Thraulodes solstitium, Orlando & Salles & Boldrini & Krolow, 2021

Orlando, Thales Yann, Salles, Frederico Falcão, Boldrini, Rafael & Krolow, Tiago Kütter, 2021, Updated records for Leptophlebiidae (Ephemeroptera) and a new species of Thraulodes Ulmer, 1920 from Tocantins State, Northern Brazil, Zootaxa 5076 (1), pp. 39-55 : 47-48

Thraulodes solstitium sp. nov. ( Figs. 2–8 )

Diagnosis. Male imago: 1) costal cross veins basal to bulla either absent or colorless and very thin and 8 cross-veins distal ( Fig. 5 ); 2) area between C and Sc yellowish brown; 3) terga II–V yellowish white, with a pair of submedian blackish dots and one pair of sublateral blackish dots, terga VI anteriorly yellowish-white and posteriorly light brown, terga VII–X light brown ( Fig. 2 ); 4) penes light-brown with blackish pigmentation on “ear” area ( Fig. 8 ); 5) styliger plate triangular, with a median rounded projection covering 2/3 of penes ( Fig. 8 ); 6) telopenes short and slender, 1.7 times the width of the medial region of the penes, lanceolate, narrowing towards the apex, arising on dorsal side of penes and directed median-anteriorly ( Fig. 7 ).

Description.

Male imago

Length of body: 5.5–6.6 mm; forewings: 5.2–6.4 mm; hind wings: 0.9–1.2 mm. General coloration light brown with yellowish brown areas.

Head ( Figs. 2, 3 ). General coloration brown. Antenna with scapus light brown, pedicellus brown, flagellum light brown. Ocelli white, surrounded by black at base. Eyes black, turbinate portion orangish brown, contiguous medially.

Thorax ( Figs. 2, 3 ). General coloration brown. Prothorax whitish brown with pair of dark brown stripes transversal to coxa. Meso- and metanotum brown; prescutum and scutum light brown, scutellum dark brown. Pleura brown, membranous parts whitish. Sterna brown; basisternum light brown.

Wings ( Figs. 5–6b ). Forewing ( Fig. 5 ) with veins yellowish brown; wing membrane hyaline; area between C and Sc yellowish brown. Fore and hind wings each with dark brown macula at base; costal cross veins basal to bulla either absent or colorless and very thin and 8 cross-veins distally. Trajectory line that connects bullae barely crossing MA fork. Hind wing ( Fig. 6a–6b ) with blunt costal projection; wing membrane hyaline; veins yellowish-brown.

Legs. Coxae and trochanters yellowish-brown. Cuticle of legs mostly yellowish-brown. Fore femur light brown with brown macula and blackish stripe on distal half; light brown, wide macula sometimes present on proximal half. Fore tibia yellowish brown, proximal region light brown. Fore tarsus yellowish brown with pigmented articulations. Middle and hind femora yellowish brown, distal 1/3 of femur brown with pre-apical, blackish-brown band; light brown, wide spot sometimes present on proximal half. Mid- and hind tibiae yellowish brown, proximal region light brown. Tarsus light brown with pigmented articulations.

Abdomen ( Figs. 2, 4 ). Tergum I brownish, with pair of submedian blackish spots. Terga II–VI yellowish translucent with pair of submedian blackish dots and one pair of sublateral blackish dots; terga VI yellowish translucent anteriorly and light brown posteriorly; terga VII–X light brown. Abdominal sternum I-VI yellowish translucent, remaining light brown. Caudal filaments mostly yellowish brown, with black maculae on proximal ½ of alternated segments.

Genitalia ( Figs. 7–8 ). Styliger plate yellowish translucent. Forceps mostly yellowish brown with pigmented articulations; middle of segment I strongly curved, proximal ½ of inner margin and distal ⅔ of outer margin light brown. Penes light brown with blackish pigmentation on “ear” area. Styliger plate triangular, median projection distally rounded and covering 2/3 of penes. Penes lobes short and distally divergent; each lobe gradually widened towards apex; lateral pouch present; apico-lateral area with ear-like projection. Medio-ventral ridge projected and distally integrated with oblique preapical ridge, forming “lapel.” Telopenes short and slender, 1.7 times width of penes on its median portion, lanceolate, narrowing towards apex, arising on dorsal side of penes and directed median-anteriorly.

