Andrena risha WOOD, 2024, spec. nov.
Creators: name: WOOD, T. J.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Andrenidae
Andrena
Andrena risha

description: Andrena (incertae sedis) risha spec. nov.
Figures 81A–H.
HOLOTYPE: ALGERIA: Oran [inferred 35.7072 oN, -0.6646 oE], 8.iii.1960, ♀, leg. J. Barbier, OÖLM.
Description. Female. Body length: 9.5 mm (Figure 81A). Head: Dark, 1.3 times wider than long (Figure 81B). Clypeus domed, densely but shallowly punctate, punctures separated by 0.5–1 puncture diameters, with hint of weak impunctate mid-line, underlying surface shagreened, weakly shining. Process of labrum rounded trapezoidal, slightly wider than long, surface shining (Figure 81C). Gena slightly exceeding width of compound eye; ocelloccipital distance 1.5 times diameter of lateral ocellus. Foveae moderately broad, occupying slightly more than malar areas space between compound eye and lateral ocellus, ventrally slightly passing lower margin of antennal insertions; foveae filled with dark brown hairs. Head covered with dark brow to light brown plumose hairs, hairs lightest around antennal insertions and on frons, none equalling length of scape. Antennae dark, A5–12 ventrally lightened by presence of grey scales; A3 exceeding A4, shorter than A4+5.
Mesosoma: Scutum and scutellum strongly microreticulate and predominantly dull, with obscure punctures disappearing into underlying sculpture (Figure 81D). Pronotum with weak hint of humeral angle. Mesepisternum and dorsolateral part of propodeum with fine and uniform granular shagreen, weakly shining; propodeal triangle finely delineated by fine rim, internal surface with fine and uniform granular shagreen, basally with short raised rugae, propodeal triangle therefore poorly differentiated from remaining parts of propodeum (Figure 81E). Mesepisternum with long, densely plumose light brown hairs, becoming shorter and darker brown on scutum and scutellum (Figure 81F). Propodeal corbicula complete, dorsal and anterior fringes composed of long densely plumose light brown hairs, internal surface with sparse, long, simple light brown hairs. Legs dark, apical tarsal segments lightened orange-brown; fore and mid femorae with long fringes of plumose light brown hairs, remaining legs with light to dark brown pubescence. Flocculus complete, composed of light brown plumose hairs; femoral scopae composed of mixture of light brown simple and plumose hairs (Figure 81G). Tibial scopae composed of simple hair, dorsally dark brown to black, ventrally light brown. Hind tarsal claws with inner tooth. Wings hyaline, stigma and venation orange, nervulus weakly antefurcal.
Metasoma: Terga dark, T1–2 with marginal areas broadly lightened hyaline brown (Figure 81H). Tergal discs strongly shagreened, weakly shining; surface weakly punctate, punctures separated by 1–2 puncture diameters, disappearing into underlying sculpture. Marginal areas of T2–4 weakly but distinctly depressed. Discs of T1–4 with sparse brown hairs, longest on T1, becoming progressively shorter on subsequent discs; T1–4 with weak apical hairbands, not obscuring underlying surface. Apical fringe of T5 and hairs flanking pygidial plate dark brown. Pygidial plate rounded triangular, apical rim slightly raised, internal surface densely punctate, punctures confluent, interspaces slightly shining.
Male. Unknown.
Diagnosis. Andrena risha presents a combination of characters that prevent confident placement in an existing subgenus. It is morphologically closest to A. (? Euandrena) ramosa Wood, 2022 (Spain and Portugal) and more broadly falls into the broad Euandrena -Margandrena-crocusella -group derived part of the Andrena phylogeny (Pisanty et al. 2022b) due to the pronotum with a very weak humeral angle; propodeum with almost no sculpture (Figure 81E), propodeal triangle thus subtly delineated; facial foveae relatively broad (occupying slightly more than ½ space between compound eye and lateral ocellus) and not narrowing ventrally; clypeus domed; A3 exceeding A 4 in length, shorter than A4+5; pollen collecting hairs complex, flocculus composed of strongly plumose hairs (Figure 81G); strongly plumose hairs present also on femoral scopae, ventral margins of fore and mid femorae, mesepisternum, and comprising propodeal corbiculae, propodeal corbiculae essentially complete; hind tibial scopae composed of simple hairs; and absence of other defining characters. The presence of abundant strongly plumose hairs that contrast the simple hairs of the tibial scopae (Figures 80F–G) are strongly reminiscent of A. ramosa which is uncertainly placed close to the subgenus Euandrena (see Wood 2023b). The weak humeral angle, lack of sculpture on the propodeum, and relatively broad facial foveae that do not narrow ventrally make it difficult to place it in the subgenus Euandrena with any confidence, as these characters are most closely associated with the crocusella -group. Andrena risha is therefore best left as incertae sedis for the time being.
In direct comparison to A. ramosa (characters of A. ramosa illustrated in Wood et al. 2022), A. risha can be separated due to the process of the labrum which is rounded trapezoidal, only slightly wider than long (Figure 81C; in A. ramosa with the process of the labrum broad, 3 times wider than long), the clypeus which is evenly shagreened and weakly shining over its entire surface (in A. ramosa the clypeus is shagreened laterally and basally, dull, shagreen becoming weaker and almost disappearing centrally, clypeus here almost smooth and shining), foveae occupying slightly more than ½ of the space between the compound eye and lateral ocellus (in A. ramosa with the foveae occupying slightly less than ½ of the space between the compound eye and lateral ocellus), pronotum with weak humeral angle (in A. ramosa with the pronotum rounded), scutum strongly microreticulate and predominantly dull, with obscure punctures disappearing into underlying sculpture (Figure78D; in A. ramosa with the scutum shagreened and dull to weakly shining but with clear shallow punctures, punctures separated by 1–3 puncture diameters), and the finely shagreened propodeum with minimal sculpture, propodeal triangle almost undifferentiated from dorsolateral parts of propodeum (Figure 81E; in A. ramosa with clear different between propodeal triangle and dorsolateral parts of propodeum, these latter parts covered with granular microreticulation overlain by loose network of raised reticulation, sculpture thus contrasting smooth surface of propodeal triangle).
Etymology. From the Arabic noun “ risha ” meaning feather, in reference to the plumose hairs covering the body of this species. It is a noun in apposition.
Distribution. North-western Algeria.
description: Published as part of WOOD, T. J., 2024, Further revisions to the Palaearctic Andrena fauna (Hymenoptera: Andrenidae), pp. 1-150 in Zootaxa 5483 (1) on pages 134-137, DOI: 10.11646/zootaxa.5483.1.1, http://zenodo.org/record/13209307