Glyptoma denieri, (Bernhauer)

Moreno, Carlos, Newton, Alfred F. & Casari, Sônia A., 2025, The larval description of Glyptoma denieri (Bernhauer) from Brazil provides clarification on new status of the subtribe Glyptomina (Coleoptera, Staphylinidae, Osoriinae), Zootaxa 5620 (2), pp. 295-314 : 298-310

Glyp­toma denieri (Bernhauer)

Calocerus denieri Bernhauer, 1939: 232

Glyptoma denieri (Bernhauer) ; Blackwelder, 1944: 108

Calocerus sanctaecatharinae Scheerpeltz, 1970: 13 (synonymized by Irmler 2015: 313)

Redescription of adult

Material Examined: Holotype ♂. ARGENTINA: Salta. 28.VI.1933, Denier col. ( FMNH) . Other material: BRAZIL. São Paulo: Peruíbe, 27–29.IX.1984. Exp. MZUSP col., 2 larvae in 70% ethanol (MZSP 588); same data, 6 adults in 70% ethanol (2 ♂ and 1 ♀, dissected on slides), 6 larvae in 70% ethanol (1 larva dissected) (MZSP 570).

Diagnosis. Adult with integument dark reddish-brown, with antennae and legs clearer; irregularly and coarsely sculptured with large punctures and ridges, giving rugose appearance; antenna without distinct club; neck distinct; gular sutures absent except on neck. Pubescence long, dense, erect, and yellowish-white, denser on dorsal head and antennae. Elytra each with an irregular discal carina. Procoxal fissure absent and protrochantin concealed; procoxae small and separated by a prosternal process. Abdominal sternite VIII not projecting dorsad in front of tergite VIII. Aedeagus narrow, with small rounded sensilla near base, parameres short, not reaching the apex of median lobe.

Redescription

Length: Male: 2.9–3 mm. ( Fig. 1 A-B, 2A)

Female: 3.1–3.2 mm ( Fig. 2B )

Head. Slightly wider than long (W/L: 1.2); lateral margins curved, rounded and narrowed near base and wider at eyes level; posterior margin emarginate, fitting in narrow neck ( Fig. 7 A-B, D); eyes prominent, continuous with lateral margins of head, both together giving an elliptical shape to head ( Fig. 7A ). Head surface covered with coarse, deep and irregular punctures bearing shiny short bristles; interspace between punctures irregular and glabrous ( Figs 2 A-B, 7A). Neck densely punctuated ( Fig. 7D ). Antennae with 11 antennomeres; scape elongate, short, cylindrical; antennomere 2 subglobular; 3 longer than 2; antennomeres 4–10 subequal, wider than long, slightly increasing in width apicad; 7 slightly longer than any other between 1–10; 11 longer, conical. Antennae densely covered with moderately long yellowish-white bristles. Labrum ( Fig. 3G ) sclerotized, transverse, band-like with rounded angles, transversely rugose, bearing about 7 pairs of long erect bristles in a row near anterior margin. Epipharynx with one branch of ramified bristles on each anterior angle, narrow triangular comb of bristles medially. Mandibles ( Fig. 3A ) asymmetrical, robust, narrowed apicad; apex acute and inwardly directed; molar area ( Fig. 3B ) transversely striated and with transverse rows of tiny bristles; right mandible with short subapical rounded tooth (in Fig. 3A , indicated by red arrow). Dorsally with four long bristles near apex and three short below previous, near lateral margin of each mandible. Maxillae ( Fig. 3 E-F) wide, sub-rectangular; stipes longer than wide, subtriangular with two basal bristles; cardo transverse, rounded; galea broader and longer than lacinia; galea with transverse basal sclerite and spongy branch of bristles at apex ( Fig. 3F ); ventrally bristles wide and curved; lacinia narrow, divided in two lobes, separated by one suture ( Fig. 3F ); external lobe with one longitudinal row of short bristles on half of inner margin; apical bristles wider; internal lobe with one distal uncus and three thick and curved bristles at apex. Maxillary palpi 4-articled: palpomere 1 short and narrow, band-like; 2, the largest, elongate and wide with lateroexternal margin longer, giving oval appearance, with two long and one short lateral bristles; 3, reduced, elongate, subtriangular, with lateroexternal margin rounded and with one long bristle, laterally fitting at base of palpomere 4; 4 elongate, subcylindrical, narrow apicad. Labium ( Fig. 3C ). Labial palpi 3-articled; palpomere 1 broad, longer than wide; 2, shorter, transverse, with one lateroexternal bristle; 3, cylindrical, longer than wide, with small peg-like sensilla at apex. Ligula ( Fig. 3C ) short and broadly arcuate; bearing dorsally two long and wide sensilla near center, and two shorter and thinner on each side; with small sensitive pores on surface. Mentum and submentum distinct. Mentum ( Fig. 3D , 7C ) subpentagonal, longer than wide, anterior margin prominent at middle; lateral margins with prominent angles, diverging posteriorly; posterior margin straight; seven long bristles near anterior margin, four long bristles medially, and four long bristles near posterior margin. Submetum transverse, band-like with 4 bristles ( Fig. 7C ). Gular sutures absent, represented by basal curved line near neck.

