Chimarra

Desidério, Gleison Robson, Barcelos-Silva, Patrik & Hamada, Neusa, 2018, New species, records, and immature stages of Chimarra Stephens (Trichoptera: Philopotamidae) from Campos Amazônicos National Park, northern Brazil, Zootaxa 4500 (2), pp. 258-270 : 264-268

Chimarra (C.) usitatissima Flint 1971

( Figures 3–5)

Chimarra usitatissima Flint 1971: 24 (Type locality: Brazil, Amazonas, Rio Branquinho, bei Cachoeira; NMNH; ♂); Flint 1974: 29 (♂; distribution); Blahnik 2002: 119 (♂; ♀); Paprocki et al. 2004: 15 (checklist); Paprocki & França 2014: 78 (checklist); Desidério et al. 2017: 167 (checklist); Holzenthal & Calor 2017: 398 (catalog).

Material examined. BRAZIL: Amazonas: Manicoré, Campos Amazônicos National Park, confluence of the Rio Macaco with the Rio Branco , 08°22'04.5''S, 61°43'28.3''W, 77 m a.s.l., 1 female, 1 male, 06–07.vii.2017, N. Hamada, G. R . Desidério, P. V . Cruz, J.O. Silva legs., Pennsylvania trap ( INPA); 11 larvae, 07.vii.2017, N. Hamada, G. R . Desidério, P. V . Cruz, J.O. Silva legs. ( INPA); Igarapé do Veado , 08°26'27.4''S, 61°39'37.3''W, 93 m a.s.l., 1 larva, 07.vii.2017, N. Hamada, G. R . Desidério, P. V . Cruz, J.O. Silva legs. ( INPA); Rio Branco , 08°26'15.5''S, 61°45'01.9''W, 66 m a.s.l.: 1 male, 04–05.vii.2017, N. Hamada, G. R . Desidério, P. V . Cruz, J.O. Silva legs., Pennsylvania trap ( INPA); 2 pharate males, 60 larvae, 06.vii.2017, N. Hamada, G. R . Desidério, P. V . Cruz, J.O. Silva legs. ( INPA); 2 males, 3 females, 07.vii.2017, N. Hamada, G. R . Desidério, P. V . Cruz, J.O. Silva legs., Sheet LED light ( INPA) ; Mato Grosso: Colniza, Rio Jatuarana , 08°48'07.6''S, 61°25'09.5''W, 107 m a.s.l., 2 larvae, 05.vii.2017, N. Hamada, G. R . Desidério, P. V . Cruz, J.O. Silva legs. ( INPA) .

Larva (5th instar) ( Figs. 3–4). Length 8.41–11.05 mm (mean = 9.87 mm, SD = 0.95 mm, n = 5).

Head. Subrectangular in dorsal view; pale yellow. Stemmata double, anterior larger than posterior; each stemma set surrounded by pale oval spot in lateral view. Spots on head conspicuous; 6–7 pale oval spots posteriorly on each parietal apotome in dorsal view ( Fig. 3B). Chaetotaxy consisting of #01, #02, #03, #04, #05, #06, #09, #14 [dorsal setae], #07, #12, #13 [lateral setae], and #08, #18 [ventral setae] (i.e., setae #15, #16, and #17 not evident); primary setae mostly long, thick and dark; seta 18 short, pale brown, located midanteriorly and about 1/4 length of head behind ventral apotome ( Fig. 3F). Anterior margin of frontoclypeus pale brown; asymmetrical, deep notch, left margin projecting farther than right and with medial lobe small, rounded; frontoclypeal suture keyhole-shaped ( Figs. 3B, 3C). Coronal suture 1/4 as long as head. Labrum pale yellow, membranous, T-shaped; anterior margin straight, with setal brush along all its anterior margin and with small median notch ( Fig. 3B). Mandibles asymmetrical, each with external margin bearing two fine, pale setae; left mandible with 1 slightly bilobed molar tooth, 6 finely serrate mesal teeth, 1 pointed subapical tooth, 1 sharp large apical tooth, and 1 pointed, subapicodorsal tooth between latter two teeth; right mandible with 1 triangular molar tooth, 3 finely serrate mesal teeth, 1 pointed subapical tooth, 1 sharp large apical tooth, and 1 pointed subapicodorsal tooth between latter two teeth ( Fig. 3D). Lateral sides of head with three to four pale brown muscle scars barely visible near occipital margin ( Fig. 3E). Submentum trapezoidal, large, anterior margin slightly accentuated medially, with two long, dark anterolateral setae. Ventral apotome transversely subtriangular, 1/2 as broad as head ( Fig. 3F).

