Euryachen seuzei a new genus and species of Placusini (Coleoptera: Staphylinidae Aleocharinae) from Brazil Pires-Silva, Carlos M. Zootaxa 2023 2023-01-24 5230 4 467 477 Pires-Silva, 2023 Pires-Silva 2023 [151,365,1159,1186] Insecta Staphylinidae Euryachen Animalia Coleoptera 2 469 Arthropoda species seuzei gen. et sp. nov.   Material Examined.   Holotype.J MZSP 21308: BRAZIL. São Paulo: Peruíbe,  27–29.IX.1984. Exp. MZUSPcol., in EtOh 70% ( Figs. 1, 3–5, 7)    Paratypes.All paratypes are in EtOH 70%, have the same data as holotype, and are cataloged as follows:  9 ♀ MZSP 21309,  MZSP 21313,  MZSP 21315,  MZSP 21316,  MZSP 21317,  MZSP 21318,  MZSP 21319,  MZSP 21321,  MZSP 21322; 5 J  MZSP 21310,  MZSP 21311,  MZSP 21312,  MZSP 21314,  MZSP 21320.  Other material. Additional material has the same data as holotype: 2 J and  1 ♀( MZSP) dissected on slides; 2 adultswith undetermined sex.   Diagnosis:Same as for the genus, with the inclusion of color data. Overall body light ferruginous: head and thorax slightly darker; legs and abdominal segment IX light yellow, tergites VII and VIII reddish-yellow on males and lighter on females.   Description  Length: 2 mm–2.2 mm ( Figs. 1–8)  Head ( Fig. 9).Spherical, about 1.3 times as wide as long; microsetae sparse and uniformly distributed on head surface and ventral regions. Antenna ( Fig. 11) with 11 antennomeres, scape elongated; antennomeres I–III subcylindrical, longer than wide; IV quadrate, the shorter; V–VI subequal in length, slightly wider than long; VII–X distinctively transverse; XI conical. Labrum ( Figs. 12, 38) membranous and broadly rounded, setae p1-p2/m1-m2/d1-d2 present, with a small rounded lobe bearing a-sensilla. Epipharyngeal region with a longitudinal irregular band of pores, laterally bordered by a longitudinal curved row of scale-like structures. Mandibles ( Figs. 13, 37) asymmetrical. Dorsal molar area bearing seven transverse rows of large denticles, denticles of each row decreasing basad; ventral region smooth, without denticles. Right mandible with a distinct subapical tooth, absent on left mandible, which has broader apex. Dorsal sensory pores present, transversally distributed. Prostheca short. Maxilla ( Fig. 14) slender, with galea slightly longer than lacinia; lacinia broad, with a longitudinal row of lacinial teeth, occupying almost ½ of the total length of lacinia; teeth longest at apex. Galea with a patch of four spines at apex. Maxillary palpi ( Fig. 15) 4-articulated: palpomere 1 short, transverse; 2, subcylindrical, broader at apex; 3, suboval; and 4, and subulate. Labium ( Figs. 16, 39). Labial papi 2-articulated, short; palpomere 1 broad, longer than palpomere 2; 2 cylindrical. Setae a, b, d, f, h present. Ligula ( Figs. 16, 39) short and broadly rounded; with small sensitive pores on surface. Mentum-submentum distinct. Mentum ( Figs. 10, 40) transverse, trapezoidal, anterior margin slightly emarginate, posterior margin almost straight and lateral margins diverging posteriorly. Apical, preapical and proximal setae present, symmetrically distributed. Gula long, occupying about 2/3 of head length. Gular sutures parallel.   FIGURES 1–2.  Euryachen seuzei  gen. et sp. nov.habitus lateral. 