Prothorax. Pronotum ( Figs 1 , 2 , 7E ) convex, longer than wide (W/L: 1.02); narrowed in short anterior area and in basal half, giving curved shape to lateral margins; anterior margin fitted in the broad neck; posterior margin narrow and almost straight; punctation large, heterogeneous and deep, with rugose appearance, denser posterolaterally than discal, forming deep grooves; laterally punctuation makes lateral margins with several small tooth-like emarginations; pronotal surface covered with shiny bristles; long and thick bristles on lateral margins; interspace between punctures glabrous and carina-like.Proventrite wider than long, intercoxal prosternal process wide and short, surpassing posterior margin of procoxal cavity ( Fig. 3H ). Meso-, metaventrite ( Fig. 3I ) sclerotized; mesoventrite narrow on anterior half, distal half wider and curved laterally, mesosternal process short and wide, with small grooves and puncture-like impressed anteriorly; metaventrite elongate, slightly widened posteriorly, lateral margins curved on apical third, with sparse and short bristles distributed on whole surface; lateral margins of metaventrite with sparse, irregular grooves, each with one bristle; posterior margin with distinct prominent lateral angles. Scutellum subtriangular, longer than wide with rounded angles; surface with small net-like impressions. Meso-and metanotum membranous ( Fig. 3J ), shorter than meso- and metaventrite. Membranous wings present, well developed. Elytra ( Fig. 3K , 7F ) elongate (W/L: 1.94), convex; anterior and posterior margins declivous, convergent to sutural margin; lateral margins rounded, with rounded subapical angles; apices truncate; punctation heterogeneous, large, forming irregular longitudinal rows; short bristles on each puncture, and glabrous areas between punctures; elytra surface with irregular discal carina; lateral carina absent; with long bristles across surface, more concentrated laterally. Legs. Pro- and mesocoxae rounded, metacoxae triangular. Femora broad, dilated, with many bristles. Tibiae slightly longer and narrower than femur, bearing rows of short bristles, more concentrated near tarsi, with one tibial spur. Tarsal formula 4-4-4; tarsomeres 1–3 short, with long bristles beneath; tarsomeres 1–2 connate; tarsomere 4 twice as long as tarsomeres 1–3 combined, with two long bristles below; each tarsus with two unciform claws ( Fig. 4A–C ); empodium with two long bristles.