Thorax. Pronotum sclerotized, pale brown, posteriorly with black border, divided by longitudinal ecdysial line, and with dorsolateral depressions on anterior third and posterior quarter of each side of sclerite; with 5 pairs of pale marginal setae and 3–4 pairs of medium to long, slender, dark brown submarginal setae, on mid-region (two pairs of setae), and posterior third (four pairs of setae) ( Fig. 4A); black posterolateral pronotal margin reaching base of one short brown seta, and interrupted laterally by light spot before posterior margin ( Fig. 4B). Meso- and metanota membranous, white, with two posterior, long, dark setae on mesonota ( Fig. 3A). Foretrochantin short, with blunt anterior apex; with long, slender posterior portion tapering to rounded apex ( Fig. 4B). Legs yellowish brown. Foreleg coxae each with one median, pale, mid-lateral spike-like seta, and two long ventro-distal setae on external surface in lateral view ( Fig. 4C 1), two dark mid-dorsal setae (one short and one long), and one median seta ventrodistal on internal surface in dorsal view ( Fig. 4C 2); coxal process subapicodorsal, long, slender, tapering to apex with one short, pointed distal seta. Foretrochanters each with one median, pale, ventro-proximal seta, four median and long, pale, ventro-distal setae in lateral view ( Fig. 4C 1), and one median, dark, distal seta on internal surface in dorsal view ( Fig. 4C 2). Forefemora each with four median, pale, mid-ventral setae; one long, dark, mid-dorsal seta; and one long, pale, dorso-distal seta. Foretibiae each with pair of median, pale, ventro-distal spike-like setae; two long, pale, dorso-distal setae, and one median, latero-distal seta in lateral view. Foretarsi each with ventral row of about 25 short pales along all of its length; one long, pale dorso-distal seta; and three latero-distal setae ( Fig. 4C 1). Mid- and hind legs similar in size, form, and chaetotaxy to foreleg except that femora each with two long, dark, and pale, mid-ventral setae, and one short, pale, latero-distal spike-like seta; tibiae each with one short, brown, ventrodistal spike-like seta; tarsi each without ventral row of setae ( Figs. 4D 1 –4D 2, 4E).

Abdomen. Abdominal segments membranous, whitish, with few long, thin, dark, hair-like setae. Gills absent ( Fig. 3A). Segment X with one pair of long, thin, dark, ventral hair-like setae, and membranous anal papillae (may be retracted) ( Fig. 4F). Anal prolegs each with one median pale ventral hair-like seta, another long, brown, dorsodistal seta, and with bent simple claw ( Fig. 4F).

Pupa ( Fig. 5). Length 4.29–4.66 mm (n = 2).

Head. Labrum with anterior margin rounded and bearing two pairs of long setae; one pair of long, basolateral setae, and about 30 short setae grouped in middle ( Fig. 5B). Mandibles symmetrical, pale brown, broad basally, curved mesad, each tapering to bifid, pointed apex, with one long, pale seta basolaterally; inner margin with numerous short, finely serrated teeth over all its length ( Fig. 5C).

Thorax. Dark brown, without conspicuous features other than those of adult specimens of Chimarra (Chimarrita) ( Fig. 5A).

Abdomen. Covered with sparse setae. Lateral fringes absent. Abdominal terga with pairs of anterior hook plates (a) on segments III–VIII with hooks directed posterad; pair of posterior hook plates (p) on segment V with hooks directed anterad ( Figs. 5A, 5D); hook-plate pair IIIa each with 1 spatulate-shaped hook bearing shallow notch; hook-plate pair IVa each with 1 spatulate-shaped hook; hook-plate pair Va each with 1 sharply pointed hook; hook-plate pair Vp each with 4 pointed, upturned hooks and 1 smaller; hook-plate pair VIa each with 3 pointed hooks; hook-plate pair VIIa each with 1 sharply pointed, long hook; hook-plate pair VIIIa each with 1 pointed, stout hook ( Fig. 5D). Apical processes of segments IX–X globose and covered with numerous long, dark setae ( Fig. 5E).

Known distribution. Brazil (Amazonas, Maranhão, Minas Gerais, Pará, Rondônia), Ecuador, Guyana, Peru, Suriname, Venezuela.

Remarks. This species was initially placed in the C. (Chimarra) aterrima Group, although very different from most other described species in the group ( Flint 1971). The phylogenetic analysis of C. ( Otarrha ) performed by Blahnik (2002) indicated that C. usitatissima and its close sister taxon C. angularis are possibly basal taxa in this latter subgenus, but this hypothesis was weakly supported, and these species were retained as incertae sedis.

Chimarra usitatissima and C. angularis are morphologically very similar in the adult stage, but with slight differences in the shape of tergum X and inferior appendage of the male genitalia. In the larval stage, C. usitatissima can be distinguished from the few other species in the genus with known immatures by the following characters: 6–7 pale oval spots posteriorly on each parietal apotome; the anterior margin of the frontoclypeus is asymmetrical with a deep notch, the left margin projecting farther than the right and with its medial lobe small, rounded; each mandible has its external margin bearing two fine, pale setae; the left mandible has one slightly bilobed molar tooth and six fine serrations; the right mandible has one triangular molar tooth and three fine serrations; the pronotum has 5 pairs of medium to long, slender, pale marginal setae and 3–4 pairs of medium to long, slender, dark brown submarginal setae, two pairs setae on the mid-region and four pairs on the posterior third; the shape of the coxal process of foreleg; the number and position of setae on the legs (for example, foreleg tibiae each with a pair of medium, pale, ventro-distal spike-like setae; the tarsi each have a ventral row of about 25 short, pale setae; and the mid- and hind tibia each have one short, brown, ventro-distal spike-like seta.

The pupa of C. usitatissima is recognized mainly by the mandibles each tapering to a bifid, pointed apex and the inner margin with numerous short, finely serrated teeth; and the number and shape of hooks on the hook-plates of the abdominal terga (for example, hook-plate pairs IIIa and IVa each with 1 spatula-shaped hook).

Chimarra usitatissima is widely distributed in the Amazon Basin, mainly in the forested region of the Brazilian portion of the basin. However, in Brazil it also occurs in fragments of Cerrado in the states of Maranhão, Minas Gerais, and Amazonas ( Campos Amazônicos National Park ) .