Xenogaster kymopoleia Pires-Silva, 2023

Pires-Silva, Carlos M., 2023, Two new species of the termitophilous rove beetle genus Xenogaster Wasmann from Brazil (Staphylinidae, Aleocharinae, Corotocini), Zootaxa 5239 (2), pp. 247-264 : 254-262

publication ID	https://doi.org/ 10.11646/zootaxa.5239.2.4
publication LSID	lsid:zoobank.org:pub:D54F4D1B-8D3A-4A28-9044-A71B8FABC666
DOI	https://doi.org/10.5281/zenodo.7624243
persistent identifier	https://treatment.plazi.org/id/03ECC457-FFE0-4049-FF4A-FE27FCB4F9EB
treatment provided by	Plazi
scientific name	Xenogaster kymopoleia Pires-Silva
status	sp. nov.

Treatment

Xenogaster kymopoleia Pires-Silva , sp. nov.

( Figs. 47–91, 93, 95 View FIGURES 47–49 View FIGURES 50–52 View FIGURES 53–67 View FIGURES 68–82 View FIGURES 83–86 View FIGURES 87–90 View FIGURES 91–96 , 99 View FIGURES 98–99 )

Type material. HOLOTYPE, male. BRAZIL: “Itanhaém–S„o Paulo ; 23.II.1979; L. R. Fontes, S. A. Marques, col”. Dissected on slides ( MZUSP 21151 View Materials ). PARATYPES, 1 male, “Itanhaém–S„o Paulo; 24.XII.1978; L. R. Fontes” col. Dissected on slides ( MZUSP 21152 View Materials ); 1 female. BRAZIL: “Icapara—S„o Paulo; 15.VI.1990; L. R. Fontes, col”. Dissected on slides ( MZUSP 21362 View Materials ).

Male: ~3.1 mm ( Figs. 47–49 View FIGURES 47–49 )

Female: ~2.8mm ( Figs. 50–52 View FIGURES 50–52 )

Diagnosis. Body dark ferruginous, outer margins of elytra and pronotum dark reddish-brown. X. kymopoleia sp. nov. is characterized especially by the chaetotaxy of sternite VIII, which has a transversal row of four bristles, and by the antennomeres III–IV distinctively transverse and shorter than II and V.

Head ( Fig. 53 View FIGURES 53–67 ). Rounded, slightly longer than wide. Sides behind eyes parallel in short area, narrowed apicad, forming rounded angles at base. Finely punctures on the dorsal area of the head, contrasting with the ventral, which has fine impressions, giving a rough appearance. Clypeus membranous, deflexed in front of antennal fossae, producing a transversal carina between posterior margins of antennal insertions. Gula elongated, triangular widest at base, elongate with about ⅔ of the total length of head. Gular sutures diverging gradually towards base. Antennae ( Fig. 54 View FIGURES 53–67 ) partially cylindrical with 11 antennomeres; scape elongate, with about the same length of antennomeres II–V combined, slightly narrowed at base, almost straight internally. Antenommere I elongate, narrowed at base; III–V almost as long as wide; antennomere II elongated than antennomere III; VI–X transverse; V–VI subquadrate slightly decreasing apicad; VII–X subequal in length, wider than long, with anterior and posterior margins slightly arcuate. Antennomere XI ( Fig. 55 View FIGURES 53–67 ) with one pair of coeloconic sensilla. Labrum membranous and slightly wider than long, membranous, with two long bristles on posterior margin. Mandibles ( Fig. 56 View FIGURES 53–67 ). Symmetrical and widest at base; with an apical and subapical tooth; subapical tooth near apical and fronswardly directed. Sensitive pores at basal region of each mandible. Prostheca inconspicuous, occupying almost the entire mesal length (in fig. 56 indicated by red arrows). Maxilla ( Fig. 58 View FIGURES 53–67 ) with cardo rounded laterally (not showed in the photo), stipes short, rectangular, slightly longer than wide; galea and lacinia narrow, arcuate and elongated, widest at base; galea and lacinia subequal in length, a thick bristle comb on the apex of internal edge of galea; Maxillary palpi 4-articulated, arcuate and longer than stipes; palpomere I reduced, almost indistinct, ring-like; II elongated, rounded at apical margin and strongly narrow at base, subcylindrical, with small bristles; III oval, globose, slightly shorter than previous, with a pair of long bristles at apex; IV with half of the length of previous segment, narrowed apicad. Labial palpi ( Fig. 57 View FIGURES 53–67 ) 3-articulated; palpomere I elongated, cylindrical; II almost as long as wide, about ½ of the length of palpomere I; III elongated, narrow, longer than previous; Ligula prominent and bilobed, slightly emarginate; each lobe with surface somewhat scale-like; with a digitiform projection between lobes, bearing two apical spiniform sensilla. Prementum membranous, short. Mentum fused to submentum, with anterior margin straight, anterior and posterior angles divergent; one apical bristle on each edge of anterior margin and two small bristles sparsely distributed on medial region of anterior margin; sensitive pores sparsely distributed across the surface ( Figs. 59 View FIGURES 53–67 , 98 View FIGURES 98–99 ). Postmentum fused to gula.

