Triplectides gracilis ( Burmeister, 1839 )

Henriques-Oliveira, Ana Lucia, Nessimian, Jorge Luiz, Takiya, Daniela Maeda & Santos, Allan Paulo Moreira, 2025, Hidden diversity of the long-horned caddisfly genus Triplectides Kolenati, 1859 (Trichoptera: Leptoceridae) in Brazil revealed by DNA and morphology: new species descriptions and larval associations, Arthropod Systematics & Phylogeny 83, pp. 757-796 : 757-796

3.2. 1. Triplectides gracilis ( Burmeister, 1839)

Figures 2 , 3

Triplectides gracilis ( Burmeister, 1839: 921), as Mystacides gracilis (type locality: Brazil; specimen collected by Beske, probably from Nova Friburgo, Rio de Janeiro). Holotype destroyed, depository: ZIUH. Ulmer 1905: 27 (redescription). Mosely 1936: 96 (redescription). Holzenthal 1988: 195 (redescription, neotype designation: Brazil, Rio de Janeiro, 950 m, Nova Friburgo, municipal water supply; depository: MZSP). Sganga et al. 2013: 26 (larva and pupa from Argentina).

Triplectides principes ( Burmeister, 1839: 921), as Mystacides principes (type locality: Brazil; specimen collected by Beske, probably from Nova Friburgo, Rio de Janeiro). Holotype destroyed, depository: ZIUH. Ulmer 1905: 27 (to synonymy).

Triplectides ramulorus ( Müller, 1921: 241), Tetracentron ramulorum, only larva and pupa (type locality: Brazil, Santa Catarina). Type material and depository not designated. Holzenthal 1988: 195 (to synonymy).

Material examined.

BRAZIL • 1 ♂; Rio de Janeiro, Guapimirim, Parque Nacional da Serra dos Órgãos, Trilha das Ruínas, tributary of Rio Soberbo ; 22°29′45.0″S 42°59′46.6″W; alt. 344 m; 25 mar. 2010; L. L. Dumas, J. L. Nessimian leg.; light trap; [DNA voucher ENT 0672]; DZRJ TRICHOPTERA 9166 • 1 ♂; Rio de Janeiro, Nova Friburgo, Rio Bonito, km 13.5 ; 01–03 Oct. 2021; light trap; A. P. M. Santos leg. [DNA voucher ENT 5922]; DZRJ TRICHOPTERA 9167 • 1 larva; Rio de janeiro, Petrópolis, Araras, ROCIO, stream in the road ; 22°28′25.5″S 43°15′49.10″W; 08 May 2018; A. L. H. Oliveira, J. L. Nessimian, C. Novais leg.; [DNA voucher ENT 4358]; DZRJ TRICHOPTERA 9171 • 1 larva; same data as for preceding, except, small stream near to SINDACTA ; 22°28′19.2″S 43°17′44.5″W; alt. 1194 m; 08 May 2018; A. L. H. Oliveira, J. L. Nessimian, C. Novais leg.; [DNA voucher ENT 4359]; DZRJ TRICHOPTERA 9170 • 1 larva; Rio de Janeiro, Petrópolis, Araras, Reserva Biológica de Araras, trilha das águas (poço) ; 22°26′06″S 43°15′33.1″W; alt. 993 m; 29 Jan. 2020; A. L. H. Oliveira leg.; [DNA voucher ENT 5388]; DZRJ TRICHOPTERA 9169 • 1 larva; same data as for preceding; [DNA voucher ENT 5389]; DZRJ TRICHOPERA 9172 • 1 larva; Rio de Janeiro, Teresópolis, Parque Nacional da Serra dos Órgãos, Rio Paquequer (bridge) ; 22°27′25.05″S 42°59′51.80″W; alt. 1112 m; 21 Aug. 2014; A. L. H. Oliveira leg.; [DNA voucher ENT 1998]; DZRJ TRICHOPTERA 9168 .

Description.

