Nemozoma gymnosternalis, Kolibáč, Jiří, 2014

Kolibáč, Jiří, 2014, Nemozoma gymnosternalis sp. nov., a new anomalous species of Trogossitidae from Brazil, Zootaxa 3815 (3), pp. 417-427 : 418-424

Nemozoma gymnosternalis sp. nov.

Type specimens. Holotype (sex unknown): “BR-SP-Ilha Solteira / UNESP campus / 20°25’11.65”S 51°20’28.19”W / ex broken Anadenanthera fal- / cata limb attacked by Pseu - / dochramesus acuteclavatus / Flechtmann, C.A.H. col. // 28/V/2011 ”. Six paratypes (2 males, 2 females, 2 sex unknown): same label. The holotype and three paratypes are deposited in the collection of MEFEIS ( UNESP, Ilha Solteira, state of São Paulo, Brazil); three paratypes are in the Moravian Museum, Dept. of Entomology (Brno, Czech republic).

Description. Measurements of holotype (in millimetres): Body length (from abdominal apex to cranial horns) 3.7, head visible part length along middle 0.76, head visible part length along horns 1.05, head maximum width behind eyes 0.76, head width through eyes 0.75, head width between eyes 0.67, antenna length 0.8 (flagellum 0.33, club 0.47), pronotum maximum length 0.72, pronotum width at anterior part 0.78, elytral length along suture 1.12, elytral maximum width (at 2/3 length) 0.88, elytral width at humeral part 0.77, protibia 0.45, mesotibia 0.41, metatibia 0.4, protarsus 0.36, mesotarsus 0.32, metatarsus 0.41 (all tarsi measurements excluding claws), length of abdominal segments visible from above 0.81. Variability in size among specimens of the type series is minimal.

Coloration and sculpture ( Figs 1 A–C): Body slender and distinctly elongate, moderately convex (cylindrical); all dorsal and ventral surfaces shiny, completely black or dark brown but elytra with oblique pale stripe at the second half of each elytron; legs dark brown from coxae to end of femora, tibiae and tarsi gradually lighter (light brown to yellowish); antennal segments 3–7 (i.e., excepting club) light brown but scape, pedicel and club (segments 8–10) dark brown to black.

Head finely, sparsely punctate (interspaces larger than diameter of punctures) at dorsal surface; punctures distinctly elongate or lens-shaped; cranium bare, head with only several short setae on eye surface and along anterior margin. Pronotum also sparsely punctate (interspaces larger than diameter of punctures), punctures rounded or lens-shaped (shorter than those of head); pronotum bare, only anterior and posterior margins with short yellowish setae. Elytra with shallow sparse punctation composed of round punctures; each elytron with light (whitish to yellowish) oblique stripe in apical half, stripes not touching elytral suture nor side margins; elytral punctation irregular (rows of punctures indistinct); elytra without carinae, perfectly bare (lacking pubescence). Ventral surface shiny; metathorax and abdomen glabrous, without punctation; meso- and prothorax with sparse but distict punctation except glabrous hypomeron and its projection; head with distinct punctation similar to that of prosternum. Pubescence of ventral surface sparse, conspicuous only in anterior margins of pro- and mesothorax, formed by short, rigid setae. Each side of cranium with distinct, long sensory setae. Last abdominal ventrite with row of long erect black setae along apex, several setae also at ventral surface of previous ventrite. Legs without sculpture, femora and tibiae sparsely pubescent. Antennae with short fine hairs.

Head ( Figs 1 A–C; 3D): extremely elongate, longer than pronotum; almost prognathous (position in Fig. 1 B artificial); frons weakly convex but flat or concave in centre of anterior (clypeal) portion; anterior margin of cranium deeply emarginate at dorsal side so that two conspicuous horns project forwards; longitudinal line or groove between horns present, conspicuous up to posterior part of cranium; eyes relatively small (space between them approximately 16 times as wide as eye width), flat (not elevated and not exceeding contour of head), not emarginate, nearly rounded, situated laterally. Gular sutures extremely short and strongly convergent; antennal grooves in ventral side of cranium short, relatively shallow, running along eyes; frontoclypeal suture absent; antennal sockets not visible from above; epicranial acumination inconspicuous; cervical sclerites well-developed. Ventral part of cranium with pair of long sensory setae at sides ( Fig. 1 C).