1, holotype; 2, paratype (female). Scale bars = 0,55 mm   FIGURES 3–6.  Euryachen seuzei  gen. et sp. nov.habitus dorsal. 3–5, holotype, detail of tergite V (4) showing the spine-like bristles on male and tergite VII (5), showing the thicker bristles near lateral margins; 6, paratype (female). Scale bars = 0,5 mm (3, 6)   FIGURES 7–8.  Euryachen seuzei  gen. et sp. nov.habitus ventral. 7, holotype; 8, paratype (female). Scale bars = 0,5 mm  Prothorax.Pronotum ( Fig. 17) transverse, about 1.2 times as wide as long, slightly narrower than elytra; anterior margin straight with short, almost indistinct, rounded angles; posterior margin broadly and weakly arcuate; with distinct posterior angles. Uniformly covered with short and sparse bristles. Hypomera distinct. Prosternum ( Fig. 18) like a distinct transverse and trapezoidal plate. Meso- metathorax ( Fig. 19) weakly sclerotized, with sparse and short bristles along the postero-lateral margins. Metendesternite Y-shaped; basal stalk narrow, with a digitiform projection between furcal arms; furcal arms reaching the level of mesocoxal cavities. Scutellum transverse. Metanotum ( Fig. 20) membranous, slightly shorter than metathorax. Elytra ( Fig. 21) elongated; almost reaching anterior margin of tergite III; anterior margin forming rounded angles; posterior margin individually slightly sinuose. Short bristles uniformly distributed along elytral surface. Legs.Procoxae ( Fig. 22) transverse, flattened; mesocoxae ( Fig. 24) rounded; metacoxae ( Fig. 26) somewhat triangular, flattened; ventrally covered with bristles. Tibia slightly longer than femur; bearing thick spine-like bristles. Protibia bearing a pair of tibial spurs, meso- and metatibia each with a single tibial spur. Tarsal formula 4-4-5 ( Figs. 23, 25, 27). Pro-, meso- and metatarsi each with two unciform claws.   FIGURES 9–21.  Euryachen seuzei  gen. et sp. nov.9, head, venral view; 10, mentum-submentum, ventral view; 11, antenna; 12, labrum, dorsal view; 13, mandibles, dorsal view; 14, maxilla, dorsal view; 15, maxillary palpi 2–4, dorsal view; 16, labium, ventral view; 17, pronotum, dorsal view; 18, prosternum, ventral view; 19, meso- and metaventrite, ventral view; 20, meso- and metanotum, dorsal view; 21, elytra, dorsal view. Scale bars = 0,25 mm (13); 0,125 mm (11, 18, 19); 0,08 mm (17, 20); 0,075 mm (9, 15); 0,05 mm (10, 21); 0,03 mm (14); 0,025 mm (12, 16).  Abdomenparallel-sided, narrowed at apex. Tergites and sternites separated by two pairs of narrow paratergites on abdominal segments III–VII. Tergites II–VII coarsely covered with bristles. Tergite I indistinct; tergites II–VI transverse; males with tergite V ( Figs. 28, 41) bearing 7–9 spine-like bristles centered and thick bristles on the postero-lateral margins of tergite VII. Tergite VII ( Figs. 30–31, 43–44) broader at base, slightly longer than tergite VI. Tergite VIII ( Fig. 32) subquadrate, with same chaetotaxy pattern for males and females. Tergite IX broad, with longitudinal rows of bristles. Tergite X ( Fig. 33) broad, quadrate; with a dense and subquadrate patch of setae. Aedeagus. Median lobe ( Fig. 34) elongated, piriform, weakly rounded at base. Lateral lobes ( Figs. 34–35) with a long and very narrow distal segment, bearing three short bristles. Spermatheca( Fig. 36) spherical and sclerotized.   