Xenochilicola diminuta Toro and Moldenke
Creators: name: Genaro, Julio A.
name: Packer, Laurence
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Colletidae
Xenochilicola
Xenochilicola diminuta

description: Xenochilicola diminuta Toro and Moldenke
(Figs. 2, 5, 7–9, 14–17)
Xenochilicola diminuta Toro and Moldenke, 1979. An. Mus. Hist. Nat. Valparaíso 12: 147. Male. Xenochilicola fulva Toro and Moldenke, 1979. An. Mus. Hist. Nat. Valparaíso 12: 148. Female. New synonymy.
FIGURES. 4–9. Xenochilicola species. 4–6, Lateral habitus of: 4. X. mamigna; 5. X. diminuta; 6. X. haroldotoroi n. sp. 7–9, Metasoma in dorsal view of: 7. male, X. diminuta; 8, 9 female of X. diminuta. Top scale for Figs 4–6, bottom scale for Figs 7–9.
Diagnosis. The metasomal colour pattern is variable in females (Figs. 8 and 9) but always mostly red, orange or yellowish whereas other species in the genus have the terga almost entirely black. The males are unique in having metasomal terga with yellow bands (Fig. 7) and S5 with a distinct, posteriorly directed, lateral process on each side (Fig. 14) whereas the other species have the posterior margin of S5 merely concave and hairy laterally. Mesoscutellum with dense punctures (i<d) around margins, sparse punctures (i=1–2.5d) on disk. This species has the eyes most strongly convergent below and the longest head and malar space in the genus (Fig. 2).
Description. Male. Body length 2.40–2.60 mm, forewing length 1.96–2.04mm (Fig. 5).
Colouration (Fig. 5). Black, except: yellow on mandibles (except apex brown), labrum, clypeus, spot on malar space variable in size; spots on pronotal lobe and tegula, ventral surface of scape, apex of all femora, dorsal surface and apex of fore tibia, apices of mid and hind tibia, tarsi, broad median band on terga (occupying much of the disc, but variable in extent on T3–T6); flagellum brown, background colouration of metasoma from black­brown to red­brown (particularly in X. diminuta holotype). Two small lateral dark brown to red­brown spots on terga (Fig. 7).
Surface sculpture. Microsculpture imbricate throughout except: labrum, supraclypeal area, frons and vertex shiny. Clypeus and malar space with sparse punctures; frons, paraocular area and vertex punctate­reticulate; gena with punctures longitudinally effaced, sparse (i>>d); irregularly punctate on mesoscutum (i~d on disk, i<d medially), mesoscutellum and metanotum both (i>d); hypoepimeral area and metepisternum rugulose with sparse punctures; preepisternum and mesepisternum with denser punctures (i<d); basal area of propodeum reticulate or striate, latero­dorsal area of posterior surface of propodeum with sparse punctures (i>d); T1 irregularly punctate (i=0.5–3d on disc, i<d laterally), smaller and sparser on marginal area, acarinarium impunctate; T2 with shallow, irregular punctures on disc (i=1–2d), few sparse punctures on apical margin; T3–T6 and sterna with few, small, sparse punctures.
Pubescence. White apressed pubescence dense on lower paraocular area, apical margin of pronotum, basal margin of mesoscutum (<MOD), apressed pubescence shorter (<<MOD) on posterior margin of mesoscutum; short, sparse erect hairs (<MOD) on clypeus and malar space, longer (~MOD) on frons and vertex, those of gena of similar length but denser; sparse erect hairs on mesoscutellum and mesepisternum (=MOD), shorter on preepisternum, mesepisternum and legs; short and dense on basal area of propodeum; short, sparse on terga (slightly denser laterally) and sterna (<MOD); brush of hairs (~MOD) at apex of lateral process of S5.
Structure. Head much longer that broad (0.98–1.04 mm: 0.80–0.88 mm). Stipes and cardo very long (~ 7–9MOD); clypeus convex, projecting 0.7–0.8 of its length below lower ocular tangent of eyes (Fig. 2), apical margin of clypeus slightly concave; clypeal surface with shallow median longitudinal sulcus variable in depth; labrum wider than long (21:10), apical margin convex; eye twice the diameter of gena, in lateral view (2:1). OOC:IOC (1.1:1.7), UOD:LOD (5.2:2.3), LMA:MW (19:7). Basal area of propodeum same length as metanotum and half as long as mesoscutellum, in dorsal view (1:1:2). Apical margin of S5 deeply concave, with median obtuse process and elongate, posteriorly directed, somewhat bilobed, lateral process on each side, outer lobe hairy, inner lobe longer and glabrous (Fig. 14).
FIGURES 14–17. Xenochilicola diminuta male: 14. ventral surface of S5; 15. S7; 16. S8; 17. genitalia. Dorsal views to left, ventral to right.
Terminalia. S7 with a small triangular disc, apodemal arms expanded posterolaterally and considerably extended anteriorly (Fig. 15). S8 gradually narrowing to base, median apical process slender not enlarged towards apex; lateral lobe with angulate apodeme on anterolateral margin (Fig. 16). Genital capsule as in Fig. 17. Digitus extends posteriorly beyond cuspis.
