Dilacera exokosmos Zilberman & Pires-Silva, 2022

Zilberman, Bruno & Pires-Silva, Carlos M., 2022, Dilacera, a new astonishing Amazonian genus of termitophilous rove beetle (Staphylinidae: Aleocharinae: Termitonannini) and updated checklist of the subtribe Termitonannina with their termite hosts, Zootaxa 5194 (1), pp. 122-132 : 123-128

Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov.

Type material: HOLOTYPE, MZSP 21306 ( male): BRAZIL. Amazonas : Manaus ( BR-174, Km 102 ), 5.VIII.1987, José Wellington de Morais col. (with Uncitermes teevani, MZUSP 8953), in alcohol . PARATYPE, MZSP 21307 , same data as and collected with the holotype, dissected on slides .

Measurements: Body length ~ 4.5 mm (male, abdomen distended) ( Figs. 1 , 3 , 5 ), ~ 4.5 mm (female) ( Figs. 2 , 4 , 6 ).

Diagnosis: Same as for the genus, with the inclusion of color data not discussed in the generic diagnosis because it is conceivably easy to vary within a genus. Head is light brown, antenna yellowish pale, pronotum light brown (slightly darker in female), legs with coxae, femora and tarsi yellowish, and tibiae dark brown; elytra light brown, abdomen mostly light yellow through segment VI, with tergites a little darker, somewhat lighter in tergite II; segment VI and tergite X dark brown, paratergites VII gradually darkening through the apex.

Description: Head about 1.3 times wider than long, widest at the eyes level, with a strong depression starting middle vertex deepening all through the front, leaving an impression of the eyes laterally popping out from the head; a pair of medium-sized setae on vertex, medially, right before the posterior limit of the eyes ( Figs. 1-4 ); mentumsubmentum distinct; gula short, slightly widening through the posterior region. Antenna fusiform, with 10 antennomeres and with pedicels not visible: scape dilated at apex, about the length of antennomere II-III combined, antennomeres II-III elongated, IV-IX wider than long, antennomere X elongated and bearing two coeloconic sensilla ( Figs. 1-6 , 8 ). Labrum more than twice wider than long, narrowing through a subtle emarginated apex; d 2- d 1, m 2- m 1, and p 2- p 1 setae present; p 1 very close to m 1 ( Figs. 9 , 33 ). Mandibles symmetrical, bending through apex and with a broad and short mesal tooth ( Fig. 7 ). Maxilla robust, stipes longer than wide, galea elongated, with a modified apex occupying about 35% of total galea length, bearing many short to medium sized bristles; lacinia divided by almost their entire length into internal and outer lobes, internal lobe longer than outer lobe and slightly shorter than galea, bearing 10 long setae at apex, first two conspicuously longer than the others; outer lobe shorter, covered with many medium sized setae from middle margin to apex, and base with scarce short setae; maxillary palp 4-articulated: palpomere I very short, subquadrate; palpomere II elongated, widening through apex; palpomere III short, with outer margin dilated; palpomere IV well developed, about 1.5 times longer than palpomere III, narrowing through apex, which bears a large sensorial pit ( Figs. 11 , 32 ). Prementum with 3-articulated labial palp and with a bilobed ligula; lobes widely separated ( Fig. 10 ).

Prothorax with pronotum wider than long, narrowing posteriorly; anterior margin concave, and posterior margin convex (more deeply concave and with more prominent anterior angles in male); chaetotaxy as follows: six setae on each margin, mostly long, but two first on internal apex only moderately long; a pair of middle-apical very short setae, right on the concave region; a pair of two moderately long setae a little below the medial margin of the pronotal disk, followed below by a pair of very short and more closed pair of setae posteriorly ( Figs. 1-2 , 12 , 38-39 ); prosternum represented only by a small sclerite ( Fig. 13 ). Mesothorax and metathorax combined a little shorter than prothorax ( Figs. 5-6 , 12-13, 14, 16 ); scutellum suboval ( Figs. 16-17 ); wings present and of typical staphylinid venation; elytron slightly trapezoidal ( Fig. 18 ). Metendesternite with arms ending in spoon-like sclerotized regions ( Figs. 14-15 ). Legs developed, 4-4-5 tarsal formula ( Figs. 19-24 ); proleg with coxa elongated, slightly longer than femur, tibia about twice the length of tarsi; tibia densely covered with a comb of bristles, scarcely setose in female; fourth tarsomere slightly longer than the remaining tarsomeres combined; tarsomeres I-III each with a distal spinelike seta ( Figs. 19-20 ); mesoleg with coxa shorter than femur, tibia about twice the length of tarsi; fourth tarsomere slightly shorter than the remaining tarsomeres combined; tarsomeres I-III each with a distal spine-like seta ( Figs. 21-22 ); metaleg with coxa short, trochanter very large, longer than the coxa; femur about the same length as tibia; fifth tarsomere about as long as the first; tarsomeres more setose, still with a distinctive distal seta on tarsomeres I-IV ( Figs. 23-24 ).