FIGURES 22–36.  Euryachen seuzei  gen. et sp. nov.22, front leg, lateral view; 23, front tarsus, lateral view; 24, middle leg, lateral view; 25, middle tarsus, lateral view; 26, hind leg, latral view; 27, hind tarsus, lateral view; 28, tergite V of male, dorsal view; 29, tergite V of female; 30, tergite VII of male; 31, tergite VII of female; 32, tergite VIII; 33, tergite X; 34, aedeagus, dorsal view; 35, detail of lateral lobe; 36, spermatheca; ts: tibial spur. Scale bars = 0,1 mm (32); 0,08 mm (30, 31); 0,075 mm (22, 24, 26, 28, 29); 0,05 mm (33, 34); 0,025 mm (23,25, 35, 36); 0,02 mm (27).  Biologica notes:The material studied was collected in trunks in a newly felled forest. Adults of  Euryachen seuzeiwere collected under bark, together with larvae of  GlyptomaErichson. Bothare together in the sample (MZSP 570). Studying more material of the same locality, other samples were found with both taxa mixed: in one (MZSP 570), larvae of  Glyptomawere together with adults of Placusini, and in another (MZSP 590), some Aleocharinaelarvae ( Homalotini) were together with  Glyptomaadults. These observations let to conclude that adults and larvae of Placusiniand  Glyptomacan share the same subcortical habitat, and although  Euryachenlarvae were not found, one cannot rule out the possibility that they also live with the adults.   Etymology.The specific epithet “  seuzei” is a noun in the genitive case in honor of my grandfather, José Pires Ferraz. A kind-hearted man who prioritizes his family above all else. “Seu Zé” is a common nickname in Brazilfor “José”, and also how he is called by his family and friends.   Distribution. Brazil— São Paulo: Peruíbe. 4020020310 1984-09-27 1984-09-29 1984-09-27 MZUSP Brazil Peruibe 2 469 MZSP 21308 1 Sao Paulo holotype 4020020303 [199,1382,1304,1331] 1984-09-27 1984-09-29 1984-09-27 MZUSP Brazil Peruibe 2 469 2 Sao Paulo paratype 4020020307 MZSP Brazil 2 469 MZSP 21309 9 9 Sao Paulo paratype 4020020306 [313,468,1340,1366] MZSP Brazil true 2 469 MZSP 21313 1 Sao Paulo paratype 4020020312 [474,629,1340,1367] MZSP Brazil 2 469 MZSP 21315 1 Sao Paulo paratype 4020020318 [635,790,1340,1366] MZSP Brazil 2 469 MZSP 21316 1 Sao Paulo paratype 4020020311 [797,952,1340,1366] MZSP Brazil 2 469 MZSP 21317 1 Sao Paulo paratype 4020020309 [958,1113,1340,1366] MZSP Brazil 2 469 MZSP 21318 1 Sao Paulo paratype 4020020302 [1119,1274,1340,1366] MZSP Brazil 2 469 MZSP 21319 1 Sao Paulo paratype 4020020317 [1281,1436,1340,1366] MZSP Brazil 2 469 MZSP 21321 1 Sao Paulo paratype 4020020315 [151,304,1376,1402] MZSP Brazil 2 469 MZSP 21322 1 Sao Paulo paratype 4020020316 [364,520,1376,1402] MZSP Brazil 2 469 MZSP 21310 1 Sao Paulo paratype 4020020314 [527,682,1376,1402] MZSP Brazil 2 469 MZSP 21311 1 Sao Paulo paratype 4020020308 [689,845,1376,1402] MZSP Brazil 2 469 MZSP 21312 1 Sao Paulo paratype 4020020305 [852,1008,1376,1402] MZSP Brazil 2 469 MZSP 21314 1 Sao Paulo paratype 4020020313 [1015,1169,1376,1402] MZSP Brazil 2 469 MZSP 21320 1 Sao Paulo paratype 4020020301 [383,1044,1412,1439] 1984-09-27 1984-09-29 1984-09-27 MZUSP Brazil Peruibe 2 469 1 Sao Paulo 4020020304 [1052,1411,1412,1439] MZSP Brazil 2 469 1 1 Sao Paulo