Isthmiade laevicollis Tippmann, 1953

Clarke 1, Robin O. S., 2009, Bolivian Rhinotragini II: ISTHMIADE Thomson, 1864 (Coleoptera, Cerambycidae), with two new species Robin O. S. Clarke, Papéis Avulsos de Zoologia 49 (44), pp. 577-591 : 579-582

Isthmiade laevicollis Tippmann, 1953

( Figs. 1A, 1B )

Isthmiade laevicollis Tippmann, 1953 a: 215 , pl. 16, fig. 26a; Zajciw, 1972b: 579; Julio et al., 2000: 17 (holotype); Tavakilian & Peñaherrera-Leiva, 2005: 43, figs. 16, 26a-c; Monné, 2006: 482 (cat.).

Isthmiade laevicollis var. rubrosignata Tippmann, 1953 a: 215 , pl. 16, fig. 26b.

Isthmiade carinifrons Zajciw, 1972a: 13 , syn. nov.

Diagnosis. Isthmiade laevicollis is readily separated from the other Bolivian species by the following combination of characters: rostrum and front legs entirely yellow, apices of elytra chestnut, obliquely truncate, outer angle usually with large tooth; wings with broad black and yellow bands.

Redescription. Male general colour: translucent yellow, and black. Head mostly black, including tip of mandibles, scape, pedicel and antennomeres III-V, rest of antennomeres dusky brown; mouthparts, labrum and clypeus rufous, and entire rostrum yellow. Prothorax black, except pronotum with narrow, reddish-yellow fascia across middle, this widening to occupy middle of sides, front and hind margins of this band scalloped by encroaching areas of black. Mesothorax, scutellum and apical fifth of elytra black, rest of elytra and mesosternal process yellow. Sides of metasternum, metepimeron and metepisternum black, inner two-thirds of metasternum orange-yellow. Urosternites I, II and most of III orange-yellow (abdominal process paler), apex of III, and all of IV and V blackish. Front legs entirely yellow; middle legs with hind part of coxa, tibia and tarsus chestnut, rest yellow; hind legs with coxa, trochanter, base of peduncle, dorsad of apex and broad ring around middle of femoral club, tibia and tarsus black, rest yellow; onychia darker than rest of tarsomeres, or black. Broad pre-apical band and apex of wings blackish, preapical yellow band broad and distinct.

General pubescence: Head almost glabrous; short scattered, yellow hairs on genae and line of denser hairs adjacent to apex of inferior lobes; submentum and gula glabrous except for a few scattered long hairs at sides. Front of prothorax and disc of pronotum glabrous; a round patch of dense, unruly, short and long hairs in front of prosternal process, sides of pronotum with large, hemispherical patch of short, very dense, semi-erect, white hair. Scutellum with uniform, fine, recumbent, white pubescence. Mesosternum with fine sparse hair at centre and apex of process, very dense, white and glistening on mesepimeron; and coxae with long recumbent hair. Basal half of metasternum, inner front corner and apex of metepisternum with dense, recumbent, white, glistening pubescence; apical half of metasternum moderately densely hirsute, otherwise glabrous. Abdomen almost glabrous, urosternites IV and V with short, semi-recumbent, yellow pubescence.

