph: Body length (mm): 4.5–5.1, cerci: 5.0–6.5, terminal filament shorter than abdominal segment X.

Diagnosis. (1) Terminal filament very short, less than half the length of abdominal segment X, (2) labium with glossae very short, less than half the length of paraglossae, (3) labrum expanded laterally, with submarginal row of four setae, (4) coxal gills absent and (5) abdominal tubercles absent.

Habitus coloration. Head. Light brown, yellowish areas around the eyes. Translucent greyish-brown antennae. Thorax. Pronotum pale yellow with brown colouring in the center. Mesonotum dark brown. Dorsally, a thin longitudinal yellow line throughout the mesonotum. Two yellowish spots placed over the top of the anterior wing pads. Dark brown pleural sclerites and slightly yellowish sternites with some brown areas. Coxa dark brown. Dorsal region of the femur with dark brown margins, yellowish inner region and ventral region pale yellow. Tibiae light brown with yellow line patterns on the dorsal surface. Ventral region of tibiae yellowish. Hind legs lighter than other legs. Abdomen: Terga blackish brown with posterior margin light beige. Last abdominal tergum lighter than the others. Abdominal sterna whitish beige. Terminal filament beige.

Head. Inverted drop-shaped head, filiform antennae about twice the width of the head. Labrum ( Fig. 1 ). Expanded laterally, the length twice the width. Lateral setae long, fine and simple. Anterolateral setae short and pectinate. Medial setae long and pectinate. Dorsally with short, fine and simple setae scattered over surface, submarginal row of four apically pointed setae, inner setae longer. Ventrally with short, spine-like setae distributed in the medial region. Left mandible ( Fig. 2 ). Incisor completely fused, outer and inner set of incisors, respectively with 3 + 4 denticles. Row of fine setae on the inner margin of the last incisor. Prostheca robust, apically denticulate with at least 11 filamentous projections. Outer margin slightly convex. Basal half with short, fine, simple setae scattered over dorsal surface. Right mandible ( Fig. 3 ). With incisor complete fused, outer and inner set of incisors, respectively, with 4 + 4 denticles. Row of fine setae on the inner margin of the last incisor. Prostheca filiform. Basal half with short, fine, simple setae scattered over dorsal surface. Maxillae ( Fig. 4 ). Crown of galea-lacinia with four denticles; row of setae on inner-dorsal margin of maxilla with most of the setae pectinate; medial protuberance of galea-lacinia with five spine-like setae, palp long 2x longer than galea-lacinia, segment II 1.1x length of segment I. Hypopharynx ( Fig. 5 ). Lingua with distal margin triangular and subequal in length to superlingua, superlingua not expanded, short, fine, simple setae scattered over distal margin of lingua and superlingua. Labium ( Fig. 6 ). Reduced glossae, less than one third of the length of the paraglossae. Inner margin with seven spine-like setae, apex with seven long setae and one pectinate setae, outer margin bare. Paraglossa subrectangular in shape with rounded apical end, three rows of apically pectinate setae with the rest of its surface bare, first row of setae finely pectinate, remaining two rows more strongly pectinate. Palpi: segment I 1.2x length of segments II and III combined, segment I bare, segment II without distomedial protuberance, bare, segment III rounded, length 2.25x width, covered with spine-like setae. Segments of the palp without micropores.

Thorax. Posterior and anterior margin of pronotum forming a tight narrowing in the centre. Hind wing pads absent. Forefemur ( Fig. 7 ): Length about 4.5x maximum width; dorsally with a row of long, fine and simple setae alternating with 8 –11 clavate setae, length 0.2 width of femur; ventrally with micropores; short, fine, simple setae and one row of spine-like setae. Coxal gills absent. Tibia: 1.1x length of femur, dorsally with one row long, fine, simple setae, ventrally with one row of short, fine, simple spine-like setae. Tarsus: 2.6x shorter than the tibia. Dorsally with short, fine, simple setae; ventrally with one row of short spine-like setae; tarsal claw ( Fig. 9 ) with one row of 9–10 denticles increasing in size distally.

