Callibaetis stictogaster Navás 1915

Cruz, Paulo Vilela, Salles, Frederico Falcão & Hamada, Neusa, 2017, Additions and corrections to the systematics of mayfly species assigned to the genus Callibaetis Eaton 1881 (Ephemeroptera: Baetidae) from South America, Zootaxa 4231 (4), pp. 500-534 : 523-525

Callibaetis stictogaster Navás 1915 revalidated species

( Figs. 17 A–18E)

Callibaetis stictogaster Navás 1915b: 121 ; Gillies 1990: 28. (previously syn. with C. jocosus by Gillies 1990)

Known stages. I ♀♂.

Diagnosis. Male imago: 1) costal margin of forewing with pigmentation extending beyond R1 and less intense after R2 ( Fig. 17 D); 2) marginal intercalary veins paired ( Fig. 17 D); 3) hind wing with pointed costal process; 4) marginal intercalary veins present on hind wing.

Female imago: 1) forewing completely brown ( Figs. 17 F, 18C, 18D); 2) marginal intercalary veins paired ( Figs. 17 F, 18C, 18D); 3) hind wing with brown marks ( Fig. 18 E); 4) hind wing with pointed costal process ( Fig. 18 E); 5) marginal intercalary veins on hind wing present ( Fig. 18 E); 6) abdominal terga and sterna covered with brown spots ( Figs. 17 B and 18A); 7) abdominal terga with longitudinal mark medially, near anterior margin; 8) anterior margin of terga II–IX with one pale triangle, inside of it with spots ( Fig. 18 A); 8) abdominal sterna with pigmented medioanterior and medioposterior sigilla ( Fig. 18 B); 9) abdominal sterna with two large brown marks on anterior margin, one medially and other anterolaterally ( Fig. 18 B).

Redescription. Female imago: Head. Yellowish with red “M” mark ( Fig. 18 A). Thorax. Anteronotal protuberance rounded. Metascutellar protuberance pointed. Wings. Forewing completely brown, with hyaline cross veins ( Figs. 18 C and 18D); stigmatic area with 12 cross veins touching Sc vein; marginal intercalaries paired; length of each intercalary vein 0.9 × distance between adjacent longitudinal veins; length of forewing about 2.8× width. Hind wing ( Fig. 18 E) with some brown marks; with two intercalary marginal veins; costal process pointed. Abdomen. Terga ( Fig. 18 A) with longitudinal mark medially, near anterior margin, and small light brown spots; anterior margins of terga II-IX each with one white triangular mark, inside with spots. Sterna ( Fig. 18 B) covered with reddish spots; with one longitudinal line medially; two large brown marks medially and anterolaterally, medial mark formed by spots. Caudal filaments light brown, segments brown at base and apex.

Comments. The female imago of C. stictogaster revalidated species can be distinguished from C. (C.) jocosus , C. (C.) zonalis , C. (C.) willineri , C. (C.) guttatus and C. (A.) dominguezi , as well other species of the genus, by the following characteristics: forewing completely brown ( Figs. 17 F, 18C, 18D); marginal intercalary veins on hind wing present ( Fig. 18 E); abdominal terga and sterna covered with brown spots ( Figs. 17 B and 18A); anterior margin of terga II–IX with one white triangular mark, inside of it with brown spots ( Fig. 18 A); and abdominal sterna with two large brown marks on anterior margin, one medially and other anterolaterally ( Fig. 18 B).

Based on the re-evaluation of the morphological evidence, we propose the revalidation of Callibaetis stictogaster revalidated species and designate the female imago housed in MZLP as lectotype ( Figs. 17 A and 17B), the male imago housed in MZLP as paralectotype ( Figs. 17 C and 17D) and the female imago housed in MZB as paralectotype ( Figs. 17 E and 17F).

Females collected from Brazil possess egg–nymph development inside their abdomens, indicating a possible ovoviviparous mode of reproduction.

Material examined. Callibaetis stictogaster , one female (lectotype by present designation), ARGENTINA, Prov. de Buenos Aires, 15.x.1913, C. Bruch coll., MZLP . Callibaetis stictogaster , one male imago (paralectotype by present designation), ARGENTINA, Prov. de Buenos Aires, 15.x.1913, C. Bruch coll., MZLP . Callibaetis stictogaster , one female imago (paralectotype by present designation), ARGENTINA, Prov. de Buenos Aires, 15.x.1913, C. Bruch coll., MZB . Four female imagoes, BRAZIL, Rio Grande do Sul state, Bossoroca, Barra do Angico , Piratini River , 112m alt., 28°032’06.2” S / 54°057’29.9” W, light trap, 20.x.2013 - 03.xi.2013, A. M. O. Pes coll., INPA.

Distribution. Argentina: Prov. Buenos Aires, Brazil: Rio Grande do Sul state.

Figures

FIGURE 17. Callibaetis stictogaster revalidated species male and female imagoes (lectotypes). A. labels (MLP); B. dorsolateral view of female (MLP); C. labels (MLP); D. dorsal view of the forewing of the male imago (paralectotype) (MLP); E. labels (MZB); F. dorsal view of the forewing of the female imago (paralectotype) (MZB).

FIGURE 18. Callibaetis stictogaster revalidated species female imago. A. dorsal view; B. ventral view; C. forewing; D. forewing variation; E. hind wing.