Mayetia atlantica Chaul & Lopes-Andrade, 2022

Chaul, Júlio Cezar Mário & Lopes-Andrade, Cristiano, 2022, First record of Mayetiini (Coleoptera: Staphylinidae: Pselaphinae) from Brazil with the description of a new macropterous and macrophthalmic species of Mayetia Mulsant & Rey, 1875, Zootaxa 5175 (1), pp. 126-136 : 129-132

Mayetia atlantica Chaul & Lopes-Andrade sp. nov.

( Figs. 1–4 )

Type material. Holotype. Male, dry-pinned: Brazil, Espírito Santo, Santa Teresa , -19.9460715 -40.6797418, 829 m, 21.xi.2018, winkler JCMC00438 , Leg. Chaul, J.; Prado, L.; Silva, O. [unique specimen identifier CELC003054 , previously slide-mounted for imaging and then dry-pinned, housed at CELC].

Paratypes. Four specimens with the same collection data as the holotype: one dry-pinned female [ CELC000072 , housed at CAMB]; one dry-pinned female [ CELC000087 , housed at MZSP]; one female slide-mounted [ CELC003038 , housed at CELC]; one dry-pinned female [ CELC000148 , housed at CELC] .

Non-type material. Three slide-mounted specimens with the same data as the holotype: one with several body parts missing, impossible to determine sex [ CELC003063 , housed at CELC], one female [ CELC003058 , housed at CELC and pinned together with paratype CELC003038 ]; one female [ CELC001034 , housed at CELC]. One female, dry-pinned: Brazil, Bahia, Parna do Pau-Brasil, regeneration area (17 years), -16.522167 -39.310778, 87 m, 14.ii.2020, 30x 30cm winkler of litter plus 2 cm of soil, JCMC00773 , Leg. Safar, N.; Deambrozi, S.; Moreira, T.; Jacintho, G.; Martins, G. [ CELC001048 ; housed at CELC]. One female, slide-mounted: Brazil, Bahia, RPPN Estação Veracel , regeneration area (26 years), -16.459152 -39.200219, 5.ii.2020, 76 m, 30x 30cm winkler of litter plus 2 cm of soil, JCMC00731 , Leg. Safar, N.; Deambrozi, S.; Moreira, T.; Jacintho, G.; Martins, G. [ CELC001049 , housed at CELC]. One dry-pinned female: Brazil, Minas Gerais, Cataguases, Sinimbú, 10.xii.2021, Vieira, V.; Assis. C. [ CELC000969 , housed at CELC previously slide-mounted for imaging and then dry-pinned] .

Measurements. HW 0.107 –0.111 (0.107), HL 0.107 (-), PrnL 0.119 –0.131 (0.119), PrnatW 0.066 –0.074 (0.074), PrnW 0.107 –0.115 (0.107), PrnptW 0.066 –0.074 (0.070), EL 0.156 –0.164 (0.156), EW 0.123 –0.152 (0.152), Abd7 W 0.123 –0.131 (0.131).

Distribution. Known from forest remnants of the Brazilian Atlantic Forest biome in the states of Minas Gerais and Espírito Santo (Southeast Region) and Bahia (Northeast Region).

Diagnosis. Having all the diagnostic characters of the genus ( Orousset, 2022, and see above) plus the following: macrophtalmic; macropterous; vertexal foveae small and at the eye level; sulci anterior to vertexal foveae very shallow, fainting; sensorial tubercles present dorsally on maxillary palpomeres 3 and 4.

