Johannesia reticulosa

Johannesia reticulosa (Thiele, 1905)

(Figure 6, Table 6)

Synonyms: Vosmaeria reticulosa Thiele (1905): 423, Fig. 45a–c; Erpenbeck & van Soest (2002): 815. Johannesia reticulosa: Gerasimova et al. (2008): 19, Fig. 10 –12; Polo et al. (2022): 330–331, Fig. 3

Material examined. Nine specimens. MNRJ 11493 and MNRJ 11496, Don Martin Island, Huacho, Lima (1101′11.14″S 7740′08.78″W), 11 and 1.8 m depth, respectively, coll. B. Cóndor Luján, Y. Hooker & Ph. Willenz, 23.X.2007. MNRJ 12073, ENAPU Pier, Ilo, Moquega (1738′43.00″S 7129′04.60″W), 18.3 m depth, coll. Y. Hooker, Ph. Willenz & M. Ríos. 08.XI.2008. MNRJ 12161 and MNRJ 12171, Inlet north of Quilca, Quilca, Arequipa (1642′06.10″S 7226′54.00″W), 9.2 and 4.4 m depth, coll. Y. Hooker, M. Vilchez & Ph. Willenz. 30.XI.2008 and 01.XII.2008. MNRJ 12198, El Avion Islet, San Juan de Marcona, Ica (1523′26.20″S 7510′45. 20″W), 18.9 m depth, coll. Y. Hooker, M. Vilchez & Ph. Willenz, 05.XII.2008. MNRJ 12845, MNRJ 12846 and MNRJ 12852, Bocana, Laguna Grande, Paracas, Ica (1409′31.10″S 7614′55.90″W), 5.6, 5.7 and 4.8 m depth, coll. Y. Hooker & Ph. Willenz, 12.XII.2008.

Description. Encrusting, massively spreading, lobate, ridged, lamellate or slightly tubiform. Dimensions can exceed 5 cm in thickness and 50 cm in largest diameter. Oscula circular (diam = 1–2 mm), flat, or more often apical with short membranes. Differentiable and detachable ectosome. Surface slightly reticulated, as observed in some underwater images. Compressible consistency.

Colour. Light yellow to orange, greenish and/or with brownish spots in life and beige in ethanol (Fig. 6A, B).

Skeleton. Ectosomal, a dense, criss-crossed layer of subtylostyles forming loose brushes, slightly piercing the surface. Few oxeas were also observed in the ectosome, mostly laying tangentially (Fig. 6C). Choanosomal, much less dense, composed of paucispicular to multispicular tracts of oxeas, irregular, loosely reticulated, overlaid by subtylostyles disposed in confusion. Large subectosomal lacunae were also seen (Fig. 6D).

Spicules. Megascleres. Oxeas, slightly to markedly curved, and with acerate tips. (166–840 x 5–22 µm, Fig. 6E–G). Subtylostyles, mostly slightly curved but also straight, faintly pronounced heads, and with acerate tips (129–465 x 4–13 µm, Fig. 6H–J, Table 6).

Ecology. This species was found associated with the sponge Plicatellopsis expansa (Thiele, 1905) and with the holdfast of Lessonia trabeculata (Polo et al. 2022). The specimens analysed were found occurring associated to anemones (Anthotoe chilensis), polychaetes (e.g. Sabellid), the brachyopod Discinisca lamellosa, cirripeds, mytilids, schrimps, and other sponges (Clathrinidae). Some specimens were found underneath rocks or in shaded habitats. Some crabs were observed living in galleries of the largest sponge specimen.

Geographic and bathymetrical distributions. SE Pacific: From central Peru (Huacho, Lima, 11°S, this study) to northern Chile (Iquique, 20°S, Thiele 1905) including intermediate localities (Paracas, Marcona and Quilca, this study, Gerasimova et al. 2008; Polo et al. 2022). MEOW in Peru: Central Peru and Humboldtian ecoregion (Spalding et al. 2007). From 2 m (this study) to 30 m (Iquique, Thiele 1905).

Remarks. The analysed specimens conform to Johannesia reticulosa from Chile in external morphology and internal anatomy. Although slight differences in spicule dimensions were observed in specimens from Laguna Grande (Paracas, Ica) as they bear smaller oxeas and subtylostyles (Table 6), this can be attributed to the species geographic variation. Previously, Gerasimova et al. (2008) reported significant spicule size differences in Peruvian specimens, when compared to the type material.