Ephydatia muelleri (Lieberkühn, 1856)

Fig. 4

Spongilla mülleri Liberkühn, 1856: 510 .

Material examined (18 specimens, Table 1)

SWEDEN – Dalsland • 2 specs; Lake Vänern, Mellerud, Sunannå harbour; 58.7092° N, 12.5072° E; 11 Oct. 2017; Chloé Robert and Raquel Pereira leg.; UPSZMC 188237, 188239 . – Uppland • 1 spec.; Lake Erken, Norr Malma, Erken freshwater laboratory; 59.8353° N, 18.6331° E; 30 May 2016; Raquel Pereira leg.; UPSZMC 188244 • 1 spec.; Lake Erken, bath Svanberga; 59.837° N, 18.6559° E; 30 May 2016; Raquel Pereira leg.; UPSZMC 188242. – Dalarna • 1 spec.; Dalälven, Grådö; 60.2471° N, 16.027° E; 28 Aug. 2013; Mikael Thollesson leg.; UPSZMC 188062 • 1 spec.; Dala-Floda, Lake Flosjön, boating site; 60.513° N, 14.8089° E; 28 Aug. 2013; Mikael Thollesson leg.; UPSZMC 188052 • 3 specs; Lake S Mojesjön, bath; 60.6003° N, 15.0885° E; 28 Aug. 2013; Mikael Thollesson leg.; UPSZMC 188066, 188068, 18807 , • 3 specs; Malungs camping, outlet into Västerdalälven; 60.6847° N, 13.7023° E; 29 Aug. 2013; Mikael Thollesson leg.; UPSZMC 188076, 188078, 188080 . – Hälsingland • 2 specs; Delsbo, Lake S Dellensjön; 61.8097° N, 16.5706° E; 28 Aug. 2017; Raquel Pereira leg.; UPSZMC 188143, 188145 . – Härjedalen • 1 spec.; Hedeviken; 62.4083° N, 13.6697° E; 30 Aug. 2017; Chloé Robert and Raquel Pereira leg.; UPSZMC 188168 . – Medelpad • 3 specs; Lake Gissjön; 62.5233° N, 16.179° E; 29 Aug. 2017; Chloé Robert and Raquel Pereira leg.; UPSZMC 188149, 188151, 188153 .

Description

HABITUS. Collected specimens had a bright green colour. Ridges on the surface are directed towards the centre of the sponge (Fig. 4A).

SPICULAE. This species presents two categories of spicules: megascleres and gemmuloscleres. Megascleres are fusiform and spiny oxeas. Spine abundance can be significant or limited on oxeas within the same individual (Fig. 4B). Usually, apices contain less spines than median part. Gemmuloscleres are birotulated. Shaft is terminated by rotules incised into smaller rays (Fig. 4B). Quantity of rays varies between specimens. Megascleres 255 μm (190–295 μm) long and 11.5 µm (5–22.5 μm) wide. A total of 30 gemmuloscleres were measured with an average length and width of 16 μm (length 12.5–20 μm, width 15–20 μm).

Distribution and habitats

Wide distribution, entire sampling area, 17 from lakes, 1 from a river.