Prothorax ( Figs. 62–65 View FIGURES 53–67 , 83–86 View FIGURES 83–86 ): Pronotum slightly wider than long, ferruginous with outer margins dark reddish-brown; posterior margin almost straight; lateral margins parallel, forming weak rounded angles; pronotum longitudinally and irregularly impressed, with a deep impression at the central region of pronotal disc; two longitudinal impressions each one near lateral margins forming a weak wave-like carina on each side; surface with irregular geometric shapes, bearing sparse and thick short bristles entirely, giving a crenulated and spiny appearance ( Fig. 83 View FIGURES 83–86 ). Three bristles longitudinally distributed on each lateral margin. Meso- metathorax ( Fig. 67 View FIGURES 53–67 ) weakly sclerotized, finely punctuated at posterior margin. Metendesternite ( Fig. 61 View FIGURES 53–67 ) U-shaped internally, basal stalk bilobed at base; fucal arms wide and parallel, not reaching mesocoxal margins. Scutellum transverse and oblong. Metanotum ( Fig. 66 View FIGURES 53–67 ) membranous, fused to metasternum; longer than metanotum. Wings reduced to stubs. Elytra ( Fig. 60 View FIGURES 53–67 , 87–90 View FIGURES 87–90 ) elongated, sides almost parallel; outer margin dark yellowish-brown, straight and densely punctuated, with a grainy appearance. Anterior margin declivous; inner margin almost straight, widely rounded from distal third to outer margin; apices convergent at suture; posterior margin forming a broad and rounded angle. Bearing a single long bristle on anterior margin. Elytra with irregular and geometrical shapes, each with a short stout bristle. Legs ( Figs. 68–70 View FIGURES 68–82 ). Procoxae longer and subtrapezoidal, mesocoxae oval, and metacoxae triangular. Femora elongated and cylindrical; metafemur with inner margin narrow; tibia with almost the same length as the femur; covered with short bristles along the whole surface; protrochanter the shorter; meso- and metatrochanter about the same length; metatrochanter bearing a single long bristle. Tarsi ( Figs. 71–73 View FIGURES 68–82 , 91, 93, 95 View FIGURES 91–96 ); tarsal formula 5-5-5, with 4 th and 5 th tarsomeres almost fused, presenting a clear line of division between them–(In figs. 91, 93, 95, division line indicated by arrows). First tarsomere of pro- and mesotarsus almost of the same length as tarsomeres 4–5 combined; first tarsomere of metatarsus with almost the same length as metatarsomeres 2–4 combined. Last tarsomere each with two unciform claws and an angular dentiform projection between claws.

