Ephydatia fluviatilis ( Linnaeus, 1759 )

Van Soest, Rob W. M., 2025, Typification of Porifera described in the 10 edition of Linnaeus’ Systema Naturae, volume II, 1759, Zootaxa 5638 (1), pp. 1-65 : 45-49

Ephydatia fluviatilis ( Linnaeus, 1759)

Figs 25A–E , 26A–C , 27A–B

Spongia fluviatilis Linnaeus, 1759: 1348 , sp. 11; Pallas 1766: 384, sp. 231 (also Boddaert 1767: 483, and Wilkens 1787: 221);

Linnaeus 1767: 1299, sp. 16; Gmelin in Linnaeus 1791: 3825, sp. 16. Spongia lacustris ; Esper 1794: 233, pl. XXIIIA (in part). Ephydatia fluviatilis ; Lamouroux, 1816: 6; Penney & Racek 1968: 82 (with comprehensive list of synonyms); Pronzato &

Manconi 2001: 15; Manconi & Pronzato 2002: 939, figs 27–30.

Original description: ‘ Spongia erecta fragilis, ramis teretiusculis’ (i.e. erect fragile sponges with delicate branches), copied from Linnaeus (1745: 390, from Upland Sweden), and Linnaeus (1753: 1171)

Type material: Unknown. Neotype RMNH Por. 1166, Netherlands, Abcoude , Angstel river, 52.272331°N 4.973077°E, coll. A.W. Lacourt, 12–IX–1942, designated by A.A. Racek in Penney & Racek, 1968: 84.

Molecular sequences: none

Remarks: Linnaeus (1753b: 1171) cited Linnaeus (1745: 1133 (Uppsala, Sweden) and Plukenet (1691: 356, Pars Altera: pl. CXII fig. 3), with description ‘ Spongia fluviatilis anfractuosa per fragilis ramosissima nostras in Isi fluvio’ (i.e. a curved freshwater sponge, fragile, branched, from the river Thames, England), here reproduced in Fig. 25A ). Furthermore he cited Loesel (1703: 172, fig. 52) with name ‘Muscus aquaticus ceranoides’ (i.e. a horned freshwater moss, from Schwanis (Prussia, currently Sosnovka in Poland), figure here reproduced as Fig. 25B ), and Ruppius (1718: 368, pl. III fig. 1) as ‘ Spongia ramosa fluviatilis polysperma ad confervam accedens’ (i.e. a many-seeded branched freshwater sponge) with image of a conifer, reported near Eisenberg, Germany, figure here reproduced as Fig. 25C ). Allegedly, Buxbaum (1729: 343) reported this species as ‘ Badiaga major’. The name Badiaga is still in use in Russia for dried freshwater sponges (usually Spongilla fluviatilis , cf. Manconi & Pronzato 2015: 149), which supposedly have medicinal effects against various illnesses and pains.

Pallas (1766) claimed not to recognize Linnaeus’ (1759) Spongia lacustris , but admitted that it was possible that what he identified as Spongia fluviatilis could be the same species as S. lacustris . Indeed, the original images labeled in the pre-Linnaean literature were not easy to recognize as either one of the two freshwater species distinguished by Linnaeus. Pallas also cited Ruppius and Loesel, but gave a new reference, Reneaume [1717: 231, pl. 9, ‘ Spongia fluviatilis ramosa fragilis et piscem olens’ (i.e. a fragile river sponge with branches and smelling of fish, here reproduced in Fig. 25D )].

Esper (1794: 233) stated that Spongia fluviatilis sensu Pallas would be S. lacustris and that his own S. lacustris var. would be E. fluviatilis (pl. XXIIIA), but these were indicated by Lamouroux (1816) as belonging to the present species, not to Spongilla lacustris , again indicating that late 18 th century authors confused the two. See also Kops et al. (1865) pl. 909, here reproduced in Fig. 26A , who depicted a likely Spongilla lacustris as ‘ Badiaga fluviatilis’, with synonyms both Linnaeus’ Spongia fluviatilis et (= ànd) lacustris .

The possible confusion of the species Spongilla lacustris and Ephydatia fluviatilis in the late 18 th and early 19 th century literature may be due to the fact that notably E. fluviatilis may occur frequently in thickly encrusting and barely lobate growth forms (see Figs 25E , 26C , 27A ), whereas branching forms ( Figs 25A–D , 27A ) are only infrequently reported.If the two species occur together as shown in Fig. 26B, E . fluviatilis is recognized by having only irregularly developed upright branches, contrasting with regularly dichotomously branched S. lacustris . Gemmulebearing specimens are easily recognized microscopically as either species on the basis of the gemmoscleres. Nongemmule bearing species can be easily distinguished microscopically by the occurrence of smaller acanthoxeas in S. lacustris , lacking in E. fluviatilis .

