Lumbriculidae

Schenková, Jana, Pařil, Petr, Petřivalská, Karla & Bojková, Jindřiška, 2010, Aquatic oligochaetes (Annelida: Clitellata) of the Czech Republic: check-list, new records, and ecological remarks, Zootaxa 2676, pp. 29-44 : 35-37

Family: Lumbriculidae

Trichodrilus strandi Hrab ĕ, 1936

Records. Bílé Potoky Spring Fen, Valašské Klobouky, 49°06'52"N / 18°01'40"E, lgt. JB, det. JSc (2006); Hrubý Mechnáč Spring Fen, Lopeník, 48°56'27"N / 17°47'51"E, lgt. JB, det. JSc (2006); Kalábová Spring Fen, Březová, 48°56'22"N / 17°44'39"E, lgt. JB, det. JSc (2006); Chmelinec Spring Fen, Vyškovec, 48°56'22"N / 17°51'20"E, lgt. JB, det JSc (2006); Hutĕ Spring Fen, Žítková, 48°59'27"N / 17°54'33"E, lgt. JB, det. JSc (2006).

Characteristics of sites. T. strandi was recorded in 2006 in the Western Carpathian spring fens, which are situated in the easternmost part of the Czech Republic, on the boundary with Slovakia ( Fig. 1 ). We have collected this species from altitudes 350–642 m a.s.l. in extremely mineral-rich spring fens with precipitation of cold water travertine (tufa). The bottom substrate of spring fens was dominated by inorganic material (gravel and sand) and coarse particulate organic matter (leaves and wood). Tufa precipitated on all submerged surfaces forms either small incrustations or strong layers.

Ecology. T. strandi is well adapted for this rather hostile environment because of a tiny flexible body that enables it to utilise small interstitial spaces, particularly those in tufa-covered substrates. In studied sites, it represented the eudominant species followed by 16 additional oligochaete taxa, mostly taxa in the family Enchytraeidae . Its main adaptation can be feeding on specific kinds of bacteria that colonise surfaces in mineral-rich waters (Tarmo Timm pers. com.). Although the environment in spring fens is rather stable with small temperature fluctuations, we recorded seasonal variations in the ratio between juveniles and adults from 50% of juveniles in spring to their prevalence (80%) in autumn. T. strandi is a monocyclic gatherer-collector burrowing in sediments of xenosaprobic streams, and it is considered a K-strategist ( Šporka 2003).

Morphology. This species can be distinguished from other taxa in that all chaetae are bifid with tiny upper teeth, the male pores are located on conical porophores in IX, and spermathecal pores are present in X ( Fig. 2 ). The positions of sexual pores in T. strandi (porophores in X, spermathecal pores in IX) are opposite of those in the genus Stylodrilus , with which young T. strandi can be confused. We have recorded variability in the spermathecae position of 200 individuals: 36% had spermathecae in X, 38% in between X and XI (crossing the septa) and 26% in XI. We did not observe any lateral wings in the genital region, but we identified only fixed individuals.

Distribution. The nearest known localities for T. strandi are in the Valča Brook—a tributary of the Turiec River in the Malá Fatra Mts. ( Slovakia) ( Šporka 1996a), which is approximately 80 km from our sites ( Šporka 1996a), and the spring outflow of an ice cave in the Tatra Mts.—approximately 150 km from our sites ( Hrabĕ 1942). European distribution is highly scattered with records from karstic or flysh areas in France ( Giani 1979; Juget & Dumnicka 1986), Croatia ( Karaman 1987) and Italy ( Brinkhurst 1963). According to Fauna Europaea ( Timm & Giani 2004), the species was found in the Czech Republic, but unfortunately no additional information for this report was provided, nor is available. These data most likely represent records reported from areas in what is now known as Slovakia prior to its split from the former Czechoslovakia. T. strandi as the stygophilous species, representative of the Lumbriculidae , is more limited in global distribution ( Martin et al. 2008). This species is worth further investigation since its populations seem to be geographically separated and there is even the question if they represent the same species.

Figures

FIGURE 1. The distribution of Trichodrilus strandi, Pristina jenkinae, Pristina osborni, Rhyacodrilus subterraneus, Aulodrilus limnobius and A. pigueti in the Czech Republic.

FIGURE 2. Trichodrilus strandi. A: Schematic drawing of reproductive organs in IX, X, XI segment, lateral view. mp: male pore on conical porophorus, sp: spermatheca, ov: ovarium. B: dorsal chaeta.