Maxilla ( Fig. 2 B): lacinia short, its convex outer margin with about five spines (thickened setae) along middle (see detail in right of Fig. 2 B); apices of lacinia and galea without thorns or hooked spines; body of lacinia with few medium sized soft non-ciliate setae; basigalea relatively large, feebly pigmented; galea elongate, not clavate, its inner margin and apex with long ciliate setae while outer margin with numerous thick and rigid setae; body of galea with long non-ciliate setae; mediostipes relatively small, perfectly free, not fused with lacinia, nearly triangular in shape; basistipes distinct (pigmented) but probably fused with lacinia (weakly pigmented); palpifer relatively large, trapezoidal, not denticulate along outer margin; maxillary palps 4-segmented, terminal joint conical, distinctly elongate; several ciliate setae sparsely distributed also on palpifer, basi- and mediostipes; cardo with only two nonciliate setae.

Mandible ( Figs 2 A; 3D): with two apical teeth situated above one another (in vertical axis); medial tooth distinct; mola absent; vertical ciliate furrow situated along mid-part of outer margin; small area with short hairs placed directly above cutting edge (in place of prostheca but these structures may be not homologous); elliptic dimple with short sensillae situated in centre of ventral surface of mandibles; basal notch well-developed.

Labrum ( Figs 2 C–D; labral sclerite and epipharynx figured separately): free (not fused with cranium); oblong, weakly emarginate in apical part; epipharynx with distinct dark triangular sclerite; tormal processes inconspicuous; labral (= dorsal) sclerite with several long ciliate setae along apical margin and in anterior part, epipharynx also with ciliate setae in anterior portion and with fine sensillae near pharynx orifice.

Labium ( Fig. 2 H): submentum deeply emarginate, perfectly conjoined with cranium, without ctenidium; mentum strongly transverse, narrowed along midpart, anterior corners extended, anterior margin emarginate, lateral margins obliquely sloping (general shape trapezoidal); prementum not divided into two parts, shallowly emarginate; ligula weakly pigmented, very deeply emarginate, with numerous long ciliate setae; “mental apodeme” (sclerites beneath mentum or between mentum and prementum) composed of two separated elongate sclerites; hypopharyngeal sclerite(s) (frequent cleroid structure on hypopharyngeal membrane between mentum and submentum) absent; hypopharynx without longitudinal strip(s) of sensillae; labial palps 3-segmented, relatively very long; terminal joint of palps conical, as long as palpomeres 1+2 together.

Antennae ( Figs 1 C–E; 2G): 10-segmented; antennal club 3-segmented, loose and relatively large; scape robust, pedicel smaller than scape but larger than antennomere 3; 2–7 symmetrical, same in length; 8–10 (club) strongly asymmetrical and with conspicuous sensorial fields; all antennomeres with sparse pubescence; antennae relatively long, extending backwards to the anterior-most quarter of pronotum.

Prothorax ( Figs 1 A, B; 3C): pronotum elongate; anterior margin weakly sinuate or nearly straight, anterior corners not projecting, rounded; anterior four-fifths of lateral margins straight, evenly rounded towards base; lateral edge distinct, oblique, running from base of pronotum to anterior margin of prosternum; prosternal process distinctly dilated at apex; procoxal cavities transverse, internally open, externally perfectly closed by postcoxal projections, tips of which are hidden beneath apex of prosternal process; trochantin inconspicuous.

Mesothorax: mesoventrite extremely shortened; prepectus absent; mesocoxal cavities relatively large, lensshaped, obliquely situated, narrowly separated, externally narrowly open; mesoventral process shorter than coxal diameter; projection of metaventrite short, not reaches apex of mesoventral process; mesotrochantin minute; scutum relatively narrow, scutellum triangular.

Wing ( Fig. 3 A): perfectly folded beneath elytra, well-developed but not pigmented and with reduced venation; lower margin of wing with relatively long pubescence; radial cell reduced; r4 missing; pigmented fleck (below Rc) absent; medial field with two indistinct veins AA3+4 and AA1+2.

