A new species of Fidelia Friese , 1899 ( Hymenoptera , Megachilidae ) , with a key to the species of the genus

A new species of Fidelia Friese, 1899 is described from southern Africa: Fidelia (Fideliopsis) whiteheadi Litman & Kuhlmann sp. nov. Diagnostic characters are provided to distinguish this species from others in the genus, particularly from the closely related F. hessei; an updated description for Fidelia hessei is also given. The host plant preferences and seasonal activity of F. whiteheadi Litman & Kuhlmann sp. nov. and F. hessei are discussed. Finally, a revised, illustrated key to species of the genus Fidelia is presented.


Introduction
The twelve members of the genus Fidelia Friese, 1899 are solitary, ground-nesting bees.A single species is known from the xeric regions of the Atlas Mountains in Morocco (Warncke 1980;Whitehead & Eardley 2003).The remaining eleven species are distributed throughout the winter and summer rainfall areas of western and northwestern South Africa, as well as the deserts of Namibia; some observations have also been made in Botswana.
Members of Fidelia are robust bees, ranging in size from approximately 7.5 to 20.0 mm (Whitehead & Eardley 2003).Their pilosity may be white through yellow to orange, while the integument is mostly brown to black, although also yellow on the clypeus, mandibles, labrum, and legs of some species.All females and some males exhibit a pygidial plate, which is typically black but yellow in some species.The male seventh tergum has either a simple or bifid apex bordered by lateral spines.Females have a metasomal scopa, as well as a brush of long dense hairs on their hind basitarsi.The female hind basitarsus itself is flattened and paddle-like and is used in nest excavation (Rozen 1977).
Extensive host plant records for the genus Fidelia were reported in Whitehead & Eardley (2003).Although the records listed in Whitehead & Eardley (2003) do not distinguish between floral visits for pollen and visits for nectar, the ensemble of these records suggest that most fideliines are oligolectic: Members of Fidelia exhibit an unusual combination of morphological characters, including three submarginal wing cells and a metasomal scopa.They also exhibit peculiar nesting behavior: they build unlined nests, a behavior rarely seen in bees.A recently published molecular phylogeny identified the genus Fidelia as one of the earliest branching lineages of the family Megachilidae (Litman et al. 2011).Members of the genus Fidelia are thus phylogenetically significant bees and the discovery of a new species is an important finding that justifies the description of a single new species in the context of a recent revision of the genus (Whitehead & Eardley 2003).
Collecting trips undertaken by J.R.L. and C.D.E. to the Northern Cape Province in October 2008 and February 2009 yielded two series of specimens that both key out to Fidelia (Fideliopsis) hessei in Whitehead & Eardley's (2003) key.Upon close inspection, however, both series of specimens exhibit distinctly different features.A thorough re-examination of the type material used in the description of F. hessei Whitehead & Eardley, 2003 indeed revealed two distinct but apparently closely related species.We describe the new species here as Fidelia (Fideliopsis) whiteheadi Litman & Kuhlmann sp.nov., redescribe its close relative F. (F.) hessei and provide a revised key to the species of Fidelia.

Materials and methods
The majority of the type material used in this description is deposited in the Iziko South African Museum in Cape Town, South Africa; a limited number of specimens are also deposited in the Natural History Museum of Neuchâtel (Neuchâtel, Switzerland), the Oberösterreiches Landesmuseum, Biologiezentrum (Linz, Austria) and in the Litman-Praz Collection (Neuchâtel, Switzerland).Morphological terminology is taken from Michener (2007).

Abbreviations
We use the following abbreviations: Bl = Body length (measured between anterior margin of clypeus and apex of metasoma) Iw = Intertegular width (width of body measured between wing bases) T = Metasomal tergum (when followed by a number, refers to number of tergum; for example, T1 refers to the first metasomal tergum) S = Metasomal sternum (when followed by a number, refers to number of sternum; for example, S1 refers to the first metasomal sternum) The following abbreviations are used for collections and institutions: SAM = Iziko South African Museum, Cape Town, South Africa MHNN = Natural History Museum of Neuchâtel, Neuchâtel, Switzerland OÖLM = Oberösterreiches Landesmuseum, Biologiezentrum, Linz, Austria LPC = Litman-Praz Collection, Neuchâtel, Switzerland CSCF = Centre Suisse de Cartographie de la Faune, Neuchâtel, Switzerland The following abbreviations are used in the list of material examined: NCP = Northern Cape Province, South Africa WCP = Western Cape Province, South Africa Photographs were taken with a Dino-Lite AM413T digital microscope at the Natural History Museum of London, as well as with a VHX-1000 Keyence digital microscope co-hosted by the MHNN and the CSCF.

