Callibaetis fluminensis, Cruz & Salles & Hamada, 2009

Cruz, P. V., Salles, F. F. & Hamada, N., 2009, Two new species of Callibaetis Eaton (Ephemeroptera: Baetidae) from Southeastern Brazil, Zootaxa 2261 (1), pp. 23-38 : 25-30

Callibaetis fluminensis sp. n.

( Figs. 1–26 )

Male Imago. Maximum length: Body 6.1 mm; cerci 10.0 mm; forewing 5.4 mm; hind wing 0.8 mm; antenna 1.3 mm; tibia I 1.9 mm; tibia II 1.4 mm; tibia III 1.2 mm.

Head. Coloration brown. Tubinate portion of compound eyes with dorsal area and stalk orange ( Figs. 1– 2 ). Antenna with apex of scape and pedicel dark brown, flagellum brownish.

Dorsal portion of turbinate eyes oval ( Fig. 1 ); length 1.8 × width; stalk height 1.1 × width of dorsal portion; inner margins parallel, not touching each other.

Thorax ( Figs. 1–2 ). Anteronotal protuberance and medioscutum light yellowish brown; submesoscutum whitish brown; posterior scutal protuberance brown; scutellum white surrounded with dark brown.

Anteronotal protuberance rounded.

Metascutellar protuberance pointed.

Legs. Femur I with trachea pigmented, tibia I with brown marks at base and apex, tarsi I white; femur II and III with trachea pigmented, tibia II and III with two brown marks at base and one at apex, tarsi II and III white. Leg I: tibia 1.5x length of femur; tarsi 1.4 × length of femur; and with four segments decreasing in length apically. Leg II and III: tibia 0.9 × length of femur; tarsi 0.2 × length of femur.

Wings. Forewing hyaline, except for stigmatic area brownish and small brownish spots along costal vein ( Fig. 3 ); veins brown; stigmatic area with seven cross veins touching Sc; marginal intercalaries paired, except between veins MP and A; length of each intercalary vein 0.4 × distance between adjacent longitudinal veins; length of forewing about 2.5 × width.

Hind wing hyaline with three complete longitudinal veins and five cross veins ( Fig. 4 ); costal process rounded, located on basal third.

Abdomen. Terga light yellowish brown, lateral margin brown; tracheation not pigmented. Sterna light yellowish brown, with black round mark anterolaterally. Caudal filaments white, base and apex of every segment dark brown.

Genitalia. Forceps segment I light yellowish brown, segment II white with apex reddish brown, segment III white ( Fig. 5 ). Forceps segment I wide at base and with small distomedial projection, 0.5 × length of segment II; distance between base of forceps 4.7 × distance between lateral margins of forceps. Forceps segment II narrow medially. Forceps segment III oval, 1.3 × as long as wide; 0.1 × length of segment II. Posterior margin of styliger plate straight, with wide and small dorsal projection.

Female Imago. Maximum length: body 6 mm; cerci 11.5 mm; forewing 5.5 mm; hind wing 1.1 mm; antenna 1.4 mm; tibia I 1.1 mm; tibia II 1.2 mm; tibia III 1.2 mm.

Head. Coloration brown ( Fig. 6 ); compound eyes black with longitudinal brown line. Antenna with apex of scape and pedicel dark brown, flagellum brownish.

Thorax ( Fig. 6 ). Anteronotal protuberance blackish dark brown; medioscutum brown; submesoescutum black washed with white; posterior scutal protuberance dark brown; scutellum white with posterior margin dark brown.

Anteronotal protuberance rounded.

Metascutellar protuberance pointed.

Legs. Femur I, II and III with trachea pigmented, one brown spot apically, other subapically; tibia I, II and

III with one brown spot basally, subapically and apically; tarsi I, II and III light brown. Leg I: tibia 1x length of femur; tarsi 0.5 × length of femur; and with 4 segments decreasing in length apically. Leg II: tibia 0.7x length of femur; tarsi 0.4 × length of femur. Leg III: tibia 0.6 × length of femur; tarsi 0.2 × length of femur.

