Helicopsyche (Feropsyche) planorboides Machado, 1957

Dumas, Leandro Lourenço & Nessimian, Jorge Luiz, 2019, New species of Helicopsyche von Siebold 1856 (Trichoptera: Helicopsychidae) from Brazil, including the redescription of Helicopsyche (Feropsyche) planorboides Machado 1957, Zootaxa 4619 (2), pp. 231-250 : 245-246

Helicopsyche (Feropsyche) planorboides Machado

( Figures 7 A–7B, 8A–8G)

Helicopsyche (Feropsyche) planorboides Machado 1957: 193 [Type locality: Brazil, Minas Gerais, Tarumirim, Rio Doce valley; type depository not designated, now in DZRJ; ♂; ♀; larva; pupa; case].— Johanson 1995:115 [catalog].— Johanson 2002: 135 [distribution].— Paprocki et al. 2004: 6 [checklist].— Paprocki and França 2014: 18 [checklist].

The types of Helicospyche (F.) planorboides were donated by Dr. Angelo Machado to Coleção Entomológica Professor José Alfredo Pinheiro Dutra, Universidade Federal do Rio de Janeiro (DZRJ). Specimens were stored in vials with alcohol; however, they are greatly damaged, stiffened, and distorted due to the lower concentration of alcohol in which they were stored. The male holotype is slightly better preserved, but with broken wings and several missing parts: antennae, palps, all legs, portions of thorax, and some genital structures (inferior appendages and phallus). Thus, this redescription of H. (F.) planorboides was also based on additional specimens which have the same pattern when compared with the male holotype, especially the distinctive tergum X, avoiding the complete damage of the type specimens in this way.

Diagnosis. Helicopsyche (F.) planorboides is easily distinguished by the unusual tergum X, which has a pair of large tab-like midlength projections, a distal thorn-like process in lateral view, and a longitudinally cleft apically. Only H. (F.) luziae sp. nov. has a similar pattern of tergum X among American species of the subgenus Feropsyche , but in the new species the tergum X projections are much less developed. Furthermore, both species can be also distinguished by the general structure of the inferior appendages, as discussed in the H. (F.) luziae sp. nov. diagnosis. Also, H. (F.) planorboides is recorded for the first time for Rio de Janeiro and Espírito Santo states.

Description. Adult. Similar to H. (F.) bendego sp. nov. except as follows: Antennae golden-brown, palps and legs yellowish-brown. Cephalic setal warts narrow, drop-like; postantennal warts apparently absent. Unpaired eversible membranous structure in dorsal portion of head, located close to coronal suture, concealed by pair of movable sclerites in male holotype and some of additional specimens included here; membranous structure tubular, directed anteriorly between antennal scapes, extremely developed, about as long as antennal scapes ( Figs. 7A, 7B ). Maxillary palps covered with several yellow setae. Each foreleg anterior apical tibial spur about 3x longer than posterior spur. Male forewings each 4.8 mm (n = 2). Forewing discoidal cell about half as long as thyridial cell; hindwings each with forks I, III, and V present. Abdominal sternum VI ventral process much shorter than segment VI, lanceolate, slightly narrower at base in ventral view, nearly straight in lateral view, apex acute in lateral and ventral views, with microtrichiae along length but without lamellae apicoventrally ( Figs. 8F, 8G ).