Abdomen elongate, cylindrical, slightly narrowed on last two segments; segment I dorsally fused to metanotum; tergite II transverse, band-like. Segments III–VII wider than long, with tergites and sternites fused laterally; segments III–VI rectangular; VII trapezoidal; VIII elongate, triangular with rounded apex. Punctation irregular, wide and deep, giving rugose appearance; with long and shiny bristle more concentrated laterally and forming one transverse row near posterior margins of segments III–VII; segment VIII with bristles dispersed on distal 2/3, more concentrated laterally. Sternites with two transverse rows of long bristles. Sternite VIII not projecting dorsad in front of tergite VIII; slightly longer than wide, anterior margin with distinct angles; posterior margin broadly arcuate; integument with wide punctures on distal ¾, smaller and more concentrated near base; one transverse row of 8 long bristles medially, two near apex on each side in males ( Fig. 5C , 6A ), two near apex of each side and four apical bristles in females ( Fig. 5D , 6B ); several short bristles on distal third and lateral margins; lateral margins of female sternite VIII with several long bristles. Tergite IX ( Figs 5E, 5G , 6 C-D) dorsally covering partially tergite X in males, and divided dorsally by tergite X in females; gradually narrowing apicad forming two narrow projections bearing two long bristles at apex in males; females with tergite IX broad, glabrous. Tergite X ( Figs. 5F , 6C - D ) elongate, with apex widely rounded, bearing one pair of widely separated apical macrosetae in both sexes; in females ( Fig. 5H ), bearing one additional row of fringing bristles across posterior margin. Sternite IX of males ( Fig. 6C ) elongate, slightly narrow than tergite X, with adjacent pair of very large apical macrosetae at middle, and one short bristles on each side. Female without sternite IX; with paired proximal and distal gonocoxites, wide ovipositor, narrowed apicad, with many long bristles and small one-segmented apical stylus bearing one long bristle at apex ( Fig. 5I , 6D ). Aedeagus (5J–K) with median lobe elongated, strongly curved, with acute apex, irregular rows of small rounded sensilla near base of apical lobe; parameres short and dorsal. Spermatheca ( Fig. 5L ) rounded, lightly sclerotized.

Remarks. The specimens under study are notably darker than the holotype of Glyptoma denieri , from Argentina ( Fig. 1 ), and by coloration resemble G. obscuricolle (Bernhauer, 1908) from Brazil. Despite this similarity in coloration, the type of Glyptoma denieri is smaller than G. obscuricolle , and among the studied specimens we verified a large variation of size, some with similar length to G. obscuricolle , but both species display notable variations in microsculpture patterns and shape of the aedeagus. In G. obscuricolle , the microsculpture is weaker, contrasting with the conspicuous microsculpture on the body of G. denieri . Moreover, the apical lobe of the aedeagus in G. denieri is longer and thinner than in G. obscuricolle , with fewer sensilla, whereas G. obscuricolle has a great number of sensilla in the apical portion ( Irmler 2015). In Irmler's re-description of G. denieri , it was observed that the elytral punctation pattern of the region between the suture line and discal carina differs slightly from that of Brazilian and Paraguayan specimens. However, the author noted that the punctation varies significantly intraspecifically and therefore, "seems not to be a specific character" ( Irmler 2015). With regard to the studied specimens, no significant differences were found in the punctation of the pronotum and elytra surface when compared to the holotype of G. denieri . Similarly, there were no discernible intraspecific differences in the distribution of sensilla or the shape of the aedeagus.

Biological notes: The specimens analyzed were collected in decayed trunks in a newly deforested area. Adults and larvae of some staphylinid species, including Glyptoma denieri , were found together under the bark and were grouped together in the sample (MZSP 590).After investigation of other samples of the same locality and date, mixed taxa were also found. In one sample (MZSP 570), larvae of Glyptoma were found alongside adults of Euryachen seuzei Pires-Silva ( Staphylinidae , Aleocharinae ), while in another (MZSP 590), adults of Glyptoma were found with larvae of some Aleocharinae ( Homalotini ) and Osoriinae species (excluding Glyptoma ) as well as adults of Leptochirus Germar and Lispinus Erichson. Considering that these samples were collected a long time ago and were never analyzed or identified by specialists, these materials were mixed since they came from the field.

Distribution. Argentina: Salta (Aguas Blancas-Yaculica). Brazil: Goiás; Paraná (Campo Largo, Morro Três Irmãos); Rio de Janeiro; Santa Catarina; São Paulo. Paraguay: Caazapá, Hermosa.