Diagnosis
Fidelia (Fideliopsis) whiteheadi Litman & Kuhlmann sp.nov.can be distinguished from members of the subgenera Fidelia and Fideliana by the length of the marginal cell of its forewing, which is approximately 0.75× the distance between the apex of the marginal cell and the distal edge of the wing (length of marginal cell less than half this distance in the subgenera Fidelia and Fideliana).
F. whiteheadi Litman & Kuhlmann sp.nov.can be further distinguished from the two members of the subgenus Parafidelia.It differs from Fidelia (Parafidelia) friesei by the gentle curve of the female mid-tibial spur (strongly sickle-shaped in female F. friesei) and by the unswollen forefemur and forebasitarsus of the male (swollen in F. friesei) and from F. pallidula by the presence of two equalsized mandibular teeth in females (apical and preapical tooth present in female F. pallidula) and by the bifid, triangular T7 of the male (T7 long, parallel-sided and rounded at the apex in F. pallidula).
From other members of the subgenus Fidelia (Fideliopsis) (except F. hessei), F. whiteheadi Litman & Kuhlmann sp.nov.can be distinguished by the unmodified forebasitarsus of the male (modified in other members of F. (Fideliopsis)), the yellow, convex-sided pygidial plate of the female (black or brown and concave-sided in other members of F. (Fideliopsis)) and the shape of the male S7 and S8 (see below for details).
Fidelia whiteheadi Litman & Kuhlmann sp.nov. is morphologically most similar to F. hessei.F. whiteheadi Litman & Kuhlmann sp.nov. is smaller and less broad than F. hessei.Both females and males of Fidelia whiteheadi Litman & Kuhlmann sp.nov.exhibit relatively short pilosity on the thorax, metasoma and legs (Fig. 1A).In F. hessei, pilosity is comparatively longer (Fig. 1B).In female F. whiteheadi Litman & Kuhlmann sp.nov., hairs on the forebasitarsus are brushy and the tips of hairs are often bent at a sharp angle (Fig. 1C); in comparison, the hairs on the forebasitarsus of F. hessei are shaggy and unmodified (Fig. 1D).The posterior margin of the pygidial plate in F. whiteheadi Litman & Kuhlmann sp.nov. is evenly rounded and nearly triangular (Fig. 1E); in F. hessei, it is slightly flattened apically (Fig. 1F).
A triangular protuberance at the base of the male T7 in F. whiteheadi Litman & Kuhlmann sp.nov. is strongly elevated; when examined in profile, the posterior margin of the protuberance meets the surface of the tergum at a nearly 90 degree angle (Fig. 2A).In F. hessei, the protuberance at the base of T7 is less pronounced and the angle where the protuberance meets the surface of T7 is less sharp (Fig. 2B).
A half-moon shaped protuberance on the male S2 is present in F. whiteheadi Litman & Kuhlmann sp.nov.but is only slightly elevated and often completely hidden by the pilosity of S2; the length of the protuberance is about a quarter of the length of the sternum (Fig. 2C).In F. hessei, the half-moon shaped protuberance is more strongly elevated and is usually easily visible despite the surrounding pilosity; the length of the protuberance is about one-third of the length of the sternum (Fig. 2D).
The most striking differences between F. whiteheadi Litman & Kuhlmann sp.nov.and F. hessei are found in the male hidden sterna and genitalia.In both F. whiteheadi Litman & Kuhlmann sp.nov.and F. hessei, the male S7 bears two apicolateral processes but in F. whiteheadi Litman & Kuhlmann sp.nov. the processes of S7 are relatively narrower, more weakly sclerotized, less hairy and shorter (Fig. 3A) than those of F. hessei (Fig. 3B).The male S8 of F. whiteheadi Litman & Kuhlmann sp.nov.narrows sharply in the posterior third (Fig. 3C), while that of F. hessei narrows more gradually (Fig. 3D).The gonostylus of F. whiteheadi Litman & Kuhlmann sp.nov. is distinctly narrower and the basal outer edge more rounded (Fig. 3E) than in F. hessei (Fig. 3F).

Etymology
This species is named for the late Vincent Booth Whitehead (1921Whitehead ( -2005)), whose extensive collection of fideliine bees deposited at the Iziko South African Museum in Cape Town, South Africa provided the majority of the material for this species description.