Wings. Forewing hyaline, except C, Sc, R1 and area around bulla brown colored ( Fig. 7 ); veins brown; stigmatic area with minimum of three cross veins touching Sc; marginal intercalaries paired, except between veins CuA and A; length of each intercalary vein 0.4 × distance between adjacent longitudinal veins; length of forewing about 2.4 × width.

Hind wing hyaline, except brown spot at base ( Figs. 8 ); three complete longitudinal veins and six cross veins; costal process rounded, located on basal third.

Abdomen. Terga light yellowish brown, laterally brown with many red spots ( Fig. 6 ). Tracheation not pigmented. Sterna white with many red spots ( Fig. 9 ). Caudal filaments white, base and apex of every segment dark brown.

Mature nymph. Length of body: 7.2 mm; cerci: 7.2 mm; terminal filament: 4.8 mm; antennae: 6.4 mm.

Head. Light yellowish brown. Antenna yellowish white.

Antenna ( Fig. 10 ) with fine, simple setae on apex of each segment. Lateral branch of epicranial suture curved. Frontal keel absent.

Labrum. Sub-rectangular; length about 0.6 × maximum width; distal margin with subquadrangular small emargination ( Fig. 11a ); with lateral and anterolateral long, fine, simple setae; medially with, short, robust, apically serrated setae ( Fig. 11b ); dorsally with long, fine, simple setae scattered over surface; submarginal row of setae absent; ventrally with short, spine-like setae near anterolateral margin.

Right mandible ( Fig. 12 ). Incisors deeply cleft in two sets, inner and outer set of incisors respectively with 4 + 4 denticles; prostheca stout, bifurcated at apex; margin between prostheca and mola straight with tuft of setae; tuft of spine-like setae at base of mola present; tuft of setae at apex of mola present; lateral margins slightly convex; basal half with short, fine, simple setae scattered over dorsal surface.

Left mandible ( Fig. 13 ). Incisors cleft in two sets, inner and outer set of incisors respectively with 4 + 4 denticles; prostheca robust and bifid; margin between prostheca and mola straight with tuft of setae; tuft of spine-like setae at base of mola present; subtriangular process wide, at the same level as area between prostheca and mola; denticles of mola not constricted; tuft of setae at apex of mola present; lateral margins slightly convex; basal half with short, fine, simple setae scattered over dorsal surface.

Hypopharynx ( Fig. 14 ). Lingua with three lobes in distal margin; superlingua not expanded; short, fine, simple setae scattered over distal margin of lingua and superlingua.

Maxilla ( Fig. 15 ). Crown of galea-lacinia with four denticles; double row of setae with two denti-setae. Medial protuberance of galea with 1+ 5 spine-like setae. Maxillary palp long, 1/5 longer than length of galealacinia; palp segment II 1 × length of segment I; segment I of maxillary palp with short and pointed setae on over surface; segment II with robust, short and pointed setae in medial surface.

Labium. Glossa with regular width along entire length and subequal in length to paraglossa ( Fig. 16a ); inner margin with 14 spine-like setae increasing in length apically; apex with many short, spine-like setae; outer margin with many long spine-like setae. Ventral surface scattered with long, fine, simple setae and one robust, short pectinated spine-like seta near apical margin ( Fig. 16b ). Paraglossa curved inward ( Fig. 16a ); apex with two rows of simple setae. Ventrally with many long, fine and simple setae. Labial palp with segment I 0.9 × length of segments II and III combined; segment I covered with short, robust, simple setae and micropores; inner and outer margin with many robust, simple setae and many long, fine simple setae; dorsally with row of many long, fine and simple setae; segment III concave, length 1.5 × width, covered with spinelike simple setae along margins and fine, simple setae, scattered over outer surface.