Female. Body length 2.80–3.04 mm, forewing length 1.92–2.00 mm.
Colouration. Black, with variable (pale, bright or dusky) yellow marks on labrum, clypeus and malar space (those on clypeus and malar space absent in some specimens, including the holotype of X. fulva), mandible (except apex), spot on pronotal lobe and tegula; legs as in male. Flagellum and wing veins, brown. Metasoma variable in colouration (Figs. 8 and 9), usually yellow to amber, with red brown to brown on anterior face of T1, dark spot laterally on each side of T1–T5 (these are occasionally absent in the most pale­coloured specimens). a broad dark band is found anteriorly on T2–T6 particularly in those specimens marked with yellow rather than amber or red, this band widest medially (in one specimen that on T2 completely divides the yellow transverse band). Sterna variable, from yellow to brown correlating with colour of terga; females with light terga have sterna of the same color.
Surface sculpture. Microsculpture as in male. Labrum, clypeus and vertex with sparse punctures; paraocular area with dense punctures (i<d; near antennal socket i=d), supraclypeal area and frons with dense punctures (i<d), malar area irregularly punctate (i=1–1.5d); mesoscutum irregularly punctuate (i<d on disk; i~d towards margins), mesoscutellum and metanotum more sparsely punctuate, i>d. Basal area of propodeum reticulate (in some specimens with subparallel striae, not attaining posterior margin).
Pubescence. Similar to that of male except as follows: apressed pubescence on paraocular area slightly sparser, hairs on hind leg scopa ~MOD; sternal scopa of long hairs on S1–S3 (~2.5 MOD); no lateral brushes of hairs on S5.
Structure. As in male except as follows: Clypeus with shallow median longitudinal sulcus, apical margin of clypeus concave, clypeus projecting 0.8–0.9 of its length below lower margin of eyes; malar area very long, about twice as long as the width of mandible at base (2.0:1.1). OOC:IOC (1:2), UOD:LOD (5:3). Gena narrower than eye (1:2).
Holotype of X. diminuta: CHILE, Santiago, Quebrada La Plata, 11.x.1996, colls. Schlinger and Irwin, male, in collection Toro (AMNH). Holotype of X. fulva: CHILE, Antofagasta, Taltal, 30.ix.1972, coll. J. Neff, female, in collection Toro (AMNH).
Material Examined: (Fig. 13). Type series localities: CHILE, Región Metropolitana, Quebrada de La Plata and Región II, Antofagasta (Taltal). Additional records: Región II: 23–27 km NW of San Pedro de Atacama, Hwy 23, 15.x.2001, colls. L. Packer and G. Fraser (9 females; 1 male); Q[uebrada]. Taltal, 20 and 31x.1993, colls. H. Toro and E. Chiappa, on Calandrinia salsoloides Barn., Portulacaceae (37 females; 4 males). ESE of Calama, km 39, Hwy 23, 11.x.2001, colls. L. Packer and G. Fraser (1 female); Región III: Travesia, 29.ix.1983, coll. F. Rodríguez (5 females); E of Chañaral, Pan American km 1012–17, 10.x. 2001, colls. L. Packer and G. Fraser (3 females). Región IV: Limari Province, Chañar, S30º 16' 49.4'', W 70º 38' 24.8'', 11/ 30.ix.2004, coll. A Ugarte Peña (1 female); Elqui Province, Pangue, S30º 09' 14.2'', W 70º 39' 50.6'', 11/ 30.ix.2004, coll. A. Ugarte Peña (1 female). Región Metropolitana: Cerro Roble near Til–Til, 19.xi.2001, coll. L. Packer (1 female); same data but collected 17.xi.2001 (1 female, 1 male). These specimens are at the AMNH, Universidad Católica de Valparaíso, Chile or Packer collection at York University, Canada.
Comments. Xenochilicola diminuta was described from four males. The female was described in the same paper, as X. fulva (known only from females). The collection and study of a larger sample of females and males taken together, in the same localities, allows us to synonymise X. fulva with X. diminuta
Variation is as follows for the male: spot on malar space sometimes extending to the eye margin anteriorly and beyond the ventral margin of the eye posteriorly. Yellow metasomal bands variable on T3–T6: interrupted medially in some specimens, narrower than those on T1–T2, irregular in shape.
Female with metasomal colour pattern variable in extent of pale background markings and also in colouration; yellow, amber, brown and red brown. The type of X. fulva has the base of T1 red brown but the terga are otherwise amber. In general, variation in colour pattern was not associated with geographic distribution.
The junior author saw large numbers of males and females of this species on flowers of Cistanthe sp. (Portulacaceae), between the Pan American Highway and the town of Diego de Almagro, Región III, in October 2001.
description: Published as part of Genaro, Julio A. & Packer, Laurence, 2005, A revision of the genus Xenochilicola (Hymenoptera: Apoidea, Colletidae), with the description of a new species, pp. 1-14 in Zootaxa 1054 on pages 5-11, DOI: 10.5281/zenodo.170069