Xanthopygus pexus
Creators: name: Chatzimanolis, Stylianos
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Xanthopygus
Xanthopygus pexus

description: Xanthopygus pexus (Motschulsky, 1858)
(Figs. 14, 40–46)
Belonuchus pexus Motschulsky, 1858: 667.
Lampropygus pexus (Motschulsky); Fauvel 1901: 85.
Xanthopygus pexus (Motschulsky); Blackwelder 1943: 450.
Type material. Neotype, here designated, male, with labels: “ COLOMBIA: Magdalena, PNN Tayrona Cañaveral, 30 m, 11°20’N, 74°2’W [11.33°, -74.03°], malaise, 15.xii.2000 – 2.i.2001, R. Henriquez leg., M963” / “SM0549128”. In the collection of SEMC.
Additional Materials. ARGENTINA: Misiones: Campo Grande [-27.2079°, -54.9797°], xii.1957, Scheerpeltz coll. (1 ♂ NMW); Iguazú P. N. [-25.616°, -54.333°], 2.i.1991, S. & J. Peck leg., forest TV tower road, log and bark litter, 90-147, FMNHINS3975545, FMNHINS3975547, FMNHINS3975544, FMNHINS3975548, FMNHINS3975546 (1 ♂, 4 ♀ FMNH); same locality, iv.1981, S. Bolle leg., FMNHINS3975562 (1 ♂ FMNH); Posadas [-27.36°, -55.9°], vii.1954, FMNHINS3975426, FMNHINS3975427 (2 ♀ FMNH); Reserva Vida Silvestre Urugua-1, [-25.97°, -54.11°], 400m, 15–17.xii.2003, B. Brown, G. Kung, L. Gonzalez leg., SM0765027 (1 ♂ SEMC); BRAZIL: Bahia: Itabuna [-14.785°, -39.28°], rotting cacao pods (1 ♂, 1 ♀ NHMUK); unknown locality, Cameron coll. (1 ♀ NHMUK) Espírito Santo: unknown locality, Fruhstorfer leg., FMNHINS3975424 (1 ♂ SDEI; 1 ♀ FMNH); unknown locality, Bang-Haas leg., FMNHINS3975413 (1 ♀ FMNH); unknown locality, Descourtilz [leg.], Fry coll., FMNHINS3975418 (1 ♀ FMNH); unknown locality, Sharp coll. (1 ♀ NHMUK); Mato Grosso: unknown locality; Rohde [leg.] (3 ♀ ZMHB); Minas Gerais: unknown locality (1 ♂ NHMD); unknown locality, Reinhardt leg. (1 ♂ NHMD); Pará: Faz. Taperinha [-2.491°, -54.303°], 19–22.xi.1969, J. & B. Campbell leg. (2 ♀ CNC); same locality, 16–18.xi.1969, J. & B. Campbell leg. (2 ♀ CNC); Santarém [-2.4394°, -54.6987°] (1 ♀ CMNH); Paraná: Londrina [-23.31°, -51.1628], viii.1939, E. Reitter leg., Scheerpeltz coll. (1 ♂ NMW); Virmond [25.38°, -52.19°] (1 ♀ ZMHB); Rio de Janeiro: Itatiaya [Itatiaia, -22.496°, -44.563°], 700m, 20.iii.1924, on fallen bananas, J. Zikan leg., FMNHINS3975423 (1 ♀ FMNH); Nova Friburgo [-22.281°, -42.531°], Schaufuss coll. (1 ♂ ZMHB); Rio [de] Jan [eiro] [-22.91°, -43.20°], Fry coll., FMNHINS3975335, FMNHINS3975421, FMNHINS3975420, FMNHINS3975492, FMNHINS3975493 (1 ♂, 4 ♀ FMNH); same locality, Sharp coll. (1 ♀ NHMUK); Santa Catarina: Hansa Humboldt [-26.425°,-49.242°], viii.1939, E. Reitter leg., Scheerpeltz