Hydromastodon cf. mikei ( Thomas & Boutonnet, 2004 )

Lima, Myllena, Brasil, Leandro Schlemmer, Juen, Leandro, Rivera-Pérez, Juan Mateo, Dias-Silva, Karina & Salles, Frederico Falcão, 2023, Hermanella complex on Northern Brazil (Ephemeroptera: Leptophlebiidae): New species and stage descriptions, Revista Brasileira de Entomologia (e 20230063) 67, pp. 1-10 : 2-4

Hydromastodon cf. mikei ( Thomas & Boutonnet, 2004)

Hydrosmilodon mikei Thomas et al. 2004: 72 ; Sartori 2005: 243; Domínguez et al. 2006: 407

Hydromastodon mikei : Polegatto & Batista 2007: 54

Hermanella (Needhamella) mikei : Kluge 2007: 398

Diagnosis. The male imago of Hydromastodon cf. mikei can be distinguished from those of H. sallesi by the following combination of characteristics: a) body color pattern, especially abdominal terga, translucent white with terga I to IV washed with black on posterior margins ( Fig. 2C, D ); b) compound eyes anteriorly rounded ( Fig. 2A, B ); c) medial projection of styliger plate short; d) penis lobes close to each other and with posterolateral projection as long as ½ of its length (2E and 4D- F).

Description of male imago (in alcohol).

Lengths (in mm). Body 4.2-4.5; fore wings 5.6-5.7; hind wings 1.1.

Head ( Fig. 2A, B ): yellowish-white, tinged with orange between ocelli; upper portion of eyes orangish, lower portion black.Eyes meeting on meson of head; ocelli white, surrounded with black and orange. Antennae light yellowish-brown.

Thorax ( Fig. 2A, B ): pronotum yellowish-brown, with transversal median black line and with lateral margin tinged with black; mesonotum light orangish-brown, except for yellow sublateroscutum and outer margin of posterior scutellar protuberance. Metanotum light brown. Pleurae purplish-gray. Prosternum with wide, X-shaped median carina, with similar anterior and posterior arms.Mesosternum orangish-brown, except for white marks medially.Membranous areas between pro- and mesosternum purplish-gray. Metasternum orangish-brown anteriorly, yellowish-brown posteriorly.

Wings ( Fig. 4A, B and C ): membrane of fore and hind wings hyaline. Fore wing with costal arch, C, Sc, RA, RP and MA brown, lighter towards apex, remaining veins light yellowish-brown. Fork of MA and fork of MP asymmetrical. Legs: translucent white, except for coxae yellowish-brown, fore femur, apex of mid and hind femora and claws yellow.

Abdomen ( Fig. 2C, D ): Terga I–VII translucent, VIII–X yellowish-white; terga I–IV washed with black on posterior margins, pigmentation stronger and wider medially; tracheae of segments I–IX washed with black, restricted to a small area on segments III–VII, completely covering tracheae on remaining segments.; Sterna I–VII translucent white, sterna VIII–IX light yellowish-white.

Genitalia ( Fig. 2E , 4D, E and F ): yellowish-white, except for yellow telopenis; styliger plate with strong, dorsally curved, medial short projection; Penis lobes close to each other and with posterolateral projection as long as ½ of its length. Caudal filaments white, washed with brown except at base.

Description of female imago ( Fig. 3A, B, C and D ) (in alcohol). Lengths.Body 4.9 mm; 5.9 mm fore wings; 1.0 mm hind wings. Head yellowish, except ocelli surrounded with black. Eyes black. Pronotum yellowish, with transversal median black line and with lateral margin tinged with black. Mesonotum light yellowish-brown with sutures yellowish-white. Metanotum yellowish-brown. Abdominal color pattern similar to male imago and sternum IX deeply and broadly cleft apically

Material examined. 162 ♂ imagos (Pennsylvania trap), Brazil , Pará State , Altamira, P 01, Xingu River (03º28’55.4” S 51º40’55.5” W), 31.iii.2021, Gonçalves A and Lobato C, cols. (70 UFVB; 92 LABECO). One imago (Pennsylvania trap), Brazil, Pará State, Altamira P 02, Xingu River, (3°11 ‘35.0 “S 51°26’45.1”W), 24.iv.2021, Prata EG, col. ( LABECO) . 4 ♂ imagos (Pennsylvania trap), Brazil , Pará State, Altamira, P 03, Xingu River, (3°07’27.4”S 51°23’00.6”W), 28.iv.2021, Prata EG, col. ( LABECO) . 5 ♀ imagos (Pennsylvania trap), BRAZIL, Pará State , Altamira, P 04, Xingu River (03º58’52.7” S 51º81’31.0” W), 28.iii.2021, Gonçalves A and Lobato C, cols. (2 UFVB; 3 LABECO) .

Comments

The imago herein described fits well with the concept ofHydromastodon as proposed bySalles et al. (2016) while describing H.sallesi , but definitely represents a distinct species. For example, they both share similar forceps shape (relatively long and bent approximately at mid length) and the presence of a strong and dorsally curved, medial projection at the styliger plate. They also present a posterolateral projection at the penis lobe, which was not described for H. sallesi , but can be seen in Figs. 4D, E ( Salles et al., 2016). As the adults of only two species of Hydromastodon have been described, the diagnosis herein present is enough to highlight the differences between H. cf.mikei and H. sallesi . As we have not found nymphs of H. mikei and could not associate them by rearing or any other technique, we do not discard the possibility that the material described here represents a third and new species of Hydromastodon . On the other hand, the length of the body of H. mikei matches those of our specimens and, more importantly, the abdominal coloration described for mature nymphs of H. mikei fits exactly the abdominal coloration of our material, as detailed in the original article by Thomas et al. (2004, p.77): “Coloration très différente de celle d’H. gilliesae par la présence d’une dominante pigmantaire sur une grande partie des tergites I à IV, ou même I à V; tergites V-X ou VI-X clairs, jaunes ou brun jaunâtre”. Since none of the alternatives is 100% safe, we opted for a more conservative approach until we are able to find and associate nymphs with adults.

Distribution and Biology. Brazil (Pará State) (but if the specific determination is confirmed, it is also present in French Guiana). The specimens were collected in the Xingu River, with predominant vegetation in the Amazonian biome. The river stretch was large and presented open natural areas, with moderate to fast currents.

Figures

Figure 2 Hydromastodon cf. mikei, male imago. A, head and thorax, dorsal view; B, head and thorax, lateral view; C, habitus, lateral view; D, abdomen, dorsal view; E, male genitalia, lateral view.

Figure 3 Hydromastodon cf. mikei, female imago.A, head and thorax, dorsal view; B, abdomen, dorsal view; C, abdomen, lateral view; D, female sternum IX, ventral view.

Figure 4 Hydromastodon cf.mikei, male imago.A, fore wing; B, hind wing; C, hind wing, enlarged; D, genitalia, ventral view; E, penis, ventral view and F, genitalia, lateral view.