Abdomen. Abdominal tubercles absent, gills ovoid and whitish ( Fig. 8 ). Length of gill I 1.25x length of first abdominal segment, length of gill IV 1.5x length of fourth abdominal segment. Terga with a row of long, fine and simple setae, sterna bare. Cerci and terminal filament light brown. Terminal filament less than half the length of the abdominal segment X.

Male imago. Body length (mm): 4.82, antennae: 0.3, fore wing width: 2.17, fore wing length: 6.01, femur I: 1.26, tibia I: 2.12, femur II: 1.24, tibia II: 1.42, femur III: 1.24, tibia III: 1.43.

Diagnosis. (1) absence of abdominal tubercles, (2) turbinate eyes moderately large and erect, and non-contiguous apically, (3) segment I of forceps with a marked distomedial projection.

Head. ( Figs 10–11 ) Brown. Turbinate eyes orange dorsally, stalk orange-gray, and black ventrally. In lateral view, moderately long, length 1.3x width. Oval shape in dorsal view. Inner margins of turbinate eyes divergent. Ocellus black. Antennae: scape and pedicel brownish, flagellum translucent beige.

Thorax. ( Figs 10–11 ) Pronotum yellowish brown with blackish spots. Mesonotum brownish with spots light brown and sutures. Metanotum brownish. Anteronotal protuberance brownish and rounded, a pale line along its length. Median longitudinal suture developed. Medioparapsidial suture slightly concave and blackish. Medioscutum beige. Foreleg measurements: femur 1.26, tibia 2.12, tarsus I 0.63, tarsus II 0.55, tarsus III 0.32, tarsus IV 0.14. Middle legs measurements: femur 1.24, tibia 1.42, tarsus I 0.09, tarsus II 0.07, tarsus III 0.10. Hind leg measurements: femur 1.24, tibia 1.43, tarsus I 0.10, tarsus II 0.07, tarsus III 0.11.

Fore wings. ( Fig. 14 ) Translucent with a hyaline area at the distal apex of the wing, between costal and R2 veins. Stigmatic area with six veins. Double marginal intercalary veins present between all veins, except between cubital and anal veins, where they are single. Length 2.9x width of the forewing. Hind wing absent.

Abdomen. ( Figs 10–11 ) Translucent with brown and white regions. Abdominal tubercles absent. Terga I–VI translucent, the anterior and middle regions brown. Terga VII–X brownish, posterior and lateral regions whitish. Sterna I–VI, translucent, VII–X whitish. Terminal filament beige translucent.

Genitalia. ( Figs 12–13 ) Forceps whitish, base of segment I light brown. Segment I with a distomedial projection, projection 0.2x width of segment I. Segment II with a slight constriction. Forceps segment I 0.25x length of segment II. Distance between the base of the forceps and the lateral margins 0.4x of the forceps. Segment III with rectangular shape globular apically, width 0.2x length. Posterior margin of the subgenital plate with a convex process in the center, and concave curves on each side contiguous to the forceps.

Female imago. Unknown

Material examined. 30 nymphs, 1 male imago. Peru, Lima Region, Huarochirí Province, Canchacalla River. Nymphs were collected from August 2018 to July 2019 and imago was collected in November 2018 by Karen Velásquez. The material is deposited at the Laboratorio de Invertebrados Acuáticos of the Facultad de Ciencias Biológicas of the Universidad Nacional Mayor de San Marcos .

Identification to the species was made following the original description. The redescription of the nymph was based on the specimens collected by the authors; the type material was not revised. The association of the nymph and the adult was made by field rearing.

Distribution. Peru, Lima Region, Chillon River Basin (Domínguez et al. 2012; Mayo 1972).

Figures

FIGURES 1–9. Baetodes traverae, nymph; 1, labrum (gray lines represent ventral position, black lines represent dorsal position). 2, left mandible (dorsal view). 3, right mandible (dorsal view). 4, maxilla (dorsal view). 5, hypopharynx. 6, labium (dorsal view).7, foreleg. 8, abdominal gill. 9, tarsal claw.

FIGURES 10–11. Baetodes traverae, male imago; 10, lateral view. 11, dorsal view.

FIGURES 12–14. Baetodes traverae, male imago; 12–13, male genitalia (ventral view). 14, fore wing.