Chilicola (Chilioediscelis) aenigma Packer

Packer, Laurence & Genaro, Julio A., 2007, Fifteen new species of Chilicola (Hymenoptera: Apoidea; Colletidae), Zootaxa 1468, pp. 1-55 : 51-55

Chilicola (Chilioediscelis) aenigma Packer , n. sp.

( Figs.17A–R )

Diagnosis: The strongly curved apical spurs to the hind tibia ( Figs. 17F and G ) combined with the very small tooth on the hind pretarsal claw are suggestive of the subgenus Chilioediscelis ( Toro and Moldenke 1979; Michener 2000). However, this species possesses the episternal groove below the level of the scrobe, the absence of which has generally been taken as diagnostic for the subgenus. Thus, this species seems intermediate between the subgenera Chilicola and Chilioesdiscelis. Two additional characters place it among the latter: the lack of a true corbicula on S 2 in females (within Chilicola this reversal is a synapomorphy of the subgenus Chilioediscelis) and the absence of an apical spine on the female S6 [this is an additional synapomorphy for the subgenus Chilicola (Gibbs and Packer 2006) ]. Both sexes can be readily differentiated from all Chilicola with robust hind tibial spurs by the length of the malar space ( Figs. 17A and D ), which is longer than the basal depth of the mandible in C. aenigma but shorter in all other Chilioediscelis and Chilicola s. str. species. The comparatively unmodified hind legs of the male ( Fig. 17F ), which are somewhat swollen but lacking marked protuberances or carinae and similar in shape to those of the female ( Fig. 17G ), as well as the transverse swellings on S3–S5 are unique for Chilioediscelis and related subgenera and the male pygidial plate-like area on T7, apical protuberances on S6 and form of the terminalia are unique among all Xeromelissinae.

Description. Male: Length 4.9mm, forewing length 3.2mm, head width 1.3mm.

Colouration: Black with following parts pale yellow: labrum, mandible (except apex dark red-brown), clypeus except laterodorsal extreme, lower paraocular area up to lower margin of antennal socket mesally up to middle of supraclypeal area laterally, transverse line at apex of hypostomal area, anterior spot on tegula, dorsobasal spot on fore- and midtibiae, midbasitarsus ventrally. Following parts orange: apical two-thirds of forefemur except dorsal surface (apical one-third), foretibia except for large brown blotch posteriorly, foretarsus, apical ring to mid- and hindfemur, basal and apical rings to mid- and hindtibiae, ventral surface of midtibia, midtarsus. Tegula pale amber. Metasoma brown-black. Terga and sterna with apical impressed areas amber. Apical lobes of S6 orange-brown. Wing veins brown except base of M+Cu orange.

Surface Sculpture: Microsculpture strongly imbricate, punctures small and shallow throughout, particularly obscure on frons, pronotum and metanotum; somewhat larger on clypeus and lower paraocular area. Labrum mostly shiny, sparsely punctate laterally, densely (i<d) medially. Clypeus irregularly punctate, i=1– 4d, punctures elongate. Supraclypeal area with punctures somewhat less irregular, i=1–3d. Lower paraocular area with more even punctuation, i=1–2d. Frons with few punctures. Vertex more densely punctate, i>d. Genal area with elongate weak irregular punctures, i=1–3d on longitudinally microstriate background. Pronotal collar, mesoscutum and scutellum finely and moderately densely punctate, i=1–2d, punctures not noticeably denser anteriorly on mesoscutum or sparser on disk of scutellum. Metanotum with dense microsculpture, dull, lacking punctures. Mesopleuron with larger denser punctures, i~d. Dorsal surface of propodeum with sparse irregular striae not attaining posterior margin; lateral surface shiny; dorsolateral area weakly but densely punctate, i<d. Metasomal terga with strong microsculpture and dense but shallow and indistinct punctures, i~d. Apical impressed areas with microsculpture slightly weaker than on discs.

Pubescence: Whitish, long and somewhat woolly throughout. Head and thorax with sparse erect pubescence, <2MOD, longest hairs on frons somewhat yellowed. Genal beard sparse. Lateral portion of propodeum with minute hairs, dorsolateral portion with long hairs, <2MOD. T1–T5 with broad apicolateral hair patches of somewhat woolly, subappressed pubescence; T4–T6 and S6 with sparse, erect long hairs, <2MOD. S3–S5 with sparse subapical row of short, erect hairs, 0.5MOD, just anterior to similar but posteriorly directed hair row.

