Trypoxylon scrobiferum Richards, 1934

Amarante, Sérvio Túlio P., 2005, On The Systematics Of Trypoxylon scrobiferum Richards and T. anapaike Amarante With The Recognition Of A New Species Group In The Subgenus Trypoxylon (Hymenoptera: Crabronidae: Trypoxylini), Papéis Avulsos de Zoologia 45 (9), pp. 91-101: 93-95

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Trypoxylon scrobiferum Richards, 1934


Trypoxylon scrobiferum Richards, 1934  

(Figs. 4-6, 9)

Trypoxylon scrobiferum Richards, 1934: 253   , Fig. 4. Holotype: female: Guyana: Essequibo: Essequibo River, Moraballi Creek, 22.ix.1929, (Oxf. Univ. Expedn.), (B.M. 1929-485; 2584; B.M. Type Hym. 21.481); Richards, 1936: 462; Vesey-Fitzgerald, 1938:191; Bohart & Menke, 1976:349; Amarante, 2002:51.

I examined the holotype, a female, five other females and one male, noticing some details imprecisely described by Richards (1934). I also present a description of the hitherto unknown male.

Description of Male

Measurements. HW = 1.63-2.00 mm, FWL = 4.3-5 mm; Proportions: HW/HL = 1.13-1.15, HW/EV = 4.5-5.5, HW/EC = 8.75-9.55, EV/EC = 1.8-1.9, FS/EV = 0.7-0.8; Ratios: EL:EC:EV:EE = 1.08-1.1:0.15-0.15:0.25-0.3:1.0, OO:IO:HO = 0.17-0.2:0.5-1:1.0, AA:EA:AF = 0.2-0.3:0.2-0.3:1.0.

Color: Body black. Pale to orange yellow are: scape, pedicel, anterior of flagellum or flagellomeres I-VIII and apex of XI, mandibular basal half, fore and mid tibiae and tarsi, apex of fore and midfemora, base of hindtibia, basal 0.5 of hindbasitarsus, apex of hindtarsomeres I-III, hindtarsomere IV, tibial spurs, basal 0.66 of tergum II, apex of terga II, III and IV, sternum II. Medial portion of mandible red. Dark reddish brown are: apex of mandible, dorsum of scape, posterior surface of flagellomeres I-VIII, whole flagellomeres IX and X and base of XI, apical margin of clypeus, trochanters and femora, hind tibia and tarsus, terga I, III-VI, apical 1/3 of tergum II, sterna I, III-VI. Hind margin of pronotal collar whitish yellow.

Plate 2: Figs. 4-6. Trypoxylon scrobiferum Richards   , male; 4, sternum VIII, ventral view; 5 and 6, male genitalia; 5, left half, dorsal view, right half, ventral view; 6, lateral view.

Vestiture: Silver to pale gold, except for white to yellowish white on tibiae and tarsi. Clypeus and frons below anterior ocellus with dense vestiture, denser and concealing sculpture below dorsal margin of eye emargination. Clypeus with scattered, downwardly oriented, long pale yellow setae. Gena densely covered by decumbent setae. Thorax laterally and ventrally with moderately dense decumbent setae. Scutum, scutellum and propodeal dorsum with erect, short setae. Patches of dense, decumbent setae on: hind dorsal margin of collar, lateral margin of scutum, mesopleura anteriorly to episternal sulcus and midcoxa, subalar area anteriorly, posterior surface and posterolateral angles of propodeum. Terga pubescent, through I and II more sparsely.

Head: Frons and eye emargination narrow, dull, colliculate. Supraantennal carinae sharp, long, markedly elevated, diverging from each other, forming an obtuse angle at its middle, reaching the tangent line of upper edge of eye emargination. Frontal prominence elevated, enclosed laterally by supraantennal carina; frontal carina fine, slightly elevated, posterior truncation equal to 0.5 diameter of median ocellus, bifurcating arms U-shaped, short, with length about 0.33x length of lower branch. Clypeal disc almost flattened; clypeus free margin reflexed, thin; apical rim distinct, shiny, superficially rugulose; apical border gently sinuate, with a short mid lobe gently concave at apical margin, excavated from beneath. Anterior ocellus in shallow depression. Vertex with small swelling behind each hindocellus. Flagellomere I 0.65x as long as II+III, 3x as long as wide, flagellomeres II and III 2x as long as wide, IV 1.5x, V 1.15x, VI-X 1x, flagellomere XI sub conical 1,15x as long as X+IX. Occipital carina interrupted behind hypostomal carina, interrupted tip connected to hypostomal carina by fine longitudinal carinulae; horizontal area behind hypostomal carina 1,7x as broad as fore basitarsus width.

