Ytu hermes, Sampaio & Ferreira-Jr, 2018

Sampaio, Brunno Henrique Lanzellotti & Ferreira-Jr, Nelson, 2018, Five new species of Ytu Reichardt (Coleoptera: Myxophaga: Torridincolidae) and new records from Brazil, Zootaxa 4402 (3), pp. 508-524 : 514-516

Ytu hermes sp. nov.

( Fig. 3 )

Diagnosis. Dorsal surface coarsely granulated and iridescent, except for an area on each elytron which combined takes a form similar to an "X". Elytra together much broader than pronotum; elytral formula 10d + 2a(IVa,VIa) + 1sl / 0d + 0sl; with ten complete striae and two accessory striae each: one between striae IV and V, another between striae VI and VII; intervals raised, with iridescent microscales, and row of granules. Male genitalia with parameres conspicuously longer than phallobase’s process and long phallus, with a slight constriction on basal half; digitiform apex and some regions of phallus less chitinous.

Description: Holotype. Antennae black; dorsal surface black and shiny ( Fig. 3a ); ventrally dark brown ( Fig. 3b ), except for epipleuron which is light brown; legs brown, darker on distal parts. Measurements: total length: 2.22 mm; maximum head width: 0.37 mm; pronotal length: 0.52 mm; maximum pronotal width: 0.67 mm; elytral length: 1.37 mm; maximum elytral width: 0.62 mm.

Labrum ( Fig. 3c ) with anterior margin arcuate with denticules; anterolateral angles bearing claviform setae; medial region of anterior margin with a small process; lateral margin oblique; surface smooth and glabrous, except for the region near anterolateral angles where there are punctures bearing setae. Clypeus ( Fig. 3d ) with anterior margin slightly arcuate; anterolateral angles oblique; lateral margin subparallel; posterior margin arcuate, especially on medial region; punctures visible near lateral and anterior margin. Head surface with iridescent microscales from clypeus to posterior margin; surface on a band posterior to eyes slightly less iridescent. Supraorbital carina extending from clypeal suture to posterior margin of eye; middle line of head feebly raised because of a depressed area beside each supra-orbital carina. Antenna with nine antennomeres; last antennomere as long as antennomeres IV–VIII together. Mandibles asymmetrical ( Figs. 3e–f ); left mandible with two incisive teeth—one immobile (distal), one movable (proximal); distal incisor bearing two denticules on inner margin; outer margin of mandibles arcuate, without projection; right mandible similar to the left one, but with only an immobile incisor; incisor of right mandible with outer margin slightly more arcuate than on left mandible. Maxilla ( Fig. 3g ) with lacinia and galea fused into mala; mala bearing apical cuticular teeth; maxillary palp with four articles; second article 1.5× as long as first one; third article 1.5× as long as second one; apical one very small.

Anterior margin of pronotum sinuate ( Fig. 3a ), slightly projected medially; anterolateral angles pronounced; lateral margin arcuate; posterior margin bisinuate, pronounced medially as much as on posterolateral angles; posterior margin with a single medial incision; pronotum broader on posterior half; surface with microscales and sparse granules larger than an ommatidium; small oval impression on each side of median line on the anterior third; medial inconspicuous depression on second third; last third of pronotum impressed near posterolateral angles. Scutellar shield black and equilateral triangle shaped. Elytra together ( Fig. 3b ) much broader than pronotum; anterior margin of each elytron bisinuate; humeral callus feebly pronounced; lateral margin crenulate, subparallel on anterior half and convergent on posterior half; elytral formula 10d + 2a(IVa,+VIa) + 1sl / 0d + 0sl; elytral intervals raised, with iridescent microscales, and with row of granules larger than those of pronotum; humeral callus with confused distribution of granules, reflecting poorly marked striae; epipleuron smooth, wide on anterior half of elytron. Hind wings developed ( Fig. 3h ); margin fringed with long setae from radial hinge to anterior region anal lobe; ScP and RA1+2 extending toward radial hinge; RA3+4 beginning on radial hinge, extending toward anterior margin just after a feeble sinuosity on margin, limiting a pigmented area; RA4 and RP very weakly marked; r1 very short, not crossing any other vein; r4 oblique; MP1+2 strongly marked, angulated on medial hinge, crossing rp-mp1 and rp-mp2, forming oblong cell, its apex pointing toward posterior margin; Cu vein parallel to MP1+2, extending toward posterior margin, reaching AA3, which extends to posterior margin; AA3+4 limited to basal area; AP3+4 following posterior margin of anal lobe, which is relatively narrow. Anterior margin of prosternum ( Fig. 3b ) crenulate and feebly emarginate; prosternal carina slightly oblique, constricted between coxae, diverging posteriad; posterior margin of prosternal process arcuate. Mesoventrite with a gibbosity on anterior margin, which fits an internal concavity on prothorax; lateral margin oblique; posterior margin truncate. Metaventrite with discrimen marked from anterior to posterior margin; metaventral carinae complete, extending from anterior to posterior margin; metaventral tubercles absent. Legs with fine sparse setae on femora, tibiae and tarsi; profemur robust, with a shallow impression on anterior face to fit tibia; protibia with a row of fine setae on anterior face; meso- and metafemur with shallow impression on posterior face to fit tibiae; metacoxa with similar impression to fit hind femur; tarsi four-segmented; third tarsomere twice as long as first and second together; last tarsomere twice as long as third one.

