Archistempellina perkovskyi, 2014

Zakrzewska, Marta, Krzemiński, Wiesław & Giłka, Wojciech, 2016, Towards the diversity of non-biting midges of the tribe Tanytarsini from Eocene Baltic amber (Diptera: Chironomidae), Palaeontologia Electronica (Ottawa, Ont.) 12 (1), pp. 1-21 : 3-4

Archistempellina perkovskyi

Giłka and Zakrzewska, 2014

Figure 1

2014 Archistempellina perkovskyi Giłka and Zakrzewska in Zakrzewska and Giłka, p. 336, 342 (male, in key), figures 1, 2.

Material examined. Adult male (complete specimen) in 11.5 x 6 x 3.5 mm piece of amber (Eocene, ~40-45 Ma, Gulf of Gdańsk; CCHH 1754-4, Figure 1 ).

Remarks. Archistempellina perkovskyi is a unique species known from the adult male, which bears distinct semicircular posterolateral lobes on the hypopygial tergite (see Zakrzewska and Giłka, 2014). We assume that these unusual structures can be incorrectly recognized as lobes of the superior volsellae, thus we confirm them as parts of the tergite (well developed in the examined specimen), probably homologous with those called “shoulders” (e.g., Ekrem et al., 2003). The original description of A. perkovskyi should be also supplemented with the following characters: wing length 1245 μm, VRCu 1.28; clypeus with at least 12 setae; thorax chaetotaxy: Ac at least 14, Dc at least 11-13, Pa 3, Scts at least 12; hind leg tibia with at least one spur ca. 45 μm long. Measurements of leg segments and leg ratios are compiled with those taken from the holotype specimen in Table 3. Unfortunately, some characters are still impossible to define on the basis of the presently examined male trapped in resin as freshly emerged (AR unmeasurable, hypopygium sunk into the abdomen with the anal point reaching the mid length of the inferior volsellae).

Figures

FIGURE 1. Tanytarsini - inclusions in Baltic amber from the Hoffeins collection (for details see Table 1 and Material examined).