Anacroneuria divisa ( Navás, 1924 ), Navas, 1924

Gutiérrez-Fonseca, Pablo E. & Springer, Monika, 2011, Description of the final instar nymphs of seven species from Anacroneuria Klapálek (Plecoptera: Perlidae) in Costa Rica, and first record for an additional genus in Central America, Zootaxa 2965, pp. 16-38 : 21-23

Anacroneuria divisa ( Navás, 1924)

Figs. 6–7

Forquilla divisa Navás, 1924

Description. Body length: 8–13 mm. Head ( Fig. 6 ): brown forward of ocelli with a pale, well-defined m- line and pale anterior frontoclypeus, often with pale spots on the outer side of the ocelli. Pronotum: rectangular; brown in lateral third with pale, indistinct medial stripe. Surface covered with fine short setae, lacking bristles. Margins completely fringed with short thick bristles, somewhat variable in length. Meso- and Metanotum: pale irregular spots around the midline; wing pads dark when well developed. Dorsal surfaces covered with fine short setae, and scattered thick bristles; well-defined anterior and lateral lines of thick bristles. Margins completely fringed with short thick bristles, somewhat variable in length. Foreleg ( Fig. 7 ): dorsal surfaces covered with fine short setae, except for hairless median bar and basal posterior triangle-shaped area on femur. Posterior margin laterally with dense fringe of long setae. Femur dorsally with well-defined transverse row of around six long, thick spines; basal posterior patch of very small spines along margin, reaching transverse row of long spines.

Distribution. Costa Rica, Nicaragua.

Local distribution ( Fig. 8 ): Lowland and middle elevation streams on both Pacific and Caribbean slopes.

Reared specimens. Alajuela : Trib. Río Pizote Upala, 24.viii.2008, Gutiérrez, 3 3; Quebr. Rugama, Nuevo Arenal, Tilarán, 550 m, 20.ix.2008, Gutiérrez, 2 3.

Additional material examined. Alajuela : Río Las Musas, San Ramón, 1100 m, 25.x.2003, A. Y. Jiménez, 1 3; Río Peñas Blancas, San Carlos, 260 m, 8.xii.1998, Springer & Y. Astorga, 2 3; Heredia: Quebrada Tigre, Rara Avis, Est. Biol. El Plástico, 560 m, 27.i.1998, Springer & OTS students, 9 3, 13 Ƥ; same, i.1999, Springer & OTS students, 3 3, 5 Ƥ; Quebrada El Salto, Est. Biol. La Selva, Pto. Viejo, Sarapiquí, 50 m, vi.1998, OET students Agroecología, 1 3; Trib. Río Puerto Viejo, Est. Biol. La Selva, Pto. Viejo, Sarapiqui, 50 m, 17.ix.2005, M. Losilla, 2 3, 1 Ƥ; Quebrada sin nombre, Est. Biol. La Selva, Pto. Viejo, Sarapiqui, 50 m, 19.vi.1996, E. Martínez, 1 Ƥ; Guanacaste: Río Sanjosecito Est. Biol. Cacao, Volcán Cacao, 700 m, 22.iii.1990, W. Flowers, 2 Ƥ; Puntarenas: Río Ojochal, Ojochal, Península de Osa, 0 m, 15.ix.2005, T. Cotta, 1 Ƥ; Quebrada Naranjal, Golfito, 10 m, 21.i.2000, Springer & UCR students, 1 Ƥ; Quebr. Cañaza, below waterfall, Golfito, 10 m, i.1997, A. Villalobos, 6 3, 4 Ƥ.

Habitat and substratum. Submerged leaf litter packs in strong current, mostly in small to medium size streams in forested areas.

Diagnosis. The nymph of A. divisa is very similar to A. holzenthali and A. benedettoi in color pattern, shape and size ( Fig. 6 ), but A. divisa differs from the latter, by having less spines (≤9) ( Fig. 7 ) in the transverse row on the femur, than in the other two species (>10).

Figures

FIGURE 8. Map of Costa Rica showing distribution of Anacroneuria divisa.

FIGURES 6 − 7. Anacroneuria divisa, 6. Head and thorax (pro, meso and meta notum); 7. Foreleg.