Description Female
MeasureMents.Bl= 10-11 mm; Iw = 3 mm.Head.Broader than long.Integument black.Clypeus basally black, apically yellow, mandible yellow with two red-brown teeth, upper tooth longer than lower.Head covered by dense white pilosity.Pilosity near vertex either white or pale yellow.Clypeus convex, flattened medially.Clypeus densely, minutely, superficially punctate apically; punctation gradually becoming larger and sparser basally, with spaces between punctures reaching the diameter of one-half a puncture, rarely one puncture, at clypeal base.Antennal scape and pedicel dark red-brown to black.Flagellum dorsally red-brown to pale yellow, ventrally most often yellow, although occasionally also yellow-red.
MesosoMa.Integument dark red-brown to black.Mesosomal disc very densely punctate, almost no spaces between punctures.Pilosity white to pale yellow, dense, generally short but often longer on mesopleuron and scutellum.Wings colorless, venation light brown, papillate beyond veins.Integument of legs red-brown, slightly lighter at apex of foretibia and forebasitarsus.Integument of hind femur lighter in color than that of fore and mid femur.Foretrochanter, forefemur, most of foretibia covered in white hairs.Apex of foretibia and forebasitarsus covered in shorter, golden hairs.Forebasitarsus with brushy, erect hairs, often bent at a 90 degree angle; length of hairs at posterior base of basitarsus shorter than width of basitarsus at its base (Fig. 1C).Mid and hind legs covered in long, dense white hairs.Hind basitarsus with long yellow-brown hairs on dorsal and ventral edges; dorsal hairs longer than ventral hairs.
MetasoMa.Integument red-brown to black on tergal discs, tergal margins transparent, light brown to yellow.Pilosity white to yellow.Pilosity on T1 slightly longer than that of T2-T5.Pilosity on discs of T2-T5 nearly uniform in density and length.Pilosity in longer tufts laterally on T1-T5.Pilosity longest on T6, both on tergal disc and laterally.Lateral tufts on T6 seldom reach apex of pygidial plate (Fig. 1A).Outline of pygidial plate evenly rounded in dorsal view, nearly triangular in form.Color of pygidial plate variable, from pale white-yellow to dark yellow (Fig. 1E).Integument of sterna red-brown.Pilosity of metasomal scopa white.

Same as for female except as follows:
Head.Clypeus uniformly dark red-brown.Pilosity on head uniformly white, even on vertex.MesosoMa.Pilosity on mesosoma white.Integument of forecoxa, foretrochanter and forefemur dark brown, that of foretibia and foretarsus yellow.Pilosity on forelegs entirely white.Pilosity on forebasitarsus approximately three times as long as width of basitarsus.On mid and hind legs, all segments dark brown except apex of basitarsus and tarsal segments.Pilosity on mid and hind legs white.MetasoMa.Protuberance at base of T7 strongly elevated, making a 90 degree angle with surface of tergum.Half-moon shaped protuberance on S2 weakly elevated, often hidden by pilosity on ventral metasoma (Fig. 2C).S7 with two apicolateral processes; each process narrow, weakly sclerotized and, except at tip of each process, only sparsely hairy (Fig. 3A).Length of each process of S7 approximately two-thirds as long as length of central disc of sternum (Fig. 3A).S8 sharply narrowed in posterior third, such that width of apex approximately one-fifth of width of base of sternum (Fig. 3C).S8 without paraspiculae (Fig. 3C).Gonostylus narrow and, in dorsal view, basal outer edge rounded (Fig. 3E).

General distribution
Winter rainfall area of northwestern South Africa and southwestern Namibia; summer rainfall area of north-central South Africa and southeastern and south-central Namibia (Fig. 4).

Seasonal activity
Two periods of activity a year, one from February to May (in summer rainfall area) and the second from September to November (in winter rainfall area) (Fig. 4).

Remarks
To clearly distinguish Fidelia (Fideliopsis) whiteheadi Litman & Kuhlmann sp.nov.from Fidelia (Fideliopsis) hessei, we also provide a description for the latter.Other material examined (all specimens deposited in SAM unless otherwise noted)