Abdomen physogastric with membranous areas among sclerites. Tergites and sternites separated by two pairs of paratergites in abdominal segments III–VI; bristles of tergites always on sclerites; inner paratergites sclerotized, subquadrate, outer paratergites narrow. Segment I membranous, reduced, fused to metanotum; segment II with a reduced tergite, shorther than tergite III, with anterior margin emarginate at middle; second sternite transverse, plate-shaped; tergites III–V rectangular; tergite III with posterior margin emarginate. Tergite VII ( Fig. 71 View FIGURES 68–82 ) band-like and subtrapezoideal, with posterior margin slightly curved, anterior margin with a pair of glandular reservoirs, each widely separated; one row of 4 large bristles in the medial region, finely punctuated in the whole surface; posterior margin marginated by fringe of fine bristles. Tergite VIII subquadrate, wider than long, anterior margin slightly emarginate; lateral margins rounded; covered with fine short bristles on medial to posterior region. One transverse row of four bristles symmetrically distributed. Sternite VIII ( Fig. 75 View FIGURES 68–82 ) subquadrate, wider than long, continuous laterally by sclerotized extension on females; and forming short angles in anterior margin of males; lateral margins slightly curved and posterior margin with rounded angles. One transversal row of four bristles on posterior region symmetrically distributed; small bristles and sensitive pores distributed across the whole surface; posterior margin marginated by fringe of fine bristles; sternite IX represented by a pair of hemisternites laterally attached to tergite IX in female ( Fig. 77 View FIGURES 68–82 ), on males represented by three long extensions (apodemes) ( Fig. 80 View FIGURES 68–82 ). Tergite IX subtriangular, covered with short bristles; two long bristles in a longitudinal row parallel to lateral margin. Tergite X ( Figs. 78, 80 View FIGURES 68–82 ) band-like, fore angles rounded, covered with short bristles and with two transversal rows of bristles symmetrically distributed parallel to anterior margin. Aedeagus rounded, basal capsule broadly rounded, apical lobe narrowing apicad and bilobed ( Fig. 82 View FIGURES 68–82 ). Lateral lobes with distal segment short, with short bristles on apex; medial segment broader and proximal segment elongate. Spermatheca ( Fig. 79 View FIGURES 68–82 ) sclerotized. Stem elongated, with almost the same length as the capsule, which is cylindrical and elongated.

Type-locality. Brazil. S„o Paulo–Intanhém.

Remarks. Xenogaster kymopoleia differs from X. pseudonuda in the shape of mentum and pronotum, which has distinctive longitudinal impressions on each lateral margin. The shape of elytra, with the inner margins widely rounded from distal to outer margin and apices convergent, while X. pseudonuda have the anterior and posterior margins declivous and convergent. Finally, the species are also differentiated by the antennal segments: while X. kymopoleia has distinctive transverse segments VI–X, but X. pseudonuda has these segments subquadrate, to slightly wider than long.

Host. The holotype was collected together with Araujotermes caissara Fontes (MZSP 7716). The male paratype, with Nasutitermes sp. (MZSP 7739). The female paratype was collected with Nasutitermes jaraguae (Holmgren, 1910) collected on a thin, rotten, fallen branch (L. R. Fontes pers. comm.).

Data on the label of the termite cataloged as “MZSP 7716” (29.VII.–3.VIII.1978; L.R. Fontes & S.A. Marques col.) does not correspond to the information on the label of the holotype of X. kymopoleia ([presumably collected with termites MZSP 7716] MZUSP 21151— 23.II.1979; L.R. Fontes col.). Curiously, the corresponding data is found only on the labels of termites cataloged as “MZSP 7816” (Dr. M. M. Rocha (MZUSP), pers. comm). Probably a mistake occurred when the collector was writing the data (‘7716’ should have been written as ‘7816’). This is reinforced by the fact that the termite MZSP 7716 is identified as Araujotermes caissara , while MZSP 7816 as Nasutitermes sp. Due to the historical association of Xenogaster being found only with termites of the genus Nasutitermes , the association with A. caissara can be considered improbable.

Etymology. The specific epithet is an allusion to the wave-like impressions on the pronotum. The name is transcribed from the ancient Greek Κυμο- (Kymo-) + πόλεια (póleia), referring to the Greek goddess of violent sea and storms, daughter of the sea god Poseidon. Noun in apposition.