Johannesia reticulosa ( Thiele, 1905 )

Gerasimova, Elena, Erpenbeck, Dirk & Plotkin, Alexander, 2008, Vosmaeria Fristedt, 1885 (Porifera, Demospongiae, Halichondriidae): revision of species, phylogenetic reconstruction and evidence for split, Zootaxa 1694, pp. 1-37 : 19-27

Johannesia reticulosa ( Thiele, 1905)

Synonymy:

Vosmaeria reticulosa – Thiele, 1905: 423, figs. 45a–c; Erpenbeck & van Soest, 2002: 815.

Additional material (collected by Helmut Lehnert and fixed in alcohol):

Region of Paracas, Peruvian Coast: HL 2352 (1 specimen) and HL 2354 (1 specimen used for both morphological studies and molecular analysis): Isla San Gallan; 12–15 m; 13.08.2002. HL 2425 (1 specimen): Islotes Dos Marias; 12–15 m; 18.08.2002.

Description:

External characters

Holotype a massive fist-shaped sponge, measuring approx. 50x 48x 34 mm (fig. 10). Colour beige in alcohol. Surface smooth and ridged. Several oscula of 1–4 mm in diameter visible on the surface, ostia cannot be seen macroscopically. Ectosome loose and detachable.

According to the description of Thiele (1905), the specimen grew together with Plicatellopsis expansa ( Plicatella expansa in the original description), another sponge described by him. At the time of our study these two sponges had been separated from each other already, and stored in different jars. Type material of P. expansa was represented by two fragments which macroscopically could not be distinguished from the specimen of Vosmaeria reticulosa but differed greatly from it by skeleton structure and spicules (only styles were observed in P. expansa ).

Peruvian samples are represented by small sponge fragments each of few cubic cm. Their surface and inner texture are similar to those of the holotype.

Skeleton

Choanosomal skeleton made by tracts of (sub)tylostyles running from sponge base to the surface (fig. 11A). The tracts branch and anastomose. Their thickness 10–50 µm. Free tylostyles and oxeas scattered between the principal tracts. Ectosomal skeleton measuring 300–500 µm in thickness constituted by the diverging principal tracts intercrossed with tylostyles and oxeas (fig. 11B). In tangential surface view this intercrossing forms an irregular network (fig. 12).

Aquiferous system

Oscula and ostia located in the holes of the ectosomal network. Ostia connected with large subectosomal cavities (300–650 µm in diameter — fig. 11B). Inhalant canals run from the subectosomal cavities to the choanosomal chambers. Exhalant canals come from the choanocyte chambers to the choanosomal atriums, which are connected to oscula at the surface.

Spicules (means in parentheses)

-(Sub)tylostyles (figs. 13C–F): Altogether, 240 tylostyles observed (30 ectosomal and 30 choanosomal spicules in each specimen). Tylostyles always with acerate distal tips and usually slightly curved. In the holotype most tylostyles with well developed tyles, which are located terminally in choanosomal spicules and slightly displaced in many ectosomal ones (table 5). Measurements (table 6): length 104–369 µm (255 µm), proximal diameter 4.2–11.7 µm (6.7 µm), diameter of tyle 5.0–11.7 (8.0 µm), central diameter 4.2–11.7 (7.3 µm).

In the Peruvian specimen HL 2352 most tylostyles with weakly developed tyles, which are terminally located in choanosomal spicules but slightly displaced in many ectosomal ones (table 5). In the other two Peruvian specimens most tylostyles with weakly developed tyles, terminally located both in choanosomal as well as ectosomal spicules. Altogether, the tylostyles of the Peruvian specimens measure 158–400 µm (276 µm) in length, 3.5–12.5 µm (5.9 µm) in proximal diameter with tyle diameter of 3.5–15 (7.3 µm) and 3.5–15 (6.5 µm) in central diameter (table 6).

-Oxeas (figs. 13A–B): Altogether, 240 oxeas observed (30 ectosomal and 30 choanosomal spicules in each specimen). All spicules with acerate tips. In the holotype, oxeas usually moderately or even considerably curved (table 5), measuring 292–550 µm (447 µm) in length and 4.2–13.3 µm (10.8 µm) in central diameter (table 6). In the Peruvian specimens, oxeas mainly slightly curved (table 5), measuring 215–710 µm (503 µm) in length and 5–20 µm (11.8 µm) in central diameter (table 6).

Number of spicules characterized by the respective feature is given in every cell. Abbreviations: Curvature: S–straight, SC–slightly curved, MC–moderately curved, CC–considerably curved; Slenderness: F–fusiform, SL–slender; Tyle development: A–absent, WK–weakly developed, WL–well developed; Tyle location: T–terminal, SD–slightly displaced, MD–moderately displaced, CD–considerably displaced.

(Sub)tylostyles Oxeas Islotes Dos Ectosome 1 28 1 0 0 30 7 23 0 21 2 0 0 2 28 0 0 Marias

All measurements are given in µm. Each measurement is given as minimum-mean-maximum. Length is given in the upper row; diameter is given in the lower row. Diameter of tylostyles is given as proximal diameter / central diameter.

Specimen Region (Sub)tylostyles Oxeas -Variability of spicule size: Variability of spicule size within each specimen insignificant, with no differences observed between ectosomal and choanosomal spicules (figs. 14–16; table 7). Conversely, among-specimens variability of spicule length significant. Ectosomal (sub)tylostyles of the Peruvian specimen HL 2354 longer than those of other specimens (fig. 16A). Both choanosomal and ectosomal oxeas of the Peruvian specimens HL 2352 and 2354 longer than those of other specimens (fig. 16C).

Spicule type Factors SS dF MS F P

(Sub)tylostyles Specimen 111569 3 37190 12.30 2*10-7 Part of body 5099 1 5099 1.69 0.195 Specimen+Part of body 36010 3 12003 3.97 0.009 Error 701644 232 3024

Oxeas Specimen 744742 3 248247 47.29 7*10-24 Part of body 1246 1 1246 0.24 0.627 Specimen+Part of body 37732 3 12577 2.40 0.069 Error 1217818 232 5249

Distribution:

Chilean and Peruvian Coast, south-east Pacific (fig. 17), depth 12– 30 m.