Thorax: Dorsolateral angles of pronotal collar narrowly rounded, prominent. Pronotal collar with distinct median dorsal prominence. Prosternal transverse carina sharp, reflexed and raised, vanishing toward middle. Scutum, scutellum and mesopleuron moderately shiny, finely and superficially reticulate, with moderately close to sparse, superficial, fine punctures. Omaulus evanescent, indicated under pronotal lobes, short, running by 0.15x of distance to episternal sulcus, subomaulus well developed, elevated, ending well beyond episternal sulcus. Length of precoxal carina 0.5x length of mesopleural suture. Mesopleural wing pro- cess bordered by simple ridge, a little widened on hind margin. Metapleural flange narrow. Intercoxal carina arcuate, ventrolateral intercoxal carina present. Dorsoposterior carina of hindtibiae straight, uniformly elevated, ending abruptly subapically, well apart from trochanter emargination. Hindtibial anterior surface flattened, forming an angle with dorsal surface. Forewing vein R1 not extending beyond apex of marginal cell; forewing veinlet 1r-m of submarginal cell forming approximately 90º with vein sector RS+M. Outer row of hamuli on hindwing 2x its length apart from inner row.

Propodeum: Dorsal surface of propodeum with longitudinal or diagonal ridges that become transverse toward apex, dorsal enclosure slightly depressed posteriorly. Posterior surface with broad, moderately deep longitudinal sulcus, ending at short transverse carina, separated by its length from border of petiole socket; depressed area above petiole socket subtrapezoidal, well-defined dorsally by fine and elevated carina. Lateral surface shiny, with sparse, superficial foveolae and fine diagonal ridges, more distinct near posterolateral and dorsolateral angles. Propodeal side delimited dorsally by longitudinal carina that extends from spiracle to petiole socket. Dorsal border of petiole socket flat except by a deep concavity above orifice of apodeme. Propodeal sternite present, forming Y-shaped sclerite that encircles the base of coxae and touches the ventral margin of propodeum.

Gaster: Tergum I-IV moderately convex. Tergum I with well defined, II and III with ill-defined subapical constrictions. Tergum I 3.2x as long as apical width, 1.45x as long as II, with sides slightly diverging at basal third, more strongly so on median, and slightly again in apical third; sternum VIII (Fig. 4) very similar to that of T. anapaike   , but narrower at base, about two times broader at base than at apex, 1,65x as long as broad at base, shallowly emarginate apically, with two blunt lateroapical tooth-like processes; gonostyle with inner subapical tooth (Fig. 5).

Notes on Females

Richards’ description is sufficient to characterize the female, but the following important characters were overlooked or imprecisely described by him. The hindocelli almost touch the eyes (as corrected by Richards in a latter paper [1936]), the separation is less than 0.2x a hindocellar diameter. The antennal sockets are separated by 0.6x a socket diameter. The free clypeal margin has an ill-defined sub-rectangular median lobe. The omaulus is present, although very short, almost indiscernible. The hindcoxa has a minute subapical ventral tubercle (Fig. 9). The propodeum has a dorsolateral carina (Richards described it as “[Propodeum] Sides well defined above”). A propodeal sternite is present.

Material examined: GUYANA: Essequibo: Essequibo River, Moraballi Creek , 22.ix.1929, (Oxf. Univ. Expedn.), (B.M. 1929-485; 2584; B.M. Type Hym. 21.481) 1 female ( BMNH, Holotype)   . BRAZIL: Amapá: Rio Anicohi ,, J. Lane col., 1 female ( MZSP)   . Pará: Santarém, Curuá-Una , 17.xi.1997, bacia amarela [yellow pan], A. R   . Lisboa. Amazonas: Manaus, Faz. Esteio , 2°24’26”S, 59°43’40”W, 11.ix.1989, E.F. Morato col., 1 female ( MZSP) Rio Solimões , 3°15’S, 58°58’W, 19.viii.1991, M. V GoogleMaps   . B. Garcia col. ( MZSP); Rio Tarumã-mirim , various dates, M. V   . B. Garcia col. 2 females ( INPA) 1 female ( MZSP)   . Goiás: Serra da Mesa survey ( Niquelândia ), 14°1’3”S, 48°18’4”W, malaise across stream, N. Johnson col., 1 male ( MZSP) GoogleMaps   .


Sao Paulo, Museu de Zoologia da Universidade de Sao Paulo


Departamento de Geologia, Universidad de Chile


Royal British Columbia Museum - Herbarium


Instituto Nacional de Pesquisas da Amazonia














Trypoxylon scrobiferum Richards, 1934

Amarante, Sérvio Túlio P. 2005

Trypoxylon scrobiferum Richards, 1934: 253

Amarante 2002: 51
Richards 1936: 462
Richards 1934: 253