Surface ornamentation: labrum with line of twelve small punctures at base; clypeus impunctate, adjacent area of frons with regular, moderately large, isolated punctures, these becoming confused towards front margin of inferior lobes, and line of close small punctures adjacent to inner side of lobes; upper part of frons with single row of relatively small punctures to each side of frontal suture, these passing around inner margins of superior lobes in two rows of confluent punctures, and reverting to single row adjacent to hind margin of eyes; in this way leaving most of vertex impunctate; submentum irregularly and moderately densely punctured with mix of large and small punctures, gula smooth and impunctate. Prothorax with patch of somewhat confused punctures in front of prosternal process, the punctures a mix of large, smaller and micro-punctures; base and sides of process with very small punctures, apex micro-sculptured without obvious puncturation; sides of pronotum with large, semicircular patch of rugose punctures (representing the sexual puncturation), the punctures of mixed sizes and many confluent, the interstices reticulate; disc of pronotum almost impunctate, two groups of three large punctures adjacent to apex of central callus, otherwise the punctures small and scattered. Mesothorax (x40) with very small, dense punctures at centre of mesosternum, but increasingly impunctate laterally; scutellum densely micro-punctate; elytra almost impunctate on disc, with small group of asperate punctures on humeri and denser larger punctures on epipleuron, only becoming contiguous at extreme apex. Metathorax with moderately dense, large, shallow punctures where it is hirsute, micro-punctate where the pubescence is dense and recumbent, otherwise smooth and shining. Abdominal urosternites I-III almost impunctate, IV with a few scattered punctures throughout, most of V with denser, slightly asperate punctures.

Structure: Head. Rostrum relatively long; lengths of gena/inferior lobe 0.6/ 0.8 mm; inferior lobes almost contiguous (interocular distance/width of lobe 0.18/ 0.85 mm), separated by deep, V-shaped frontal suture (which is well marked to hind margin of superior lobes); superior lobes proximate, interocular distance/ width of lobe 0.45/ 0.23 mm. Submentum separated from mentum by narrow declivity, somewhat poorly delimited, separated from short gula by two inconspicuous carinas. Antenna long and filiform, reaching apex of urosternite III; scape (0.9 mm) four times longer than pedicel (which is slightly elongate), two-thirds length of antennomere III (1.4 mm); antennomere IV (0.9 mm), V (1.3 mm) slightly shorter than III, VI subequal (1.2 mm), remaining antennomeres gradually shortening to X (0.9 mm), X1 slightly longer (1.0 mm).

Thorax. Prothorax distinctly longer (2.2 mm) than width of front and hind margins (1.6 mm), deeply constricted at apex and base (the latter complete to hind angles), sides strongly rounded and widest (2.0 mm) at middle; disc of pronotum with single, well-marked, elongate callus at centre, and two pairs of indistinct rounded calli to either side of centre; the prosternal process weakly arched, base narrow (about 1/11 width of coxal cavity) and elongate, apical triangle moderately large, with strongly raised sides.

Mesothorax abruptly declivous before mesosternal process, the latter broad at base (1/4 width of coxal cavity), apex cordiform without elevated sides, the whole process somewhat deformed by coarse puncturation. Scutellum subtrapezoidal, sides of basal half slightly emarginate, apical half parallel sided, apex slightly rounded. Elytra elongate (3.2 times width of humeri), reaching basal third of urosternite III; for basal two-thirds, strongly dehiscent, acuminate almost to apex, where they are widened; humero-apical costa incomplete for middle third (imparting flat look to elytron), salient and widening at extreme apex; apices obliquely truncate, slightly emarginate, sutural angle with small tooth, lateral angle with large tooth.

Metasternum moderately strongly convex (pro- and mesocoxae planar with metasternum), longitudinal suture almost entire, deeply impressed behind.

Legs large but femoral clubs not robust, profemur with short peduncles and relatively narrow clave; mesofemoral club almost slender; hind leg slender (5.7 mm), femora subcylindrical without distinct clave, tarsus not robust, metatarsomere I cylindrical, longer (1.1 mm) than II (0.5 mm) and III (0.4 mm) together.

Abdomen. Narrow and long, widening to apex, urosternite I longest (2.3 mm), narrow and constricted at middle; II (1.5 mm trapezoidal, slightly constricted; III (1.5 mm) quadrate, sides subparallel; IV quadrate (1.3 mm); V (0.7 mm) trapezoidal, depressed at middle, convex at apex, apical margin straight; abdominal process long and narrow with elevated sides.

Variation: Transverse reddish-yellow band across middle of pronotum may be wider; teeth at apex of elytra may be shorter and of equal size. Antennae may not reach middle of urosternite III.