Male genitalia. Segment IX short ventrally; in lateral view with anteromesal margin well-developed, anterodorsal margin slightly sinuous, and anteroventral margin almost straight; lateral apodeme well-developed, located midlaterally in the segment ( Fig. 8A ); in dorsal view with anterior margin strongly concave, inverted V-shaped, lateral margins slightly convex ( Fig. 8B ); in ventral view with anterior margin very strongly concave, dorsal margin concave in middle ( Fig. 8C ). Segment X, in lateral view, taller at base, with ventral and dorsal margins parallel from midlength, rounded apically, bearing two large projections: midlateral projection tab-like, apical projection forming thorn-like, both upturned ( Fig. 8A ); in dorsal view surpassing apices of inferior appendages, dorsally with two marginal rows of 5–6 setae at apical fourth, apex with longitudinal V-shaped notch at apical fourth, midlateral projections acute, apical projections forming pair of auriculate rims with crenulate margins ( Fig. 8B ). Superior appendages originate dorsolaterally, large, setose, rounded in lateral view, club-like in dorsal view ( Figs. 8A, 8B ). Basal plate of inferior appendages tapering anterad in lateral and ventral views, surpassing anteroventral margin of segment IX ( Figs. 8A, 8C ); primary branches of inferior appendages covered by stout, long setae; in lateral view each racket-like, with distal portion rounded, about 3x as broad as its proximal portion, basodorsal margin strongly concave, ventral margin slightly concave, apicodorsal margin strongly convex, slightly undulating, with long, stout setae along apical margin ( Fig. 8A ); in dorsal view curved mesad, subrectangular, with small protuberance subapically on inner margin, bearing several small spine-like setae ( Fig. 8B ); in ventral view, with inner margin concave and with rounded protuberance near base bearing 6 long stout setae, and subapically projecting strongly mesad and bearing several apical spines ( Fig. 8C ); basomesal lobes of inferior appendages thumb-like, very long, strongly protruding beyond primary branches in lateral view ( Fig. 8A ), in ventral view finger-like, slightly broader at base, with row of 4 marginal short, stout, subapicolateral setae on distal 1/3 ( Fig. 8C ). Phallus tubular, strongly down-curved along its length; phallobase narrow, slightly inflated basally and mesoventrally, with apicoventral margin elongate, sclerotized apically, in lateral view with lateral sclerotized lobes curved anteroventrad (not visible in ventral view); endotheca membranous lobe extending dorsally over endophallus; phallotremal sclerite small, C-shaped, apically with two semi-membranous structures ( Figs. 8D, 8E ).

Material examined: BRAZIL: Minas Gerais: Tarumirim, Rio Doce valley , v.1956, male holotype ( DZRJ) ; same data as holotype, 5 female paratypes ( DZRJ) ; Espírito Santo: Santa Teresa, Reserva Biológica Santa Lúcia , 09-10.i.2003, AL Carvalho leg., 3 males ( DZRJ) ; Rio de Janeiro: Campos dos Goytacazes, Mocotó, Parque Estadual do Desengano , Rio Mocotó (poço), 21°48’53.6” S, 41°45’18.5” W, 17.iv. 2016, 237 m, LL Dumas, JL Nessimian, CS Portela & JF Barbosa leg., 1 male, 1 female ( DZRJ) — male used for illustrations of genital structures here; São Fidélis, Itacolomi, afluente de 1ª ordem do Rio do Colégio , 21°49’49.7” S, 41°51’35.1” W, 23.x. 2016, 421 m, LL Dumas, JL Nessimian & JF Barbosa leg., 1 male ( DZRJ) .

Distribution. Brazil (Espírito Santo, Minas Gerais, and Rio de Janeiro).

Notes on membranous head structure. Glandular structures on the male head are unusual among Trichoptera , being common only in some microcaddisflies ( Hydroptilidae ), like many Hydroptila Dalman 1819 , Leucotrichia Mosely 1934 and Zumatrichia Mosely 1937 . These eversible head organs have been speculated to produce chemical signals and are concealed by moveable lateral occipital sclerites when they are not extended. There are no experiments to determine the function of these glands, but Roemhild (1980) assumed that they produce sex-pheromone, since they occur only in males at the sexually active stage. There is no mention in the literature about the presence of these eversible head organs in Helicopsychidae species. Helicopsyche (F.) luziae sp. nov. has similar occipital sclerites found in H. planorboides head, however membranous structures were not observed (we did not use lactic acid for the head due the low number of male specimens). So, more morphological and behavioral studies are required to establish the glandular pheromone function of these structures in Helicopsyche species.

Figures

FIGURE 7. Helicopsyche (Feropsyche) planorboides Machado 1957. 7A–7B, Specimen from Rio de Janeiro state, Brazil, head (red arrows indicating unpaired eversible membranous structure): 7A, left lateral; 7B, dorsal.

FIGURE 8. Helicopsyche (Feropsyche) planorboides Machado 1957. 8A–8E, Male genitalia: 8A, left lateral; 8B, dorsal; 8C, ventral; 8D, phallus, left lateral; 8E, phallus, ventral. 8F, Abdominal sterna VI and VII, left lateral. 8G, Abdominal sternum VI ventral process, ventral. Scales = 0.5 mm.