Description of larva

Length: 3.2–3.5mm ( Fig. 8A–B )

Larva campodeiform, each segment with lateral margins curved, stemmata absent; mandibles short, asymmetrical and scoop-like apically; gula absent; abdomen with long looped gut filled with indeterminant matter; and bulbous one-segmented urogomphi. Coloration: after fixation, cream with segments VIII and IX darker, head yellowish and tibiae and tarsunguli brownish. Head pale at base and yellowish apicad; mouthparts darker; sclerites of thorax and abdomen feebly pigmented; membrane between sclerites unpigmented.

Elongate, slightly flattened with sides almost parallel, constricted between segments; each segment with lateral margins curved; urogomphi each with a single bulbous segment, short, setose and articulated at base. Pubescence long and erect, more concentrated dorsally and longer laterally.

Head ( Fig. 9A–B ) flattened, prognathous, wider than long (W/L: 1.53), widest near middle, lateral margins rounded; foramen wide, bordered by sclerotized narrow bands. Stemmata absent. Ecdysial lines indistinct; epicranial suture visible only in a small sclerotized area near base of mandibles. Frontal region with one pair of short bristles on each fore angle and two pairs of longer bristles at middle, near anterior margin; each epicranial area with eight long bristles (one shorter). Ventrally, each side with two long and one short bristles near lateral margin. Hypostomal ridges and gula absent. Posterior tentorial pits curved.

Antennae ( Fig. 9C–D ) long, slightly longer than head, inserted dorsally, with three elongated antennomeres: basal slightly elongate with one dorsal campaniform sensillum; second long, obliquely truncate on inner side with a membranous cupuliform sensorium; dorsally with two long bristles and a longitudinal band of microspines; ventrally with four long and one short lateroexternal bristles; distal antennomere shorter and narrower than previous, narrowed at apex; dorsally with three long bristles on distal third and one campaniform sensillum near base; ventrally with three long bristles; three solenidia at apex.

Labrum and clypeus separated by distinct suture ( Fig. 10A ). Labrum wider than long, almost trapezoidal with basal margin strongly curved and lateral margins slightly divergent basad; distal margin with one weak emargination on each side; one row with four long bristles near anterior margin and two shorter near middle; one bristle on each side, at base outside labrum. Epipharynx ( Fig. 10B ) trapezoidal with two long bristles on each lateral margin; lateral margins with narrow irregular sclerites; one tiny bristle on each side of anterior margin and one each side, between long bristles; many short bristles mesially directed; median region weakly sculptured with two campaniform sensilla; sculptures marked by microsetae; many sensilla below sculptures; two larger sensilla near base; basal margin with sclerite at middle, margined anteriorly and laterally by sensilla.

Mandibles ( Fig. 10D–F ) short and stout, less than one-third as long as head width, asymmetrical; asymmetry in teeth sizes and quantity of longitudinal grooves; wide with internal apices slightly scoop-like with five-seven irregular rounded teeth; inner region scoop-like with several irregular longitudinal weak grooves; without mola; four external long bristles, two basal shorter. Maxillae ( Fig. 11A–B ) elongate; cardo transverse with one short bristle; stipes elongate with one long bristle near middle and two shorter lateroexternal bristles (one at base of palpus). Galea completely fused to lacinia; mala narrowed apicad, ventrally with four moderately long bristles and one well-developed campaniform sensillum; laterointernal and distal margins with many wide and long bristles inserted dorsally. Palpi with three palpomeres: basal almost as long as wide with two campaniform sensilla; second elongate with two short bristles and one campaniform sensillum; distal longer and narrower than previous, 2x longer, with one elongate and wide seta in groove, and one campaniform sensillum near apex; apex with several peg-like sensilla. Labium ( Fig. 9E ) narrow and elongate; postmentum constricted near base, with lateral margins sinuous, and three pairs of long bristles and one pair of campaniform sensilla. Prementum ( Fig. 9E ) short and glabrous; palpiger almost as long as wide, each with one long and wide bristle and two campaniform sensilla. Ligula wide with two long bristles and two tiny apical bristles; anterior margin widely rounded and marginated by short bristles. Palpi with two palpomeres; basal palpomere elongate with one ventral campaniform sensillum; distal shorter and narrower than previous, with one campaniform sensillum and some peg-like sensilla at apex. Hypopharynx ( Fig. 10C ) with a mediobasal subtriangular sclerome with one prolongation on each side; two transverse rows of curved short setae, in weakly sclerotized transverse bands above sclerome; distal area with sculptures marked by row of tiny bristles.

