Andrena (Euandrena) isolata Wood, sp. nov.

Wood, Thomas J., 2023, The genus Andrena Fabricius, 1775 in the Iberian Peninsula (Hymenoptera, Andrenidae), Journal of Hymenoptera Research 96, pp. 241-484 : 241

Andrena (Euandrena) isolata Wood, sp. nov.

Type material.

Holotype. Spain: Granada, Sierra Nevada, Trevélez to Refugio La Campiñuela, 37.0239°N, - 3.2656°W, 1700-2400 m, 14.vi.2021, 1♀, leg. T.J. Wood, OÖLM [BOLD accession number WPATW368-21].

Description.

Female. Body length: 9.5 mm (Fig. 48A ). Head: Dark, 1.2 times wider than long (Fig. 48B ). Clypeus weakly domed, densely and evenly punctate, punctures separated by <0.5 puncture diameters, interspaces shiny. Process of labrum trapezoidal, twice as broad as long, apical margin with very weak emargination medially. Gena slightly exceeding width of compound eye; ocelloccipital distance 1.5 times diameter of lateral ocellus; vertex behind ocellar triangle densely punctate, punctures separated by 0.5 puncture diameters. Fovea dorsally narrow, occupying ⅓ of space between lateral ocellus and compound eye, ventrally reaching level of antennal insertions, here narrowing to ½ dorsal width; fovea filled with black hairs. Face, gena, and scape covered with uniformly short black hairs, vertex dorsally with predominantly golden-brown hairs with scattered intermixed black hairs. Antennae dark, A3 slightly exceeding A4+5, shorter than A4+5+6. Mesosoma: Scutum and scutellum densely punctate, punctures predominantly separated by <0.5 puncture diameters, at most by 1 puncture diameter medially, underlying surface finely shagreened and weakly shiny (Fig. 48C ). Pronotum rounded. Mesepisternum microreticulate, weakly shiny to dull, with obscure raised reticulation. Dorsolateral parts of propodeum microreticulate, weakly shiny, densely and shallowly punctate, punctures separated by 0.5-1 puncture diameter. Propodeal triangle narrow, internal surface finely granulate and impunctate, basally with obscurely and weakly raised rugosity, propodeal triangle thus strongly contrasting punctate dorsolateral parts of propodeum. Mesepisternum ventrally with moderately long black hairs, becoming intermixed with golden-brown hairs medially, with entirely golden-brown hairs dorsally, hairs at most equalling length of scape. Scutum and scutellum dorsally with short golden-brown hairs, scutum medially with very short and obscure black hairs. Propodeum with long golden-brown hairs, propodeal corbicula incomplete, dorsal fringe composed of long plumose golden-brown hairs, internal surface with numerous plumose light hairs, becoming darker ventrally. Legs predominantly dark, hind femorae ventrally and posterior face of hind tibiae obscurely lightened reddish-orange; pubescence black to orange-brown. Flocculus incomplete, short, composed of weakly plumose orange hairs; femoral and tibial scopa orange, tibial scopa with at most occasional brown hairs dorso-basally. Hind tibial claws with strong inner tooth. Wings weakly infuscate, stigma and venation dark brown, nervulus interstitial. Metasoma: Terga dark, apical rim of marginal areas very narrowly lightened hyaline-brown (Fig. 48D ). Tergal discs regularly punctate, punctures separated by 1-2 puncture diameters, underlying surface shagreened, weakly shiny; punctures extending onto marginal areas, here weak and obscure, separated by 2-3 puncture diameters. T1-2 with orange-brown hairs basally, laterally, and apically; T2-3 with orange-brown hairs forming weak apical hair bands, not obscuring underlying surface, T4 with weak apical hair band black; discs of T3-4 with short black hairs. Apical fringe of T5 and hairs flanking pygidial plate black; pygidial plate rounded triangular, with slightly depressed and densely punctate area medially, lateral margins impunctate.

Male. Unknown.

Diagnosis.

Andrena isolata can be quickly recognised as a Euandrena due to the narrow facial foveae (dorsally occupying ⅓ of space between the lateral ocellus and the compound eye) which narrow further ventrally combined with the long A3 (slightly exceeding length of A4+5) and the simple, non-plumose hairs of the tibial scopae. Its generally dark appearance with orange-brown hairs dorsally on the mesosoma and tibial scopa plus at least some black hairs on the mesepisternum place it immediately close to A. bicolor and allied taxa. As discussed above, the subgenus Andrena Euandrena is taxonomically complex, and multiple genetically distinct taxa have been lumped under A. bicolor . In an Iberian context, A. isolata is best diagnosed against A. bicolor s.l., A. fortipunctata Wood, 2021, and the distinct and probably undescribed taxon in north-western Africa identified above. Extreme care should be taken when identifying specimens morphologically, and barcodes should be used whenever possible.

In direct comparison to barcoded A. bicolor s.l. specimens, the only consistent character that can be identified is the structure of the clypeus. Andrena isolata has the clypeus densely punctate, with punctures separated by <0.5 puncture diameters, interspaces shiny but overall the clypeus only weakly shiny due to the small size of the interspaces (Fig. 48B ). In A. bicolor s.l., the clypeal punctures are separated by an average of at least 1 puncture diameter, sometimes more, and the clypeus is therefore more strongly shiny due to the larger interspaces. The dense clypeal punctures place A. isolata close to A. fortipunctata , but the two species can be separated by the tergal structure (see illustrations in Wood et al. 2021), with the tergal margins weakly depressed with at most the apical rim lightened hyaline yellow (tergal margins strongly depressed and extensively lightened semi-translucent brown in A. fortipunctata ), terga punctate with some punctures extending onto tergal margins, here separated by 2-3 puncture diameters (tergal margins impunctate in A. fortipunctata ), margins of T2-3 with weak light brown hair fringes apically, T4 with entirely black hairs (T2-4 with white hair fringes emerging from junction between disc and margin, these hair fringes overlying marginal areas in A. fortipunctata ), terminal fringe of T5 and hairs flanking pygidial plate black (terminal fringe and hairs flanking pygidial plate dark brown in A. fortipunctata ). Andrena isolata is almost identical to the probably undescribed taxon from north-western Africa, but can also be separated by the structure of the clypeus. Andrena isolata has the clypeus densely punctate with punctures separated by <0.5 puncture diameters and with the interspaces shiny, whereas in the taxon from north-western Africa, the punctures are equally dense but the interspaces are shagreened and dull. Furthermore, this latter taxon has a short and shallow longitudinal furrow at the apex of the clypeus that is absent in A. isolata .

Remarks.

Andrena isolata probably represents a relictual species that has become isolated on the Sierra Nevada from what is now a remaining North African population. Additional genetic sampling is needed to establish whether it is found away from the Sierra Nevada, but a specimen from the nearby Sierra de Baza collected at an altitude of 2000 m barcoded as A. bicolor s.l. [WPATW297-21]. Andrena isolata may well be restricted to the Sierra Nevada. Additional sampling is required to establish its ecology, including its voltinism. Its capture on Campanula implies that it has a similar ecology to A. bicolor s.l. (see Praz et al. 2019), but this requires dedicated study.

Etymology.

Derived from the Latin insulatus, to be made into an island, Andrena isolata (feminine form) thus means to be isolated, in reference to its presence on the Sierra Nevada, separated from its nearest genetic relative in North Africa.

Distribution.

Spain (Sierra Nevada).

Figures

Figure 48. Andrena (Euandrena) isolata sp. nov. female A profile B face, frontal view C scutum, dorsal view D terga, dorsal view.