Eumerus lyneborgi, Ricarte & Hauser & Kinnee & Marcos-García, 2020

Ricarte, Antonio, Hauser, Martin, Kinnee, Scott & Marcos-García, Ángeles, 2020, A new Eumerus hoverfly (Diptera: Syrphidae) from Namibia and South Africa with notes on similar species, Zootaxa 4890 (4), pp. 493-508 : 502-503

Remarks on Eumerus lyneborgi sp. nov. and similar species

Eumerus lyneborgi sp. nov. is similar to E. vestitus Bezzi, 1912 in body size and constitution, predominantly pollinose frons, with punctured pollinosity (females), swollen metafemur, with two ventral rows of short black spinae, one antero-apically and other postero-apical, lateral margins of terga III and IV pollinose, and tergum IV widely pollinose posteriorly. Bezzi (1912) described E. vestitus based on males and females from ‘ Guinea Portoguese’ (nowadays, Guinea-Bissau), supposedly the male and three females the authors of the present paper found in the MCSNG collection. These specimens are all labelled as ‘syntypus’ and a female has an additional label of ‘Typus’. Bezzi (1912) did not mention a holotype or type specimen for his new species in the description. Thus, according to articles 73.1.1 and 73.1.2 of the International Commission on Zoological Nomenclature (1999), this ‘Typus’ is not a valid holotype and therefore all specimens are syntypes. In addition, no subsequent type designation for E. vestitus is known to the authors of the present paper. In the past, curators sometimes labelled arbitrarily as ‘Typus’ the best looking specimen within the type series (M.A. Alonso-Zarazaga in lit.), and this is likely to be the case for this ‘Typus’ specimen. Thus, lectotype designation is possible for this nominal species in order to stabilise this species concept, especially because it is a mixed type series and the newly described species in this paper is similar to E. vestitus . Thus, we here designate the male specimen as lectotype ( Fig. 9 ). All other specimens (females) become automatically paralectotypes ( Figs 10 , 11 ).

All specimens of the type series, except for one are recognised to be conspecific. The outlier specimen (female paralectotype) has (1) denser and longer eye pilosity (eye with very short and scattered pile in the other two females) ( Fig. 10C, D ), (2) slight but obvious pollinosity surrounding posterior ocelli (this same area is shiny or nearly so in the other two females), (3) individual dots of frontal pollinosity very small (larger in the other females) ( Fig. 10A, C ), (4) basoflagellomere tapering dorsally for the apical two thirds (for the apical half or less, in the other two females) ( Fig. 10C, D ), (5) metatibia bumped ventrally (less bumped, tending to straight, in the other two females), (6) apex of metatibia without short black spinae (apex of metatibia with two short black spinae in the other two females) ( Fig. 11 ). This outlier female is similar to the female of E. obliquus ( Fabricius 1805) (widespread in Africa) and E. figurans Walker, 1859 (not recorded from Africa). However, it differs from that of E. obliquus in the pollinose vertex (broadly shiny in E. obliquus ), wide pollinose posterior margin of scutellum (much narrower to almost absent in E. obliquus ), narrow diagonal vittae of terga III and IV (wider in E. obliquus ), and shiny posterior margin of tergum IV (extensively pollinose in E. obliquus ); and differs from the female of E. figurans in the pollinose vertex and occiput (vertex and occiput shiny in E. figurans ), the densely and homogeneously pollinose frons (frons with a medial line of sparser pollinosity in E. figurans ), and the short spinae of the anteroapical row of metafemur (longer spinae in E. figurans ). The outlier specimen did not key out with Lyneborg’s manuscript key to the Afrotropical species of Eumerus , and might represent an undescribed sister species of E. vestitus . However, we decided not to describe it as a separate taxon due to the absence of other specimens, including males with conspecific morphology.