Abdomen mostly sclerotized, with only segment II with significant areas of membrane exposed, flattened, widest at segments IV-VI ( Figs. 1-6 ); segment I represented only by a distinctive tergite of sinuous pattern attached to metanotum ( Fig. 16 ); segment II with a tergite and a thinly sclerotized sternite; segments III-VII each with a sternite, tergite and a partergite, last two visible on dorsal view ( Figs. 1-6 , 25-26 , 36-37 ); sternites wider, with lateral margins reaching to a point where it roughly matches the level and width of tergites and partergites together; segment VII with paratergites highly modified, semi triangular and big ( Figs. 1-2 , 25 , 36 ) and sternite VII modified accordingly as it matches the shape of the tergite and paratergites together ( Figs. 26 , 37 ); paratergite VII apex more acute in male ( Fig. 1 ); tergite VIII broader posteriorly, gradually narrowing anteriorly, with three p setae ( p 3- p 2- p 1), medial-posterior margin slightly acute ( Figs. 30 , 34-35 ); sternite VIII transverse; tergite IX (female) divided into two portions of scarcely sclerotized pieces, with the medial-longitudinal more sclerotized and bearing seven main long setae ( Figs. 27-28 ); sternite IX (female) feebly sclerotized and fused to tergite IX; tergite X elongated, spear-head shaped, with many setae on margins ( Figs. 27, 29 ). Spermatheca with capsule dome-like and stem constricted at base ( Fig. 31 ).

Etymology: The specific epithet is derived from ancient Greek έξω (exo-, “out”) and κόσμος (kósmos, “world”, “universe”). Thus, exokosmos means “out of this world”, reffering to the unique characteristics of Dilacera , which differ by far from the other taxa in Termitonannina . Noun in apposition.

Host relationship: The individuals of Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov. were collected from the soil in Brazilian Amazon, along termites determined as Uncitermes teevani ( Emerson, 1925) , previously considered Armitermes Wasmann (Syntermitinae) . Association with other Syntermitinae has already been recorded within Termitonannina , all with Procornitermes Emerson or Syntermes Holmgren ( Seevers 1957) . It is noteworthy that current evidence suggests Armitermes paraphyletic with the inclusion of Uncitermes Rocha & Cancello ( Rocha et al., 2017) , and it is likely to be back considered Armitermes in the future. Either way, it is the first solid record of a termitophile association with Uncitermes (or Armitermes ). However, the natural history of the termitophile needs more investigation. The closest record to a termitophile association with Armitermes comes from the record of Timeparthenus seeversi Campbell, 1973 (Corotocini) found in a mixed nest of Procornitermes sp. and Armitermes sp. ; still, such association with Armitermes is doubtful, and it was likely associated with the former, given the host relationship records for the genus Timeparthenus Silvestri (Jacobson et al., 1986) .

Figures

FIGURES 1–­ 2. Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov., habitus dorsal. 1, male; 2, female. Both are about 4.5 mm in body length, with the abdomen distended.

FIGURES 3–­ 4. Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov., habitus lateral. 3, male; 4, female. Both are about 4.5 mm in body length, with the abdomen distended.

FIGURES 5–­ 6. Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov., habitus ventral. 5, male; 6, female. Both are about 4.5 mm in body length, with the abdomen distended.

FIGURES 7–­ 24. Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov., female. 7, mandibles; 8, antenna; 9, labrum; 10, prementum; 11, maxilla; 12, pronotum; 13, prosternum; 14, meso- metasternum; 15, metendesternite; 16, meso- metanotum; 17, scutellum; 18, elytron; 19, proleg; 20, protarsus; 21, mesoleg; 22, mesotarsus; 23, metaleg; 24, metatarsus. Scale bars = 0.004 mm (9), 0.005 mm (7, 8, 10–­ 18, 20, 22, 24), 0.02 (19, 21, 23).

FIGURES 25–­ 31. Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov., female. 25, paratergites and tergite VII; 26, sternite VII; 27, tergite X and sternite IX; 28, sternite IX (one side); 29, tergite X; 30, tergite VIII; 31, spermatheca. Scale bars = 0.01 mm

FIGURES 32–­ 39. Dilacera exokosmos Zilberman & Pires-Silva gen. et sp. nov. schemes, 32, maxilla; 33, labrum; 34, tergite VIII (male); 35, tergite VIII (female); 36, tergite VII and paratergites VII; 37, sternite VII; 38, pronotum (male); 39, pronotum (female).