Anacroneuria singularis Righi-Cavallaro & Lecci

Ribeiro, José Moacir Ferreira, Gorayeb, Inocêncio De Sousa & Bispo, Pitágoras Da Conceição, 2015, Description of the nymph of Anacroneuria singularis Righi-Cavallaro & Lecci (Plecoptera: Perlidae) and a new locality record for northern Brazil, Zootaxa 4057 (2), pp. 295-300 : 296-299

Anacroneuria singularis Righi-Cavallaro & Lecci

( Figs. 1–11 )

Anacroneuria singularis Righi Cavallaro & Lecci, 2010: 42 , figs. 13–18 Material examined. BRASIL, Pará, São Geraldo do Araguaia, Serra dos Martírios-Andorinhas, Sucupira stream, 24.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (4 nymphs, MPEG); Santa Cruz stream, 24.x.2011, light trap, J.M.F. Ribeiro & C.R.M. Santos (1 adult female, MPEG); stream near the bridge over the river Sucupira, 24.x.2011, reared in stream, J.M.F. Ribeiro & C.R.M. Santos (1 adult female, 1 exuvia, MPEG); Sucupira stream (near the bridge), 24.x.2011, reared in stream, J.M.F. Ribeiro & C.R.M. Santos (1 adult female, 1 exuvia, UNESP); Água Bonita stream, 06º13´36,8´´S; 48º30´05,4´´W, 26.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (18 nymphs, MPEG); Água Bonita stream, 26.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (1 nymph, 1 exuvia, MPEG); Água Bonita stream, 26.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (10 nymphs, MPEG); Brejão stream, 26.x.2011, reared in stream, J.M.F. Ribeiro (2 adult males, MPEG); Jatobá stream, 27.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (4 nymphs, MPEG); Gamelerinha stream, 27.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (23 nymphs, MPEG); tributary of Sucupira stream, 6º17´59´´S; 48º25´20´´W, 28.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (8 nymphs, MPEG); Água Verde stream, 06º04´16,5´´S; 48º 50´15,5´´W, 30.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (5 nymphs, 2 exuvias, MPEG); Água Verde stream, 30.x.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (3 nymphs, MPEG); Água Bonita stream, 29.x.2011, reared in stream, J.M.F. Ribeiro, & C.R.M. Santos (1 female, 1 exuvia, MPEG); Água Verde stream, 06º04´16,5´´S; 48º 50´15,5´´W, 30.x.2011, reared in stream, J.M.F. Ribeiro & C.R.M. Santos (1 adult female, MPEG); Sucupira stream (near the bridge), 07–12.xii.2013, Malaise trap, J.M.F. Ribeiro (2 adult males, MPEG); Água Bonita stream, 07–12.xii.2011, aquatic net, J.M.F. Ribeiro & C.R.M. Santos (5 nymphs, MPEG); 07.xii.2013, light trap, J.M.F. Ribeiro (1 adult male, MPEG); Água Bonita stream, 07–12.xii.2013, J.M.F. Ribeiro (29 nymphs, 3 exuvias).

Description of nymph. General color dark brown ( Fig. 1 ). Head, antennae brownish, basally light yellow; two ocelli; frons uniformly dark brown with M-line indistinct and with small lateral spots near the ocelli; parietalia whitish, brown on coronal and postfrontal lines; compound eyes black; postfrontal line U-shaped ( Fig. 2 ); labrum brown with fine bristles; labium as in Fig. 3 and with ochraceous palpi; maxilla as in Fig. 4 and also with ochraceous palpi; mandible robust with the 2nd, 3rd and 4th teeth subequal ( Figs. 5, 6 ); in molar area, two rows of bristles, one starting at the base of the 2nd tooth and the other at the base of the 4th tooth ( Figs. 5, 6 ). Thorax, pronotum dorsally brown with ochraceous spots, lateral margins light brown, anterior and posterior margins dark brown ( Fig. 2 ); ventrally pale yellow with sulci well marked ( Figs. 8 ); mesonotum and metanotum dark brown with ochraceous spots ( Fig. 7 ). Gills ASC1, PSC1 with two branches, AT2, AT3, PT3, A1 with double trunk; ASC, PSC (2,3) and SL absent. Fore leg dorsally ochraceous ( Fig. 9 ), whitish ventrally ( Fig. 10 ); coxa with few bristles; trochanter with few robust bristles; femur with two transverse dorsal rows of long robust bristles ( Fig. 9 ), ventral face with few bristles ( Fig. 10 ); base of the tibia dark yellow; tibia apically with rows of short fine bristles, a group of dense fine white long bristles form a fringe, in posterior margin (barely visible in Figs. 9 and 10 ); tarsus ochraceous. Abdomen brown, intersegmental membranes ochraceous; rows of bristles around the posterior margin are complete on segments 8 to 10; in females, presence of a median sulcus on sternite 8. Cerci brownish ( Fig. 11 ).

Variation. General body color varies from dark to light brown. Younger nymphs have additional and stouter bristles, appearing more pilose. Markings on the pronotum vary in color, shape, and size.

Discussion. A. singularis has been collected mainly in central Brazil and this is the first report of the species from the municipality of São Geraldo do Araguaia, Serra dos Martírios-Andorinhas, Pará State. The nymph of this species ( Figs. 1–11 ) resembles those of A. debilis (Pictet, 1841) ( Silva et al. 2011) and A. marlieri Froehlich 2001 ( Ribeiro & Gorayeb 2014) , principally in general body form and coloration. It differs from A. debilis in the color of anterior dorsal portion of the head, which in A. singularis is uniformly dark brown to the postfrontal line; in A. debilis it becomes lighter near ocelli ( Silva et al. 2011). Anacroneuria singularis differs from A. marlieri by the presence of ochraceous spots on the brown pronotum (in A. marlieri , uniformly brown, Ribeiro & Gorayeb 2014).

Ecological notes. Nymphs of A. singularis were collected from five relative pristine streams in a protected natural area in southern Pará State in northern Brazil. The physical and chemical parameters of the sampled streams were: water temperature (24–29o C); pH (6.0–6.7); specific conductance (9.1–86.8 uS /cm); dissolved oxygen (11,0– 20,0 mg/l); width of stream (2.7–6.6 m); depth of stream (0.17–0.60 cm); velocity of flow (0.06– 0.31 m /s), and stream discharge (0.10–0.77 m 3/s). Nymphs were always collected from riffle areas with from sandy and loose rocky substrates.

Figures

FIGURES 1 – 6. Female Anacroneuria singularis nymph. 1. Body; 2. Head and pronotum, dorsal view; 3. Head, ventral view; 4. Maxillae and lacinia; 5. Mandible, dorsal view; 6. Mandible, ventral view (Photos: J. M. F. Ribeiro).

FIGURES 7 – 11. Female Anacroneuria singularis nymph. 7. Wing pad; 8. Sternal sulci and gills; 9. Legs, dorsal view; 10. Legs, ventral view; 11. Abdomen, ventral view (Photos: J. M. F. Ribeiro).