According to De Ridder & Segers (1997), T. clypeata is a widespread species occurring in the marine littoral and brackish waters all over the Palaearctic region.
Marine habitat: Balearic Archipelago (De Manuel et al. 1992); Albufera de Minorca (De Manuel 1995; Pretus et al. 1992); Camargue – France (De Ridder 1960, 1961); Spain (De Ridder 1962); Rovigno (Wulfert 1942a); Marismas, Spain (De Ridder, 1963b); Salt marsh near Puerta da Pollense, Mallorca, Sp. (De Ridder, 1967c); Spain: Barcelona & Huelva; Baleares: Mallorca (Velasco, 1990); Ionic and North Adriatic Sea (Fontaneto at al. 2008): Roscoff (d’Hondt 1970); Belgium (De Ridder (1957a, b); Nieuport – Belgium (Gillard 1959); Southern Finland (Godske Bjorklund 1972b); Sea & brackish water pools, S Finland (Björklund, 1972a); Norway (Godske Eriksen 1968); Baltic Sea (Remane 1929); Germany (Rentz 1940); Black Sea (Rudescu 1961); UK (Saunders-Davies 1995); North Germany (Schwarz 1955/1956; 1962); Baltic Sea (Sick 1933); Romania (Rudescu, 1960); Brackish water pools in Norway (Eriksen, 1968); Coast of S Finland (Eriksen, 1969); Gulf of Riga, Baltic Sea, Belt Sea, Kattegat, Skagerak, N & S North Sea, E & W English Channel, Bristol Channel & Irish Sea, S & W Ireland, Norwegian Sea (Berzinš, 1960); Oostduinkerke & Oostende, Belgium (De Ridder, 1986); Channel Nieuwpoort-Duinkerke in Oostduinkerke, Belgium (De Maeseneer, 1979); Zuiderzee; r. Tjunmer near Tjun; channel Harlingervaart; near Midlum, NL (Dresscher, 1976); Scandinavian coastal waters (Thane-Fenchel, 1968).
Continental water: Hortobagy Nat. Park, Hungary (Forro & Ronkay, 1983); Caspian area (Berzinš, 1978); Rügener, Hiddenseer & Darszer Boddengewässer, Germany (Schwarz, 1963); Lake Balaton, Hungary (Zankai, 1968); W Iceland (De Ridder, 1969b, 1970 & 1972); Obretin embanked basin, Danube delta, Romania (Godeanu et al., 1973); Ponds in Oltina, Dobrogea, Romania (Popescu-Gorj & Costea, 1961); One brackish & 2 freshwater localities in Poland (Radwan, 1967); River Volga, R.F. (Mordukhai-Boltovskoi, 1979); Waters near river Bodrog, NE Hungary (Dévai et al., 1972/1973); Cap Breton Island, Nova Scotia, Canada (Chengalath & Koste, 1987).
The reports from freshwater habitats are probably misidentifications concerning T. elliptica. De Ridder & Segers (1997) also report the species from the Nearctic region (Cap Breton Island, Nova Scotia, Canada), incorrectly referring to Chengalath & Koste (1988). However, the specimens mentioned sub T. elliptica by Jersabek et al. (2003; ANSP Catalog Number 1828) and originating from a brackish pool near Atlantic City, New Jersey, USA are distinctly T. clypeata, illustrating the species’ presence in the Nearctic.
This species is easily recognized by the elliptical lorica (length/width ratio 1.30–1.55, average 1.45), which is often slightly angular postero-laterally apparently depending on the state of contraction or fixation. The dorsal anterior margin is convex, and the ventral anterior margin shows a broad Vshaped sinus; a dorsal transversal fold is often present at the end of the lorica. In cross-sectional view the dorsal margin appears convex, the lateral edges are broadly rounded and separated by a shallow sulcus from a convex median part ventrally. The characteristic foot-opening is a wide inverted U-shaped slit, situated ventral and sub-terminal. The foot is composed of a long and wrinkled proximal part, a clearly offset slender distal pseudosegment and a less defined short penultimate pseudosegment. The dorsal and lateral antennae are situated somewhat posterior to the anterior third of the lorica: ratio lorica length/position of antenna(e) relative to antero-dorsal margin varying from 2.70–2.85 (average 2.75) and 2.35–2.75 (average 2.58) respectively. Two red eyespots.
The trophi are characterized by 14–16/14–16 (left/right) unci teeth. The three major teeth show a slender and distinctly offset head. The manubria are composed of three large superimposed chambers, the dorsal, median and ventral, and a strongly reduced sub-ventral chamber. About 28–30/25–26 arched rami scleropili are apparent in caudal view. The fulcrum shows a distinct proximal opening frontally.
Measurements. Lorica length 150–170 μm, lorica width 100–130 μm, distal foot pseudosegment 18–22 μm.
Catalog number: 1828
Collection: Academy of Natural Sciences of Drexel University, Philadelphia, USA
Prepared by: Myers, F J
Preparation: Slide Preparation
Specimen Count: 3
The species has apparently often been confused with T. elliptica.
Depth range (m): 0.75 - 0.75
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Marine species, usually in the littoral zone.