Thorax slightly increasing in width from pro- to metathorax; metathorax wider than first abdominal segment. Prothorax narrower and almost same length than meso-, or metathorax. Pronotum ( Fig. 12A ) wider than long (W/L: 1.57) with lateral margins almost straight with rounded angles; marginated by long bristles forming rows, parallel to margins: six bristles near anterior and posterior margins, and five bristles (one shorter) near lateral margins; one transverse row with four bristles at middle. Meso- and metathorax almost same length, with lateral margins rounded. Meso- and metanotum, each with six long bristles near anterior and six near posterior margin, and three on each side (one shorter). Region between pro- and mesothorax with a membranous lobe with a circular spiracle; each spiracle with one lateral bristle. Legs ( Fig. 12B ) slightly brownish, darker to apex direction; coxae inserted distant from midline of thorax. Coxa short and wide, with three moderately long bristles and three short; trochanter with one long bristle ventrally and three moderately long bristles internally and three campaniform sensilla externally; femur long and wide with seven bristles; tibia longer and narrower than femur, slightly narrowed apicad, with seven moderately short bristle (one shorter and wider); internal face with microspines on distal third; tarsungulus ( Fig. 12C ) with two short and wide bristles.

Abdominal segments I-VIII (in Fig. 13A , segments VIII–X) almost of same width, slightly longer and narrower apicad; dorsally, each with twelve long bristles, besides a few short: two median, six near posterior margin and two on each side; each side with a circular spiracle ( Fig. 13D ) dorsolaterally near posterior margin of each segment. Segment IX narrower and shorter, abruptly constricted near apex, with many bristles of varied sizes; two apical irregular dorsal bulbous urogomphi. Urogomphi ( Fig. 13E–F ) bulbous, one segmented; dorsally with seven long bristles and one apical campaniform sensillum, and one short and wide bristle near internal margin; ventrally with seven long bristles and one short and wide bristle, and with a deep invagination in basal half near internal edge ( Fig. 13F ). Segment X ( Fig. 13 A-C) elongate, tubular ventrally; when apex everted, membranous with microspines ( Fig. 13C ); dorsally with four long bristles; ventrally with two long bristles and two tiny bristles near each lateral margin, one inclined row with three short bristles each side, and two short bristles near middle; one transverse row with four moderately long bristles on basal fourth and two bristles each side, below previous.

Remarks

Comparing the larvae of Glyptoma denieri with Glyptoma sp. (in Grebbenikov & Newton 2012), it was verified that the bristles on basal antennomere, stemmata, mandibular mola, hypostomal ridges, and gula are absent in the former. The epicranial suture of Glyptoma sp. was considered as a not observed character; in G. denieri it is indistinct, visible only in a small area near base of mandibles. The mandibles are similar in overall shape in both species. However, certain characteristics were consistent between them. These include the second antennomere with membranous sensory appendage near anterior margin, labrum separated from clypeus, galea completely fused to lacinia forming mala, the fusion of the mentum and submentum forming postmentum, the well-developed ligula, and the one-segmented urogomphi.

Comparing the larvae of Glyptoma denieri ( Thoracophorini ) with the detailed published descriptions of Cylindropsis corsica ( Osoriini ) ( Orousset 1988) and Thoracophorus corticinus ( Thoracophorini : Thoracophorina ) ( Burakowski & Newton 1992), it was verified that they are similar in the campodeiform body shape, with long antennae having three antennomeres and similar shapes. Additionally, the larvae exhibit a free labrum, maxillary palpi with three palpomeres, and labial palpi with two palpomeres. The epicranial suture is indistinct, and stemmata are absent in all species.

