Phylloicus angustior Ulmer 1905

Datto-Liberato, Felipe Henrique, Moreira-Silva, Larissa & Paprocki, Henrique, 2025, Description of the final instar larva of Phylloicus paprockii and morphological notes of Phylloicus angustior (Trichoptera: Calamoceratidae) in the Southeastern region of Brazil, Zootaxa 5653 (2), pp. 196-210 : 203-206

Phylloicus angustior Ulmer 1905

( Figs 24–43 )

Phylloicus angustior Ulmer 1905 a: 78 [Type locality: Brazil, Rio Gr. do Sul [sic]; NMW; male]. Thienemann 1909: 129–132 [larva]. Flint 1966: 11 [lectotype male]. Botosaneanu & Flint 1982: 24 [redescription of larva].

Material examined. BRAZIL: Minas Gerais: Aldeia da Cachoeira das Pedras, Senzala Stream (20°06'52.1"S, 44°01'23.2"W; 925 m a.s.l.), vii–x.2018, collected by F. H. D. Liberato, H. Paprocki, L. Moreira-Silva & V. H. M. Machado. Twelve final-instar larvae and six adults of P. angustior were examined from this material. All six adults were reared from larvae in the laboratory, emerging on 5.vii.2018 (♂), 2.viii.2018 (♂, 2 ♀), 13.viii.2018 (♂), and 14.viii.2018 (♂). All specimens are deposited in MCN-PUC Minas .

Distribution. Argentina, Brazil (Espírito Santo, Goiás, Mato Grosso do Sul, Minas Gerais, Paraná, Santa Catarina, São Paulo, Rio Grande do Sul), Colômbia, Paraguay, Uruguay and Venezuela.

Morphological Notes

Larva. Body length mean = 13.5 mm (range 10.6–16.5 mm; n = 12). Head and thorax dark brown, abdomen pale yellow.

Head. Elongate, oval in dorsal view. In ventral view, contour of head capsule basally convex to flattened genal regions. Head darker than pronotum and with evident yellowish muscle scars ( Figs 24, 25 ). Frontoclypeal apotome triangular, wider anteriorly with weak constriction between eyes, four small pale anterior spots and one large, transversely oval spot posteriorly at 2/3 length. Labrum with transverse row of 16 setae ( Fig. 24 ). Triangular ventral apotome reaching occipital foramen, anterior central region covered with microspicules ( Figs 26–28 ). Genae ornamented with pair of patches of microspicules beside posterior portion of ventral apotome ( Figs 27, 28 ). Head chaetotaxy as in ( Fig. 24 ).

Thorax. Pronotum sclerotized, light brown, without evident muscle scars; anterolateral processes reaching midlength of head laterally, bearing three long setae and one short seta ( Figs 29, 30 ). Posterior margin of pronotum darker, anterior margin with lightly sclerotized apodeme and bearing two pairs of long setae and two pairs of minor yellowish setae, five pairs of setae (setae 2, 5, 6, 7, 8) near anterolateral edges ( Fig. 31 ). Mesonotum with pair of central irregular sclerites, each with anterolateral and anteromesal margins sclerotized and depressed. Paired setal areas present, Sa1 with one short seta, Sa2 with one long seta (seta 2), and one short seta (seta 3), Sa3 on prominent anterolateral sclerite, with five long setae and two short setae (collectively seta 10). Metanotum membranous with paired setal areas: Sa1 with one long seta, Sa2 with one long seta and one short seta, Sa3 slightly sclerotized with four short setae and one long seta ( Fig. 31 ). Legs pale yellowish; coxae, trochanters, femora of forelegs shorter and slightly more robust than the other legs; midtibiae and hind tibiae each with conspicuous distal spine; Foretrochantins well developed, sinuous, each with long subapical seta, anteriorly tapered to acute upturned apex, reaching anterior part of head; ornamented by basally triangular and apically acute microspicules ( Figs 35–36 ).

Abdomen. Membranous, yellowish, lighter than head and thorax. Gills each with three or four filaments, distributed as in ( Figs 37, 39 ). Segment I with dorsal and ventral hump well developed, round, membranous; ventral hump bearing pair of sclerites on anterior part of hump ( Fig. 37 ). Segments III–VIII setose along lateral line, from anterior edge of segment III through posterior part of segment VIII ( Fig. 37 ). Tergites VIII and IX each with one pair of long, dark dorsal setae and three pairs of short setae ( Fig. 41 ). Anal prolegs with terminal claw strongly sclerotized and with short accessory hook on medial margin ( Figs 42, 43 ), with three long and two short, stout setae dorsally ( Fig. 41 ).