Structure: Head: Longer than broad (92:86) ( Fig. 17A ). Labrum short, transverse (length to breadth 9:28), apex slightly convex. Mandible 2.5X as long as basal depth. Clypeus broader than long, 65:52; apical twothirds extending beyond lower ocular tangent, with very weak longitudinal groove ( Fig. 17A ). Epistomal suture straight to ventral margin of depression around anterior tentorial pit and then abruptly curved laterad; epistomal suture expanded below anterior tentorial pit and extending somewhat dorsolaterad onto paraocular area, pit separated from suture by almost 2X its diameter ( Fig. 17A ). Subantennal sutures outwardly concave, upper end on lower tangent of antennal socket. Supraclypeal area almost 2X as long as greatest breadth (22:12) ( Fig. 17A ). Frons flat, lacking swellings or depression dorsad of antennal sockets. Facial fovea absent. Frontal line slightly raised for lower half of distance between supraclypeal area and median ocellus. Inner margin of compound eye emarginate; eyes convergent below, UOD:LOD 50:40. Interocellar area slightlyraised above adjacent vertex, vertex otherwise very slightly convex and short, 0.75 LOL. IOC greater than OOC, 16:10. Upper ocular tangent goes through lateral ocellus below middle. Occipital margin rounded. Antenna not unusually elongate; scape 3X as long as greatest breadth, as long as pedicel and F1 and F2 combined; F2 shortest, ratio of pedicel:F1:F2:F3 7:6:5:7; flagellum somewhat broadening apically, lacking modifications of setal pattern or structure. Face somewhat protuberant. Malar space slightly longer than basal width of mandible, 12:11 ( Fig. 17B ). Malar suture well defined. Gena narrow, width:eye, 11:25 ( Fig. 17B ).

Mesosoma: Mesosoma slightly more than 1.5 times as long as greatest depth, 105:65. Pronotal collar almost entirely declivous medially, medial length 0.3LOL, anterior surface turning somewhat abruptly into lateral surface but anterolateral margin not angulate or protuberant ( Fig. 17E ). Episternal groove present below scrobal groove; scrobal groove weak but entire. Dorsal area of propodeum less than 0.5X as long as scutellum (12:25), not much longer than metanotum (10); propodeal sulcus narrow and very shallow, undetectable on posterior surface. Hind leg lacking conspicuous swellings and carinae ( Fig. 13F ), similar to that of female ( Fig. 13G ).; trochanter unmodified; femur slightly less than 3X as long as maximum depth, ventral surface convex; tibia somewhat swollen, 4X as long as greatest depth ( Fig. 17F ); tibial spurs robust and strongly curved; basitarsus 5 times longer than greatest depth, subparallel; hind tarsal claws not bifurcate, with small inner tooth. Basal vein weakly curved; ratio of length of stigma to marginal cell on wing margin 28:40; stigmal margin in marginal cell almost straight; distal stigmal perpendicular crossing second submarginal cell close to base; both recurrent veins reach Rs+M in second submarginal cell.

Metasoma: T1 shorter than broad (65:79). Apical impressed areas of T2–T6 elongate, from 0.33X to ½ as long as terga, slightly upturned at apex; T7 with pygidial plate in form of raised triangular area ( Fig. 17H ). S1 sinuate in lateral view, lacking process; gradulus of S2 with posteriorly directed lateral portion very short; S3– S6 with strong medial portion to gradulus, posterior lateral extensions lacking; S3–S5 depressed behind graduli with transverse protuberances broadly interrupted medially, those on S2 very weak; S6 with closely approximated short apical lobes, in apical view lobes almost as long as distance that separates them ( Fig. 17I ).

Terminalia : S7 with one pair of lateral lobes, broadly attached to rest of sternum, apically comparatively strongly sclerotised, expanded ventrally as quadrate protuberances ( Fig. 17J ). S8 apical process short, broad at base, gradually converging to rounded apex, lateral processes broad, terminating in narrow posteriorly directed process that extends somewhat past apex of apical process ( Fig. 17K ). Gonobase short with very broadly concave ventral process appearing as pair of posterolaterally directed angulations. Volsella somewhat transversely oriented with cuspis at angle to main body of structure and longitudinally oriented, digitus with teeth restricted to apex, which is curved laterad, basal area of volsella somewhat produced ventrally. Gonocoxite with inner margin sinuate; ventrobasal lobe forming rounded right angle; gonostylus very short, poorly demarcated from gonocoxite. Penis valve lacking membranous lobes ( Figs. 17L and M ).

Female. As in male except for usual secondary sexual characteristics and as follows: Length 4.7mm, forewing length 3.4mm, head width 1.3mm.

Colouration: Black with ventral surface of F3–F9 dusky yellow. Apex of mandible red-brown. Wing veins brown. A pical impressed areas of metasomal terga and medial portions of T2–T4 orange-red.

Surface Sculpture: Punctures slightly deeper, denser and more distinct than in male except on mesopleuron and metasomal terga, weaker and sparser than in male. Dorsal surface of propodeum with striae tending to rugae, slightly longer and more numerous than in male.

