Parochlus kiefferi (Garrett, 1925)

Jambrović, Martina, Čerba, Dubravka & Hamerlik, Ladislav, 2023, First record of Parochlus kiefferi (Garrett, 1925) in a sediment sequence from a Slovak mountain lake with notes on paleolimnological interpretation, CHIRONOMUS Journal of Chironomidae Research 2023 (36), pp. 4-7 : 5

Parochlus kiefferi occurrence and distribution

One of the analysed sediment core samples, from the depth of 42–42.5 cm, contained a particularly inter- esting find - that of the larval head capsule of a podonomine, Parochlus kiefferi ( Fig. 2 ). This species was identified only in the aforementioned subsample, and not found in others. In the past, P. kiefferi has been recorded in the neighbouring Czech Republic, Poland and Austria ( Saether and Spies 2004, Syrovátka and Langton 2015). However, this finding represents the first record of the species in Slovakia, either in recent benthic fauna ( Saether and Spies 2004), or in lake sediment samples from paleolimnological studies (P. Bitušík, personal communication). Though it is not possible to identify the larval remains to species level, P. kiefferi is the only species of the genus known in Europe ( Brundin 1966), therefore, the larval remains can confidently be attributed to P. kiefferi . It is a cold-stenothermal species which usually requires a con- stant flow of water, and so is typical of springs and fast-flowing brooks, streams and rivers ( Brooks et al. 2007, Moller Pillot 2013 and references therein). However, P. kiefferi has also been found among mosses in a high-altitude glacial pond in the Italian Alps (Lencioni et al. 2009) and in cool Icelandic lakes ( Brooks et al. 2007 and references therein). P. kiefferi is seemingly never abundant in the localities where it has been recorded, and is quite rarely found in lake sediments ( Brooks et al. 2007, Hayford 2012 and references therein).

Including P. kiefferi , a total of 66 head capsules were found in the sample, and 19 chironomid taxa were identified, belonging to six subfamilies: Podonominae , Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae, including the two tribes of Chironomini and Tanytarsini . The chironomid assemblage was dominated by the Tanytarsini , with Tanytarsus lugens - type making up 42% of all identified head capsules, followed by the Orthocladiinae, notably Psectrocladius psilopterus - type and Limnophyes / Paralimnophyes sp.; however, most orthoclad taxa were present in low abundances. A full list of all chironomid taxa recorded in the sediment sample, along with their relative abundances, is shown in Table 1.

Several other taxa like P. kiefferi were recorded in the sample, such as the similarly cold-stenothermal and rheophilic Prodiamesa sp. and Pseudodiamesa sp. , although the latter genus can also be found in cold lakes and ponds. Additionally, the cold-stenothermal Derotanypus sp. , Paratanytarsus austriacus - type and T. lugens - type, as well as the rheophilic Chaetocladius piger - type, and Rheocricotopus effusus - type were identified. Generally, the chironomid assemblage of the lake sediment sample is indicative of cold, oli- gotrophic conditions, and of the presence of an increased water flow. The sediment sequence has not yet been dated. However, owing to the depth of the sample within the sequence, and its comparison with other sequences from the Tatra Mountains ( Stoklasa et al. 2017), we assume that the P. kiefferi head capsule can be dated back to the Little Ice Age.

Figures

Figure 2. Detail of the head capsule of Parochlus kiefferi found in lake Vrbické pleso. Photo: Martina Jambrović.