Adult. For a full description of adult of T. gracilis see Holzenthal (1988). Photographs of adult wings are provided in Figure 2 . — Larva. Total length 10–17 mm (n = 5) (Fig. 3 A ). — Head: Coloration (in alcohol) reddish brown to dark brown, with many pale spots on the front and posterior portions, and a pale oval area around the stemmata (Fig. 3 B ). Head almost sub-rectangular, slightly enlarged posteriorly, in dorsal view (Fig. 3 B ). Labrum pale brown, in dorsal view, subtrapezoidal with anterolateral corner rounded, three pairs of labral setae in the middle length with brush of short, secondary setae on its anteroventral margin. Mandible dark, asymmetrical, typical for Triplectides (left mandible with 6 teeth around a concavity and right mandible with 5 teeth). Submentum oval. Ventral apotome subtriangular, slender, and narrow (Fig. 3 B ), slightly wide anteriorly with a small constrict in mid-length, narrowing posteriorly to an acute pointed tip (Fig. 3 B ). — Thorax: Pro- and mesonotum reddish brown with pale muscle scars and spots (Fig. 3 D ). Pronotum with anterior and lateral margins crenulate; slightly protruded on the corners, posterior margin rounded (Fig. 3 C ). Mesonotum covered by a pair of large sclerites: sa 1 each with long single seta; sa 2 each with 3 setae: (one mesal longer than the others); sa 3 each with 6 setae (2 long setae on the corner, and other 4 short). Metanotum covered by 3 pairs of thin and pale brown sclerites: sa 1 subquadrate, bearing a long seta each, sa 2 subquadrate with a very long seta each, sa 3 elongate, oval, bearing 3 setae each (Fig. 3 D ). Prosternum narrow with a dark subtriangular sclerite. Mesosternum with pair of subtriangular sclerites, curved laterally; anterior margin dark brown (Fig. 3 E ). Metasternum with setal area bearing 8–10 setae (Fig. 3 E ). Foretrochantin with anterodorsal margin straight, with corner pointed and upturned and anteroventral corner rounded (Fig. 3 C ). Legs yellowish brown with dark brown stripes, setose (Fig. 3 G ). — Abdomen: Gills simple, present on segments II – VIII, segments II – VI with dorsal, lateral, and ventral filaments; segment VII with lateral and ventral filaments; segment VIII with ventral filaments (Fig. 3 H ). Segments III – VIII with lateral fringes. Segment I with two pairs of long setae at the base of dorsal hump. Segment VIII with a pair of posteromesal setae. Segment IX dorsal sclerite with 6 very long setae on posterior margin and 2 pairs of very short, lateral setae, one anterolateral short seta at each side of the sclerite (Fig. 3 F ). Anal claws single, large, and pointed, with a small dorsal accessory hook (Fig. 3 F ). — Larval case: Length up to 16 mm. Simple hollow stick (Fig. 3 I ).

Distribution.

Argentina, Brazil, and Paraguay.

Remarks.

Triplectides gracilis was described by Burmeister (1839) based on a specimen collected by Beske, probably from Nova Friburgo municipality, Rio de Janeiro State, Southeastern Brazil. The male holotype of T. gracilis and the type of Triplectides principes ( Burmeister, 1839) , a junior synonym from the same locality, were apparently destroyed in World War II ( Holzenthal 1988). According to Ulmer (1905), Burmeister (1839), and Kolenati (1859) later, recognized this second species probably due to size differences observed between the specimens. Holzenthal (1988), when revising the Neotropical Triplectides , designated a neotype for T. gracilis from a male also from Nova Friburgo municipality, Rio de Janeiro, Brazil. In the same work, Holzenthal (1988) synonymized the name T. ramulorum , used by Müller (1921) for immatures from Santa Catarina State ( Brazil), with T. gracilis . Since the holotypes of T. gracilis and T. principes are destroyed ( Holzenthal 1988) and there is no material of T. ramulorum , we do not propose any changes related to these synonyms.

Triplectides gracilis is one of the most widespread species of Triplectides in South America, occurring from Northeastern to Southern Brazil, and extending through Argentina and Paraguay ( Holzenthal 1988; Desidério et al. 2020). Due to its wide distribution, sequences of COI from many specimens previously identified as Triplectides gracilis from different localities in Brazil were used to evaluate its identity as a species. Not surprisingly, we found high genetic divergences among the specimens of T. gracilis , with six potential species being detected in our analyses. Based on rigorous reanalysis of male morphology, we were able to identify and describe as new five species within this group: T. bandeira sp. nov., T. cerradoensis sp. nov., T. iguassu sp. nov., T. mantiqueira sp. nov., and T. paragracilis sp. nov. Although these six species (including the redefined T. gracilis ) can be recognized by male morphology, they are very similar to each other, therefore previous identification of T. gracilis and distribution data should be viewed with caution. Because of this high morphological similarity, contrasting with high molecular divergences, we describe these new species below within the informal group of species.

