Andrena (?Planiandrena) ramosa Wood

Wood, Thomas J., Molina, Francisco P., Bartomeus, Ignasi & Mars, Champs de, 2022, A new Andrena species (Hymenoptera: Andrenidae) from the overlooked Doñana Protected Areas of southern Spain, Belgian Journal of Entomology 127, pp. 1-13 : 8-10

Andrena (?Planiandrena) ramosa Wood , sp. nov.

( Figs 1–9 )

urn:lsid:zoobank.org:act:009DC619-4B2E-4529-98E2-298259B92585

HOLOTYPE. SPAIN: Seville Province, Aznalcázar , 37.262 oN, -6.223 oW, 10.iii.2020, 1♀, leg. F.P. Molina. Deposited in the Oberösterreichisches Landesmuseum, Linz, Austria .

DESCRIPTION. FEMALE. Body length 12 mm ( Fig. 1 ).

Head: Dark, 1.1 times wider than long ( Fig. 2 ). Clypeus domed and weakly flattened centrally, clearly protruding from face when viewed in profile ( Fig. 1 ). Clypeus surface shagreened laterally and basally, dull, shagreen becoming weaker and almost disappearing centrally, clypeus here almost smooth and shining ( Fig. 3 ). Entire clypeal surface covered with large, irregular punctures, these separated by 1–3 puncture diameters. Process of labrum broad, weakly trapezoidal, three times wider than long, glossy ( Fig. 9 ). Gena broad, wider than width of compound eye, ocelloccipital distance moderate, equalling width of lateral ocellus. Fovea narrow, occupying slightly less than half distance between lateral ocellus and compound eye, slightly wider than width of flagellum, not separated from inner margin of compound eye. Gena with long light brown plumose hairs, these becoming mixed brown and black on vertex, longest hairs nearly equalling width of scape. Face and scape with shorter brown and black plumose hairs, brown hairs clustered around antennal insertions, predominantly black elsewhere. Antennae dark, A3 exceeding A4+5, slightly shorter than A4+5+6.

Mesosoma : Scutum and scutellum clearly but shallowly punctured, punctures separated by 1– 3 puncture diameters, underlying surface finely microreticulate, dull laterally to weakly shining centrally ( Fig. 4 ). Pronotum with extremely weak humeral angle, almost absent. Episternum and propodeum with fine granular reticulation, dull, with pattern of slightly raised reticulation that becomes stronger on propodeum. Propodeal triangle well differentiated, slightly depressed, internal surface with fine granular reticulation but without raised reticulation. Episternum with long light brown plumose hairs, these exceeding length of scape ( Fig. 5 ). Propodeal corbicula complete, composed of long very strongly plumose light brown hairs ( Fig. 6 ), internal surface with scattered plumose hairs. Legs uniformly dark, pubescence whitish to brownish. Flocculus dense, composed of strongly plumose whitish-light brownish hairs ( Fig. 7 ). Femoral scopa dorsally with long plumose hairs, anterior fringe with hairs simple ( Fig. 7 ). Tibial scopa with simple or only weakly branched hairs, these light brown ventrally, becoming dark brown apically, strongly so at the basitibial plate. Venation and stigma dark brown, nervulus interstitial.

Metasoma: Terga dark, apical part of apical margins narrowly lightened dark brown ( Fig. 8 ). Tergal integument finely reticulate, weakly shining, tergal discs with fine, obscure scattered punctures, punctures separated by 2–3 puncture diameters; tergal margins impunctate. Tergal discs with scattered light brown hairs, T5 and hairs flanking pygidial plate dark brown; pygidial plate with weak centrally raised longitudinal area, poorly differentiated from surrounding area.

MALE. Unknown.

DIAGNOSIS. Andrena ramosa is difficult to place into a subgenus due to its unusual combination of characters, specifically the very broad process of the labrum, the pronotum without lateral furrow, the essentially smooth and unornamented propodeal triangle, unbroadened hind tibial spur, three submarginal cells, interstitial nervulus, hind femur without projecting teeth, simple and comparatively narrow fovea that do not narrow below, lack of squamous hairs, medium body size, lack of tergal hairbands, and domed clypeus. It therefore does not fit into existing West Palearctic concepts ( WARNCKE, 1968) even following up-to-date revisions ( PISANTY et al., 2021).

However, it is similar to the subgenus Planiandrena which was described from Central Asia, with four species distributed across Kazakhstan, Uzbekistan, and Turkmenistan ( OSYTSHNJUK, 1983). A further 3-4 species are known from Israel and Iran and are currently being described (T.J. WOOD & G. PISANTY, in prep.). The important original characters used to define the subgenus were the flattened or concave clypeus, very wide and short process of the labrum, narrow fovea occupying not more than half the distance between the lateral ocellus and the inner margin of the compound eye, hind tibial spur is widened, dorsal surface of propodeal triangle matt, with entirely granular shagreenation to shining, the triangle itself defined overall by having softer sculpturing than the lateral parts of the propodeum, and propodeal corbicula well defined. Andrena ramosa disagrees with some of these characters, specifically by its domed clypeus and unbroadened hind tibial spur. However, some of the Israeli and Iranian species also present these characters, and so a broader interpretation of this subgenus is taken in the interests of forming a hypothesised relationship. Because of the lack of male material, A. ramosa is not firmly placed in the Planiandrena at this point, though it is considered its possible future placement.

Because subgeneric placement is both highly technical and the nearest comparison species are found in the East Mediterranean, diagnosis is made also to superficially similar but unrelated Iberian taxa. Because of the strong propodeal corbicula composed of plumose hairs and the thick flocculus composed of long and strongly plumose hairs which contrast with the tibial scopa of simple or scarcely plumose hairs, A. ramosa could potentially be confused with members of the subgenus Leucandrena Hedicke, 1933 (recently reviewed in Iberia by FIDALGO et al., 2021). Andrena ramosa can easily be separated from Leucandrena species by a combination of the broad labrum ( Figs 9–16 , triangular to rounded in Leucandrena species) and the comparatively narrow fovea (occupying less than half of the distance between the lateral ocellus and the compound eye, occupying at least half the distance in Leucandrena species), and very obviously by the extraordinary plumose hairs that extend onto the episternum where they are much more conspicuous than in other similar species ( Fig. 5 ). Indeed, this final character allows separation from any Iberian Andrena species known to date.

ETYMOLOGY. The name derived from the Latin ‘ramosus’ meaning branched, in reference both to the strongly plumose hairs that make up its propodeal corbicula and flocculus, and which are present on the episternum, and also to refer to its observed host plant Asphodelus ramosus that is present on the sandy soils around Aznalcázar.

Figures

Figs 1–8. Andrena ramosa sp. nov. female. 1, habitus in lateral view. 2, face. 3, clypeus detail. 4, scutum. 5, episternum, viewed from behind. 6, propodeal corbicula. 7, flocculus. 8, terga.

Figs 9–16. Process of the labrum of Andrena ramosa sp. nov. and Andrena (L.) females. 9, A. ramosa sp. nov. 10, A. tunetana Schmiedeknecht, 1900. 11, A. leptopyga Pérez, 1895. 12, A. barbilabris (Kirby, 1802).13, A. sericata Imhoff, 1868. 14, A. argentata Smith, 1844. 15, A. parviceps Kriechbaumer, 1873. 16, A. ventralis Imhoff, 1832.