Description. Female and male. Head, including mouthparts, roughly piramidal in dorsal view. Relative dimensions: about as long as wide; head depth about 0.85x head width; in lateral view, maximum diameter of eye about 0.4x head depth; occiput as wide as anterior head width, about 0.7x maximum head width. In dorsal view, vertexal corners curved, slightly protuberant; median section of posterior vertexal margin slightly concave. In lateral view, dorsal margin almost straight, except for section of antennal tubercle, which bumps dorsally; ventral margin convex. Antennal insertions close to each other; distance between lateralmost points of the margins of antennal tubercles a third of head width; interantennal bridge almost straight; antennal tubercles not separated from each other by cleft. Anterior margin of cephalic capsule delimited by an arched carina, which originates next to anteriormost point of compound eye and arches all through clypeus to the other compound eye (here called the ocular-clypeal carina, occlc). Submentum with a pair of relatively long setae (compared to the setae on gular region) positioned imediately posterad mentum basolateral corners; mid way between each seta of the pair is positioned a pit which is larger than the sockets of these setae but smaller than gular fovea. Compound eyes with 10 to 13 ommatidia; each ommatidium coarse and slightly bumping. Labrum with three pairs of spiny protuberances, the outermost pair more developed and more separated from the two medial pairs; medial notch very reduced; three pairs of long setae, the longest (macrochatae) as long as or longer than labrum width. Left mandible with a single retinacle, right with bifid retinacle; terebra very long, falciform. Maxilla with first palpomere L-shaped, very small; second palpomere the largest, its outer surface curving broadly, separated from the inner surface by carinae both ventrally and dorsally, longitudinal imaginary axis crossing its basal foramen through the middle forming an angle of 45 to 60 degrees with the axis of the apical foramen; third palpomere disc-shaped, about twice as wide as long, partially buried on the apical surface of the previous, with a basal, dorsolateral conical tubercle which bears tiny setae on its truncate apex; fourth palpomere ovoid to round, also with a similar basal tubercle in the same position as in the previous palpomere, with palpal cone about the size of the basal tubercle, positioned slightly ventromesad from the apex, and with one tiny sensilla smaller than the palpal cone and positioned close to it, slightly laterad to the apex. Maxillary cardo wider than long, with a curved basal margin; palpifer longer than wide, with curved outer margin; basistipe triangular; mediostipe roughly square, but with irregular apical margin; galea bearing a tuft of setae about as long as the fourth palpomere; lascinia with a set of very tiny thickened setae about the length of the second labial palpomere. First and second labial palpomeres cylindrical, second slightly larger, their combined length less than the width of the third maxillary palpomere; third labial palpomere subulate. Ligula width less than the combined length of first and second palpomeres. Tentorium internally Y-shaped, perpendicular to the longitudinal axis of the head, giving rise to gular fovea ventrally and to vertexal foveae dorsally. Gular region simple, mildly convex, except for middle section where the gular fovea is located. Each vertexal fovea slightly smaller than gular fovea. Frons and vertex forming a simple, mildly convex surface, without marked ridges or cavities, except for a pair of inconspicuous sulci and by anterolateral ridges formed by the elevated antennal tubercles. Sulci barely visible, anteromedially turned, originating just anterad of the vertexal foveae and fading well before meeting. Antenna 11- segmented; 10th and 11th antennomeres forming a globular apical club; scape only slightly longer and wider than pedicel; antennomeres from 3rd to 9th disc-like, gradually enlarging towards apex, except for the 7th larger than the 8th; apical antenomere with long, basally originated, flatenned sensilla.

Thorax.Pronotum disc mildly convex, slightly longer than wide; anterior corners round, posterior corners slightly more angled, but still round. Pronotal maximum width anterior to midlength and about as much as head width; lateral margins curved, with inconspicuous notches just posterad midlength. Pronotal antebasal sulcus absent, but a faint line can be seen in some mounted specimens; foveae or cavities absent from pronotal disc, except for longitudinal medial sulcus almost entirely confined to the pronotum posterior half. Elytra longer than wide, widest posterior to its midlength; without carinae or striae, except for sutural striae; basal elytral foveae present; some specimens with one pit, some with two. Hind wing developed, membranous, about four times as long as elytron; venation absent, its margin fringed with setae twice as long as hind wing’s width. Propleura trapezoidal, posterolaterally with a pair of lateral procoxal foveae. Scutellar shield roughly triangular; margins sinuous. Metendosternite stalk and furcal arms cylindrical, about the same caliber, except for tips of furcal arms which get thinner; stalk straight and furcal arms U-shaped; entire structure anterodorsally inclined. Intermetacoxal space reduced to the width of bispinose intermetacoxal process. Legs subequal in length, each smaller than the combined length of pronotum and elytra. Coxae adjuct, pro- and mesocoxae pyramidal, dorsoventrally tall; metacoxae dorsoventrally short, broad mediolaterally, triangular. Trochanters small, with mildly convex ventral margins. Femora thicker at midlength; tibiae thickiest point past midlength. Inner and outer margins of coxae convex; inner margin of tibiae flat, outer margins convex. Apex of each tibia with a single short and thick spiny spur; distally, tibiae with dense suberect, simple setae. Tarsomeres appearing to be only two (see discussion), the basal (tarsomere 2) only slightly longer than half the length of the apical (tarsomere 3). Pretarsal claw single.

Abdomen elongate, about as long as head and thorax, slightly dorsoventrally flattened, curving ventrally. In dorsal view, widest at about sixth or seventh abdominal segment (4th or 5th visible); segments 3–6 subequal in shape, but gradually elongating and widening posteriorly; paratergites conspicuous from third to sixth, thinner on seventh. Seventh tergite (fifth visible) square, the longest in abdomen. Tergite spiracles on tergites II (internal), III, VII and VIII. Conspicuous, brick-like; intersegmental membrane between segments 3 and 4, 4 and 5, 5 and 6, and 6 and 7. Sternite III anteromedially keeled; sternite VIII posterior margin with two concavities; sternite IX of females small, triangular.

Male. No pronounced sexual dimorphism, except for a tiny pair of spines on the metatrochanters, tergite VIII apparently longer than in females, posterior margin of sternite VIII V-shaped and presence of hemisternites. Aedeagus sinuose both in lateral and in ventral (or dorsal) views, more so in ventral view, as the apex of distal apophysis is inclined to left; a few calluses or swellings laterad the basal foramen; ventral sulcus or constriction separates basal portion from basal capsule, the latter is not swollen and is continuous to the flattened and apically truncate distal apophysis.