A detailed description of T. gracilis was provided by Holzenthal (1988). We analyzed many specimens from Rio de Janeiro, including Nova Friburgo municipality (where the holotype and the neotype were collected). We are retaining the name T. gracilis to those that fit in the description provided by Holzenthal (1988) based on the neotype. Seven species in the T. gracilis complex have very similar male genitalia, but they can be consistently distinguished from each other by some details. Triplectides gracilis is very similar to T. paragracilis sp. nov. and T. iguassu sp. nov. in the general aspect of male genitalia, with segment IX, in dorsal view, subtriangular and protruded over tergum X; preanal appendages slender, digitate, rounded, and setose; tergum X, in dorsal view, almost straight, with apicomesal incision extending beyond half the length of the tergum, bearing short and stout setae on its surface. Triplectides gracilis differs from these two species by the mesal lobe of inferior appendages without a sclerotized tooth on basolateral margin (Fig. 13 A ). Other important feature is related to wing venation (Fig. 2 A, B ), where the fork I of hind wing can be sessile with R 2 arising anteriorly to R 3 (Fig. 2 D ), corroborating those drawn by Holzenthal (1988) or with R 2 and R 3 arising together forming a very small petiole (Fig. 2 E ).

The fisrt larval descriptions for Triplectides gracilis were provided by Müller (1921), as Tetracentron ramulorum , when some general characteristics of the immature forms from Santa Catarina State were given. Sganga et al. (2013) provided a detailed description of T. gracilis immatures from Argentina. However, those specimens may not be part of T. gracilis after the taxonomic delimitation provided here. The larvae associated here from Rio de Janeiro are slightly different from those observed by Sganga et al. (2013) in relation to head and thorax coloration, labrum, form of ventral apotome, edge of pronotum, and thorax sclerites. Triplectides gracilis larvae described here have head almost rectangular with coloration reddish brown to dark brown with several pale spots and labrum brown and subtrapezoidal, while those in Sganga et al. (2013) possessed head coloration homogeneous dark brown, with yellowish oval areas around stemmata, with labrum stramineous, and brown lateral stripes parallel to lateral borders. In the thorax, larvae associated here had pronotum with anterior margin and lateral margin crenulate, and posterior margin rounded; prosternal sclerite subtriangular and metasternum with 8–10 setae, without basal circular sclerite; whereas the larvae from Argentina had pronotum reddish brown; mesal half of anterior edge of each pronotal sclerite with three smooth, rounded crenulations; lateral half plain, slightly produced and rounded; prosternum sclerite rectangular, slightly produced anteriorly and metasternum with 6–9 long setae, with a variable number of basal, circular sclerites ( Sganga et al. 2013).

Figures

Figure 2. Triplectides gracilis (Burmeirster, 1839), male wings (DNA voucher ENT 5922). A Forewing; B Hind wing; C Forewing cross veins in detail; D, E Hind wing fork I in detail (E: DNA voucher ENT 0672). — Abbreviations: Sc = subcostal vein; R = radial vein; M = median vein; Cu 1 A = anterior first cubital vein; Cu 1 P = posterior first cubital vein; Cu 2 = second cubital vein; A = anal vein; s = sectorial cross vein, r-m = radial-median cross vein; m-cu = median-cubital cross vein; Dc = discoidal cell; Th = thyridial cell; I, III, V = forks I, III, and V, respectively.

Figure 3. Tripletides gracilis, larva (DNA voucher ENT 4359). A Habitus, lateral view; B Head, dorsal, ventral, and lateral views; C Pronotum and protrochantin, lateral view; D Thorax, dorsal view; E Thorax, ventral view; F Abdominal segments VII – X, dorsal and lateral views; G Right fore-, mid-, and hind legs; H Diagram of distribution of abdominal gills (I – IX = abdominal segments); I. Larval case.

Figure 13. Triplectides iguassu sp. nov., male genitalia (holotype). A Lateral view; B Dorsal view; C Ventral view (detail of tooth-like projection at base of mesal lobe of inferior appendage); D Phallic apparatus, ventral view; E Phallic apparatus, lateral view.