coll. (2 ♂, 6 ♀ NMW); same locality, xii.1944, A. Maller leg. (1 ♀ AMNH); same locality, iv.1948, A. Maller leg. (1 ♀ AMNH); Nova Teutônia [-27.25°, -50.33°], 1868 [likely erroneous], F. Plaumann leg. Scheerpeltz coll. (1 ♀ NMW); same locality, 300–500m, ix.1950, F. Plaumann (1 ♀ CNC); unknown locality, Fry coll., FMNHINS3975431 (1 ♀ FMNH); Rio Laeiss, A. Hepp leg., Blackelder coll. (1 ♂ AMNH); São Paulo: Butantâ [-23.57°, -46.72°], 16.v.1920, R. Fischer leg. (1 ♀ SDEI); Cantareira [-23.40°, -46.59°], J. Guerin leg., FMNHINS3975903 (1 ♂ FMNH); Caraguatatuba [-23.62°, -45.413°], 40m, 22.v–1.vi.1962 (1 ♀ CNC); Indiana [-22.174°, -51.251°], J. Guerin leg., FMNHINS3975902 (1 ♂ FMNH); São Paulo [-23.55°, -46.63], 26.vi.1927 (4 ♀ SDEI); same locality, Mráz leg. (2 ♀ AMNH); same locality, Mráz leg., Bernhauer coll., FMNHINS3975402, FMNHINS3975399, FMNHINS3975397, FMNHINS3975398, FMNHINS3975400, FMNHINS3975401, FMNHINS3975403, FMNHINS3975404 (2 ♂, 6 ♀ FMNH); Umgbg. v. Ribeirâo Preto [-21.178°, -47.806°], iii–vii.1899, Riedel [leg.], Bernhauer coll., FMNHINS3975405, FMNHINS3975406, FMNHINS3975407, FMNHINS3975408 (2 ♂, 2 ♀ FMNH); Unknown state: unknown locality, Sharp coll. (1 ♀ NHMUK); unknown locality, FMNHINS3975414 (1 ♀ FMNH); COLOMBIA: Magdalena: Santa Marta [11.241°, -74.205°], Fry coll. (1 ♀ NHMUK); unknown department: unknown locality, M. Cameron coll. (1 ♀ NHMUK); unknown locality, Sharp coll. (1♀ NHMUK); unknown locality (1 ♀ CNC; 1 ♂ MHNG; 1 ♂ NMW); FRENCH GUIANA: Kourou (roches de) [5.16°, -52.65°], W. Chapman leg., Griveau coll. (1 ♂, 1 ♀ MHNG); Goudronville [5.01°, -52.65°], Scheerpeltz coll. (1 ♂ NMW); Nouveau Chantier (1 ♀ MHNG); same locality, Le Moult leg. (3 ♀ MHNG); Saint-Laurent-du-Maroni [5.499°, -54.031°] (1 ♀ MHNG); unknown locality (1 ♀ MHNG; 1 ♂, 1 ♀ NHMD; 2 ♂, 1 ♀ NHMUK); GUYANA: Region 8: Iwokrama Forest, Pakatau hills [4.748°, -59.026°], 70 m, 25–29.v.2001, FIT, R. Brooks & Z. Falin leg., SM0253206 (1 ♂ SEMC); Tukeit [5.20°, - 59.45°], 21.xii.1911 (1 ♂ AMNH); PARAGUAY: Cazaapá: San Rafael Reserve, Estancia Condesa / Toro Blanco, [- 26.307°, -55.674°], 110m, 9.xii.2000, Z. Falin leg., fermenting tree stump, SM0235560, SM0235558, SM0235562, SM0235553 (1 ♂, 2 ♀ SEMC; 1 ♀ UTCI); Reserve, Hermosa prop. Sosa family, [-26.3208°, -55.7486°], 90m, 5.xii.2000, Z. Falin leg., fermenting tree wound, SM0567905 (1 ♂ SEMC); Guairá: Calle Florida [-25.739°, - 56.265°], 9.ix.1994, U. Drechsel leg., SM0671382 (1 ♀ SEMC); Villarica [-25.750°, -56.433°], xii.1925, F. Schade leg. Scheerpeltz coll. (1 ♂ NMW); Itapúa: Hohenau [-27.078°, -55.645°], i.1995 (1 ♂ NHMD); unknown department: unknown locality, Drake leg. (1 ♀ SDEI); unknown locality, Plason leg., FMNHINS3975900 (1 ♂ FMNH); SAINT VINCENT AND THE GRENADINES: Saint Vincent: unknown locality, H. Smith (1 ♀ NHMUK; 1 ♂ NMW); SURINAME: Paramaribo: Paramaribo [5.852°, -55.203°], Crampton leg. (1 ♂, 1♀ MCZ); unknown locality, Bierig coll., FMNHINS3975901 (1 ♀ FMNH); TRINIDAD and TABAGO: Trinidad: Balandra Bay [10.715°, -60.99°], 23.iii.[19]22, F. Psota coll., FMNHINS3975428, FMNHINS3975429, FMNHINS3975430 (3 ♂ FMNH); Brasso [10.399°, -61.317°], 28.v.1941, from banana stem with Cosmopolites sordidus, E. McG. Callan leg., (1 ♀ NMNH); Caparo [10.449°, -61.328°], Heyne [leg.], FMNHINS3975412, FMNHINS3975410, FMNHINS3975411, FMNHINS3975415, FMNHINS3975416, FMNHINS3975409 (1 ♂, 5 ♀ FMNH); same locality, Scheerpeltz coll. (1♀ NMW); same locality, Blackwelder coll. (1 ♀ AMNH); Four Roads [10.686°, -61.549°], R. Thaxter leg. (1 ♂, 1 ♀ MCZ); Guaico (Sangre Grande) [10.587°, -61.144°], 26.viii.1969, H. & A. Howden leg. (2 ♀ CNC); Maracas [10.757°, -61.440°], 16.iii.1961, N. Gopaul leg. (1 ♂ CNC); Morne Bleu [10.716°, -61.283°], 823m, 21.viii.1969, H. & A. Howden leg. (1 ♀ CNC); Mt. Tucuche [10.732°, -61.417°], vi.1929, Darlington leg. (1 ♀ MCZ); Port of Spain [10.659°, -61.508°], 30.i.[19]12, G. Marshall leg. (1 ♂ NHMUK); Port of Spain, Ariapata Vall. [10.66°, -61.52°], Blackwelder coll. (1 ♀ AMNH); St. Augustine [10.647°, -61.399°], vi.1929, Darlington leg. (1 ♀ MCZ; 2 ♀ NMNH); Arima, Vardant Vale [10.685°, -61.281°], vi. [19]13, R. Thaxter leg. (2 ♂, 2 ♀ MCZ); same locality, 28.xii.1912, R. Thaxter leg. (1 ♀ MCZ); unknown locality, i.1903, G. Bryant leg., FMNHINS3975422 (1 ♀ FMNH; 2 ♂, 2 ♀ NHMUK); unknown locality, A. Busck leg. (1 ♀ NMNH); unknown locality, 1904, F. Birch leg., Sharp coll. (3 ♀ NHMUK); VENEZUELA: Capital District: Caracas [10.48°, -66.90°], 1938, G. Vivas, FMNHINS3975433 (1 ♀ FMNH); same locality, ii.[19]50, Marcuzzi leg., Scheerpeltz coll. (2 ♀ NMW); same locality, 7.v.[19]50, Marcuzzi leg., Scheerpeltz coll. (1 ♀ NMW); Vargas: La Guaira [10.6°, -66.933°], 2.vii–10.viii.1900, W. Robinson leg. (1 ♀ MCZ); Unknown state: Chacoa, FMNHINS3975417(1 ♀ FMNH); unknown locality, Sharp coll. (2 ♀ NHMUK); unknown locality, Fry coll., FMNHINS3975419, FMNHINS3975432 (2 ♂ FMNH); unknown locality, FMNHINS3975425 (1 ♂ FMNH); unknown locality, 1858, D. Moritz leg. (2 ♂, 2 ♀ NMW); unknown locality, Kraatz coll. (2 ♂, 1 ♀ SDEI); unknown locality, Scheepeltz coll. (1 ♂ NMW).