Female sexual dichromatism: gula may be almost white; prosternum as male, or only black anteriorly to process and laterally orange-yellow; pronotum almost entirely orange-yellow (only front dusky with irregular orange intrusions), or more like male, but basal margin only black at middle and central orange-red band much wider, occupying all of sides and disc from apical 1/4 to basal margin; remaining sterna may be like male (except black changed for chestnut), or entirely orange-yellow (except apex of mesepimeron black); abdomen may be entirely orange-yellow (except for apical segment black), or entirely blackish (except urosternite I); black band on metafemoral club paler than male, or only suggested by slight darkening to orange-brown colour.

Female sexual dimorphism: rostrum very long, gena (1.0 mm) longer than inferior lobe (0.9 mm); interocular space (0.8 mm) more than four times wider than male and slightly wider than inferior lobe (0.7 mm), frontal suture not deeply incised, between suture and lateral margins broadly and shallowly impressed, impunctate (except a few small punctures towards antennal tubercles, which extend to back of inferior lobes as in male); antennae relatively shorter, reaching apex of urosternite II; prosternal process with very short base and larger apex; prothorax weakly constricted at base, pronotum more elongate (2.5 mm), sides much less rounded (2.2 mm), glabrous and impunctate; calli reduced to salient central callus with single, low, rounded callus to either side at front (the posterior pair of calli completely eliminated by the very broad basal constriction); length of elytra 2.9 times width of humeri, nearly reaching apex of urosternite II; metasternum more convex than male, planar with procoxae, more salient than mesocoxae); abdomen fusiform, widest at middle of urosternite III, urosternite V long (1.3 mm), conical (apical margin rounded) and convex.

Measurements (mm): 6 males / 2 females respectively: total length 13.0-15.8/15.3-18.5; length of pronotum 1.8-2.2/2.1-2.5; width of pronotum 1.7-2.0/2.0-2.2; length of elytra 6.2-7.0/7.1-8.4; width of humeri 2.1-2.2/2.4-2.8.

Material examined (in the RCSZ collection): BOLIVIA, Santa Cruz, 17°29’96”S/ 63° 39’13”W, 420 m, Hotel Flora & Fauna, 5 km SSE Buena Vista , R. Clarke/ S. Zamalloa col. 3 males, 4.V.2005, 12.V.2005 and 26.IV.2006 on/flying to flowers of “Bejuco hoja lanuda”; 1 male, 23.XII.2005 and 1 male 20.XII.2008 on/flying to flowers of “Sapaimosi”; 1 male, 28.X.2006, on/flying to flowers of “ Tutumillo espinoso”; 1 female, 4.IX.2005, on/flying to flowers of “ Barbasquillo ” vine; 1 female, 26.XI.2007 on/flying to flowers of “Sama blanca”. Specimen with different data from above: Road to El Cairo-Cafetal, 6 km W Buena Vista, R. Clarke / S. Zamalloa col., 1 male, 20.VII.2008, on/flying to flowers of Gomphrena vaga Mart.

Discussion: When Zajciw revised the genus more than thirty years ago I. laevicollis was thought to be endemic to Peru and, no doubt, together with the rather singular aspect of his female I. carinifrons (from Para, Brazil), led him to overlook the actual similarity between his specimen and Tippmann’s species, which was known only from males. Monné & Hovore (2006) recorded I. laevicollis from French Guiana, Brazil, Peru and Bolivia.

Figures

FIGURAS 1‑5: Bolivian species of Isthmiade Thomson, 1864. 1. Isthmiade laevicollis Tippmann, 1953, 1A female 1B male; 2. Isthmiade zamalloae sp. nov., 2A male holotype, 2B female; 3. Isthmiade ichneumoniformis Bates, 1870, 3A male, 3B female; 4. Isthmiade martinsi sp. nov., 4A male holotype; 5. Isthmiade planifrons Zajciw, 1972, 5A male, 5B female.