Etymology. The name is in reference to the Brazilian Atlantic Forest biome, from where the species is known.

Biology. Nothing is known about the biology of the species, except that all Winkler/Berlese extractors samples in which specimens were found were composed of a mixture of litter and a few centimeters of the soil below the litter (and not the litter only, as is usual, at least when the process is made through Winkler extractors). All eight specimens from the type locality (types and non-types) were sampled in the same extractor, that is, within less than one meter square.

Figures

FIGURE 1. Dorsal (A), ventral (B) and profile (C) views of female paratype (CELC000148) of Mayetia atlantica from Espírito Santo. Abbreviations: sIII-IX, sternites III to IX; tIII-VIII, tergites III to VIII; mxp2-4, maxillary palpomeres 2 to 4. Scale bars: 0.1 mm.

FIGURE 2. Various features of the head of Mayetia atlantica. A, ventral view of right maxilla and labium (CELC003058); B, anterior view of maxilla and labium (CELC003063); C and D, lateral and ventral views of head, respectively (CELC003038), asterisk indicates labral macrocheta; E and F, labrum dissected and in situ, respectively (female CELC003063 and holotype male CELC003054, respectively); G and H, mandibles in situ and dissected, respectively (male CELC003054 and female CELC003063). Triangles in A and D point to the base of mentum (mentum torn in A) and the curvature of maxillary palpomere 2; triangles in B and C point to the tip of tubercle of palpomere 4; triangles in E and F point to the right corner of labrum; and triangles in G and H point to the base of retinacle (left retinacle lost in specimen in H during preparation). Abbreviations: gf, gular fovea; gl, galea; gpr, posterior gular region; lbr, labrum; lbrma, labrum macrocheta; lbp1-2, labial palpomeres 1 and 2; lc, lascinia; lg, ligula; mt, mentum; mxp, maxillary palpomeres; oc, occipital region; occlc, ocular-clypeal carina; pc, palpal cone; sl, sensillum; vf, vertexal fovea. Scale bars are 0.02 mm.

FIGURE 3. Various features of Mayetia atlantica. A and B, female (CELC003038) and holotype male (CELC003054), respectively, in profile view; C, zoomed dorsal view of the pronotum and vertex (CELC001048); D, protarsus (CELC003063); E and F, middle and zoomed hind legs, respectively (CELC003054, triangles in F point to metatrochanter spines); G, apex of abdomen of male (CELC003054) in lateral view with aedeagus, prior to dissection, visible by transparency (triangle in G and J point to the same spot, the constriction basal to aedeagus basal capsule); H and I, apex of abdomen in ventral view of female (CELC003038) and male (CELC003054), respectively (triangles indicate posterior margin of sternite VIII; J and K, aedeagus in ventral and lateral views, respectively (CELC003054, triangle points to constriction).Abbreviations: abc, aedeagus basal capsule; abf, aedeagus basal foramen; ada, aedeagus distal apophysis; hsIX, hemi-sternite; hw, hind wing; imtcxp, intermetacoxal process; msfm, mesofemur; mstb, mesotibia; mstr, mesotrochanter; msts, mesotarsus; mtcx, metacoxa; mttr, metatrochanter; prnmls, pronotal medial longitudinal sulcus; sVIII and sIX, sternites VIII and IX; spc, spiracle; tVIII, tergite VIII; ts, tarsomere; vf, vertexal fovea. Scale bars in A, B, and C are 0.1 mm; in H and I are 0.05 mm; in D, E, F, G, J and K are 0.02 mm. Cross in J indicates anterior, posterior, dorsal and ventral positions and in K, anterior, posterior, left and right.

FIGURE 4. Various features of Mayetia atlantica. A, ventral view of the head (CELC000969); B, dorsal view of the head (CELC000969); C, dorsal view of right antenna (CELC000969); D, pronotum and left elytron (CELC000969); E, right elytron of female (CELC003058); F, right elytron of holotype male (CELC003054, two basal elytral foveae is not a male-only characteristic, see text); G, hind wings (CELC000358). Abbreviations: abl, antebasal line; an, antennomere; bef, basal elytral fovea; bs, basistipe; ca, cardo; ep, epipleuron; el, elytron; gf, gular fovea; gpr, posterior gular region; hw, hind wing; iab, interantennal bridge; lbrma, labrum macrocheta; ms, mediostipe; mt, mentum; n, notch; oc, occiput; occlc, ocular-clypeal carina; ocp, postocciput; pe, pedicel; pf, palpifer; prnmls, pronotal medial longitudinal sulcus; sc, scape; sct, scutellar shield; sl, sensilla; ss, sutural stria; su, sulcus; vc, vertexal corners; vf, vertexal fovea. Scale bars 0.05 mm, except for C where it is 0.02.