Larvae of all species mentioned above share several morphological traits: the mandibles are asymmetrical and lack a mola; the lacinia is fused to the galea, forming the mala; the labium is divided into the prementum and postmentum; and the urogomphi are one-segmented. The tarsunguli in all species bear two equally sized bristle, except in Cylindropsis corsica . The number of bristles on the labrum varies from four (in G. denieri and T. corticinus ) to seven (in C. corsica ). Only Cylindropsis corsica possesses a pseudomola with a dentiform projection, accompanied by two lateral bristles, except in Glyptoma denieri , which has four bristles. The gula is present in Cylindropsis corsica (triangular) and Thoracophorus corticinus (oblong), but absent in G. denieri .

Figures

FIGURE 1. Holotype of Glyptoma denieri (Bernhauer). A, dorsal; B, lateral; C, labels.

FIGURE 2. Glyptoma denieri (Bernhauer). Adult habitus dorsal. A, male; B, female.

FIGURE 3. Glyptoma denieri (Bernhauer). Adult. A, mandible dorsal (left, right); B, molar area; C, apex of labium (dorsal); D, mentum; E, maxilla (ventral); F, apex of maxilla; G, labrum; H, prothorax (ventral); I, meso- and metaventrite; J, scutellum, meso- and metanotum; K, elytron (dorsal, ventral).

FIGURE 4. Glyptoma denieri (Bernhauer). Adult tarsi. A, front tarsi; B, middle tarsi; C, hind tarsi. ts = tibial spur.

FIGURE 5. Glyptoma denieri (Bernhauer). Adult A–B, tergite VIII (male, female); C–D, sternite VIII (male, female); E, segments IX–X of male (dorsal); F, apices and bristles of tergites IX–X and sternite IX of male; G, tergites IX–X and ovipositor; H, bristles of tergite X of female; I, ovipositor (dorsolateral); J–K, aedeagus (lateral, dorsal); L, spermatheca.

FIGURE 6. Glyptoma denieri (Bernhauer). Illustrative schemes. Chaetotaxy of sternite VIII (A, male; B, female); segments IX–X of male (C), and female (D). SIX = sternite IX; TIX = tergite IX; TX = tergite X; Ovp = ovipositor.

FIGURE 7. Scanning electron microscopy of Glyptoma denieri (Bernhauer). A, head (ventral); B, detail of the basal area of head (ventral); C, mentum-submentum; D, neck; E, pronotum; F, right elytron (dorsal).

FIGURE 8. Glyptoma denieri (Bernhauer) larval habitus. A, dorsal: B, ventral.

FIGURE 9. Glyptoma denieri (Bernhauer), illustrative schemes of the larva. A, head (dorsal view); B, head (ventral view); C, right antenna (dorsal view); D, antenna (ventral view); E, labium. Scale bars = 0.05 mm (E), 0.1 mm (A–D). Sa = Sensory appendage.

FIGURE 10. Glyptoma denieri (Bernhauer), illustrative schemes of the larva.A, labrum and frons (dorsal view); B, epipharynx; C, hypopharynx; D, left mandible (dorsal); E, left mandible (dorsolateral); F, left mandible (ventral). Scale bars = 0.05 mm (B–F); 0.1 mm (A).

FIGURE 11. Glyptoma denieri (Bernhauer), illustrative schemes of the larva. A, maxilla and maxillary palpi (dorsal); B, mala (dorsal). Scale bars = 0.05 mm.

FIGURE 12. Glyptoma denieri (Bernhauer), illustrative schemes of the larva.A, pronotum; B, leg (dorsal view); C, tarsungulus (ventral). Scale bars = 0.025 mm (C); 0.1 mm (A–B).

FIGURE 13. Glyptoma denieri (Bernhauer), illustrative schemes of the larva. A, abdominal segments VIII–X (dorsal); B, segments IX–X (ventral); C, segment X extroverted; D, abdominal spiracle; E, urogomphi (dorsal); F, urogomphi (ventral). Scale bars = 0.05 mm (C–D); 0.1 mm (A– B, E–F).