A New Species Group in the GenusTanytarsusvan der Wulp (Diptera: Chironomidae) Based on a Fossil Record from Baltic Amber

Abstract

A new fossil chlronomid, Tanytarsus serafini, found in Baltic amber is described and illustrated based on adult males. The new species and similar extant species of the genus Tanytarsus van der Wulp are compared. Due to several distinct characters of wing, legs and hypopygium, a new species group for Tanytarsus serafini is proposed, and its diagnostic features are evaluated.

The oldest known chironomids of the tribe Tanytarsini (Diptera: Chironomidae) indicate plesiomorphic character states

“…The Tanytarsini have not been recorded in the Early Eocene amber of France dated back to $ 53 Ma Ma (Doitteau and Nel, 2007); thus the oldest Tanytarsini known to date are found in the Middle Eocene Baltic amber (40)(41)(42)(43)(44)(45). Phylogenetic relationships and systematic division within the tribe Tanytarsini are still unclear, as very few species of these dipterans have been reported from the fossil record so far (Seredszus and Wichard, 2007;Giłka, 2010Giłka, , 2011aGiłka et al, 2013;Zakrzewska and Giłka, 2013). On the one hand, this may be due to relatively low fossil species richness, but this may also result from the poor preservation of fossils and/or the troublesome preparation of minute amber inclusions and examination of very tiny diagnostic structures.…”

“…In the Eocene, the subtribe Tanytarsina was represented primarily by the genus Tanytarsus (the largest extant genus), known from three species classified in separate groups: the extinct serafini group (including Tanytarsus serafini with wing venation pattern not known in extant species, and strong setae in place of the spur on the foreleg tibia), the lugens group (Tanytarsus congregabilis), and the mendax group (Tanytarsus fereci), represented by numerous limnophilous extant species (Giłka, 2010(Giłka, , 2011Giłka et al, 2013). It is worth noting that there is only one known fossil species of the genus Caladomyia among the Eocene Tanytarsina (this genus being currently distributed almost exclusively in the Neotropics); this species (Caladomyia szadziewskii) has been described from the Baltic amber .…”

Molecular phylogeny and temporal diversification ofTanytarsusvan der Wulp (Diptera: Chironomidae) support generic synonymies, a new classification and centre of origin

“…Described Tanytarsus species from amber (e.g. Giłka, , ; Giłka et al ., ; Zakrzewska et al ., ) were not used for calibration as we could not assign a likely branch based on available morphological characters. The Markov chain Monte Carlo analyses were run for 40 million generations, sampling trees every 10 000 generations after discarding samples from the first four million generations.…”

Towards the diversity of non-biting midges of the tribe Tanytarsini from Eocene Baltic amber (Diptera: Chironomidae)

“…This family has left fossil records since the Late Triassic (Krzemiński and Jarzembowski, 1999) with most taxa described from Eocene ambers. The fossil chironomid fauna found in amber from the Baltic region is the best studied one, including the so far oldest known members of the Tanytarsini -the tribe within the second largest subfamily Chironominae (Seredszus and Wichard, 2007;Giłka, 2010Giłka, , 2011aGiłka et al, 2013;Zakrzewska and Giłka, 2013, 2015b. According to the current division, the oldest Eocene Tanytarsini are represented by genera classified in two known subtribes: Tanytarsina (see couplets 10-17 in a key given below) and Zavreliina (couplets [18][19][20][21], with the exception of the extinct genera with unexplained subtribal position (couplets 3-9) (Zakrzewska and Giłka, 2014Giłka, , 2015b.…”