Thorax. Pronotum yellowish, anterior and posterior margin brown; brownish spot near midline; mesonotum yellowish with brown and light brown marks; metanotum yellowish with brown and dark brown marks.

Foreleg. Brownish white. Ratio of foreleg 1.3: 1 (0.8mm): 0.5: 0.3. Femur ( Fig. 17a ). Length about 0.2 × maximum width; dorsally with row of short, spine-like setae and row of short, fine, simple setae; length of setae about 0.1 × maximum width of femur; apex with five or six robust spine-like setae ( Fig. 17c ); ventrally with row of short, spine-like setae and row of long, fine, simple setae. Anterior surface with robust spine-like setae near dorsal margin and robust three and two-pointed spine-like setae near ventral margin ( Fig. 17b ). Tibia. Dorsally with four to five short spine-like setae and with many long, fine, simple setae; ventrally with two rows of short, spine-like setae, one row of three-pointed spine-like setae and few long, short, fine, simple setae. Anterior surface with many short, robust, spine-like setae. Tibio-patelar suture present. Tarsus. Dorsally with one to two short, robust, spine-like setae; ventrally with two rows of long spine-like setae and one row of three-pointed spine-like setae. Tarsal claw with two rows of denticles increasing in size distally ( Fig. 17d ).

Middle and hind leg. Femora with one row of short spine-like setae dorsally and ventrally. Anterior surface with many robust, curved, pectinated setae near ventral and dorsal margin ( Figs. 18a–c ). Anterior surface of tibiae and tarsi with many robust bipectinated spine-like setae ( Fig. 18d ). Claws with two rows of small denticles ( Fig. 18e ).

Abdomen. Segments II, III, V and VII with brown pigmentation as in Figure 19 . Terga. Surface creased. Posterior margin with regular spines, 3 × as long as wide. Sterna. Surface with scattered fine, simple setae. Segments with posterior margin with spines: II–IX ( Fig. 20 ).

Gills. Margin smooth; tracheae extending from main trunk to outer margin. Gill I subequal in length to segment II ( Figs. 21a–c ); with two folds; trachea pigmented. Gill IV as long as length of segments V to VII combined ( Fig. 22 ); with two folds. Gill VII as long as length of segments VIII to IX ( Fig. 23 ); with two folds.

Paraproct with 28–30 marginal spines; surface with micropores and short fine, simple setae ( Fig. 24 ); postero-lateral extension with minute marginal spines.

Inner margin of cercus and inner and outer margins of terminal filament with tufts of long setae ( Figs. 25– 26 ). Caudal filaments ( Fig. 26 ) brown; posterior margin of segments with short spines on each segment, and long spines on every three segments.

Diagnosis: C. fluminensis sp. n. can be distinguished from other species of the genus by following combination of characters:

In the male imagines: 1) dorsal portion of turbinate eyes oval, inner margins parallel, not touching each other ( Fig. 1 ); 2) forewing hyaline, except for brownish stigmatic area and small brownish spots along costal vein ( Fig. 3 ); 3) marginal intercalaries paired, except between veins MP and A; 4) length of each intercalary vein 0.4 × distance between adjacent longitudinal veins; 5) hind wing hyaline with three complete longitudinal veins and five cross veins ( Fig. 4a–b ); 6) costal process rounded; 7) sterna with black round mark anterolaterally ( Fig. 2 ); 8) forceps segment I wide at base and with small distomedial projection ( Fig. 5 ); 9) forceps segment III oval, 1.3 × as long as wide ( Fig. 5 ).

In the female imagines: 1) forewing hyaline, except C, Sc, R1 and area around bulla brown colored ( Fig. 7 ); 2) marginal intercalaries paired, except between veins CuA and A; 3) hind wing hyaline, except brown spot at base toward costal process, three complete longitudinal veins and six cross veins ( Fig. 8a–b ); 4) costal process rounded; 5) sterna white with many red spots ( Fig. 9 ).