Abdomen with visible plastron except for a narrow strip near ventrite margins; first ventrite with medial carina almost reaching posterior margin; posterior margin of ventrites 1¯4 microserrate. Male genitalia ( Figs. 3i –h ) with parameres conspicuously longer than phallobase process; each paramere with a pair of apical setae as long as half of paramere; phallus long, with a slight constriction on basal half and digitiform apex; some regions of phallus less chitinous.

Female: unknown.

Variation. Total length: 2.22¯ 2.31 mm; maximum head width: 0.37¯ 0.41 mm; pronotal length: 0.40¯ 0.52 mm; maximum pronotal width: 0.67¯ 0.75 mm; elytral length: 1.37¯ 1.51 mm; maximum elytral width: 0.56¯ 0.62 mm.

Comparative notes. Ytu hermes sp. nov. is very similar to Y. hephaestus Reichardt in its external morphology. They differ in the phallus which is conspicuously sinuate on the apical portion in Y. hephaestus , forming a small apical hook (Reichardt & Vanin 1977, fig. 8), while in Ytu hermes sp. nov. the phallus presents a feeble sinuosity on different portions and does not form an apical hook. Ytu hermes sp. nov. also presents an area not sclerotized which is lacking in Y. hephaestus .

Etymology. This species is named after Hermes, God of commerce and the messenger of gods in Greek mythology, in reference to its similarities to Ytu zeus group (Hermes is son of Zeus).

Type material: Holotype. Male. Brasil, Espírito Santo, Dores do Rio Preto, Pedra Menina, Parque Nacional do Caparaó , Cachoeira Sete Pilões , 20°28’56.8”S; 41°49’50.3”W, 1869m alt., 06.I.2013, Col.: Sampaio, B.H.L. [ DZRJ 5644 ] ; paratype: 1 male— Brasil, Minas Gerais, Alto Caparaó, Parque Nacional do Caparaó, trilha para a base Terreirão Rio José Pedro , 20°24’51”S; 41°49’34.4”W, 2111m alt., 19.I.2014, Col.: Sampaio, B.H.L. [ DZRJ 5645 ] ; 1 male— Brasil, Espírito Santo, Dores do Rio Preto, Pedra Menina, Parque Nacional do Caparaó , Afluente do Rio Preto , Laje , 20°29’26.2”S; 41°49’17.1”W, 1507m alt., 24.III.2012, Col.,: Jardim, G.A. [ DZRJ 5646 ] .

Figures

FIGURE3. Ytu hermes sp. nov.: a̅b: habitus, a) dorsal view, b) ventral view; c) labrum, dorsal view; d) clypeus, dorsal view; e̅f: mandibles, dorsal view, e) left mandible, f) right mandible; g) right maxilla, dorsal view; h) right hind wing, dorsal view; i̅j: aedeagus, i) dorsal view, j) lateral view.(Scale bars:a̅b:0.5 mm; c̅g: 0.05 mm; h: 1 mm; i̅j: 0.5 mm).