Variations. In some male paratypes, the abdominal segment VIII is lighter than the segments VII, IX and X. Another important variation is that specimens may not have the maculae on the proximal half of the femora. Depending on the presence or absence of that characteristic, different comparisons can be drawn out when analyzing the key proposed by Kluge (2020).

Etymology. From the Latin word solstitium , solstice. In reference to the event in which a planet’s poles are most extremely inclined toward or away from the star it orbits. This Earth phenomenon occurs in June and December, the same months in which some specimens were captured. This name is used in apposition.

Distribution. Tocantins State, Brazil.

Material Examined. Holotype: 1♂ (preserved in alcohol) Brazil, Tocantins state, Palmas, distrito de Taquaruçu do Porto , vale do Vai Quem Quer , 10°22’0.9”S / 48°8’1”W, 27-30.viii.2019, white sheet light trap, Fernandes, A.S., Montanuci, P.S.B., Oliveira, L.P., Orlando, T.Y.S. cols ( INPA) . Paratypes: 87♂ (preserved in alcohol) Brazil, Tocantins state, Palmas, distrito de Taquaruçu do Porto , vale do Vai Quem Quer , 10°22’0.9”S / 48°8’1”W, 13-14.xi.2017, white sheet light trap, Krolow, T.K. coll. (2♂, UFRR; 2♂, CEUFT) ; idem, 15-16.xi.2017, U.V. light pan trap, Krolow, T.K. coll. (1♂, CEUFT) ; idem, 04-06.xii.2018, white sheet light trap, Fernandes, A.S. and team cols. (10♂, CEUFT) ; idem, 27-30.viii.2019, white sheet light trap, Fernandes, A.S. and team cols. (41♂, CEUFT; 20♂ UFVB) ; idem, cachoeira do Evilson , 10°14’0.2”S / 48°7’17”W, 13.vii.2018, white sheet light trap, Fernandes, A.S. and team cols. (11♂, CEUFT).

Comments. One of the most critical characteristics for the identification of the species of Thraulodes , at least when using taxonomic keys ( Traver & Edmunds 1967; Domínguez et al. 2006; Lima et al. 2013; Kluge 2020), is the presence or absence of a macula on the proximal half of the mid and hind femora. However, among the material examined of the new species, we found some specimens with a very light macula and others without it, which can be due to preservation or intraspecific variation.

Among the species of the genus with the maculae on the mid and hind femora, the new species is morphologically similar to T. paysandensis and T. pinhoi , sharing the abdominal terga II to VI which are yellowish translucent. The new species can be distinguished from them based on the morphology of the genitalia: in T. paysandensis the apicolateral area of each penes lobe is not ear-like ( Domínguez et al. 2006: pg 500, Fig. 189B), in T. pinhoi the posterior margin of the subgenital plate is almost straight, with medial rounded projection, and in both species the telopenes are long, slender, and medially directed (Fig. 16 from Lima et al. 2013: pg, Fig. 16). On the other hand, in T. solstitium sp. nov., an ear-like area is present apicolaterally on the penes lobe, and the telopenes are short, directed median-anteriorly.

When considering the maculae on the proximal half of femora absent, the new species is morphologically similar to T. quevedoensis by sharing the abdominal terga II–V light; VI–VII almost entirely colored and penes widened apically. The new species can be distinguished from it based on the morphology of the genitalia: in T. quevedoensis the lateral pouch is absent and the telopenes is long and directed medially ( Flowers 2009: pg 57, Fig. 3 ) while in T. solstitium sp. nov. the lateral pouch is present and the telopenes are short, directed median-anteriorly.

Figures

FIGURES 2–4. Thraulodes solstitium sp. nov., male imago: 2) habitus, (dorsal view); 3) head and thorax (lateral view); 4) abdomen (lateral view).

FIGURES 5–8. Thraulodes solstitium sp. nov., male imago: 5) forewing; 6a) hind wing; 6b) hind wing (enlarged); 7) genitalia, ventral view; 8) genitalia, dorsal view.