Note
The SAM database lists the date of collection for five male Fidelia hessei as "1982/04/25".A close look at the handwritten label on the specimens strongly suggests, however, that the labels do not read "25.iv.1982" but rather "25.ix.1982".Given the difficulty in reading the labels on these specimens, and given the total absence of other specimens of F. hessei during the fall months, we consider these specimens to have been collected in September and not April.
Head.Broader than long.Integument on head and base of clypeus black.Clypeus apically dark to yellow brown.Clypeus minutely, superficially punctate from base to apex.Mandible yellow with two red teeth, upper tooth longer than lower.Head covered in dense white pilosity.Clypeus convex, flattened medially.Antennal scape and pedicel dark red-brown.Dorsally, antennal flagellum dark red-brown basally, becoming yellow-brown apically.Ventrally, flagellum yellow.
MesosoMa.Integument black.Mesosomal disc densely, minutely punctate.Pilosity dense, shaggy, white to pale yellow, sometimes longer on mesopleuron and scutellum.Wings colorless to pale yellow, venation light brown, papillate beyond veins.legs.Dark red-brown basally, becoming paler yellow-brown apically.Forecoxa, trochanter and femur covered in white pilosity.Foretibia and foretarsus covered in golden pilosity.Pilosity on forebasitarsus long, shaggy -length of hairs at posterior base of basitarsus approximately twice as long as width of basitarsus at its base (Fig. 1D).Mid and hind coxa, trochanter and femur covered in short white pilosity.Midtibia, midtarsus and hind tibia covered in longer, denser white to white-yellow pilosity.Hind basitarsus with long yellow-brown hairs on dorsal and ventral edges; dorsal hairs longer than ventral.
MetasoMa.Integument black on tergal discs, tergal margins transparent, light brown to yellow.Pilosity shaggy white to yellow-white, with pilosity on tergal discs often erect, while pilosity on tergal margins lies flat (Fig. 1B).Longer tufts of hair present laterally on T1-T6, with pilosity on T6 longer, with lateral tufts almost reaching apex of pygidial plate.Outline of pygidial plate triangular, with flattened apex in dorsal view (Fig. 1F).Pygidial plate variable in color, from dark yellow to brown.Integument of sterna red-brown.Hairs on metosomal scopa white.

Same as for female except as follows:
Head.Integument on head and clypeus entirely dark brown to black.
MesosoMa.Pilosity white.legs.Forecoxa, trochanter and femur dark brown.Foretibia and foretarsus yellow.Pilosity on forelegs entirely white.Pilosity on forebasitarsus long at base, approximately four times as long as width of forebasitarsus at its base.Mid and hind legs and all segments dark brown except apex of basitarsus and tarsal segments.Pilosity on mid and hind legs white, except on hind basitarsus, where ventral fringe of hairs is yellow white.
MetasoMa.T7 dark brown to black.Protuberance at base of T7 usually weakly elevated, making a shallow angle with respect to surface of tergum.Half-moon shaped protuberance on S2 strongly elevated, usually visible through pilosity on ventral metasoma.S7 with two apicolateral processes (Fig. 3B); each process broader, more strongly sclerotized, and more densely hairy than in F. whiteheadi Litman & Kuhlmann sp.nov.Length of each process on S7 approximately one-half as long as length of central disc of sternum (Fig. 3B).S8 narrows gradually in posterior third, such that width of apex is approximately one-third of width of base of sternum (Fig. 3D).S8 without paraspiculae (Fig. 3D).Gonostylus distinctly broader and basal outer edge more sharply angled (Fig. 3F) than in F. whiteheadi Litman & Kuhlmann sp.nov.

General distribution
Winter rainfall area of western and northwestern South Africa (Fig. 4).

Seasonal activity
One period of activity per year, from September to November.

Key to species of Fidelia
(modified from Whitehead & Eardley 2003) Note: in couplets where color of vestiture is mentioned, color refers to that of freshly eclosed specimens.In older specimens, color of vestiture is often faded compared to that of younger specimens.Grielum sinuatum, Grielum sp. and Neuradopsis sp.In order to determine whether either F. whiteheadi Litman & Kuhlmann sp.nov.or F. hessei demonstrate a particular preference for any of these hosts, pollen slides were prepared using pollen taken from 24 female specimens representing both species.
Pollen identification proved more difficult than anticipated and these slides have yet to be fully analyzed.
They are deposited at the SAM and we encourage those interested to examine these slides for further clues as to the host plant preferences of F. whiteheadi Litman & Kuhlmann sp.nov.and F. hessei.

Fig. 4 .
Fig. 4. Distribution map of Fidelia hessei Whitehead & Eardley, 2003 (red dots), Fidelia whiteheadi Litman & Kuhlmann sp.nov., autumn period of activity (light blue dots) and Fidelia whiteheadi Litman & Kuhlmann sp.nov., spring period of activity (dark blue dots).The northernmost occurrence of F. hessei shown on the map corresponds to morphologically ambiguous specimens collected in the region around the Klinghardt Mountains of Namibia; the identification of the specimens from this region should be corroborated with DNA data.