Additional examined material of other Eumerus species. Type series of the nominal species, Eumerus vestitus Bezzi, 1912 . Lectotype: 1³, GUINEA PORTOGUESE, Rio Cassine, XII.1899 – IV.1900. L. Fea (part of the date crossed out as indicated) / SYNTYPUS ³ Eumerus vestitus Bezzi, 1912 (on pink label). Paralectotypes: 1♀, GUINEA POR- TOGUESE, Rio Cassine, XII.1899 – IV.1900. L. Fea (part of the date crossed out as indicated) / vestitus Bezzi / TYPUS (printed in red) / Eumerus vestitus n. sp. (handwritten on a pink label; ‘ n. sp. ’ is an interpretation of the actual label lettering) / SYNTYPUS ♀ Eumerus vestitus Bezzi, 1912 (on pink label) / Museo Civico di Genova; 2♀, GUINEA PORTOGUESE, Rio Cassine, XII.1899 – IV.1900. L. Fea (part of the date crossed out as indicated) / SYNTYPUS ♀ Eumerus vestitus Bezzi, 1912 (on pink label) / Museo Civico di Genova [MCSNG]. The male syntype lacks the antennae and the right prolegs, and the head is pasted to thorax in its original position. The female syntype labelled as ‘typus’ lacks the left basoflagellomere, while another female lacks the left metatarsus. There were specimens from Egypt, donated by Becker to Bezzi and found by this latter author that they were erroneously identified as E. obliquus , mentioned in the original description, which we could not locate. Additional material of Eumerus vesti-tus: 2³, 1♀, Egypt, Cairo, Gizera, 24.ix.1992, leg. M. Hauser [CSCA]; 1³, Egypt, Luxor, Westbank of Nile river 25.694N 32,628E, 1.iv.2018 leg Schmid-Egger [CSCA]; 1³, Tunisia, Monastir, 15km S Sousse, 28.vi.1994, leg. M. Hauser (first record of E. vestitus from Tunisia) [CSCA].

Eumerus obliquus : AFRICA. 1♀, ‘Cap. B. Spei.’ [ South Africa, Cape of Good Hope], Coll. H. Loew, obliquus F (hand written); 1³, Africa, Coll. H. Loew [ZMB]; 1♀ [published in Marcos-García et al. (2013)], Île de la Réunion ( France), Les Avirons, 24.vi.2010, Leg.: N. Estela Ribera, Det. as E. obliquus by A. Ricarte & M.A. Marcos-García in 2010 (CEUA00105083) [CEUA]; 1³, 2♀, Mozambique, Sofala Prov. Gorongosa Park, small lake, 18°56’39»S 34°26’35»E, 300m, ex Malaise, 19–30.iv.2015 leg. M. Hauser & A. Rung [CSCA]; 1³, Zambia Southern Prov., Livingston, 17.842 S 15.857 E, 960m, 1.v.2016, leg M. Hauser & CJ Borkent [CSCA]; 1³, Zambia, Northern Prov. 8.8 km WSW Kakumbi, S Luangwa NP, 22–26.iv. 2016, 525m, 13.115 S 31.726 E, Malaise trap, leg. M. Hauser, CJ Borkent & DM Ndalamei [CSCA]; 1³, Mali 30 km N Bamako, 20.vii.1991, leg. M. Schwarz [CSCA]; 1³, Ghana, Northern Region, Mole National Park, 165m, 09°15’33»N 01°51’43»W, Malaise trap, 28–30.iv.2014 leg. S. Gaimari & M. Hauser [CSCA]; 1³, Tunisia, Monastir, 15km S Sousse, 28.vi. 1994, leg. M. Hauser [CSCA]. AUSTRA-LIA. 1♀ with puparium, Palmwoods, nr Nambour, Qld, C. Hayward, emerged 17.v.1986, ex rotting guava infested with larvae of Dacus tryoni (UQIC Reg #94996) [CSCA]. EUROPE. 1♀, Spain (mainland), Alicante, San Juan, 01.iv.2020, Leg. M.A. Marcos; 1♀ [published in Ricarte et al. (2008)], Spain, Balearic Islands, Mallorca, Ses Salines, P/ 29.x.2005, Leg.: M.A. Marcos-García (#6844), Det. as E. obliquus by A. Ricarte in 2006 (CEUA00084841). Eumerus obliquus is widespread all over Africa, also found in the Canary and various Mediterranean islands, as well as in mainland Europe: Spain (first records in the present paper), southern France and Italy ( Speight 2020). This species is also introduced in Australia and South America ( Garcete-Barrett et al. 2020).

A female of Eumerus punctifrons Loew, 1857 with the following data: Tunis, 62285 [ZMB].

Photos of the holotype of Eumerus figurans Walker, 1859 at the Natural History Museum, London, available at https://www.nhm.ac.uk/.

Figures

FIGURE 9. Eumerus vestitus, male, lectotype, body, overall appearance. A: dorsal view with original labels; B: lateral view. Scale bar = 1 mm.

FIGURE 10. Eumerus vestitus, females, paralectotypes, frons (A, B), antennae and eyes (C, D). A, C: specimen with typical E. vestitus morphology; B, D: outlier specimen (non-conspecific?). Scale bar = 0.5 mm.

FIGURE 11. Eumerus vestitus, females, paralectotypes, metatibiae.A: specimen with typical E. vestitus morphology; B: outlier specimen (non-conspecific?). Scale bar = 0.25 mm.