Diagnosis. Xanthopygus pexus looks rather similar to X. major and X. max and it could be hard to distinguish these three species. In all of these species, abdominal segment 7 is black with posterior 1/2 or posterior 1/3 orange; in X. pexus it is typically 1/2 orange but the degree of coloration can vary. Xanthopygus major and X. max can be distinguished from X. pexus based on the following characteristics in combination: head and pronotum with small to medium size punctures (medium to large size punctures in X. pexus); pronotum with one sparse row of punctures on each half beside median line (pronotum with 1–2 dense rows of punctures on each half beside median line in X. pexus); abdominal segments 4–6 not iridescent under strong light (abdominal segments 4–6 with iridescent overtones under strong light in X. pexus). Xanthopygus pexus might also be confused with X. cognatus (due to overall habitus similarities) but X. cognatus has abdominal segment 7 orange and abdominal segment 6 with a distinct bright band of orange coloration posteriorly (abdominal segment 7 never completely orange, typically anterior half dark or light brown and abdominal segment 6 without a distinct bright band of orange coloration posteriorly in X. pexus); aedeagus with median lobe lacking subapical tooth (aedeagus with median lobe having a subapical tooth in X. pexus); and paramere in lateral view much shorter than median lobe (paramere in lateral view slightly shorter than median lobe in X. pexus).
Description. Forebody length 7.1–10.0mm; HW/HL ratio = 1.32. Antennomere 3 subequal to 2; antennomere 4 subquadrate, with tomentose pubescence; antennomere 6 transverse. Mandibles curved from apical half. Eyes as long as 2/5 length of head; head appearing convex. Head and pronotum with medium to large size punctures (see Figs 40–41); pronotum with 1–2 dense rows of punctures on each half beside median line; pronotum microsculpture with transverse lines. PW/PL ratio = 1.09. Mesoventrite with intercoxal process broad and pointed. Metacoxae with more than four spines (five or six) on posterior surface. EL/PL ratio = 1.25. Abdominal segments 4–6 with iridescent overtones; segment 6 without distinct bright band of orange coloration posteriorly; tergite 6 densely punctate; sternite 6 with single anterior transverse line; segment 7 coloration varies, in most specimens 1/2 black, 1/2 orange. In males, sternite 7 without porose structure; sternite 8 with shallow U-shaped emargination posteriorly. Aedeagus as in Figs. 44–46; in dorsal view paramere converging to rounded apex; paramere shorter and much narrower than median lobe; in lateral view paramere almost straight; paramere with peg setae as in Fig. 46. Median lobe in dorsal view converging to broadly rounded apex; median lobe with subapical tooth; in lateral view median lobe becoming narrower near apex.
Distribution. Known from Argentina, Brazil, Colombia, French Guiana, Guyana, Paraguay, the island of St. Vincent of Saint Vincent and the Grenadines, Suriname, the island of Trinidad of Trinidad and Tobago, and Venezuela. The map is shown in Fig. 14 and online at https://www.simplemappr.net/map/16395.
Habitat. Collected in lowland tropical rainforests (elevations 5–823m) using flight intercept and malaise traps, as well as sifting log and bark litter. Also, hand collected from rotting cacao pods, fallen bananas, and fermenting trees.
Remarks: The original type is considered lost (personal communication with curators in St. Petersburg and Moscow) and thus a designation of a neotype is necessary.
description: Published as part of Chatzimanolis, Stylianos, 2022, A revision of the genus Xanthopygus Kraatz (Staphylinidae: Xanthopygina), pp. 151-178 in Zootaxa 5099 (2) on pages 168-171, DOI: 10.11646/zootaxa.5099.2.1, http://zenodo.org/record/6048483