Metathorax: metaventrite strongly convex, distinctly narrowed towards anterior portion; discriminal line (discrimen) conspicuous to half of length of metaventrite; paracoxal sutures rather indistinct, parallel with coxae; metepisternum extremely large, distinctly triangular.

Elytra ( Figs 1 A–B): distinctly shortened, not covering whole abdomen; epipleura conspicuous only towards half of elytral length; interlocking mechanism probably not functional; elytra without longitudinal carinae; lateral margins of elytra not explanate.

Legs ( Figs 1 F–G; 2E–F): procoxae weakly projecting, strongly transverse; mesocoxae oval, metacoxae extended to lateral margin of metathorax; trochanters relatively small, triangular; femora (especially profemora) clavate; protibiae with four or five robust spines along outer margin; meso- and metatibiae without spines along outer margin; tibial apical spur pattern 2-2-2; large protibial spur distinctly hooked, 2nd protibial spur reduced in size; apices of all tibiae with (comb-like) row of several spines that are especially distinct in protibiae; tarsomere 1 in all pairs of legs reduced in size, seemingly conjoined with tarsomere 2; tarsomere 5 as long as 1–4 combined; tarsal lobes absent but tarsomere apices with tufts of setae; claws without denticles; empodium large, projecting, bisetose; ultimate tarsomere (5) with two long setae at apex; tarsal formula 5-5-5, seemingly 4-4-4 due to small size of first tarsomeres.

Abdomen ( Figs 1 A; 3B, E–G; 4A–G): only tergites I–III covered by elytra; tergites IV–VII not hidden beneath elytra but enwound with projected folds of abdominal ventrites 2–5(!); tergite VIII (pygidium) sometimes retracted in folds of ventrite 5 (sternite VII); six abdominal ventrites distinctly visible; female sternite VIII weakly emarginate at apical margin, with setae along apical margin and in centre; female tergite VIII with short spiculum not exceeding corners of tergite; ovipositor extremely short (uncommon within Cleroidea): membranous tube reduced, bacculi shortened and feeble, coxitae compressed together, styli minute, proctiger visible but feeble. Bursa copulatrix well-developed, spermatheca spherical. Male segment IX incomplete (reduced), only with membranous rudiment of sternite IX and its well-developed spiculum (“spicular fork”); tergite IX inconspicuous; aedeagus inverted (ventrally open), composed of a single part; parameres finely ciliate, distinctly separated from each other and fused with phallobase; lateral phallobasic struts well-developed; phallobasic apodeme absent, phallobase rounded in basal part; midpart of phallobase filled with membrane, only lateral sides and struts distinctly sclerotized.

Biology. Reared from branches of the tree Anadenanthera falcata (Mimosoideae) that fell in October 2010 in a thunderstorm and was later attacked by the bark beetle Pseudochramesus acuteclavatus Hagedorn. Another trogossitid species, Corticotomus quadrimaculatus Léveillé was also reared in addition to some members of Buprestidae and Cerambycidae . See Flechtmann & Costa (2012) for a review of other associated insect taxa.

The gut of four dissected specimens (2 males, 2 females) did not include any contents.

Etymology. Gymnos (naked, nude, unclothed, exposed); sternite (ventral abdominal sclerite; also dorsally visible in the new species).

Figures

FIGURE 1. Nemozoma gymnosternalis sp. nov.: (A) dorsal view; (B) anteriolateral view; (C) head and pronotum, ventrolateral view; (D) antenal club; (E) antenna laterally; (F) protibia and tarsus; (G) mesotibia and tarsus.

FIGURE 2. Nemozoma gymnosternalis sp. nov.: (A) mandible ventrally; (B) maxilla; (C) labrum (dorsal sclerite); (D) epipharynx incl. ventral sclerite; (E) apex of protibia and base of protarsus; (F) protarsus, apex of ultimate tarsomere; (G) penultimate antennomere; (H) labium. Scale bars = 0.1 mm.

FIGURE 3. Nemozoma gymnosternalis sp. nov.: (A) wing; (B) female copulatory organs; (C) prothorax laterally; (D) mouth foramen, some mouth parts removed; (E) tegmen semiventrally; (F) phallus semiventrally; (G) spiculum of sternite IX („ spicular fork “) with remnants of abdominal segment IX. Scale bars = 0.1 mm.