Species diagnosis: (after Manconi & Pronzato 2002: 939, figs 27–31). Freshwater sponges with various shapes, predominantly encrusting, bulbous, massive, with ridges or rounded lobes, or with digitations and irregular branches. Sizes of patches may be up to 90 cm in diameter, but usually are much smaller. The consistency is rather fragile and soft but compressible in life, when dried it becomes brittle. The surface is punctate, irregularly bumpy and hispid, with numerous round or slit-like oscules. Gemmules are scattered in the choanosome and may form an overwintering carpet on the substratum.; these carpets may in extreme cases cover 1 m in size. Colour is brown, green or whitish in situ, beige in alcohol. No special ectosomal skeleton. The choanosomal skeleton is irregularly densely anisotropic, with paucispicular main tracts and single spicule connecting tracts, spongin is only visible at the nodes. Spicules are fusiform oxeas, microspined or smooth, 210–400 x 6–19 µm. Gemmuloscleres are birotules with rotules microspined and with irregular incised margins and smooth shaft, 26–30 x 18–21 µm.

An image of the neotype is provided in Fig. 25E . Further images are the above mentioned in situ photo’s in Figs 25C and 26A .

The species is the type of the genus Ephydatia Lamouroux 1816 (subsequent designation by Annandale (1911: 108, with question mark), confirmed by Penney & Racek 1968: 80.

Distribution ( Fig. 27B ): Widespread, common in Europe (cf. map in Pronzato & Manco 2001: 15), also in North America and northern, Asia with records from South Africa, China and India. The wide distribution suggests the species may be part of a species complex.

Molecular sequence information

(Table 3)

I provide molecular sequence information on the (neo) types, if available, complemented with non-exhaustive published sequences of reliably identified specimens (Table 3). The molecular sequence data I list here are only intended to provide future integrative studies on the Linnaeus 1759 species with a basic set of sequences. I admit the data are of limited use, because various studies were done using different primers and domains which are difficult to compare and may yield different phylogenetic results. Particularly for 28SrRNA, domains of the listed sequences are frequently different between those of (neo) types and subsequently or previously obtained sequences of non-type specimens, but it is beyond the limits of the present study to discuss this in detail. Where possible, I checked the sequences available for (neo) type material using the BLAST option (https://blast.ncbi.nlm.nih.gov/Blast.cgi) against the sequences of non-type material in Genbank to demonstrate the likelihood of conspecificity of (neo) types and non-type sequences. Geographic localities from which the studied specimens originated are summarized to the nearest Marine Ecoregion (cf. Spalding et al. 2007) or the country in case of freshwater sponges.

Figures

FIGURE 25. Images assigned to Ephydatia fluviatilis by various authors (originally as Spongia). A. Plukenet’s ‘Spongia fluviatilis anfractuosa per fragilis ramosissima nostras in Isi fluvio’ (1691: pl CXII fig. 3); B. Loesel’s ‘Muscus aquaticus ceranoides’ (1703: 172 fig. 52); C. Ruppius’ ‘Spongia ramosa fluviatilis polysperma ad confervam accedens’ (1718: 368, pl. III fig. 1); D. Reneaume’s ‘Spongia fluviatilis ramosa fragilis et piscem olens’ (1717: 231, fig. 9); E1. preserved neotype specimen RMNH Por. 1166, Netherlands, Abcoude, Angstel river, coll. A.W. Lacourt, 12–IX–1942, designated by A.A. Racek in Penney & Racek 1968: 84; E2. label of neotype specimen.

FIGURE 26. A. Ephydatia fluviatilis (as Badiaga, Spongia fluviatilis et lacustris Linnaeus), image and description from Kops et al. (1865: pl. 909); B–C. both freshwater sponge species in situ growing together in the same locality at ‘s-Graveland near Loosdrecht, Province Utrecht, 52.22911°N 5.130414°E; B. Spongilla lacustris; C. Ephydatia fluviatilis (photo by Nicole J. de Voogd).

FIGURE 27. A. Ephydatia fluviatilis (L.) In situ encrusting specimen with incipient upright branches from the Boschmolenplas, Limburg Province, 51.179244°N 5.875248°E, depth 13 m (photo by Silvia Waajen, www.onderwaterwereld.org); B. distribution of Ephydatia fluviatilis (L.), image downloaded from the World Porifera Database, cf. De Voogd et al. 2023 (only an outline of the actual distribution).