Case. Length 43.05 mm (range 33.21–52.34 mm; n = 7). Dorsoventrally flattened (depressed), anterior portion slightly wider than posterior part. Dorsal and ventral surfaces formed by several irregular leaf fragments cut into different sizes, covering longitudinal central chamber, fastened together with silk; dorsal surface with anterior margin convex, larger than ventral surface; ventral surface with anterior margin straight ( Fig. 40 ).

Remarks

Phylloicus is the only Calamoceratidae genus occurring in Brazil, with 29 species, with larvae having been described for 16 of these species ( Holzenthal & Calor 2017; Calor et al. 2024). Larval descriptions were previously published for the following Brazilian species: P. abdominalis (by Huamantinco et al. 2005), P. aeneus (by Wiggins 1996), P. angustior (by Thienemann 1909; Botosaneanu & Flint 1982), P. amazonas (by De Souza-Holanda et al. 2020), P. bromeliarium (by Ulmer 1955), P. camargoi Quinteiro et al. 2011 (by Quinteiro et al. 2011), P. cressae (by Barrios et al. 2020), P. fenestratu s (by De Souza-Holanda et al. 2020), P. lituratus (by Rueda-Martín 2013), P. obliquus (by Cavalcante et al. 2020), P. passulatus (by De Souza-Holanda et al. 2020), P. elektoros Prather, 2003 (by Campos et al. 2021).

This study was carried out in a stream that originates inside Serra do Rola Moça State Park, in the municipality of Brumadinho, Minas Gerais, southeastern Brazil. The park was created in 1994 and preserves an area of 4.006 ha situated in a transition zone between Brazilian savannah and Atlantic Forest ( IBGE 1992). Thus, it is one of the main priority areas for conservation of biodiversity in Minas Gerais state, Brazil ( Drummond et al. 2005). On January 25, 2019, the collapse of the Córrego do Feijão tailings dam in Brumadinho (Minas Gerais, Brazil) released approximately 12 million cubic meters of mining waste into the Paraopeba River, destroying native Atlantic Forest vegetation and resulting in the deaths of at least 250 people ( Vergilio et al. 2020). The Senzala stream, a tributary of the Paraopeba River basin, was not directly affected by the dam collapse and has maintained a preserved aquatic biodiversity. This stream harbors a rich assemblage of aquatic insects that could serve as a source for the recolonization of the impacted Paraopeba River following its rehabilitation.

The description of the immature stages of Phylloicus paprockii and Phylloicus angustior expands our understanding of aquatic biodiversity in the Paraopeba River basin. Given that these species occur in this basin, they can act as bioindicators and contribute to the recolonization of impacted areas after the river’s rehabilitation. Therefore, preserving protected areas such as the Serra do Rola Moça State Park and its streams, including the Senzala Stream, is crucial. These ecosystems serve as biodiversity reservoirs (IEF 2025) and could play a fundamental role in the recovery of degraded habitats. These findings could provide valuable insights into environmental monitoring, decision-making processes, and conservation efforts aimed at preserving Atlantic Forest headwater streams.

Figures

FIGURES 24–28. Phylloicus angustior (Ulmer 1905) larva. 24–25, head: 24, dorsal; 25, right lateral. 26–28, Scanning Electron Microscopy (SEM): 26, ventral; 27, ventral apotome and genae, ventral; 28, detail of tiny microspicules on a gena. Fig. 24, chaetotaxy follows Wiggins (1996) and Williams & Wiggins (1981).

FIGURES 29–34. Phylloicus angustior (Ulmer 1905) prothorax and anterolateral projection. 29, 30, Scanning Electron Microscopy (SEM): 29, prothorax, right lateroventral; 30, right anterolateral projection, right lateroventral. 31–34, Thorax and legs: 31, thorax, dorsal; 32, right foreleg, posterior; 33, right midleg, posterior; 34, right hind leg, posterior. Figs 31–32, chaetotaxy follows Wiggins (1996) and Williams & Wiggins (1981), Sa1 = setal area 1; Sa2 = setal area 2; Sa3 = setal area 3.

FIGURES 35–36. Phylloicus angustior (Ulmer 1905) larval foretrochantin. Scanning Electron Microscopy (SEM), right lateroventral: 35, complete foretrochantin; 36, apex of foretrochantin.

FIGURES 37–40. Phylloicus angustior (Ulmer 1905) larva. 37, habitus, right lateral; 38, head and thorax, dorsal; 39, diagrammatic distribution of abdominal gills, left lateral; 40, case ventral.I–VIII = abdominal segments I–VIII; DL = dorsolateral gills; L = lateral gills; VL = ventrolateral gills.

FIGURES 41–43. Phylloicus angustior (Ulmer 1905) larva. 41, abdominal terga VIII and IX, dorsal. 42, 43, Scanning Electron Microscopy (SEM), abdominal segment IX: 42, caudal, with ventral side up; 43, right caudolateral with details of right anal claw.