Tanytarsus marianae Reis, Lin et Ferreira-Keppler, 2022

Dantas, Galileu P. S., Hamada, Neusa & Giłka, Wojciech, 2023, Tanytarsus van der Wulp (Chironomidae, Diptera): new species from the western Amazon region in Peru and Brazil, new records from the Neotropics, and remarks on the taxonomy of the genus, Zootaxa 5271 (1), pp. 115-139 : 133

Tanytarsus marianae Reis, Lin et Ferreira-Keppler, 2022

( Fig. 8A–F )

Tanytarsus marianae Reis, Lin et Ferreira-Keppler, 2022: 429 (adult male; Brazil, Amazonas, Manaus).

Material examined: BRAZIL. Amazonas: Manaus, Experimental Station ZF-2, Km 14, 02°35′21″S, 60°06′55′′W, Malaise trap, 15-28.ii.2017, legs. J.A. Rafael & F.F. Xavier, 2 ♁♁ ( INPA) . Tocantins: Palmas, Ig. Brejo da Jéssica , 01-14.vi.2016, 48°14′58.00″W, 10°03′53.60″S, 448m a.s.l., Malaise trap, legs. S. R . M. Couceiro, G. Amora, 2 ♁♁ ( INPA) .

Remarks. Knowledge on intraspecific variations can prevent misidentification. Variability is an inherent feature of all species, and its scale may be a derivative of different geographical locations, development conditions, a generation in a season, etc. Variable colouration, body size and other metric characters, as well as shapes of the main diagnostic structures can mislead, especially when derived from incomplete, deformed during preparation, or weakly described specimens. Failure to distinguish the characters or, on the contrary, overinterpretation or abuse slight differences of the usual variability can lead to the same result—multiplication of names (see remarks to T. pollicis ). Hundreds of synonyms, doubtful or invalid names are evidenced in Tanytarsini ( Ashe & Cranston 1990, Ashe 1992, Spies & Sżther 2004; see also Giůka & Gadawski 2022). Following this problem (see remarks to T. pollicis ), we here present variations of the main diagnostic structures in the two recently described species: Tanytarsus marianae and T. rafaeli . Descriptions of these species were based on materials collected in the central Amazonia ( Reis et al. 2022); now we supplement the knowledge on their geographic range eastward to the Brazilian Cerrado biome.

In the material examined, sampled at sites far apart from each other (~ 1500 km), we found adult males showing an interesting variety of shapes of the most important diagnostic structures, the superior volsella and the digitus, on the basis of which T. marianae was diagnosed. The superior volsella takes the shape from oval or ellipsoidal to almost rectangular, with a rounded posterolateral margin, while the digitus is always well-developed and extended far beyond the superior volsella, with more or less prominent distal part in the shape of an elongated dumpling/flap or lanceolate, with a blunt tip ( Fig. 8 C-F). These characters occur in various combinations and fit other diagnostic characters of T. marianae (cf. Reis et al. 2022), thus are defined as intraspecific variations. Slight differences we observed also in the shape of the anal point ( Fig. 8A ) with distal spinulae slightly separated from the others or fused into a bar-shaped process. This character, as well as the particularly well-developed, bottle-shaped anteromedian projection of superior volsella are typical of the kiche group to which we here include T. marianae .

Figures

FIGURE 8. Tanytarsus marianae Reis, Lin et Ferreira-Keppler, 2022, male, variations of diagnostic structures. A: anal point; B: median volsella; C–E: superior volsella and digitus photographed (C, D) and drawn (E); superior volsella in the drawings (red) with anteroventral projection (yellow) and digitus (green), in dorsal (d) and ventral aspect (v).