Pubescence: Hairs on frons and dorsal surface of thorax pale brown. Femoral and tibial scopa weakly developed, that of femur with some hairs strongly bent and up to 2MOD, those of tibia <1.5MOD. Scopa of S2 with long hairs (<3MOD) lacking corbicular structure, hairs curved mesad, with very few long branches; scopa of S3 and S4 shorter (1.5MOD);

Structure: Maxillary palpus elongate, 2/3 as long as prementum. Prementum with fovea comparatively short, less than 0.5X as long as prementum, carinate margin strongly oriented mesad leaving smoothly rounded lateral margin approximately 1/6 as wide as prementum. Mandible 2X as long as basal depth (23:11). Lacinia 4X as long as greatest breadth, triangular. Lorum elongate, well sclerotised, almost 0.5X as long as cardo. Rest of body as in male except as follows: Head slightly longer than broad (92:90) ( Fig. 17D ). Labrum very broadly V-shaped apically, length:breadth 25:35. Clypeus broader than long (50:30) ( Fig. 17D ) with broad weak longitudinal medial depression. Malar area much longer than basal width of mandible (15:11) ( Fig. 17C ). Eyes convergent below, UOD:LOD 54:49 ( Fig. 17D ). Flagellum gradually increasing in breadth from basal to apical flagellomere, all flagellomeres shorter than wide except for first and last, F1=F2+F 3 in length. Pronotal collar slightly more extensive than in male, 0.5MOD medially. Apical margins of terga not upturned. Apical lunule of S5 short, 4X broader than long.

Sting apparatus: Hemitergite 7 broad, apodemal region not much narrowed in comparison to area posterior to lateral process; medial portion of marginal ridge strongly concave; spiracle somewhat closer to lateral than medial portion of marginal ridge, spiracular atrium no larger than distance between it and lateral portion of marginal ridge; lateral process shorter than width of marginal ridge, lateral lamella 2X as long as lateral process anteriorly but for most of its length not considerably wider than adjacent marginal ridge; two angulations between lateral process and apodemal extremity; posterior margin of lamina spiracularis very slightly and gently concave ( Fig. 17N ). Hemitergite 8 with anterior ridge straight except for slight anterior inflection at apex, disk and apodeme approximately equal in size ( Fig. 17O ). First valvifer with dorsal margin convex and ventral one largely concave, ventral process longer than dorsal one and broad. Second valvifer with apodemal ridge straight, apical process slightly concave ventrally, apodeme narrow. Sting shaft almost straight ventrally ( Fig. 17P ). Furcula with dorsal arm parallel-sided and narrow, ventral arm wide in lateral view ( Figs. 17Q and R ).

Material studied. Holotype male, allotype female and two male and five female paratypes (one of each sex in glycerin): ARGENTINA, Santa Cruz, 25km S. of Los Antiguos, 46o42’654” S 0 71 o40’422”W, 653m. 22.xi.03, L. Packer. One paratype male in bad condition, Santa Cruz, 20km E. of Los Antiguos, 46o 36’595” S 0 71 o21’472”W, 237m, 20.xi.03, L. Packer, pan trap. The holotype, allotype and one female paratype are at MACN, the remaining paratypes are at PYU.

Etymology. The name refers to the unmodified hind legs of the male that are unique among Chilicola with stongly curved hind tibial spurs ( Chilicola and Chilioediscelis) and also among related subgenera such as Oediscelis and Oroediscelis.

Comments. All specimens except the last paratype male were collected at Adesmia (Fabaceae) flowers by the side of a small stream that is a tributary to the Rio Jineimeni, which forms the border between Argentina and Chile in this part of Patagonia. The banks to the stream and embankment to the road provided a small amount of respite from the strong, cold winds that precluded bee activity almost everywhere else in the area on the day the type series was collected.

This is a highly distinctive member of the genus as indicated in the diagnosis and description above. Nonetheless, based upon the reduced hind tibial claw tooth and lack of sternal corbicula in the female, it would certainly appear to be a member of the subgenus Chilioediscelis.

Figures

FIGURES 17 A – R. Chilicola aenigma Packer, n. sp. Head of male: A. frontal view, B. lateral view. Head of female: C. lateral view, D. frontal view. E. male pronotum. F. Male hind femur and tibia. G. Female hind femur and tibia. H. Male T 6, T 7 and apex of S 6. I. Lateral view of male metasomal venter. J – M. Male terminalia. J. S 7. K. S 8. L. genital capsule, dorsal views are at the left. M. Genital capsule, lateral view. N – R. Sting apparatus of female: N. hemitergite 7, O. hemitergite 8, P – Q. Furcula, dorsal and lateral views respectively. R. First and second valvifer with sting shaft. Stippling in A and B indicates pale colouration, in R a membranous region.

FIGURES 13 A – H. Chilicola denisii Packer, n. sp. Head of male: A. frontal view, B. lateral view. C. frontal view of female head. Male: D. Lateral view of portion of thorax to show notch in parascutal carina (arrow), E. Hind leg outer view of femur and tibia on left, dorsal view of tibia and basitarsus on right. F – H. Male terminalia. F. S 7. G. S 8. H. genital capsule, dorsal views are at the left.