In the nymph: 1) antenna with fine, simple setae on apex of each segment ( Fig. 10 ); 2) labrum subrectangular ( Fig. 11a ), distal margin with subquadrangular small emargination ( Fig. 11b ); 3) glossa subequal in length to paraglossa ( Fig. 16a ); 4) labial palp with inner and outer margin with many robust, simple setae and many long, fine simple setae ( Fig. 16a ); 5) anterior surface of fore femur with robust three and two pointed spine-like setae near ventral margin ( Fig. 17b ); 6) fore tarsus dorsally with one or two short, robust, spine-like setae; ventrally two rows of long spine-like setae and one row of three-pointed spine-like setae; 7) anterior surface of hind femur with many robust, curved, pectinated setae near ventral and dorsal margin ( Figs. 18b–c ); 8) anterior surface of hind tibia and tarsi with many robust bipectinated spine-like setae ( Fig. 18d ); 9) gill VII as long as length of segments VIII to IX; with two folds; 10) caudal filament with posterior margin of segments with short spines on each segment, and long spines on every three segments ( Fig. 25 ).

Etymology. After “Fluminense,” the name by which people born in the state of Rio de Janeiro are known.

Material examined. Holotype, female imago with corresponding nymphal exuviae, BRAZIL, Rio de Janeiro State, Nova Friburgo County, Lumiar (22º 23' 27,2''S; 42º 20' 03,6''W), 3 rd order tributary of the Rio Bonito , pool, V/ 2008, Souza, M. R. col . Paratypes: ten nymphs, two males same data (both reared) . Holotype and five paratypes housed at INPA. Other paratypes deposited at UFES and IBRJ .

Discussion. The adults of C. fluminensis sp. n. and C. willineri are similar, although females of C. fluminensis sp. n. have a pigmented area around bulla and hind wings have a brown spot at base, this does not occur in C. willineri . The male of C. fluminensis sp. n. has the fore wing hyaline with pigmented stigmatic area. The nymphs have maxillary palp long, 1/5 longer than length of galea-lacinia in C. fluminensis sp. n. and subequal in length to galea-lacinia in C. willineri ; anterior surface of hind femur with many robust, curved, pectinated setae near ventral and dorsal margins in C. fluminensis sp. n.; this does not occur in C. willineri .

Figures

FIGURES 1–9. Callibaetis fluminensis sp. n. Male imago: 1, dorsal view; 2, lateral view; 3, forewing; 4a, hind wing; 4b, hind wing details; 5, genitalia. Female imago: 6, dorsal body view; 7, forewing; 8a, hind wing; 8b, hind wing details; 9, ventral body view.

FIGURES 10–16. Callibaetis fluminensis sp. n. Nymphs. 10, antennae; 11a, labrum left d.v., right v.v.; 11b, anterior margin of labrum detail; 12, right mandible d.v.; 13,left mandible d.v.; 14, hypopharynx d.v.; 15, maxillae d.v.; 16a, labium left d.v, right v.v.; 16b, glossa detail v.v.

FIGURES 17–18. Callibaetis fluminensis sp. n. Nymphs. Legs: 17a, fore leg; 17b, anterior surface of fore femur near ventral margin; 17c, fore femur apex detail; 17d, fore claw; 18a, hind leg; 18b, anterior surface of hind femur near dorsal margin; 18c, anterior surface of hind femur near ventral margin; 18d, anterior surface of hind tibia; 18e, hind claw.

FIGURES 19–26. Callibaetis fluminensis sp. n. Nymphs. Abdominal structures: 19, dorsal body view (exuvia); 20, posterior margin of terga IV; 21a, lamellae I of gill I; 21b, lamellae II of gill I; 21c, lamellae I of gill I; 22, gill IV; 23, gill VII; 24, paraproct; 25, cercus; 26, terminal filament.